Merge branch ak/svn
diff --git a/.gitignore b/.gitignore
index b4355b9..75891c3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -128,8 +128,7 @@
 *.deb
 git-core.spec
 *.exe
-libgit.a
-*.o
+*.[ao]
 *.py[co]
 config.mak
 git-blame
diff --git a/Documentation/git-ls-files.txt b/Documentation/git-ls-files.txt
index e813f84..796d049 100644
--- a/Documentation/git-ls-files.txt
+++ b/Documentation/git-ls-files.txt
@@ -14,9 +14,9 @@
 		(-[c|d|o|i|s|u|k|m])\*
 		[-x <pattern>|--exclude=<pattern>]
 		[-X <file>|--exclude-from=<file>]
-		[--exclude-per-directory=<file>] 
+		[--exclude-per-directory=<file>]
 		[--error-unmatch]
-		[--full-name] [--] [<file>]\*
+		[--full-name] [--abbrev] [--] [<file>]\*
 
 DESCRIPTION
 -----------
@@ -52,6 +52,9 @@
 	If a whole directory is classified as "other", show just its
 	name (with a trailing slash) and not its whole contents.
 
+--no-empty-directory::
+	Do not list empty directories. Has no effect without --directory.
+
 -u|--unmerged::
 	Show unmerged files in the output (forces --stage)
 
@@ -98,6 +101,11 @@
 	option forces paths to be output relative to the project
 	top directory.
 
+--abbrev[=<n>]::
+	Instead of showing the full 40-byte hexadecimal object
+	lines, show only handful hexdigits prefix.
+	Non default number of digits can be specified with --abbrev=<n>.
+
 --::
 	Do not interpret any more arguments as options.
 
diff --git a/Documentation/git-ls-tree.txt b/Documentation/git-ls-tree.txt
index 5bf6d8b..018c401 100644
--- a/Documentation/git-ls-tree.txt
+++ b/Documentation/git-ls-tree.txt
@@ -8,7 +8,9 @@
 
 SYNOPSIS
 --------
-'git-ls-tree' [-d] [-r] [-t] [-z] [--name-only] [--name-status] <tree-ish> [paths...]
+'git-ls-tree' [-d] [-r] [-t] [-z]
+	[--name-only] [--name-status] [--full-name] [--abbrev=[<n>]]
+	<tree-ish> [paths...]
 
 DESCRIPTION
 -----------
@@ -40,6 +42,11 @@
 --name-status::
 	List only filenames (instead of the "long" output), one per line.
 
+--abbrev[=<n>]::
+	Instead of showing the full 40-byte hexadecimal object
+	lines, show only handful hexdigits prefix.
+	Non default number of digits can be specified with --abbrev=<n>.
+
 paths::
 	When paths are given, show them (note that this isn't really raw
 	pathnames, but rather a list of patterns to match).  Otherwise
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index b36276c..4a7e67a 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -48,6 +48,18 @@
              /
     D---E---F---G master
 
+In case of conflict, git-rebase will stop at the first problematic commit
+and leave conflict markers in the tree.  After resolving the conflict manually
+and updating the index with the desired resolution, you can continue the
+rebasing process with
+
+    git am --resolved --3way
+
+Alternatively, you can undo the git-rebase with
+
+    git reset --hard ORIG_HEAD
+    rm -r .dotest
+
 OPTIONS
 -------
 <newbase>::
diff --git a/Makefile b/Makefile
index 8d45378..4edb383 100644
--- a/Makefile
+++ b/Makefile
@@ -188,9 +188,10 @@
 	gitMergeCommon.py
 
 LIB_FILE=libgit.a
+XDIFF_LIB=xdiff/lib.a
 
 LIB_H = \
-	blob.h cache.h commit.h count-delta.h csum-file.h delta.h \
+	blob.h cache.h commit.h csum-file.h delta.h \
 	diff.h object.h pack.h pkt-line.h quote.h refs.h \
 	run-command.h strbuf.h tag.h tree.h git-compat-util.h revision.h
 
@@ -200,7 +201,7 @@
 	diffcore-delta.o
 
 LIB_OBJS = \
-	blob.o commit.o connect.o count-delta.o csum-file.o \
+	blob.o commit.o connect.o csum-file.o \
 	date.o diff-delta.o entry.o exec_cmd.o ident.o index.o \
 	object.o pack-check.o patch-delta.o path.o pkt-line.o \
 	quote.o read-cache.o refs.o run-command.o \
@@ -209,8 +210,8 @@
 	fetch-clone.o revision.o pager.o \
 	$(DIFF_OBJS)
 
-LIBS = $(LIB_FILE)
-LIBS += -lz
+GITLIBS = $(LIB_FILE) $(XDIFF_LIB)
+LIBS = $(GITLIBS) -lz
 
 #
 # Platform specific tweaks
@@ -544,12 +545,18 @@
 		-DDEFAULT_GIT_TEMPLATE_DIR='"$(template_dir_SQ)"' $*.c
 
 $(LIB_OBJS): $(LIB_H)
-$(patsubst git-%$X,%.o,$(PROGRAMS)): $(LIB_H)
+$(patsubst git-%$X,%.o,$(PROGRAMS)): $(GITLIBS)
 $(DIFF_OBJS): diffcore.h
 
 $(LIB_FILE): $(LIB_OBJS)
 	$(AR) rcs $@ $(LIB_OBJS)
 
+XDIFF_OBJS=xdiff/xdiffi.o xdiff/xprepare.o xdiff/xutils.o xdiff/xemit.o
+
+$(XDIFF_LIB): $(XDIFF_OBJS)
+	$(AR) rcs $@ $(XDIFF_OBJS)
+
+
 doc:
 	$(MAKE) -C Documentation all
 
@@ -622,7 +629,8 @@
 ### Cleaning rules
 
 clean:
-	rm -f *.o mozilla-sha1/*.o arm/*.o ppc/*.o compat/*.o $(LIB_FILE)
+	rm -f *.o mozilla-sha1/*.o arm/*.o ppc/*.o compat/*.o xdiff/*.o \
+		$(LIB_FILE) $(XDIFF_LIB)
 	rm -f $(ALL_PROGRAMS) git$X
 	rm -f *.spec *.pyc *.pyo */*.pyc */*.pyo common-cmds.h TAGS tags
 	rm -rf $(GIT_TARNAME)
diff --git a/blame.c b/blame.c
index 7e88833..396defc 100644
--- a/blame.c
+++ b/blame.c
@@ -752,6 +752,7 @@
 	int found_rename;
 
 	const char* prefix = setup_git_directory();
+	git_config(git_default_config);
 
 	for(i = 1; i < argc; i++) {
 		if(options) {
diff --git a/cache.h b/cache.h
index 1f96280..255e6b5 100644
--- a/cache.h
+++ b/cache.h
@@ -165,6 +165,7 @@
 extern int trust_executable_bit;
 extern int assume_unchanged;
 extern int only_use_symrefs;
+extern int warn_ambiguous_refs;
 extern int diff_rename_limit_default;
 extern int shared_repository;
 extern const char *apply_default_whitespace;
diff --git a/cat-file.c b/cat-file.c
index 1a613f3..761111e 100644
--- a/cat-file.c
+++ b/cat-file.c
@@ -100,6 +100,7 @@
 	int opt;
 
 	setup_git_directory();
+	git_config(git_default_config);
 	if (argc != 3 || get_sha1(argv[2], sha1))
 		usage("git-cat-file [-t|-s|-e|-p|<type>] <sha1>");
 
diff --git a/config.c b/config.c
index 7dbdce1..95ec349 100644
--- a/config.c
+++ b/config.c
@@ -232,6 +232,11 @@
 		return 0;
 	}
 
+	if (!strcmp(var, "core.warnambiguousrefs")) {
+		warn_ambiguous_refs = git_config_bool(var, value);
+		return 0;
+	}
+
 	if (!strcmp(var, "user.name")) {
 		strncpy(git_default_name, value, sizeof(git_default_name));
 		return 0;
diff --git a/count-delta.c b/count-delta.c
deleted file mode 100644
index 058a2aa..0000000
--- a/count-delta.c
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * Copyright (C) 2005 Junio C Hamano
- * The delta-parsing part is almost straight copy of patch-delta.c
- * which is (C) 2005 Nicolas Pitre <nico@cam.org>.
- */
-#include <stdlib.h>
-#include <string.h>
-#include <limits.h>
-#include "delta.h"
-#include "count-delta.h"
-
-/*
- * NOTE.  We do not _interpret_ delta fully.  As an approximation, we
- * just count the number of bytes that are copied from the source, and
- * the number of literal data bytes that are inserted.
- *
- * Number of bytes that are _not_ copied from the source is deletion,
- * and number of inserted literal bytes are addition, so sum of them
- * is the extent of damage.
- */
-int count_delta(void *delta_buf, unsigned long delta_size,
-		unsigned long *src_copied, unsigned long *literal_added)
-{
-	unsigned long copied_from_source, added_literal;
-	const unsigned char *data, *top;
-	unsigned char cmd;
-	unsigned long src_size, dst_size, out;
-
-	if (delta_size < DELTA_SIZE_MIN)
-		return -1;
-
-	data = delta_buf;
-	top = delta_buf + delta_size;
-
-	src_size = get_delta_hdr_size(&data);
-	dst_size = get_delta_hdr_size(&data);
-
-	added_literal = copied_from_source = out = 0;
-	while (data < top) {
-		cmd = *data++;
-		if (cmd & 0x80) {
-			unsigned long cp_off = 0, cp_size = 0;
-			if (cmd & 0x01) cp_off = *data++;
-			if (cmd & 0x02) cp_off |= (*data++ << 8);
-			if (cmd & 0x04) cp_off |= (*data++ << 16);
-			if (cmd & 0x08) cp_off |= (*data++ << 24);
-			if (cmd & 0x10) cp_size = *data++;
-			if (cmd & 0x20) cp_size |= (*data++ << 8);
-			if (cmd & 0x40) cp_size |= (*data++ << 16);
-			if (cp_size == 0) cp_size = 0x10000;
-
-			copied_from_source += cp_size;
-			out += cp_size;
-		} else {
-			/* write literal into dst */
-			added_literal += cmd;
-			out += cmd;
-			data += cmd;
-		}
-	}
-
-	/* sanity check */
-	if (data != top || out != dst_size)
-		return -1;
-
-	/* delete size is what was _not_ copied from source.
-	 * edit size is that and literal additions.
-	 */
-	*src_copied = copied_from_source;
-	*literal_added = added_literal;
-	return 0;
-}
diff --git a/count-delta.h b/count-delta.h
deleted file mode 100644
index 7359629..0000000
--- a/count-delta.h
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
- * Copyright (C) 2005 Junio C Hamano
- */
-#ifndef COUNT_DELTA_H
-#define COUNT_DELTA_H
-
-int count_delta(void *, unsigned long,
-		unsigned long *src_copied, unsigned long *literal_added);
-
-#endif
diff --git a/diff.c b/diff.c
index c0548ee..5eae094 100644
--- a/diff.c
+++ b/diff.c
@@ -8,8 +8,7 @@
 #include "quote.h"
 #include "diff.h"
 #include "diffcore.h"
-
-static const char *diff_opts = "-pu";
+#include "xdiff/xdiff.h"
 
 static int use_size_cache;
 
@@ -69,25 +68,10 @@
 {
 	static const char *external_diff_cmd = NULL;
 	static int done_preparing = 0;
-	const char *env_diff_opts;
 
 	if (done_preparing)
 		return external_diff_cmd;
-
-	/*
-	 * Default values above are meant to match the
-	 * Linux kernel development style.  Examples of
-	 * alternative styles you can specify via environment
-	 * variables are:
-	 *
-	 * GIT_DIFF_OPTS="-c";
-	 */
 	external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
-
-	/* In case external diff fails... */
-	env_diff_opts = getenv("GIT_DIFF_OPTS");
-	if (env_diff_opts) diff_opts = env_diff_opts;
-
 	done_preparing = 1;
 	return external_diff_cmd;
 }
@@ -101,13 +85,12 @@
 	char tmp_path[TEMPFILE_PATH_LEN];
 } diff_temp[2];
 
-static int count_lines(const char *filename)
+static int count_lines(const char *data, int size)
 {
-	FILE *in;
 	int count, ch, completely_empty = 1, nl_just_seen = 0;
-	in = fopen(filename, "r");
 	count = 0;
-	while ((ch = fgetc(in)) != EOF)
+	while (0 < size--) {
+		ch = *data++;
 		if (ch == '\n') {
 			count++;
 			nl_just_seen = 1;
@@ -117,7 +100,7 @@
 			nl_just_seen = 0;
 			completely_empty = 0;
 		}
-	fclose(in);
+	}
 	if (completely_empty)
 		return 0;
 	if (!nl_just_seen)
@@ -140,12 +123,11 @@
 	}
 }
 
-static void copy_file(int prefix, const char *filename)
+static void copy_file(int prefix, const char *data, int size)
 {
-	FILE *in;
 	int ch, nl_just_seen = 1;
-	in = fopen(filename, "r");
-	while ((ch = fgetc(in)) != EOF) {
+	while (0 < size--) {
+		ch = *data++;
 		if (nl_just_seen)
 			putchar(prefix);
 		putchar(ch);
@@ -154,92 +136,106 @@
 		else
 			nl_just_seen = 0;
 	}
-	fclose(in);
 	if (!nl_just_seen)
 		printf("\n\\ No newline at end of file\n");
 }
 
 static void emit_rewrite_diff(const char *name_a,
 			      const char *name_b,
-			      struct diff_tempfile *temp)
+			      struct diff_filespec *one, 
+			      struct diff_filespec *two)
 {
 	/* Use temp[i].name as input, name_a and name_b as labels */
 	int lc_a, lc_b;
-	lc_a = count_lines(temp[0].name);
-	lc_b = count_lines(temp[1].name);
+	lc_a = count_lines(one->data, one->size);
+	lc_b = count_lines(two->data, two->size);
 	printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
 	print_line_count(lc_a);
 	printf(" +");
 	print_line_count(lc_b);
 	printf(" @@\n");
 	if (lc_a)
-		copy_file('-', temp[0].name);
+		copy_file('-', one->data, one->size);
 	if (lc_b)
-		copy_file('+', temp[1].name);
+		copy_file('+', two->data, two->size);
 }
 
-static const char *builtin_diff(const char *name_a,
-			 const char *name_b,
-			 struct diff_tempfile *temp,
-			 const char *xfrm_msg,
-			 int complete_rewrite,
-			 const char **args)
+static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 {
-	int i, next_at, cmd_size;
-	const char *const diff_cmd = "diff -L%s -L%s";
-	const char *const diff_arg  = "-- %s %s||:"; /* "||:" is to return 0 */
-	const char *input_name_sq[2];
-	const char *label_path[2];
-	char *cmd;
-
-	/* diff_cmd and diff_arg have 4 %s in total which makes
-	 * the sum of these strings 8 bytes larger than required.
-	 * we use 2 spaces around diff-opts, and we need to count
-	 * terminating NUL; we used to subtract 5 here, but we do not
-	 * care about small leaks in this subprocess that is about
-	 * to exec "diff" anymore.
-	 */
-	cmd_size = (strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg)
-		    + 128);
-
-	for (i = 0; i < 2; i++) {
-		input_name_sq[i] = sq_quote(temp[i].name);
-		if (!strcmp(temp[i].name, "/dev/null"))
-			label_path[i] = "/dev/null";
-		else if (!i)
-			label_path[i] = sq_quote(quote_two("a/", name_a));
-		else
-			label_path[i] = sq_quote(quote_two("b/", name_b));
-		cmd_size += (strlen(label_path[i]) + strlen(input_name_sq[i]));
+	if (!DIFF_FILE_VALID(one)) {
+		mf->ptr = ""; /* does not matter */
+		mf->size = 0;
+		return 0;
 	}
+	else if (diff_populate_filespec(one, 0))
+		return -1;
+	mf->ptr = one->data;
+	mf->size = one->size;
+	return 0;
+}
 
-	cmd = xmalloc(cmd_size);
+struct emit_callback {
+	const char **label_path;
+};
 
-	next_at = 0;
-	next_at += snprintf(cmd+next_at, cmd_size-next_at,
-			    diff_cmd, label_path[0], label_path[1]);
-	next_at += snprintf(cmd+next_at, cmd_size-next_at,
-			    " %s ", diff_opts);
-	next_at += snprintf(cmd+next_at, cmd_size-next_at,
-			    diff_arg, input_name_sq[0], input_name_sq[1]);
+static int fn_out(void *priv, mmbuffer_t *mb, int nbuf)
+{
+	int i;
+	struct emit_callback *ecbdata = priv;
 
-	printf("diff --git %s %s\n",
-	       quote_two("a/", name_a), quote_two("b/", name_b));
-	if (label_path[0][0] == '/') {
-		/* dev/null */
-		printf("new file mode %s\n", temp[1].mode);
+	if (ecbdata->label_path[0]) {
+		printf("--- %s\n", ecbdata->label_path[0]);
+		printf("+++ %s\n", ecbdata->label_path[1]);
+		ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
+	}
+	for (i = 0; i < nbuf; i++)
+		if (!fwrite(mb[i].ptr, mb[i].size, 1, stdout))
+			return -1;
+	return 0;
+}
+
+#define FIRST_FEW_BYTES 8000
+static int mmfile_is_binary(mmfile_t *mf)
+{
+	long sz = mf->size;
+	if (FIRST_FEW_BYTES < sz)
+		sz = FIRST_FEW_BYTES;
+	if (memchr(mf->ptr, 0, sz))
+		return 1;
+	return 0;
+}
+
+static void builtin_diff(const char *name_a,
+			 const char *name_b,
+			 struct diff_filespec *one,
+			 struct diff_filespec *two,
+			 const char *xfrm_msg,
+			 int complete_rewrite)
+{
+	mmfile_t mf1, mf2;
+	const char *lbl[2];
+	char *a_one, *b_two;
+
+	a_one = quote_two("a/", name_a);
+	b_two = quote_two("b/", name_b);
+	lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
+	lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
+	printf("diff --git %s %s\n", a_one, b_two);
+	if (lbl[0][0] == '/') {
+		/* /dev/null */
+		printf("new file mode %06o\n", two->mode);
 		if (xfrm_msg && xfrm_msg[0])
 			puts(xfrm_msg);
 	}
-	else if (label_path[1][0] == '/') {
-		printf("deleted file mode %s\n", temp[0].mode);
+	else if (lbl[1][0] == '/') {
+		printf("deleted file mode %06o\n", one->mode);
 		if (xfrm_msg && xfrm_msg[0])
 			puts(xfrm_msg);
 	}
 	else {
-		if (strcmp(temp[0].mode, temp[1].mode)) {
-			printf("old mode %s\n", temp[0].mode);
-			printf("new mode %s\n", temp[1].mode);
+		if (one->mode != two->mode) {
+			printf("old mode %06o\n", one->mode);
+			printf("new mode %06o\n", two->mode);
 		}
 		if (xfrm_msg && xfrm_msg[0])
 			puts(xfrm_msg);
@@ -247,20 +243,45 @@
 		 * we do not run diff between different kind
 		 * of objects.
 		 */
-		if (strncmp(temp[0].mode, temp[1].mode, 3))
-			return NULL;
+		if ((one->mode ^ two->mode) & S_IFMT)
+			goto free_ab_and_return;
 		if (complete_rewrite) {
-			emit_rewrite_diff(name_a, name_b, temp);
-			return NULL;
+			emit_rewrite_diff(name_a, name_b, one, two);
+			goto free_ab_and_return;
 		}
 	}
 
-	/* This is disgusting */
-	*args++ = "sh";
-	*args++ = "-c";
-	*args++ = cmd;
-	*args = NULL;
-	return "/bin/sh";
+	if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
+		die("unable to read files to diff");
+
+	if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))
+		printf("Binary files %s and %s differ\n", lbl[0], lbl[1]);
+	else {
+		/* Crazy xdl interfaces.. */
+		const char *diffopts = getenv("GIT_DIFF_OPTS");
+		xpparam_t xpp;
+		xdemitconf_t xecfg;
+		xdemitcb_t ecb;
+		struct emit_callback ecbdata;
+
+		ecbdata.label_path = lbl;
+		xpp.flags = XDF_NEED_MINIMAL;
+		xecfg.ctxlen = 3;
+		if (!diffopts)
+			;
+		else if (!strncmp(diffopts, "--unified=", 10))
+			xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
+		else if (!strncmp(diffopts, "-u", 2))
+			xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
+		ecb.outf = fn_out;
+		ecb.priv = &ecbdata;
+		xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
+	}
+
+ free_ab_and_return:
+	free(a_one);
+	free(b_two);
+	return;
 }
 
 struct diff_filespec *alloc_filespec(const char *path)
@@ -463,6 +484,8 @@
 		munmap(s->data, s->size);
 	s->should_free = s->should_munmap = 0;
 	s->data = NULL;
+	free(s->cnt_data);
+	s->cnt_data = NULL;
 }
 
 static void prep_temp_blob(struct diff_tempfile *temp,
@@ -618,6 +641,7 @@
 	int retval;
 	static int atexit_asked = 0;
 	const char *othername;
+	const char **arg = &spawn_arg[0];
 
 	othername = (other? other : name);
 	if (one && two) {
@@ -632,36 +656,25 @@
 		signal(SIGINT, remove_tempfile_on_signal);
 	}
 
-	if (pgm) {
-		const char **arg = &spawn_arg[0];
-		if (one && two) {
-			*arg++ = pgm;
-			*arg++ = name;
-			*arg++ = temp[0].name;
-			*arg++ = temp[0].hex;
-			*arg++ = temp[0].mode;
-			*arg++ = temp[1].name;
-			*arg++ = temp[1].hex;
-			*arg++ = temp[1].mode;
-			if (other) {
-				*arg++ = other;
-				*arg++ = xfrm_msg;
-			}
-		} else {
-			*arg++ = pgm;
-			*arg++ = name;
+	if (one && two) {
+		*arg++ = pgm;
+		*arg++ = name;
+		*arg++ = temp[0].name;
+		*arg++ = temp[0].hex;
+		*arg++ = temp[0].mode;
+		*arg++ = temp[1].name;
+		*arg++ = temp[1].hex;
+		*arg++ = temp[1].mode;
+		if (other) {
+			*arg++ = other;
+			*arg++ = xfrm_msg;
 		}
-		*arg = NULL;
 	} else {
-		if (one && two) {
-			pgm = builtin_diff(name, othername, temp, xfrm_msg, complete_rewrite, spawn_arg);
-		} else
-			printf("* Unmerged path %s\n", name);
+		*arg++ = pgm;
+		*arg++ = name;
 	}
-
-	retval = 0;
-	if (pgm)
-		retval = spawn_prog(pgm, spawn_arg);
+	*arg = NULL;
+	retval = spawn_prog(pgm, spawn_arg);
 	remove_tempfile();
 	if (retval) {
 		fprintf(stderr, "external diff died, stopping at %s.\n", name);
@@ -669,6 +682,26 @@
 	}
 }
 
+static void run_diff_cmd(const char *pgm,
+			 const char *name,
+			 const char *other,
+			 struct diff_filespec *one,
+			 struct diff_filespec *two,
+			 const char *xfrm_msg,
+			 int complete_rewrite)
+{
+	if (pgm) {
+		run_external_diff(pgm, name, other, one, two, xfrm_msg,
+				  complete_rewrite);
+		return;
+	}
+	if (one && two)
+		builtin_diff(name, other ? other : name,
+			     one, two, xfrm_msg, complete_rewrite);
+	else
+		printf("* Unmerged path %s\n", name);
+}
+
 static void diff_fill_sha1_info(struct diff_filespec *one)
 {
 	if (DIFF_FILE_VALID(one)) {
@@ -698,8 +731,7 @@
 
 	if (DIFF_PAIR_UNMERGED(p)) {
 		/* unmerged */
-		run_external_diff(pgm, p->one->path, NULL, NULL, NULL, NULL,
-				  0);
+		run_diff_cmd(pgm, p->one->path, NULL, NULL, NULL, NULL, 0);
 		return;
 	}
 
@@ -771,15 +803,15 @@
 		 * needs to be split into deletion and creation.
 		 */
 		struct diff_filespec *null = alloc_filespec(two->path);
-		run_external_diff(NULL, name, other, one, null, xfrm_msg, 0);
+		run_diff_cmd(NULL, name, other, one, null, xfrm_msg, 0);
 		free(null);
 		null = alloc_filespec(one->path);
-		run_external_diff(NULL, name, other, null, two, xfrm_msg, 0);
+		run_diff_cmd(NULL, name, other, null, two, xfrm_msg, 0);
 		free(null);
 	}
 	else
-		run_external_diff(pgm, name, other, one, two, xfrm_msg,
-				  complete_rewrite);
+		run_diff_cmd(pgm, name, other, one, two, xfrm_msg,
+			     complete_rewrite);
 
 	free(name_munged);
 	free(other_munged);
diff --git a/diffcore-break.c b/diffcore-break.c
index 0fc2b86..ed0e14c 100644
--- a/diffcore-break.c
+++ b/diffcore-break.c
@@ -45,8 +45,8 @@
 	 * The value we return is 1 if we want the pair to be broken,
 	 * or 0 if we do not.
 	 */
-	unsigned long delta_size, base_size, src_copied, literal_added;
-	int to_break = 0;
+	unsigned long delta_size, base_size, src_copied, literal_added,
+		src_removed;
 
 	*merge_score_p = 0; /* assume no deletion --- "do not break"
 			     * is the default.
@@ -68,37 +68,45 @@
 
 	if (diffcore_count_changes(src->data, src->size,
 				   dst->data, dst->size,
+				   NULL, NULL,
 				   0,
 				   &src_copied, &literal_added))
 		return 0;
 
+	/* sanity */
+	if (src->size < src_copied)
+		src_copied = src->size;
+	if (dst->size < literal_added + src_copied) {
+		if (src_copied < dst->size)
+			literal_added = dst->size - src_copied;
+		else
+			literal_added = 0;
+	}
+	src_removed = src->size - src_copied;
+
 	/* Compute merge-score, which is "how much is removed
 	 * from the source material".  The clean-up stage will
 	 * merge the surviving pair together if the score is
 	 * less than the minimum, after rename/copy runs.
 	 */
-	if (src->size <= src_copied)
-		; /* all copied, nothing removed */
-	else {
-		delta_size = src->size - src_copied;
-		*merge_score_p = delta_size * MAX_SCORE / src->size;
-	}
-	
+	*merge_score_p = src_removed * MAX_SCORE / src->size;
+
 	/* Extent of damage, which counts both inserts and
 	 * deletes.
 	 */
-	if (src->size + literal_added <= src_copied)
-		delta_size = 0; /* avoid wrapping around */
-	else
-		delta_size = (src->size - src_copied) + literal_added;
-	
-	/* We break if the edit exceeds the minimum.
-	 * i.e. (break_score / MAX_SCORE < delta_size / base_size)
-	 */
-	if (break_score * base_size < delta_size * MAX_SCORE)
-		to_break = 1;
+	delta_size = src_removed + literal_added;
+	if (delta_size * MAX_SCORE / base_size < break_score)
+		return 0;
 
-	return to_break;
+	/* If you removed a lot without adding new material, that is
+	 * not really a rewrite.
+	 */
+	if ((src->size * break_score < src_removed * MAX_SCORE) &&
+	    (literal_added * 20 < src_removed) &&
+	    (literal_added * 20 < src_copied))
+		return 0;
+
+	return 1;
 }
 
 void diffcore_break(int break_score)
diff --git a/diffcore-delta.c b/diffcore-delta.c
index 1e6a691..7338a40 100644
--- a/diffcore-delta.c
+++ b/diffcore-delta.c
@@ -1,43 +1,213 @@
 #include "cache.h"
 #include "diff.h"
 #include "diffcore.h"
-#include "delta.h"
-#include "count-delta.h"
 
-static int diffcore_count_changes_1(void *src, unsigned long src_size,
-				    void *dst, unsigned long dst_size,
-				    unsigned long delta_limit,
-				    unsigned long *src_copied,
-				    unsigned long *literal_added)
+/*
+ * Idea here is very simple.
+ *
+ * We have total of (sz-N+1) N-byte overlapping sequences in buf whose
+ * size is sz.  If the same N-byte sequence appears in both source and
+ * destination, we say the byte that starts that sequence is shared
+ * between them (i.e. copied from source to destination).
+ *
+ * For each possible N-byte sequence, if the source buffer has more
+ * instances of it than the destination buffer, that means the
+ * difference are the number of bytes not copied from source to
+ * destination.  If the counts are the same, everything was copied
+ * from source to destination.  If the destination has more,
+ * everything was copied, and destination added more.
+ *
+ * We are doing an approximation so we do not really have to waste
+ * memory by actually storing the sequence.  We just hash them into
+ * somewhere around 2^16 hashbuckets and count the occurrences.
+ *
+ * The length of the sequence is arbitrarily set to 8 for now.
+ */
+
+/* Wild guess at the initial hash size */
+#define INITIAL_HASH_SIZE 9
+
+/* We leave more room in smaller hash but do not let it
+ * grow to have unused hole too much.
+ */
+#define INITIAL_FREE(sz_log2) ((1<<(sz_log2))*(sz_log2-3)/(sz_log2))
+
+/* A prime rather carefully chosen between 2^16..2^17, so that
+ * HASHBASE < INITIAL_FREE(17).  We want to keep the maximum hashtable
+ * size under the current 2<<17 maximum, which can hold this many
+ * different values before overflowing to hashtable of size 2<<18.
+ */
+#define HASHBASE 107927
+
+struct spanhash {
+	unsigned int hashval;
+	unsigned int cnt;
+};
+struct spanhash_top {
+	int alloc_log2;
+	int free;
+	struct spanhash data[FLEX_ARRAY];
+};
+
+static struct spanhash *spanhash_find(struct spanhash_top *top,
+				      unsigned int hashval)
 {
-	void *delta;
-	unsigned long delta_size;
-
-	delta = diff_delta(src, src_size,
-			   dst, dst_size,
-			   &delta_size, delta_limit);
-	if (!delta)
-		/* If delta_limit is exceeded, we have too much differences */
-		return -1;
-
-	/* Estimate the edit size by interpreting delta. */
-	if (count_delta(delta, delta_size, src_copied, literal_added)) {
-		free(delta);
-		return -1;
+	int sz = 1 << top->alloc_log2;
+	int bucket = hashval & (sz - 1);
+	while (1) {
+		struct spanhash *h = &(top->data[bucket++]);
+		if (!h->cnt)
+			return NULL;
+		if (h->hashval == hashval)
+			return h;
+		if (sz <= bucket)
+			bucket = 0;
 	}
-	free(delta);
-	return 0;
+}
+
+static struct spanhash_top *spanhash_rehash(struct spanhash_top *orig)
+{
+	struct spanhash_top *new;
+	int i;
+	int osz = 1 << orig->alloc_log2;
+	int sz = osz << 1;
+
+	new = xmalloc(sizeof(*orig) + sizeof(struct spanhash) * sz);
+	new->alloc_log2 = orig->alloc_log2 + 1;
+	new->free = INITIAL_FREE(new->alloc_log2);
+	memset(new->data, 0, sizeof(struct spanhash) * sz);
+	for (i = 0; i < osz; i++) {
+		struct spanhash *o = &(orig->data[i]);
+		int bucket;
+		if (!o->cnt)
+			continue;
+		bucket = o->hashval & (sz - 1);
+		while (1) {
+			struct spanhash *h = &(new->data[bucket++]);
+			if (!h->cnt) {
+				h->hashval = o->hashval;
+				h->cnt = o->cnt;
+				new->free--;
+				break;
+			}
+			if (sz <= bucket)
+				bucket = 0;
+		}
+	}
+	free(orig);
+	return new;
+}
+
+static struct spanhash_top *add_spanhash(struct spanhash_top *top,
+					 unsigned int hashval, int cnt)
+{
+	int bucket, lim;
+	struct spanhash *h;
+
+	lim = (1 << top->alloc_log2);
+	bucket = hashval & (lim - 1);
+	while (1) {
+		h = &(top->data[bucket++]);
+		if (!h->cnt) {
+			h->hashval = hashval;
+			h->cnt = cnt;
+			top->free--;
+			if (top->free < 0)
+				return spanhash_rehash(top);
+			return top;
+		}
+		if (h->hashval == hashval) {
+			h->cnt += cnt;
+			return top;
+		}
+		if (lim <= bucket)
+			bucket = 0;
+	}
+}
+
+static struct spanhash_top *hash_chars(unsigned char *buf, unsigned int sz)
+{
+	int i, n;
+	unsigned int accum1, accum2, hashval;
+	struct spanhash_top *hash;
+
+	i = INITIAL_HASH_SIZE;
+	hash = xmalloc(sizeof(*hash) + sizeof(struct spanhash) * (1<<i));
+	hash->alloc_log2 = i;
+	hash->free = INITIAL_FREE(i);
+	memset(hash->data, 0, sizeof(struct spanhash) * (1<<i));
+
+	n = 0;
+	accum1 = accum2 = 0;
+	while (sz) {
+		unsigned int c = *buf++;
+		unsigned int old_1 = accum1;
+		sz--;
+		accum1 = (accum1 << 7) ^ (accum2 >> 25);
+		accum2 = (accum2 << 7) ^ (old_1 >> 25);
+		accum1 += c;
+		if (++n < 64 && c != '\n')
+			continue;
+		hashval = (accum1 + accum2 * 0x61) % HASHBASE;
+		hash = add_spanhash(hash, hashval, n);
+		n = 0;
+		accum1 = accum2 = 0;
+	}
+	return hash;
 }
 
 int diffcore_count_changes(void *src, unsigned long src_size,
 			   void *dst, unsigned long dst_size,
+			   void **src_count_p,
+			   void **dst_count_p,
 			   unsigned long delta_limit,
 			   unsigned long *src_copied,
 			   unsigned long *literal_added)
 {
-	return diffcore_count_changes_1(src, src_size,
-					dst, dst_size,
-					delta_limit,
-					src_copied,
-					literal_added);
+	int i, ssz;
+	struct spanhash_top *src_count, *dst_count;
+	unsigned long sc, la;
+
+	src_count = dst_count = NULL;
+	if (src_count_p)
+		src_count = *src_count_p;
+	if (!src_count) {
+		src_count = hash_chars(src, src_size);
+		if (src_count_p)
+			*src_count_p = src_count;
+	}
+	if (dst_count_p)
+		dst_count = *dst_count_p;
+	if (!dst_count) {
+		dst_count = hash_chars(dst, dst_size);
+		if (dst_count_p)
+			*dst_count_p = dst_count;
+	}
+	sc = la = 0;
+
+	ssz = 1 << src_count->alloc_log2;
+	for (i = 0; i < ssz; i++) {
+		struct spanhash *s = &(src_count->data[i]);
+		struct spanhash *d;
+		unsigned dst_cnt, src_cnt;
+		if (!s->cnt)
+			continue;
+		src_cnt = s->cnt;
+		d = spanhash_find(dst_count, s->hashval);
+		dst_cnt = d ? d->cnt : 0;
+		if (src_cnt < dst_cnt) {
+			la += dst_cnt - src_cnt;
+			sc += src_cnt;
+		}
+		else
+			sc += dst_cnt;
+	}
+
+	if (!src_count_p)
+		free(src_count);
+	if (!dst_count_p)
+		free(dst_count);
+	*src_copied = sc;
+	*literal_added = la;
+	return 0;
 }
diff --git a/diffcore-rename.c b/diffcore-rename.c
index 55cf1c3..e992698 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -133,7 +133,7 @@
 	 * match than anything else; the destination does not even
 	 * call into this function in that case.
 	 */
-	unsigned long delta_size, base_size, src_copied, literal_added;
+	unsigned long max_size, delta_size, base_size, src_copied, literal_added;
 	unsigned long delta_limit;
 	int score;
 
@@ -144,9 +144,9 @@
 	if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
 		return 0;
 
-	delta_size = ((src->size < dst->size) ?
-		      (dst->size - src->size) : (src->size - dst->size));
+	max_size = ((src->size > dst->size) ? src->size : dst->size);
 	base_size = ((src->size < dst->size) ? src->size : dst->size);
+	delta_size = max_size - base_size;
 
 	/* We would not consider edits that change the file size so
 	 * drastically.  delta_size must be smaller than
@@ -166,23 +166,18 @@
 	delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE;
 	if (diffcore_count_changes(src->data, src->size,
 				   dst->data, dst->size,
+				   &src->cnt_data, &dst->cnt_data,
 				   delta_limit,
 				   &src_copied, &literal_added))
 		return 0;
 
-	/* Extent of damage */
-	if (src->size + literal_added < src_copied)
-		delta_size = 0;
-	else
-		delta_size = (src->size - src_copied) + literal_added;
-
-	/*
-	 * Now we will give some score to it.  100% edit gets 0 points
-	 * and 0% edit gets MAX_SCORE points.
+	/* How similar are they?
+	 * what percentage of material in dst are from source?
 	 */
-	score = MAX_SCORE - (MAX_SCORE * delta_size / base_size); 
-	if (score < 0) return 0;
-	if (MAX_SCORE < score) return MAX_SCORE;
+	if (!dst->size)
+		score = 0; /* should not happen */
+	else
+		score = src_copied * MAX_SCORE / max_size;
 	return score;
 }
 
@@ -310,6 +305,8 @@
 			m->score = estimate_similarity(one, two,
 						       minimum_score);
 		}
+		/* We do not need the text anymore */
+		diff_free_filespec_data(two);
 		dst_cnt++;
 	}
 	/* cost matrix sorted by most to least similar pair */
diff --git a/diffcore.h b/diffcore.h
index dba4f17..73c7842 100644
--- a/diffcore.h
+++ b/diffcore.h
@@ -17,8 +17,8 @@
  */
 #define MAX_SCORE 60000.0
 #define DEFAULT_RENAME_SCORE 30000 /* rename/copy similarity minimum (50%) */
-#define DEFAULT_BREAK_SCORE  30000 /* minimum for break to happen (50%)*/
-#define DEFAULT_MERGE_SCORE  48000 /* maximum for break-merge to happen (80%)*/
+#define DEFAULT_BREAK_SCORE  30000 /* minimum for break to happen (50%) */
+#define DEFAULT_MERGE_SCORE  36000 /* maximum for break-merge to happen 60%) */
 
 #define MINIMUM_BREAK_SIZE     400 /* do not break a file smaller than this */
 
@@ -26,6 +26,7 @@
 	unsigned char sha1[20];
 	char *path;
 	void *data;
+	void *cnt_data;
 	unsigned long size;
 	int xfrm_flags;		 /* for use by the xfrm */
 	unsigned short mode;	 /* file mode */
@@ -103,6 +104,8 @@
 
 extern int diffcore_count_changes(void *src, unsigned long src_size,
 				  void *dst, unsigned long dst_size,
+				  void **src_count_p,
+				  void **dst_count_p,
 				  unsigned long delta_limit,
 				  unsigned long *src_copied,
 				  unsigned long *literal_added);
diff --git a/environment.c b/environment.c
index 16c08f0..6df6478 100644
--- a/environment.c
+++ b/environment.c
@@ -14,6 +14,7 @@
 int trust_executable_bit = 1;
 int assume_unchanged = 0;
 int only_use_symrefs = 0;
+int warn_ambiguous_refs = 1;
 int repository_format_version = 0;
 char git_commit_encoding[MAX_ENCODING_LENGTH] = "utf-8";
 int shared_repository = 0;
diff --git a/fetch-pack.c b/fetch-pack.c
index 535de10..a3bcad0 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -7,8 +7,9 @@
 static int keep_pack;
 static int quiet;
 static int verbose;
+static int fetch_all;
 static const char fetch_pack_usage[] =
-"git-fetch-pack [-q] [-v] [-k] [--thin] [--exec=upload-pack] [host:]directory <refs>...";
+"git-fetch-pack [--all] [-q] [-v] [-k] [--thin] [--exec=upload-pack] [host:]directory <refs>...";
 static const char *exec = "git-upload-pack";
 
 #define COMPLETE	(1U << 0)
@@ -266,8 +267,9 @@
 	for (prev = NULL, current = *refs; current; current = next) {
 		next = current->next;
 		if ((!memcmp(current->name, "refs/", 5) &&
-					check_ref_format(current->name + 5)) ||
-				!path_match(current->name, nr_match, match)) {
+		     check_ref_format(current->name + 5)) ||
+		    (!fetch_all &&
+		     !path_match(current->name, nr_match, match))) {
 			if (prev == NULL)
 				*refs = next;
 			else
@@ -376,7 +378,11 @@
 		goto all_done;
 	}
 	if (find_common(fd, sha1, ref) < 0)
-		fprintf(stderr, "warning: no common commits\n");
+		if (!keep_pack)
+			/* When cloning, it is not unusual to have
+			 * no common commit.
+			 */
+			fprintf(stderr, "warning: no common commits\n");
 
 	if (keep_pack)
 		status = receive_keep_pack(fd, "git-fetch-pack", quiet);
@@ -426,6 +432,10 @@
 				use_thin_pack = 1;
 				continue;
 			}
+			if (!strcmp("--all", arg)) {
+				fetch_all = 1;
+				continue;
+			}
 			if (!strcmp("-v", arg)) {
 				verbose = 1;
 				continue;
diff --git a/git-clone.sh b/git-clone.sh
index 4ed861d..6887321 100755
--- a/git-clone.sh
+++ b/git-clone.sh
@@ -9,7 +9,7 @@
 unset CDPATH
 
 usage() {
-	echo >&2 "Usage: $0 [--bare] [-l [-s]] [-q] [-u <upload-pack>] [-o <name>] [-n] <repo> [<dir>]"
+	echo >&2 "Usage: $0 [--use-separate-remote] [--reference <reference-repo>] [--bare] [-l [-s]] [-q] [-u <upload-pack>] [-o <name>] [-n] <repo> [<dir>]"
 	exit 1
 }
 
@@ -40,22 +40,73 @@
 	do
 		name=`expr "$refname" : 'refs/\(.*\)'` &&
 		case "$name" in
-		*^*)	;;
-		*)
-			git-http-fetch -v -a -w "$name" "$name" "$1/" || exit 1
+		*^*)	continue;;
 		esac
+		if test -n "$use_separate_remote" &&
+		   branch_name=`expr "$name" : 'heads/\(.*\)'`
+		then
+			tname="remotes/$origin/$branch_name"
+		else
+			tname=$name
+		fi
+		git-http-fetch -v -a -w "$tname" "$name" "$1/" || exit 1
 	done <"$clone_tmp/refs"
 	rm -fr "$clone_tmp"
+	http_fetch "$1/HEAD" "$GIT_DIR/REMOTE_HEAD"
 }
 
+# Read git-fetch-pack -k output and store the remote branches.
+copy_refs='
+use File::Path qw(mkpath);
+use File::Basename qw(dirname);
+my $git_dir = $ARGV[0];
+my $use_separate_remote = $ARGV[1];
+my $origin = $ARGV[2];
+
+my $branch_top = ($use_separate_remote ? "remotes/$origin" : "heads");
+my $tag_top = "tags";
+
+sub store {
+	my ($sha1, $name, $top) = @_;
+	$name = "$git_dir/refs/$top/$name";
+	mkpath(dirname($name));
+	open O, ">", "$name";
+	print O "$sha1\n";
+	close O;
+}
+
+open FH, "<", "$git_dir/CLONE_HEAD";
+while (<FH>) {
+	my ($sha1, $name) = /^([0-9a-f]{40})\s(.*)$/;
+	next if ($name =~ /\^\173/);
+	if ($name eq "HEAD") {
+		open O, ">", "$git_dir/REMOTE_HEAD";
+		print O "$sha1\n";
+		close O;
+		next;
+	}
+	if ($name =~ s/^refs\/heads\///) {
+		store($sha1, $name, $branch_top);
+		next;
+	}
+	if ($name =~ s/^refs\/tags\///) {
+		store($sha1, $name, $tag_top);
+		next;
+	}
+}
+close FH;
+'
+
 quiet=
 use_local=no
 local_shared=no
 no_checkout=
 upload_pack=
 bare=
-origin=origin
+reference=
+origin=
 origin_override=
+use_separate_remote=
 while
 	case "$#,$1" in
 	0,*) break ;;
@@ -68,9 +119,21 @@
         *,-s|*,--s|*,--sh|*,--sha|*,--shar|*,--share|*,--shared) 
           local_shared=yes; use_local=yes ;;
 	*,-q|*,--quiet) quiet=-q ;;
+	*,--use-separate-remote)
+		use_separate_remote=t ;;
 	1,-o) usage;;
+	1,--reference) usage ;;
+	*,--reference)
+		shift; reference="$1" ;;
+	*,--reference=*)
+		reference=`expr "$1" : '--reference=\(.*\)'` ;;
 	*,-o)
-		git-check-ref-format "$2" || {
+		case "$2" in
+		*/*)
+		    echo >&2 "'$2' is not suitable for an origin name"
+		    exit 1
+		esac
+		git-check-ref-format "heads/$2" || {
 		    echo >&2 "'$2' is not suitable for a branch name"
 		    exit 1
 		}
@@ -100,9 +163,19 @@
 		echo >&2 '--bare and -o $origin options are incompatible.'
 		exit 1
 	fi
+	if test t = "$use_separate_remote"
+	then
+		echo >&2 '--bare and --use-separate-remote options are incompatible.'
+		exit 1
+	fi
 	no_checkout=yes
 fi
 
+if test -z "$origin"
+then
+	origin=origin
+fi
+
 # Turn the source into an absolute path if
 # it is local
 repo="$1"
@@ -130,6 +203,28 @@
 	GIT_DIR="$D/.git" ;;
 esac
 
+if test -n "$reference"
+then
+	if test -d "$reference"
+	then
+		if test -d "$reference/.git/objects"
+		then
+			reference="$reference/.git"
+		fi
+		reference=$(cd "$reference" && pwd)
+		echo "$reference/objects" >"$GIT_DIR/objects/info/alternates"
+		(cd "$reference" && tar cf - refs) |
+		(cd "$GIT_DIR/refs" &&
+		 mkdir reference-tmp &&
+		 cd reference-tmp &&
+		 tar xf -)
+	else
+		echo >&2 "$reference: not a local directory." && usage
+	fi
+fi
+
+rm -f "$GIT_DIR/CLONE_HEAD"
+
 # We do local magic only when the user tells us to.
 case "$local,$use_local" in
 yes,yes)
@@ -165,24 +260,14 @@
 	    } >"$GIT_DIR/objects/info/alternates"
 	    ;;
 	esac
-
-	# Make a duplicate of refs and HEAD pointer
-	HEAD=
-	if test -f "$repo/HEAD"
-	then
-		HEAD=HEAD
-	fi
-	(cd "$repo" && tar cf - refs $HEAD) |
-	(cd "$GIT_DIR" && tar xf -) || exit 1
+	git-ls-remote "$repo" >"$GIT_DIR/CLONE_HEAD"
 	;;
 *)
 	case "$repo" in
 	rsync://*)
 		rsync $quiet -av --ignore-existing  \
-			--exclude info "$repo/objects/" "$GIT_DIR/objects/" &&
-		rsync $quiet -av --ignore-existing  \
-			--exclude info "$repo/refs/" "$GIT_DIR/refs/" || exit
-
+			--exclude info "$repo/objects/" "$GIT_DIR/objects/" ||
+		exit
 		# Look at objects/info/alternates for rsync -- http will
 		# support it natively and git native ones will do it on the
 		# remote end.  Not having that file is not a crime.
@@ -205,6 +290,7 @@
 		    done
 		    rm -f "$GIT_DIR/TMP_ALT"
 		fi
+		git-ls-remote "$repo" >"$GIT_DIR/CLONE_HEAD"
 		;;
 	http://*)
 		if test -z "@@NO_CURL@@"
@@ -217,38 +303,89 @@
 		;;
 	*)
 		cd "$D" && case "$upload_pack" in
-		'') git-clone-pack $quiet "$repo" ;;
-		*) git-clone-pack $quiet "$upload_pack" "$repo" ;;
-		esac || {
-			echo >&2 "clone-pack from '$repo' failed."
+		'') git-fetch-pack --all -k $quiet "$repo" ;;
+		*) git-fetch-pack --all -k $quiet "$upload_pack" "$repo" ;;
+		esac >"$GIT_DIR/CLONE_HEAD" || {
+			echo >&2 "fetch-pack from '$repo' failed."
 			exit 1
 		}
 		;;
 	esac
 	;;
 esac
+test -d "$GIT_DIR/refs/reference-tmp" && rm -fr "$GIT_DIR/refs/reference-tmp"
+
+if test -f "$GIT_DIR/CLONE_HEAD"
+then
+	# Figure out where the remote HEAD points at.
+	perl -e "$copy_refs" "$GIT_DIR" "$use_separate_remote" "$origin"
+fi
 
 cd "$D" || exit
 
-if test -f "$GIT_DIR/HEAD" && test -z "$bare"
+if test -z "$bare" && test -f "$GIT_DIR/REMOTE_HEAD"
 then
-	head_points_at=`git-symbolic-ref HEAD`
-	case "$head_points_at" in
-	refs/heads/*)
-		head_points_at=`expr "$head_points_at" : 'refs/heads/\(.*\)'`
-		mkdir -p "$GIT_DIR/remotes" &&
-		echo >"$GIT_DIR/remotes/origin" \
-		"URL: $repo
-Pull: $head_points_at:$origin" &&
-		git-update-ref "refs/heads/$origin" $(git-rev-parse HEAD) &&
-		(cd "$GIT_DIR" && find "refs/heads" -type f -print) |
-		while read ref
+	head_sha1=`cat "$GIT_DIR/REMOTE_HEAD"`
+	# Figure out which remote branch HEAD points at.
+	case "$use_separate_remote" in
+	'')	remote_top=refs/heads ;;
+	*)	remote_top="refs/remotes/$origin" ;;
+	esac
+
+	# What to use to track the remote primary branch
+	if test -n "$use_separate_remote"
+	then
+		origin_tracking="remotes/$origin/master"
+	else
+		origin_tracking="heads/$origin"
+	fi
+
+	# The name under $remote_top the remote HEAD seems to point at
+	head_points_at=$(
+		(
+			echo "master"
+			cd "$GIT_DIR/$remote_top" &&
+			find . -type f -print | sed -e 's/^\.\///'
+		) | (
+		done=f
+		while read name
 		do
-			head=`expr "$ref" : 'refs/heads/\(.*\)'` &&
-			test "$head_points_at" = "$head" ||
-			test "$origin" = "$head" ||
-			echo "Pull: ${head}:${head}"
-		done >>"$GIT_DIR/remotes/origin"
+			test t = $done && continue
+			branch_tip=`cat "$GIT_DIR/$remote_top/$name"`
+			if test "$head_sha1" = "$branch_tip"
+			then
+				echo "$name"
+				done=t
+			fi
+		done
+		)
+	)
+
+	# Write out remotes/$origin file.
+	case "$head_points_at" in
+	?*)
+		mkdir -p "$GIT_DIR/remotes" &&
+		echo >"$GIT_DIR/remotes/$origin" \
+		"URL: $repo
+Pull: refs/heads/$head_points_at:refs/$origin_tracking" &&
+		case "$use_separate_remote" in
+		t) git-update-ref HEAD "$head_sha1" ;;
+		*) git-update-ref "refs/heads/$origin" $(git-rev-parse HEAD) ;;
+		esac &&
+		(cd "$GIT_DIR/$remote_top" && find . -type f -print) |
+		while read dotslref
+		do
+			name=`expr "$dotslref" : './\(.*\)'` &&
+			test "$head_points_at" = "$name" ||
+			test "$origin" = "$name" ||
+			echo "Pull: refs/heads/${name}:$remote_top/${name}"
+		done >>"$GIT_DIR/remotes/$origin" &&
+		case "$use_separate_remote" in
+		t)
+			rm -f "refs/remotes/$origin/HEAD"
+			git-symbolic-ref "refs/remotes/$origin/HEAD" \
+				"refs/remotes/$origin/$head_points_at"
+		esac
 	esac
 
 	case "$no_checkout" in
@@ -256,6 +393,7 @@
 		git-read-tree -m -u -v HEAD HEAD
 	esac
 fi
+rm -f "$GIT_DIR/CLONE_HEAD" "$GIT_DIR/REMOTE_HEAD"
 
 trap - exit
 
diff --git a/git-fetch.sh b/git-fetch.sh
index 6835634..954901d 100755
--- a/git-fetch.sh
+++ b/git-fetch.sh
@@ -94,6 +94,9 @@
     # remote-nick is the URL given on the command line (or a shorthand)
     # remote-name is the $GIT_DIR relative refs/ path we computed
     # for this refspec.
+
+    # the $note_ variable will be fed to git-fmt-merge-msg for further
+    # processing.
     case "$remote_name_" in
     HEAD)
 	note_= ;;
@@ -103,6 +106,9 @@
     refs/tags/*)
 	note_="$(expr "$remote_name_" : 'refs/tags/\(.*\)')"
 	note_="tag '$note_' of " ;;
+    refs/remotes/*)
+	note_="$(expr "$remote_name_" : 'refs/remotes/\(.*\)')"
+	note_="remote branch '$note_' of " ;;
     *)
 	note_="$remote_name of " ;;
     esac
@@ -147,10 +153,10 @@
 	else
 		echo >&2 "* $1: storing $3"
 	fi
-	git-update-ref "$1" "$2" 
+	git-update-ref "$1" "$2"
 	;;
 
-    refs/heads/*)
+    refs/heads/* | refs/remotes/*)
 	# $1 is the ref being updated.
 	# $2 is the new value for the ref.
 	local=$(git-rev-parse --verify "$1^0" 2>/dev/null)
diff --git a/git-fmt-merge-msg.perl b/git-fmt-merge-msg.perl
index afe80e6..5986e54 100755
--- a/git-fmt-merge-msg.perl
+++ b/git-fmt-merge-msg.perl
@@ -75,6 +75,7 @@
 		$src{$src} = {
 			BRANCH => [],
 			TAG => [],
+			R_BRANCH => [],
 			GENERIC => [],
 			# &1 == has HEAD.
 			# &2 == has others.
@@ -91,6 +92,11 @@
 		push @{$src{$src}{TAG}}, $1;
 		$src{$src}{HEAD_STATUS} |= 2;
 	}
+	elsif (/^remote branch (.*)$/) {
+		$origin = $1;
+		push @{$src{$src}{R_BRANCH}}, $1;
+		$src{$src}{HEAD_STATUS} |= 2;
+	}
 	elsif (/^HEAD$/) {
 		$origin = $src;
 		$src{$src}{HEAD_STATUS} |= 1;
@@ -123,6 +129,8 @@
 	}
 	push @this, andjoin("branch ", "branches ",
 			   $src{$src}{BRANCH});
+	push @this, andjoin("remote branch ", "remote branches ",
+			   $src{$src}{R_BRANCH});
 	push @this, andjoin("tag ", "tags ",
 			   $src{$src}{TAG});
 	push @this, andjoin("commit ", "commits ",
diff --git a/git-merge.sh b/git-merge.sh
index cc0952a..78ab422 100755
--- a/git-merge.sh
+++ b/git-merge.sh
@@ -11,11 +11,15 @@
 '
 
 all_strategies='recursive octopus resolve stupid ours'
-default_strategies='recursive'
+default_twohead_strategies='recursive'
+default_octopus_strategies='octopus'
+no_trivial_merge_strategies='ours'
 use_strategies=
+
+index_merge=t
 if test "@@NO_PYTHON@@"; then
 	all_strategies='resolve octopus stupid ours'
-	default_strategies='resolve'
+	default_twohead_strategies='resolve'
 fi
 
 dropsave() {
@@ -90,8 +94,6 @@
 	shift
 done
 
-test "$#" -le 2 && usage ;# we need at least two heads.
-
 merge_msg="$1"
 shift
 head_arg="$1"
@@ -99,6 +101,8 @@
 shift
 
 # All the rest are remote heads
+test "$#" = 0 && usage ;# we need at least one remote head.
+
 remoteheads=
 for remote
 do
@@ -108,6 +112,27 @@
 done
 set x $remoteheads ; shift
 
+case "$use_strategies" in
+'')
+	case "$#" in
+	1)
+		use_strategies="$default_twohead_strategies" ;;
+	*)
+		use_strategies="$default_octopus_strategies" ;;
+	esac
+	;;
+esac
+
+for s in $use_strategies
+do
+	case " $s " in
+	*" $no_trivial_merge_strategies "*)
+		index_merge=f
+		break
+		;;
+	esac
+done
+
 case "$#" in
 1)
 	common=$(git-merge-base --all $head "$@")
@@ -118,18 +143,21 @@
 esac
 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 
-case "$#,$common,$no_commit" in
-*,'',*)
+case "$index_merge,$#,$common,$no_commit" in
+f,*)
+	# We've been told not to try anything clever.  Skip to real merge.
+	;;
+?,*,'',*)
 	# No common ancestors found. We need a real merge.
 	;;
-1,"$1",*)
+?,1,"$1",*)
 	# If head can reach all the merge then we are up to date.
-	# but first the most common case of merging one remote
+	# but first the most common case of merging one remote.
 	echo "Already up-to-date."
 	dropsave
 	exit 0
 	;;
-1,"$head",*)
+?,1,"$head",*)
 	# Again the most common case of merging one remote.
 	echo "Updating from $head to $1"
 	git-update-index --refresh 2>/dev/null
@@ -139,11 +167,11 @@
 	dropsave
 	exit 0
 	;;
-1,?*"$LF"?*,*)
+?,1,?*"$LF"?*,*)
 	# We are not doing octopus and not fast forward.  Need a
 	# real merge.
 	;;
-1,*,)
+?,1,*,)
 	# We are not doing octopus, not fast forward, and have only
 	# one common.  See if it is really trivial.
 	git var GIT_COMMITTER_IDENT >/dev/null || exit
@@ -188,17 +216,6 @@
 # We are going to make a new commit.
 git var GIT_COMMITTER_IDENT >/dev/null || exit
 
-case "$use_strategies" in
-'')
-	case "$#" in
-	1)
-		use_strategies="$default_strategies" ;;
-	*)
-		use_strategies=octopus ;;
-	esac		
-	;;
-esac
-
 # At this point, we need a real merge.  No matter what strategy
 # we use, it would operate on the index, possibly affecting the
 # working tree, and when resolved cleanly, have the desired tree
@@ -270,11 +287,7 @@
 # auto resolved the merge cleanly.
 if test '' != "$result_tree"
 then
-    parents="-p $head"
-    for remote
-    do
-        parents="$parents -p $remote"
-    done
+    parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
     finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
     dropsave
diff --git a/git-parse-remote.sh b/git-parse-remote.sh
index 5f158c6..63f2281 100755
--- a/git-parse-remote.sh
+++ b/git-parse-remote.sh
@@ -86,14 +86,14 @@
 		local=$(expr "$ref" : '[^:]*:\(.*\)')
 		case "$remote" in
 		'') remote=HEAD ;;
-		refs/heads/* | refs/tags/*) ;;
-		heads/* | tags/* ) remote="refs/$remote" ;;
+		refs/heads/* | refs/tags/* | refs/remotes/*) ;;
+		heads/* | tags/* | remotes/* ) remote="refs/$remote" ;;
 		*) remote="refs/heads/$remote" ;;
 		esac
 		case "$local" in
 		'') local= ;;
-		refs/heads/* | refs/tags/*) ;;
-		heads/* | tags/* ) local="refs/$local" ;;
+		refs/heads/* | refs/tags/* | refs/remotes/*) ;;
+		heads/* | tags/* | remotes/* ) local="refs/$local" ;;
 		*) local="refs/heads/$local" ;;
 		esac
 
diff --git a/git-push.sh b/git-push.sh
index 73dcf06..f10cadb 100755
--- a/git-push.sh
+++ b/git-push.sh
@@ -8,7 +8,7 @@
 has_all=
 has_force=
 has_exec=
-has_thin=
+has_thin=--thin
 remote=
 do_tags=
 
@@ -24,7 +24,9 @@
 	--exec=*)
 		has_exec="$1" ;;
 	--thin)
-		has_thin="$1" ;;
+		;; # noop
+	--no-thin)
+		has_thin= ;;
 	-*)
                 usage ;;
         *)
diff --git a/git-send-email.perl b/git-send-email.perl
index b220d11..ecfa347 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -19,10 +19,16 @@
 use strict;
 use warnings;
 use Term::ReadLine;
-use Mail::Sendmail qw(sendmail %mailcfg);
 use Getopt::Long;
 use Data::Dumper;
-use Email::Valid;
+use Net::SMTP;
+
+# most mail servers generate the Date: header, but not all...
+$ENV{LC_ALL} = 'C';
+use POSIX qw/strftime/;
+
+my $have_email_valid = eval { require Email::Valid; 1 };
+my $smtp;
 
 sub unique_email_list(@);
 sub cleanup_compose_files();
@@ -31,7 +37,7 @@
 my $compose_filename = ".msg.$$";
 
 # Variables we fill in automatically, or via prompting:
-my (@to,@cc,@initial_cc,$initial_reply_to,$initial_subject,@files,$from,$compose);
+my (@to,@cc,@initial_cc,$initial_reply_to,$initial_subject,@files,$from,$compose,$time);
 
 # Behavior modification variables
 my ($chain_reply_to, $smtp_server, $quiet, $suppress_from, $no_signed_off_cc) = (1, "localhost", 0, 0, 0);
@@ -244,6 +250,16 @@
 # Variables we set as part of the loop over files
 our ($message_id, $cc, %mail, $subject, $reply_to, $message);
 
+sub extract_valid_address {
+	my $address = shift;
+	if ($have_email_valid) {
+		return Email::Valid->address($address);
+	} else {
+		# less robust/correct than the monster regexp in Email::Valid,
+		# but still does a 99% job, and one less dependency
+		return ($address =~ /([^\"<>\s]+@[^<>\s]+)/);
+	}
+}
 
 # Usually don't need to change anything below here.
 
@@ -253,13 +269,12 @@
 # 1 second since the last time we were called.
 
 # We'll setup a template for the message id, using the "from" address:
-my $message_id_from = Email::Valid->address($from);
+my $message_id_from = extract_valid_address($from);
 my $message_id_template = "<%s-git-send-email-$message_id_from>";
 
 sub make_message_id
 {
-	my $date = `date "+\%s"`;
-	chomp($date);
+	my $date = time;
 	my $pseudo_rand = int (rand(4200));
 	$message_id = sprintf $message_id_template, "$date$pseudo_rand";
 	#print "new message id = $message_id\n"; # Was useful for debugging
@@ -268,38 +283,49 @@
 
 
 $cc = "";
+$time = time - scalar $#files;
 
 sub send_message
 {
-	my $to = join (", ", unique_email_list(@to));
+	my @recipients = unique_email_list(@to);
+	my $to = join (",\n\t", @recipients);
+	@recipients = unique_email_list(@recipients,@cc);
+	my $date = strftime('%a, %d %b %Y %H:%M:%S %z', localtime($time++));
 
-	%mail = (	To	=>	$to,
-			From	=>	$from,
-			CC	=>	$cc,
-			Subject	=>	$subject,
-			Message	=>	$message,
-			'Reply-to'	=>	$from,
-			'In-Reply-To'	=>	$reply_to,
-			'Message-ID'	=>	$message_id,
-			'X-Mailer'	=>	"git-send-email",
-		);
+	my $header = "From: $from
+To: $to
+Cc: $cc
+Subject: $subject
+Reply-To: $from
+Date: $date
+Message-Id: $message_id
+X-Mailer: git-send-email @@GIT_VERSION@@
+";
+	$header .= "In-Reply-To: $reply_to\n" if $reply_to;
 
-	$mail{smtp} = $smtp_server;
-	$mailcfg{mime} = 0;
-
-	#print Data::Dumper->Dump([\%mail],[qw(*mail)]);
-
-	sendmail(%mail) or die $Mail::Sendmail::error;
+	$smtp ||= Net::SMTP->new( $smtp_server );
+	$smtp->mail( $from ) or die $smtp->message;
+	$smtp->to( @recipients ) or die $smtp->message;
+	$smtp->data or die $smtp->message;
+	$smtp->datasend("$header\n$message") or die $smtp->message;
+	$smtp->dataend() or die $smtp->message;
+	$smtp->ok or die "Failed to send $subject\n".$smtp->message;
 
 	if ($quiet) {
 		printf "Sent %s\n", $subject;
 	} else {
-		print "OK. Log says:\n", $Mail::Sendmail::log;
-		print "\n\n"
+		print "OK. Log says:
+Date: $date
+Server: $smtp_server Port: 25
+From: $from
+Subject: $subject
+Cc: $cc
+To: $to
+
+Result: ", $smtp->code, ' ', ($smtp->message =~ /\n([^\n]+\n)$/s), "\n";
 	}
 }
 
-
 $reply_to = $initial_reply_to;
 make_message_id();
 $subject = $initial_subject;
@@ -390,14 +416,14 @@
 
 }
 
-
+$smtp->quit if $smtp;
 
 sub unique_email_list(@) {
 	my %seen;
 	my @emails;
 
 	foreach my $entry (@_) {
-		my $clean = Email::Valid->address($entry);
+		my $clean = extract_valid_address($entry);
 		next if $seen{$clean}++;
 		push @emails, $entry;
 	}
diff --git a/ls-files.c b/ls-files.c
index e42119c..4a4af1c 100644
--- a/ls-files.c
+++ b/ls-files.c
@@ -11,6 +11,7 @@
 #include "cache.h"
 #include "quote.h"
 
+static int abbrev = 0;
 static int show_deleted = 0;
 static int show_cached = 0;
 static int show_others = 0;
@@ -20,6 +21,7 @@
 static int show_modified = 0;
 static int show_killed = 0;
 static int show_other_directories = 0;
+static int hide_empty_directories = 0;
 static int show_valid_bit = 0;
 static int line_terminator = '\n';
 
@@ -258,11 +260,12 @@
  * Also, we ignore the name ".git" (even if it is not a directory).
  * That likely will not change.
  */
-static void read_directory(const char *path, const char *base, int baselen)
+static int read_directory(const char *path, const char *base, int baselen)
 {
-	DIR *dir = opendir(path);
+	DIR *fdir = opendir(path);
+	int contents = 0;
 
-	if (dir) {
+	if (fdir) {
 		int exclude_stk;
 		struct dirent *de;
 		char fullname[MAXPATHLEN + 1];
@@ -270,7 +273,7 @@
 
 		exclude_stk = push_exclude_per_directory(base, baselen);
 
-		while ((de = readdir(dir)) != NULL) {
+		while ((de = readdir(fdir)) != NULL) {
 			int len;
 
 			if ((de->d_name[0] == '.') &&
@@ -288,6 +291,7 @@
 
 			switch (DTYPE(de)) {
 			struct stat st;
+			int subdir, rewind_base;
 			default:
 				continue;
 			case DT_UNKNOWN:
@@ -301,22 +305,32 @@
 			case DT_DIR:
 				memcpy(fullname + baselen + len, "/", 2);
 				len++;
+				rewind_base = nr_dir;
+				subdir = read_directory(fullname, fullname,
+				                        baselen + len);
 				if (show_other_directories &&
-				    !dir_exists(fullname, baselen + len))
+				    (subdir || !hide_empty_directories) &&
+				    !dir_exists(fullname, baselen + len)) {
+					// Rewind the read subdirectory
+					while (nr_dir > rewind_base)
+						free(dir[--nr_dir]);
 					break;
-				read_directory(fullname, fullname,
-					       baselen + len);
+				}
+				contents += subdir;
 				continue;
 			case DT_REG:
 			case DT_LNK:
 				break;
 			}
 			add_name(fullname, baselen + len);
+			contents++;
 		}
-		closedir(dir);
+		closedir(fdir);
 
 		pop_exclude_per_directory(exclude_stk);
 	}
+
+	return contents;
 }
 
 static int cmp_name(const void *p1, const void *p2)
@@ -489,7 +503,8 @@
 		printf("%s%06o %s %d\t",
 		       tag,
 		       ntohl(ce->ce_mode),
-		       sha1_to_hex(ce->sha1),
+		       abbrev ? find_unique_abbrev(ce->sha1,abbrev)
+				: sha1_to_hex(ce->sha1),
 		       ce_stage(ce));
 		write_name_quoted("", 0, ce->name + offset,
 				  line_terminator, stdout);
@@ -630,7 +645,8 @@
 static const char ls_files_usage[] =
 	"git-ls-files [-z] [-t] [-v] (--[cached|deleted|others|stage|unmerged|killed|modified])* "
 	"[ --ignored ] [--exclude=<pattern>] [--exclude-from=<file>] "
-	"[ --exclude-per-directory=<filename> ] [--full-name] [--] [<file>]*";
+	"[ --exclude-per-directory=<filename> ] [--full-name] [--abbrev] "
+	"[--] [<file>]*";
 
 int main(int argc, const char **argv)
 {
@@ -696,6 +712,10 @@
 			show_other_directories = 1;
 			continue;
 		}
+		if (!strcmp(arg, "--no-empty-directory")) {
+			hide_empty_directories = 1;
+			continue;
+		}
 		if (!strcmp(arg, "-u") || !strcmp(arg, "--unmerged")) {
 			/* There's no point in showing unmerged unless
 			 * you also show the stage information.
@@ -737,6 +757,18 @@
 			error_unmatch = 1;
 			continue;
 		}
+		if (!strncmp(arg, "--abbrev=", 9)) {
+			abbrev = strtoul(arg+9, NULL, 10);
+			if (abbrev && abbrev < MINIMUM_ABBREV)
+				abbrev = MINIMUM_ABBREV;
+			else if (abbrev > 40)
+				abbrev = 40;
+			continue;
+		}
+		if (!strcmp(arg, "--abbrev")) {
+			abbrev = DEFAULT_ABBREV;
+			continue;
+		}
 		if (*arg == '-')
 			usage(ls_files_usage);
 		break;
diff --git a/ls-tree.c b/ls-tree.c
index d005643..26258c3 100644
--- a/ls-tree.c
+++ b/ls-tree.c
@@ -13,13 +13,14 @@
 #define LS_TREE_ONLY 2
 #define LS_SHOW_TREES 4
 #define LS_NAME_ONLY 8
+static int abbrev = 0;
 static int ls_options = 0;
 const char **pathspec;
 static int chomp_prefix = 0;
 static const char *prefix;
 
 static const char ls_tree_usage[] =
-	"git-ls-tree [-d] [-r] [-t] [-z] [--name-only] [--name-status] [--full-name] <tree-ish> [path...]";
+	"git-ls-tree [-d] [-r] [-t] [-z] [--name-only] [--name-status] [--full-name] [--abbrev[=<n>]] <tree-ish> [path...]";
 
 static int show_recursive(const char *base, int baselen, const char *pathname)
 {
@@ -73,7 +74,9 @@
 		return 0;
 
 	if (!(ls_options & LS_NAME_ONLY))
-		printf("%06o %s %s\t", mode, type, sha1_to_hex(sha1));
+		printf("%06o %s %s\t", mode, type,
+				abbrev ? find_unique_abbrev(sha1,abbrev)
+					: sha1_to_hex(sha1));
 	write_name_quoted(base + chomp_prefix, baselen - chomp_prefix,
 			  pathname,
 			  line_termination, stdout);
@@ -87,6 +90,7 @@
 	struct tree *tree;
 
 	prefix = setup_git_directory();
+	git_config(git_default_config);
 	if (prefix && *prefix)
 		chomp_prefix = strlen(prefix);
 	while (1 < argc && argv[1][0] == '-') {
@@ -113,6 +117,18 @@
 				chomp_prefix = 0;
 				break;
 			}
+			if (!strncmp(argv[1]+2, "abbrev=",7)) {
+				abbrev = strtoul(argv[1]+9, NULL, 10);
+				if (abbrev && abbrev < MINIMUM_ABBREV)
+					abbrev = MINIMUM_ABBREV;
+				else if (abbrev > 40)
+					abbrev = 40;
+				break;
+			}
+			if (!strcmp(argv[1]+2, "abbrev")) {
+				abbrev = DEFAULT_ABBREV;
+				break;
+			}
 			/* otherwise fallthru */
 		default:
 			usage(ls_tree_usage);
diff --git a/merge-base.c b/merge-base.c
index e73fca7..07f5ab4 100644
--- a/merge-base.c
+++ b/merge-base.c
@@ -237,6 +237,7 @@
 	unsigned char rev1key[20], rev2key[20];
 
 	setup_git_directory();
+	git_config(git_default_config);
 
 	while (1 < argc && argv[1][0] == '-') {
 		char *arg = argv[1];
diff --git a/name-rev.c b/name-rev.c
index 0c3f547..bad8a53 100644
--- a/name-rev.c
+++ b/name-rev.c
@@ -127,6 +127,7 @@
 	int as_is = 0, all = 0, transform_stdin = 0;
 
 	setup_git_directory();
+	git_config(git_default_config);
 
 	if (argc < 2)
 		usage(name_rev_usage);
diff --git a/read-tree.c b/read-tree.c
index 1c3b09b..eaff444 100644
--- a/read-tree.c
+++ b/read-tree.c
@@ -717,6 +717,7 @@
 	merge_fn_t fn = NULL;
 
 	setup_git_directory();
+	git_config(git_default_config);
 
 	newfd = hold_index_file_for_update(&cache_file, get_index_file());
 	if (newfd < 0)
diff --git a/rev-list.c b/rev-list.c
index 812d237..441c437 100644
--- a/rev-list.c
+++ b/rev-list.c
@@ -40,13 +40,18 @@
 static int verbose_header = 0;
 static int abbrev = DEFAULT_ABBREV;
 static int show_parents = 0;
+static int show_timestamp = 0;
 static int hdr_termination = 0;
 static const char *commit_prefix = "";
 static enum cmit_fmt commit_format = CMIT_FMT_RAW;
 
 static void show_commit(struct commit *commit)
 {
-	printf("%s%s", commit_prefix, sha1_to_hex(commit->object.sha1));
+	if (show_timestamp)
+		printf("%lu ", commit->date);
+	if (commit_prefix[0])
+		fputs(commit_prefix, stdout);
+	fputs(sha1_to_hex(commit->object.sha1), stdout);
 	if (show_parents) {
 		struct commit_list *parents = commit->parents;
 		while (parents) {
@@ -335,6 +340,10 @@
 			show_parents = 1;
 			continue;
 		}
+		if (!strcmp(arg, "--timestamp")) {
+			show_timestamp = 1;
+			continue;
+		}
 		if (!strcmp(arg, "--bisect")) {
 			bisect_list = 1;
 			continue;
diff --git a/rev-parse.c b/rev-parse.c
index f90e999..f176c56 100644
--- a/rev-parse.c
+++ b/rev-parse.c
@@ -166,13 +166,17 @@
 	unsigned char sha1[20];
 	const char *prefix = setup_git_directory();
 	
+	git_config(git_default_config);
+
 	for (i = 1; i < argc; i++) {
 		struct stat st;
 		char *arg = argv[i];
 		char *dotdot;
-	
+
 		if (as_is) {
-			show_file(arg);
+			if (show_file(arg) && as_is < 2)
+				if (lstat(arg, &st) < 0)
+					die("'%s': %s", arg, strerror(errno));
 			continue;
 		}
 		if (!strcmp(arg,"-n")) {
@@ -192,7 +196,7 @@
 
 		if (*arg == '-') {
 			if (!strcmp(arg, "--")) {
-				as_is = 1;
+				as_is = 2;
 				/* Pass on the "--" if we show anything but files.. */
 				if (filter & (DO_FLAGS | DO_REVS))
 					show_file(arg);
diff --git a/revision.c b/revision.c
index 12cd052..d67718c 100644
--- a/revision.c
+++ b/revision.c
@@ -649,7 +649,7 @@
 			/* If we didn't have a "--", all filenames must exist */
 			for (j = i; j < argc; j++) {
 				if (lstat(argv[j], &st) < 0)
-					die("'%s': %s", arg, strerror(errno));
+					die("'%s': %s", argv[j], strerror(errno));
 			}
 			revs->prune_data = get_pathspec(revs->prefix, argv + i);
 			break;
diff --git a/send-pack.c b/send-pack.c
index c8ffc8d..409f188 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -362,6 +362,8 @@
 	pid_t pid;
 
 	setup_git_directory();
+	git_config(git_default_config);
+
 	argv++;
 	for (i = 1; i < argc; i++, argv++) {
 		char *arg = *argv;
diff --git a/sha1_name.c b/sha1_name.c
index d67de18..4f92e12 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -235,14 +235,21 @@
 
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 {
-	static const char *prefix[] = {
-		"",
-		"refs",
-		"refs/tags",
-		"refs/heads",
+	static const char *fmt[] = {
+		"%.*s",
+		"refs/%.*s",
+		"refs/tags/%.*s",
+		"refs/heads/%.*s",
+		"refs/remotes/%.*s",
+		"refs/remotes/%.*s/HEAD",
 		NULL
 	};
 	const char **p;
+	const char *warning = "warning: refname '%.*s' is ambiguous.\n";
+	char *pathname;
+	int already_found = 0;
+	unsigned char *this_result;
+	unsigned char sha1_from_ref[20];
 
 	if (len == 40 && !get_sha1_hex(str, sha1))
 		return 0;
@@ -251,11 +258,21 @@
 	if (ambiguous_path(str, len))
 		return -1;
 
-	for (p = prefix; *p; p++) {
-		char *pathname = git_path("%s/%.*s", *p, len, str);
-		if (!read_ref(pathname, sha1))
-			return 0;
+	for (p = fmt; *p; p++) {
+		this_result = already_found ? sha1_from_ref : sha1;
+		pathname = git_path(*p, len, str);
+		if (!read_ref(pathname, this_result)) {
+			if (warn_ambiguous_refs) {
+				if (already_found)
+					fprintf(stderr, warning, len, str);
+				already_found++;
+			}
+			else
+				return 0;
+		}
 	}
+	if (already_found)
+		return 0;
 	return -1;
 }
 
diff --git a/t/t4001-diff-rename.sh b/t/t4001-diff-rename.sh
index 2e3c20d..08c1131 100755
--- a/t/t4001-diff-rename.sh
+++ b/t/t4001-diff-rename.sh
@@ -49,7 +49,7 @@
 rename to path1
 --- a/path0
 +++ b/path1
-@@ -8,7 +8,7 @@ Line 7
+@@ -8,7 +8,7 @@
  Line 8
  Line 9
  Line 10
diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
index adc5e93..278eb66 100755
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -34,6 +34,9 @@
      mkdir a/bin &&
      cp /bin/sh a/bin &&
      ln -s a a/l1 &&
+     (p=long_path_to_a_file && cd a &&
+      for depth in 1 2 3 4 5; do mkdir $p && cd $p; done &&
+      echo text >file_with_long_path) &&
      (cd a && find .) | sort >a.lst'
 
 test_expect_success \
diff --git a/tar-tree.c b/tar-tree.c
index e478e13..8d9e31c 100644
--- a/tar-tree.c
+++ b/tar-tree.c
@@ -1,37 +1,23 @@
 /*
- * Copyright (c) 2005 Rene Scharfe
+ * Copyright (c) 2005, 2006 Rene Scharfe
  */
 #include <time.h>
 #include "cache.h"
 #include "diff.h"
 #include "commit.h"
+#include "strbuf.h"
+#include "tar.h"
 
 #define RECORDSIZE	(512)
 #define BLOCKSIZE	(RECORDSIZE * 20)
 
-#define TYPEFLAG_AUTO		'\0'
-#define TYPEFLAG_REG		'0'
-#define TYPEFLAG_LNK		'2'
-#define TYPEFLAG_DIR		'5'
-#define TYPEFLAG_GLOBAL_HEADER	'g'
-#define TYPEFLAG_EXT_HEADER	'x'
-
-#define EXT_HEADER_PATH		1
-#define EXT_HEADER_LINKPATH	2
-
 static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";
 
 static char block[BLOCKSIZE];
 static unsigned long offset;
 
-static const char *basedir;
 static time_t archive_time;
 
-struct path_prefix {
-	struct path_prefix *prev;
-	const char *name;
-};
-
 /* tries hard to write, either succeeds or dies in the attempt */
 static void reliable_write(void *buf, unsigned long size)
 {
@@ -119,230 +105,170 @@
 	write_if_needed();
 }
 
-static void append_string(char **p, const char *s)
+static void strbuf_append_string(struct strbuf *sb, const char *s)
 {
-	unsigned int len = strlen(s);
-	memcpy(*p, s, len);
-	*p += len;
-}
-
-static void append_char(char **p, char c)
-{
-	**p = c;
-	*p += 1;
-}
-
-static void append_path_prefix(char **buffer, struct path_prefix *prefix)
-{
-	if (!prefix)
-		return;
-	append_path_prefix(buffer, prefix->prev);
-	append_string(buffer, prefix->name);
-	append_char(buffer, '/');
-}
-
-static unsigned int path_prefix_len(struct path_prefix *prefix)
-{
-	if (!prefix)
-		return 0;
-	return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1;
-}
-
-static void append_path(char **p, int is_dir, const char *basepath,
-                        struct path_prefix *prefix, const char *path)
-{
-	if (basepath) {
-		append_string(p, basepath);
-		append_char(p, '/');
+	int slen = strlen(s);
+	int total = sb->len + slen;
+	if (total > sb->alloc) {
+		sb->buf = xrealloc(sb->buf, total);
+		sb->alloc = total;
 	}
-	append_path_prefix(p, prefix);
-	append_string(p, path);
-	if (is_dir)
-		append_char(p, '/');
+	memcpy(sb->buf + sb->len, s, slen);
+	sb->len = total;
 }
 
-static unsigned int path_len(int is_dir, const char *basepath,
-                             struct path_prefix *prefix, const char *path)
+/*
+ * pax extended header records have the format "%u %s=%s\n".  %u contains
+ * the size of the whole string (including the %u), the first %s is the
+ * keyword, the second one is the value.  This function constructs such a
+ * string and appends it to a struct strbuf.
+ */
+static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
+                                     const char *value, unsigned int valuelen)
 {
-	unsigned int len = 0;
-	if (basepath)
-		len += strlen(basepath) + 1;
-	len += path_prefix_len(prefix) + strlen(path);
-	if (is_dir)
-		len++;
-	return len;
-}
+	char *p;
+	int len, total, tmp;
 
-static void append_extended_header_prefix(char **p, unsigned int size,
-                                          const char *keyword)
-{
-	int len = sprintf(*p, "%u %s=", size, keyword);
-	*p += len;
-}
-
-static unsigned int extended_header_len(const char *keyword,
-                                        unsigned int valuelen)
-{
 	/* "%u %s=%s\n" */
-	unsigned int len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
-	if (len > 9)
+	len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
+	for (tmp = len; tmp > 9; tmp /= 10)
 		len++;
-	if (len > 99)
-		len++;
-	return len;
-}
 
-static void append_extended_header(char **p, const char *keyword,
-                                   const char *value, unsigned int len)
-{
-	unsigned int size = extended_header_len(keyword, len);
-	append_extended_header_prefix(p, size, keyword);
-	memcpy(*p, value, len);
-	*p += len;
-	append_char(p, '\n');
-}
-
-static void write_header(const unsigned char *, char, const char *, struct path_prefix *,
-                         const char *, unsigned int, void *, unsigned long);
-
-/* stores a pax extended header directly in the block buffer */
-static void write_extended_header(const char *headerfilename, int is_dir,
-                                  unsigned int flags, const char *basepath,
-                                  struct path_prefix *prefix,
-                                  const char *path, unsigned int namelen,
-                                  void *content, unsigned int contentsize)
-{
-	char *buffer, *p;
-	unsigned int pathlen, size, linkpathlen = 0;
-
-	size = pathlen = extended_header_len("path", namelen);
-	if (flags & EXT_HEADER_LINKPATH) {
-		linkpathlen = extended_header_len("linkpath", contentsize);
-		size += linkpathlen;
+	total = sb->len + len;
+	if (total > sb->alloc) {
+		sb->buf = xrealloc(sb->buf, total);
+		sb->alloc = total;
 	}
-	write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
-	             0100600, NULL, size);
 
-	buffer = p = malloc(size);
-	if (!buffer)
-		die("git-tar-tree: %s", strerror(errno));
-	append_extended_header_prefix(&p, pathlen, "path");
-	append_path(&p, is_dir, basepath, prefix, path);
-	append_char(&p, '\n');
-	if (flags & EXT_HEADER_LINKPATH)
-		append_extended_header(&p, "linkpath", content, contentsize);
-	write_blocked(buffer, size);
-	free(buffer);
+	p = sb->buf;
+	p += sprintf(p, "%u %s=", len, keyword);
+	memcpy(p, value, valuelen);
+	p += valuelen;
+	*p = '\n';
+	sb->len = total;
+}
+
+static unsigned int ustar_header_chksum(const struct ustar_header *header)
+{
+	char *p = (char *)header;
+	unsigned int chksum = 0;
+	while (p < header->chksum)
+		chksum += *p++;
+	chksum += sizeof(header->chksum) * ' ';
+	p += sizeof(header->chksum);
+	while (p < (char *)header + sizeof(struct ustar_header))
+		chksum += *p++;
+	return chksum;
+}
+
+static int get_path_prefix(const struct strbuf *path, int maxlen)
+{
+	int i = path->len;
+	if (i > maxlen)
+		i = maxlen;
+	while (i > 0 && path->buf[i] != '/')
+		i--;
+	return i;
+}
+
+static void write_entry(const unsigned char *sha1, struct strbuf *path,
+                        unsigned int mode, void *buffer, unsigned long size)
+{
+	struct ustar_header header;
+	struct strbuf ext_header;
+
+	memset(&header, 0, sizeof(header));
+	ext_header.buf = NULL;
+	ext_header.len = ext_header.alloc = 0;
+
+	if (!sha1) {
+		*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
+		mode = 0100666;
+		strcpy(header.name, "pax_global_header");
+	} else if (!path) {
+		*header.typeflag = TYPEFLAG_EXT_HEADER;
+		mode = 0100666;
+		sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
+	} else {
+		if (S_ISDIR(mode)) {
+			*header.typeflag = TYPEFLAG_DIR;
+			mode |= 0777;
+		} else if (S_ISLNK(mode)) {
+			*header.typeflag = TYPEFLAG_LNK;
+			mode |= 0777;
+		} else if (S_ISREG(mode)) {
+			*header.typeflag = TYPEFLAG_REG;
+			mode |= (mode & 0100) ? 0777 : 0666;
+		} else {
+			error("unsupported file mode: 0%o (SHA1: %s)",
+			      mode, sha1_to_hex(sha1));
+			return;
+		}
+		if (path->len > sizeof(header.name)) {
+			int plen = get_path_prefix(path, sizeof(header.prefix));
+			int rest = path->len - plen - 1;
+			if (plen > 0 && rest <= sizeof(header.name)) {
+				memcpy(header.prefix, path->buf, plen);
+				memcpy(header.name, path->buf + plen + 1, rest);
+			} else {
+				sprintf(header.name, "%s.data",
+				        sha1_to_hex(sha1));
+				strbuf_append_ext_header(&ext_header, "path",
+				                         path->buf, path->len);
+			}
+		} else
+			memcpy(header.name, path->buf, path->len);
+	}
+
+	if (S_ISLNK(mode) && buffer) {
+		if (size > sizeof(header.linkname)) {
+			sprintf(header.linkname, "see %s.paxheader",
+			        sha1_to_hex(sha1));
+			strbuf_append_ext_header(&ext_header, "linkpath",
+			                         buffer, size);
+		} else
+			memcpy(header.linkname, buffer, size);
+	}
+
+	sprintf(header.mode, "%07o", mode & 07777);
+	sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
+	sprintf(header.mtime, "%011lo", archive_time);
+
+	/* XXX: should we provide more meaningful info here? */
+	sprintf(header.uid, "%07o", 0);
+	sprintf(header.gid, "%07o", 0);
+	strncpy(header.uname, "git", 31);
+	strncpy(header.gname, "git", 31);
+	sprintf(header.devmajor, "%07o", 0);
+	sprintf(header.devminor, "%07o", 0);
+
+	memcpy(header.magic, "ustar", 6);
+	memcpy(header.version, "00", 2);
+
+	sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
+
+	if (ext_header.len > 0) {
+		write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
+		free(ext_header.buf);
+	}
+	write_blocked(&header, sizeof(header));
+	if (S_ISREG(mode) && buffer && size > 0)
+		write_blocked(buffer, size);
 }
 
 static void write_global_extended_header(const unsigned char *sha1)
 {
-	char *p;
-	unsigned int size;
-
-	size = extended_header_len("comment", 40);
-	write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
-	             "pax_global_header", 0100600, NULL, size);
-
-	p = get_record();
-	append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
-	write_if_needed();
+	struct strbuf ext_header;
+	ext_header.buf = NULL;
+	ext_header.len = ext_header.alloc = 0;
+	strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
+	write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
+	free(ext_header.buf);
 }
 
-/* stores a ustar header directly in the block buffer */
-static void write_header(const unsigned char *sha1, char typeflag, const char *basepath,
-                         struct path_prefix *prefix, const char *path,
-                         unsigned int mode, void *buffer, unsigned long size)
+static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
 {
-	unsigned int namelen; 
-	char *header = NULL;
-	unsigned int checksum = 0;
-	int i;
-	unsigned int ext_header = 0;
-
-	if (typeflag == TYPEFLAG_AUTO) {
-		if (S_ISDIR(mode))
-			typeflag = TYPEFLAG_DIR;
-		else if (S_ISLNK(mode))
-			typeflag = TYPEFLAG_LNK;
-		else
-			typeflag = TYPEFLAG_REG;
-	}
-
-	namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
-	if (namelen > 100)
-		ext_header |= EXT_HEADER_PATH;
-	if (typeflag == TYPEFLAG_LNK && size > 100)
-		ext_header |= EXT_HEADER_LINKPATH;
-
-	/* the extended header must be written before the normal one */
-	if (ext_header) {
-		char headerfilename[51];
-		sprintf(headerfilename, "%s.paxheader", sha1_to_hex(sha1));
-		write_extended_header(headerfilename, S_ISDIR(mode),
-		                      ext_header, basepath, prefix, path,
-		                      namelen, buffer, size);
-	}
-
-	header = get_record();
-
-	if (ext_header) {
-		sprintf(header, "%s.data", sha1_to_hex(sha1));
-	} else {
-		char *p = header;
-		append_path(&p, S_ISDIR(mode), basepath, prefix, path);
-	}
-
-	if (typeflag == TYPEFLAG_LNK) {
-		if (ext_header & EXT_HEADER_LINKPATH) {
-			sprintf(&header[157], "see %s.paxheader",
-			        sha1_to_hex(sha1));
-		} else {
-			if (buffer)
-				strncpy(&header[157], buffer, size);
-		}
-	}
-
-	if (S_ISDIR(mode))
-		mode |= 0777;
-	else if (S_ISREG(mode))
-		mode |= (mode & 0100) ? 0777 : 0666;
-	else if (S_ISLNK(mode))
-		mode |= 0777;
-	sprintf(&header[100], "%07o", mode & 07777);
-
-	/* XXX: should we provide more meaningful info here? */
-	sprintf(&header[108], "%07o", 0);	/* uid */
-	sprintf(&header[116], "%07o", 0);	/* gid */
-	strncpy(&header[265], "git", 31);	/* uname */
-	strncpy(&header[297], "git", 31);	/* gname */
-
-	if (S_ISDIR(mode) || S_ISLNK(mode))
-		size = 0;
-	sprintf(&header[124], "%011lo", size);
-	sprintf(&header[136], "%011lo", archive_time);
-
-	header[156] = typeflag;
-
-	memcpy(&header[257], "ustar", 6);
-	memcpy(&header[263], "00", 2);
-
-	sprintf(&header[329], "%07o", 0);	/* devmajor */
-	sprintf(&header[337], "%07o", 0);	/* devminor */
-
-	memset(&header[148], ' ', 8);
-	for (i = 0; i < RECORDSIZE; i++)
-		checksum += header[i];
-	sprintf(&header[148], "%07o", checksum & 0x1fffff);
-
-	write_if_needed();
-}
-
-static void traverse_tree(struct tree_desc *tree,
-			  struct path_prefix *prefix)
-{
-	struct path_prefix this_prefix;
-	this_prefix.prev = prefix;
+	int pathlen = path->len;
 
 	while (tree->size) {
 		const char *name;
@@ -358,16 +284,19 @@
 		eltbuf = read_sha1_file(sha1, elttype, &eltsize);
 		if (!eltbuf)
 			die("cannot read %s", sha1_to_hex(sha1));
-		write_header(sha1, TYPEFLAG_AUTO, basedir, 
-			     prefix, name, mode, eltbuf, eltsize);
+
+		path->len = pathlen;
+		strbuf_append_string(path, name);
+		if (S_ISDIR(mode))
+			strbuf_append_string(path, "/");
+
+		write_entry(sha1, path, mode, eltbuf, eltsize);
+
 		if (S_ISDIR(mode)) {
 			struct tree_desc subtree;
 			subtree.buf = eltbuf;
 			subtree.size = eltsize;
-			this_prefix.name = name;
-			traverse_tree(&subtree, &this_prefix);
-		} else if (!S_ISLNK(mode)) {
-			write_blocked(eltbuf, eltsize);
+			traverse_tree(&subtree, path);
 		}
 		free(eltbuf);
 	}
@@ -375,15 +304,22 @@
 
 int main(int argc, char **argv)
 {
-	unsigned char sha1[20];
+	unsigned char sha1[20], tree_sha1[20];
 	struct commit *commit;
 	struct tree_desc tree;
+	struct strbuf current_path;
+
+	current_path.buf = xmalloc(PATH_MAX);
+	current_path.alloc = PATH_MAX;
+	current_path.len = current_path.eof = 0;
 
 	setup_git_directory();
+	git_config(git_default_config);
 
 	switch (argc) {
 	case 3:
-		basedir = argv[2];
+		strbuf_append_string(&current_path, argv[2]);
+		strbuf_append_string(&current_path, "/");
 		/* FALLTHROUGH */
 	case 2:
 		if (get_sha1(argv[1], sha1) < 0)
@@ -397,17 +333,19 @@
 	if (commit) {
 		write_global_extended_header(commit->object.sha1);
 		archive_time = commit->date;
-	}
-	tree.buf = read_object_with_reference(sha1, "tree", &tree.size, NULL);
+	} else
+		archive_time = time(NULL);
+
+	tree.buf = read_object_with_reference(sha1, "tree", &tree.size,
+	                                      tree_sha1);
 	if (!tree.buf)
 		die("not a reference to a tag, commit or tree object: %s",
 		    sha1_to_hex(sha1));
-	if (!archive_time)
-		archive_time = time(NULL);
-	if (basedir)
-		write_header((unsigned char *)"0", TYPEFLAG_DIR, NULL, NULL,
-			basedir, 040777, NULL, 0);
-	traverse_tree(&tree, NULL);
+
+	if (current_path.len > 0)
+		write_entry(tree_sha1, &current_path, 040777, NULL, 0);
+	traverse_tree(&tree, &current_path);
 	write_trailer();
+	free(current_path.buf);
 	return 0;
 }
diff --git a/tar.h b/tar.h
new file mode 100644
index 0000000..3467705
--- /dev/null
+++ b/tar.h
@@ -0,0 +1,25 @@
+#define TYPEFLAG_AUTO		'\0'
+#define TYPEFLAG_REG		'0'
+#define TYPEFLAG_LNK		'2'
+#define TYPEFLAG_DIR		'5'
+#define TYPEFLAG_GLOBAL_HEADER	'g'
+#define TYPEFLAG_EXT_HEADER	'x'
+
+struct ustar_header {
+	char name[100];		/*   0 */
+	char mode[8];		/* 100 */
+	char uid[8];		/* 108 */
+	char gid[8];		/* 116 */
+	char size[12];		/* 124 */
+	char mtime[12];		/* 136 */
+	char chksum[8];		/* 148 */
+	char typeflag[1];	/* 156 */
+	char linkname[100];	/* 157 */
+	char magic[6];		/* 257 */
+	char version[2];	/* 263 */
+	char uname[32];		/* 265 */
+	char gname[32];		/* 297 */
+	char devmajor[8];	/* 329 */
+	char devminor[8];	/* 337 */
+	char prefix[155];	/* 345 */
+};
diff --git a/unpack-file.c b/unpack-file.c
index 07303f8..3accb97 100644
--- a/unpack-file.c
+++ b/unpack-file.c
@@ -30,6 +30,7 @@
 		usage("git-unpack-file <sha1>");
 
 	setup_git_directory();
+	git_config(git_default_config);
 
 	puts(create_temp_file(sha1));
 	return 0;
diff --git a/update-ref.c b/update-ref.c
index e6fbddb..ba4bf51 100644
--- a/update-ref.c
+++ b/update-ref.c
@@ -25,6 +25,7 @@
 	int fd, written;
 
 	setup_git_directory();
+	git_config(git_default_config);
 	if (argc < 3 || argc > 4)
 		usage(git_update_ref_usage);
 
diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
new file mode 100644
index 0000000..71cb939
--- /dev/null
+++ b/xdiff/xdiff.h
@@ -0,0 +1,91 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XDIFF_H)
+#define XDIFF_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* #ifdef __cplusplus */
+
+
+#define XDF_NEED_MINIMAL (1 << 1)
+
+#define XDL_PATCH_NORMAL '-'
+#define XDL_PATCH_REVERSE '+'
+#define XDL_PATCH_MODEMASK ((1 << 8) - 1)
+#define XDL_PATCH_IGNOREBSPACE (1 << 8)
+
+#define XDL_MMB_READONLY (1 << 0)
+
+#define XDL_MMF_ATOMIC (1 << 0)
+
+#define XDL_BDOP_INS 1
+#define XDL_BDOP_CPY 2
+#define XDL_BDOP_INSB 3
+
+
+typedef struct s_mmfile {
+	char *ptr;
+	long size;
+} mmfile_t;
+
+typedef struct s_mmbuffer {
+	char *ptr;
+	long size;
+} mmbuffer_t;
+
+typedef struct s_xpparam {
+	unsigned long flags;
+} xpparam_t;
+
+typedef struct s_xdemitcb {
+	void *priv;
+	int (*outf)(void *, mmbuffer_t *, int);
+} xdemitcb_t;
+
+typedef struct s_xdemitconf {
+	long ctxlen;
+} xdemitconf_t;
+
+typedef struct s_bdiffparam {
+	long bsize;
+} bdiffparam_t;
+
+
+#define xdl_malloc(x) malloc(x)
+#define xdl_free(ptr) free(ptr)
+#define xdl_realloc(ptr,x) realloc(ptr,x)
+
+void *xdl_mmfile_first(mmfile_t *mmf, long *size);
+void *xdl_mmfile_next(mmfile_t *mmf, long *size);
+long xdl_mmfile_size(mmfile_t *mmf);
+
+int xdl_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+	     xdemitconf_t const *xecfg, xdemitcb_t *ecb);
+
+#ifdef __cplusplus
+}
+#endif /* #ifdef __cplusplus */
+
+#endif /* #if !defined(XDIFF_H) */
+
diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
new file mode 100644
index 0000000..8ea0483
--- /dev/null
+++ b/xdiff/xdiffi.c
@@ -0,0 +1,469 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003	Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+
+
+#define XDL_MAX_COST_MIN 256
+#define XDL_HEUR_MIN_COST 256
+#define XDL_LINE_MAX (long)((1UL << (8 * sizeof(long) - 1)) - 1)
+#define XDL_SNAKE_CNT 20
+#define XDL_K_HEUR 4
+
+
+
+typedef struct s_xdpsplit {
+	long i1, i2;
+	int min_lo, min_hi;
+} xdpsplit_t;
+
+
+
+
+static long xdl_split(unsigned long const *ha1, long off1, long lim1,
+		      unsigned long const *ha2, long off2, long lim2,
+		      long *kvdf, long *kvdb, int need_min, xdpsplit_t *spl,
+		      xdalgoenv_t *xenv);
+static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1, long chg2);
+
+
+
+
+/*
+ * See "An O(ND) Difference Algorithm and its Variations", by Eugene Myers.
+ * Basically considers a "box" (off1, off2, lim1, lim2) and scan from both
+ * the forward diagonal starting from (off1, off2) and the backward diagonal
+ * starting from (lim1, lim2). If the K values on the same diagonal crosses
+ * returns the furthest point of reach. We might end up having to expensive
+ * cases using this algorithm is full, so a little bit of heuristic is needed
+ * to cut the search and to return a suboptimal point.
+ */
+static long xdl_split(unsigned long const *ha1, long off1, long lim1,
+		      unsigned long const *ha2, long off2, long lim2,
+		      long *kvdf, long *kvdb, int need_min, xdpsplit_t *spl,
+		      xdalgoenv_t *xenv) {
+	long dmin = off1 - lim2, dmax = lim1 - off2;
+	long fmid = off1 - off2, bmid = lim1 - lim2;
+	long odd = (fmid - bmid) & 1;
+	long fmin = fmid, fmax = fmid;
+	long bmin = bmid, bmax = bmid;
+	long ec, d, i1, i2, prev1, best, dd, v, k;
+
+	/*
+	 * Set initial diagonal values for both forward and backward path.
+	 */
+	kvdf[fmid] = off1;
+	kvdb[bmid] = lim1;
+
+	for (ec = 1;; ec++) {
+		int got_snake = 0;
+
+		/*
+		 * We need to extent the diagonal "domain" by one. If the next
+		 * values exits the box boundaries we need to change it in the
+		 * opposite direction because (max - min) must be a power of two.
+		 * Also we initialize the extenal K value to -1 so that we can
+		 * avoid extra conditions check inside the core loop.
+		 */
+		if (fmin > dmin)
+			kvdf[--fmin - 1] = -1;
+		else
+			++fmin;
+		if (fmax < dmax)
+			kvdf[++fmax + 1] = -1;
+		else
+			--fmax;
+
+		for (d = fmax; d >= fmin; d -= 2) {
+			if (kvdf[d - 1] >= kvdf[d + 1])
+				i1 = kvdf[d - 1] + 1;
+			else
+				i1 = kvdf[d + 1];
+			prev1 = i1;
+			i2 = i1 - d;
+			for (; i1 < lim1 && i2 < lim2 && ha1[i1] == ha2[i2]; i1++, i2++);
+			if (i1 - prev1 > xenv->snake_cnt)
+				got_snake = 1;
+			kvdf[d] = i1;
+			if (odd && bmin <= d && d <= bmax && kvdb[d] <= i1) {
+				spl->i1 = i1;
+				spl->i2 = i2;
+				spl->min_lo = spl->min_hi = 1;
+				return ec;
+			}
+		}
+
+		/*
+		 * We need to extent the diagonal "domain" by one. If the next
+		 * values exits the box boundaries we need to change it in the
+		 * opposite direction because (max - min) must be a power of two.
+		 * Also we initialize the extenal K value to -1 so that we can
+		 * avoid extra conditions check inside the core loop.
+		 */
+		if (bmin > dmin)
+			kvdb[--bmin - 1] = XDL_LINE_MAX;
+		else
+			++bmin;
+		if (bmax < dmax)
+			kvdb[++bmax + 1] = XDL_LINE_MAX;
+		else
+			--bmax;
+
+		for (d = bmax; d >= bmin; d -= 2) {
+			if (kvdb[d - 1] < kvdb[d + 1])
+				i1 = kvdb[d - 1];
+			else
+				i1 = kvdb[d + 1] - 1;
+			prev1 = i1;
+			i2 = i1 - d;
+			for (; i1 > off1 && i2 > off2 && ha1[i1 - 1] == ha2[i2 - 1]; i1--, i2--);
+			if (prev1 - i1 > xenv->snake_cnt)
+				got_snake = 1;
+			kvdb[d] = i1;
+			if (!odd && fmin <= d && d <= fmax && i1 <= kvdf[d]) {
+				spl->i1 = i1;
+				spl->i2 = i2;
+				spl->min_lo = spl->min_hi = 1;
+				return ec;
+			}
+		}
+
+		if (need_min)
+			continue;
+
+		/*
+		 * If the edit cost is above the heuristic trigger and if
+		 * we got a good snake, we sample current diagonals to see
+		 * if some of the, have reached an "interesting" path. Our
+		 * measure is a function of the distance from the diagonal
+		 * corner (i1 + i2) penalized with the distance from the
+		 * mid diagonal itself. If this value is above the current
+		 * edit cost times a magic factor (XDL_K_HEUR) we consider
+		 * it interesting.
+		 */
+		if (got_snake && ec > xenv->heur_min) {
+			for (best = 0, d = fmax; d >= fmin; d -= 2) {
+				dd = d > fmid ? d - fmid: fmid - d;
+				i1 = kvdf[d];
+				i2 = i1 - d;
+				v = (i1 - off1) + (i2 - off2) - dd;
+
+				if (v > XDL_K_HEUR * ec && v > best &&
+				    off1 + xenv->snake_cnt <= i1 && i1 < lim1 &&
+				    off2 + xenv->snake_cnt <= i2 && i2 < lim2) {
+					for (k = 1; ha1[i1 - k] == ha2[i2 - k]; k++)
+						if (k == xenv->snake_cnt) {
+							best = v;
+							spl->i1 = i1;
+							spl->i2 = i2;
+							break;
+						}
+				}
+			}
+			if (best > 0) {
+				spl->min_lo = 1;
+				spl->min_hi = 0;
+				return ec;
+			}
+
+			for (best = 0, d = bmax; d >= bmin; d -= 2) {
+				dd = d > bmid ? d - bmid: bmid - d;
+				i1 = kvdb[d];
+				i2 = i1 - d;
+				v = (lim1 - i1) + (lim2 - i2) - dd;
+
+				if (v > XDL_K_HEUR * ec && v > best &&
+				    off1 < i1 && i1 <= lim1 - xenv->snake_cnt &&
+				    off2 < i2 && i2 <= lim2 - xenv->snake_cnt) {
+					for (k = 0; ha1[i1 + k] == ha2[i2 + k]; k++)
+						if (k == xenv->snake_cnt - 1) {
+							best = v;
+							spl->i1 = i1;
+							spl->i2 = i2;
+							break;
+						}
+				}
+			}
+			if (best > 0) {
+				spl->min_lo = 0;
+				spl->min_hi = 1;
+				return ec;
+			}
+		}
+
+		/*
+		 * Enough is enough. We spent too much time here and now we collect
+		 * the furthest reaching path using the (i1 + i2) measure.
+		 */
+		if (ec >= xenv->mxcost) {
+			long fbest, fbest1, bbest, bbest1;
+
+			fbest = -1;
+			for (d = fmax; d >= fmin; d -= 2) {
+				i1 = XDL_MIN(kvdf[d], lim1);
+				i2 = i1 - d;
+				if (lim2 < i2)
+					i1 = lim2 + d, i2 = lim2;
+				if (fbest < i1 + i2) {
+					fbest = i1 + i2;
+					fbest1 = i1;
+				}
+			}
+
+			bbest = XDL_LINE_MAX;
+			for (d = bmax; d >= bmin; d -= 2) {
+				i1 = XDL_MAX(off1, kvdb[d]);
+				i2 = i1 - d;
+				if (i2 < off2)
+					i1 = off2 + d, i2 = off2;
+				if (i1 + i2 < bbest) {
+					bbest = i1 + i2;
+					bbest1 = i1;
+				}
+			}
+
+			if ((lim1 + lim2) - bbest < fbest - (off1 + off2)) {
+				spl->i1 = fbest1;
+				spl->i2 = fbest - fbest1;
+				spl->min_lo = 1;
+				spl->min_hi = 0;
+			} else {
+				spl->i1 = bbest1;
+				spl->i2 = bbest - bbest1;
+				spl->min_lo = 0;
+				spl->min_hi = 1;
+			}
+			return ec;
+		}
+	}
+
+	return -1;
+}
+
+
+/*
+ * Rule: "Divide et Impera". Recursively split the box in sub-boxes by calling
+ * the box splitting function. Note that the real job (marking changed lines)
+ * is done in the two boundary reaching checks.
+ */
+int xdl_recs_cmp(diffdata_t *dd1, long off1, long lim1,
+		 diffdata_t *dd2, long off2, long lim2,
+		 long *kvdf, long *kvdb, int need_min, xdalgoenv_t *xenv) {
+	unsigned long const *ha1 = dd1->ha, *ha2 = dd2->ha;
+
+	/*
+	 * Shrink the box by walking through each diagonal snake (SW and NE).
+	 */
+	for (; off1 < lim1 && off2 < lim2 && ha1[off1] == ha2[off2]; off1++, off2++);
+	for (; off1 < lim1 && off2 < lim2 && ha1[lim1 - 1] == ha2[lim2 - 1]; lim1--, lim2--);
+
+	/*
+	 * If one dimension is empty, then all records on the other one must
+	 * be obviously changed.
+	 */
+	if (off1 == lim1) {
+		char *rchg2 = dd2->rchg;
+		long *rindex2 = dd2->rindex;
+
+		for (; off2 < lim2; off2++)
+			rchg2[rindex2[off2]] = 1;
+	} else if (off2 == lim2) {
+		char *rchg1 = dd1->rchg;
+		long *rindex1 = dd1->rindex;
+
+		for (; off1 < lim1; off1++)
+			rchg1[rindex1[off1]] = 1;
+	} else {
+		long ec;
+		xdpsplit_t spl;
+
+		/*
+		 * Divide ...
+		 */
+		if ((ec = xdl_split(ha1, off1, lim1, ha2, off2, lim2, kvdf, kvdb,
+				    need_min, &spl, xenv)) < 0) {
+
+			return -1;
+		}
+
+		/*
+		 * ... et Impera.
+		 */
+		if (xdl_recs_cmp(dd1, off1, spl.i1, dd2, off2, spl.i2,
+				 kvdf, kvdb, spl.min_lo, xenv) < 0 ||
+		    xdl_recs_cmp(dd1, spl.i1, lim1, dd2, spl.i2, lim2,
+				 kvdf, kvdb, spl.min_hi, xenv) < 0) {
+
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+
+int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+		xdfenv_t *xe) {
+	long ndiags;
+	long *kvd, *kvdf, *kvdb;
+	xdalgoenv_t xenv;
+	diffdata_t dd1, dd2;
+
+	if (xdl_prepare_env(mf1, mf2, xpp, xe) < 0) {
+
+		return -1;
+	}
+
+	/*
+	 * Allocate and setup K vectors to be used by the differential algorithm.
+	 * One is to store the forward path and one to store the backward path.
+	 */
+	ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3;
+	if (!(kvd = (long *) xdl_malloc((2 * ndiags + 2) * sizeof(long)))) {
+
+		xdl_free_env(xe);
+		return -1;
+	}
+	kvdf = kvd;
+	kvdb = kvdf + ndiags;
+	kvdf += xe->xdf2.nreff + 1;
+	kvdb += xe->xdf2.nreff + 1;
+
+	/*
+	 * Classical integer square root approximation using shifts.
+	 */
+	xenv.mxcost = 1;
+	for (; ndiags; ndiags >>= 2)
+		xenv.mxcost <<= 1;
+	if (xenv.mxcost < XDL_MAX_COST_MIN)
+		xenv.mxcost = XDL_MAX_COST_MIN;
+	xenv.snake_cnt = XDL_SNAKE_CNT;
+	xenv.heur_min = XDL_HEUR_MIN_COST;
+
+	dd1.nrec = xe->xdf1.nreff;
+	dd1.ha = xe->xdf1.ha;
+	dd1.rchg = xe->xdf1.rchg;
+	dd1.rindex = xe->xdf1.rindex;
+	dd2.nrec = xe->xdf2.nreff;
+	dd2.ha = xe->xdf2.ha;
+	dd2.rchg = xe->xdf2.rchg;
+	dd2.rindex = xe->xdf2.rindex;
+
+	if (xdl_recs_cmp(&dd1, 0, dd1.nrec, &dd2, 0, dd2.nrec,
+			 kvdf, kvdb, (xpp->flags & XDF_NEED_MINIMAL) != 0, &xenv) < 0) {
+
+		xdl_free(kvd);
+		xdl_free_env(xe);
+		return -1;
+	}
+
+	xdl_free(kvd);
+
+	return 0;
+}
+
+
+static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1, long chg2) {
+	xdchange_t *xch;
+
+	if (!(xch = (xdchange_t *) xdl_malloc(sizeof(xdchange_t))))
+		return NULL;
+
+	xch->next = xscr;
+	xch->i1 = i1;
+	xch->i2 = i2;
+	xch->chg1 = chg1;
+	xch->chg2 = chg2;
+
+	return xch;
+}
+
+
+int xdl_build_script(xdfenv_t *xe, xdchange_t **xscr) {
+	xdchange_t *cscr = NULL, *xch;
+	char *rchg1 = xe->xdf1.rchg, *rchg2 = xe->xdf2.rchg;
+	long i1, i2, l1, l2;
+
+	/*
+	 * Trivial. Collects "groups" of changes and creates an edit script.
+	 */
+	for (i1 = xe->xdf1.nrec, i2 = xe->xdf2.nrec; i1 >= 0 || i2 >= 0; i1--, i2--)
+		if (rchg1[i1 - 1] || rchg2[i2 - 1]) {
+			for (l1 = i1; rchg1[i1 - 1]; i1--);
+			for (l2 = i2; rchg2[i2 - 1]; i2--);
+
+			if (!(xch = xdl_add_change(cscr, i1, i2, l1 - i1, l2 - i2))) {
+				xdl_free_script(cscr);
+				return -1;
+			}
+			cscr = xch;
+		}
+
+	*xscr = cscr;
+
+	return 0;
+}
+
+
+void xdl_free_script(xdchange_t *xscr) {
+	xdchange_t *xch;
+
+	while ((xch = xscr) != NULL) {
+		xscr = xscr->next;
+		xdl_free(xch);
+	}
+}
+
+
+int xdl_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+	     xdemitconf_t const *xecfg, xdemitcb_t *ecb) {
+	xdchange_t *xscr;
+	xdfenv_t xe;
+
+	if (xdl_do_diff(mf1, mf2, xpp, &xe) < 0) {
+
+		return -1;
+	}
+
+	if (xdl_build_script(&xe, &xscr) < 0) {
+
+		xdl_free_env(&xe);
+		return -1;
+	}
+
+	if (xscr) {
+		if (xdl_emit_diff(&xe, xscr, ecb, xecfg) < 0) {
+
+			xdl_free_script(xscr);
+			xdl_free_env(&xe);
+			return -1;
+		}
+
+		xdl_free_script(xscr);
+	}
+
+	xdl_free_env(&xe);
+
+	return 0;
+}
+
diff --git a/xdiff/xdiffi.h b/xdiff/xdiffi.h
new file mode 100644
index 0000000..dd8f3c9
--- /dev/null
+++ b/xdiff/xdiffi.h
@@ -0,0 +1,60 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XDIFFI_H)
+#define XDIFFI_H
+
+
+typedef struct s_diffdata {
+	long nrec;
+	unsigned long const *ha;
+	long *rindex;
+	char *rchg;
+} diffdata_t;
+
+typedef struct s_xdalgoenv {
+	long mxcost;
+	long snake_cnt;
+	long heur_min;
+} xdalgoenv_t;
+
+typedef struct s_xdchange {
+	struct s_xdchange *next;
+	long i1, i2;
+	long chg1, chg2;
+} xdchange_t;
+
+
+
+int xdl_recs_cmp(diffdata_t *dd1, long off1, long lim1,
+		 diffdata_t *dd2, long off2, long lim2,
+		 long *kvdf, long *kvdb, int need_min, xdalgoenv_t *xenv);
+int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+		xdfenv_t *xe);
+int xdl_build_script(xdfenv_t *xe, xdchange_t **xscr);
+void xdl_free_script(xdchange_t *xscr);
+int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+		  xdemitconf_t const *xecfg);
+
+
+#endif /* #if !defined(XDIFFI_H) */
+
diff --git a/xdiff/xemit.c b/xdiff/xemit.c
new file mode 100644
index 0000000..2e5d54c
--- /dev/null
+++ b/xdiff/xemit.c
@@ -0,0 +1,141 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003	Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+
+
+
+static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
+static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
+static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg);
+
+
+
+
+static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
+
+	*rec = xdf->recs[ri]->ptr;
+
+	return xdf->recs[ri]->size;
+}
+
+
+static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
+	long size, psize = strlen(pre);
+	char const *rec;
+
+	size = xdl_get_rec(xdf, ri, &rec);
+	if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
+
+		return -1;
+	}
+
+	return 0;
+}
+
+
+/*
+ * Starting at the passed change atom, find the latest change atom to be included
+ * inside the differential hunk according to the specified configuration.
+ */
+static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
+	xdchange_t *xch, *xchp;
+
+	for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
+		if (xch->i1 - (xchp->i1 + xchp->chg1) > 2 * xecfg->ctxlen)
+			break;
+
+	return xchp;
+}
+
+
+int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+		  xdemitconf_t const *xecfg) {
+	long s1, s2, e1, e2, lctx;
+	xdchange_t *xch, *xche;
+
+	for (xch = xche = xscr; xch; xch = xche->next) {
+		xche = xdl_get_hunk(xch, xecfg);
+
+		s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
+		s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
+
+		lctx = xecfg->ctxlen;
+		lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
+		lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
+
+		e1 = xche->i1 + xche->chg1 + lctx;
+		e2 = xche->i2 + xche->chg2 + lctx;
+
+		/*
+		 * Emit current hunk header.
+		 */
+		if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2, ecb) < 0)
+			return -1;
+
+		/*
+		 * Emit pre-context.
+		 */
+		for (; s1 < xch->i1; s1++)
+			if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
+				return -1;
+
+		for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
+			/*
+			 * Merge previous with current change atom.
+			 */
+			for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
+				if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
+					return -1;
+
+			/*
+			 * Removes lines from the first file.
+			 */
+			for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
+				if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
+					return -1;
+
+			/*
+			 * Adds lines from the second file.
+			 */
+			for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
+				if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
+					return -1;
+
+			if (xch == xche)
+				break;
+			s1 = xch->i1 + xch->chg1;
+			s2 = xch->i2 + xch->chg2;
+		}
+
+		/*
+		 * Emit post-context.
+		 */
+		for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
+			if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
+				return -1;
+	}
+
+	return 0;
+}
+
diff --git a/xdiff/xemit.h b/xdiff/xemit.h
new file mode 100644
index 0000000..e629417
--- /dev/null
+++ b/xdiff/xemit.h
@@ -0,0 +1,34 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XEMIT_H)
+#define XEMIT_H
+
+
+
+int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+		  xdemitconf_t const *xecfg);
+
+
+
+#endif /* #if !defined(XEMIT_H) */
+
diff --git a/xdiff/xinclude.h b/xdiff/xinclude.h
new file mode 100644
index 0000000..9490fc5
--- /dev/null
+++ b/xdiff/xinclude.h
@@ -0,0 +1,42 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XINCLUDE_H)
+#define XINCLUDE_H
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+
+#include "xmacros.h"
+#include "xdiff.h"
+#include "xtypes.h"
+#include "xutils.h"
+#include "xprepare.h"
+#include "xdiffi.h"
+#include "xemit.h"
+
+
+#endif /* #if !defined(XINCLUDE_H) */
+
diff --git a/xdiff/xmacros.h b/xdiff/xmacros.h
new file mode 100644
index 0000000..4c2fde8
--- /dev/null
+++ b/xdiff/xmacros.h
@@ -0,0 +1,53 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XMACROS_H)
+#define XMACROS_H
+
+
+#define GR_PRIME 0x9e370001UL
+
+
+#define XDL_MIN(a, b) ((a) < (b) ? (a): (b))
+#define XDL_MAX(a, b) ((a) > (b) ? (a): (b))
+#define XDL_ABS(v) ((v) >= 0 ? (v): -(v))
+#define XDL_ISDIGIT(c) ((c) >= '0' && (c) <= '9')
+#define XDL_HASHLONG(v, b) (((unsigned long)(v) * GR_PRIME) >> ((CHAR_BIT * sizeof(unsigned long)) - (b)))
+#define XDL_PTRFREE(p) do { if (p) { xdl_free(p); (p) = NULL; } } while (0)
+#define XDL_LE32_PUT(p, v) \
+do { \
+	unsigned char *__p = (unsigned char *) (p); \
+	*__p++ = (unsigned char) (v); \
+	*__p++ = (unsigned char) ((v) >> 8); \
+	*__p++ = (unsigned char) ((v) >> 16); \
+	*__p = (unsigned char) ((v) >> 24); \
+} while (0)
+#define XDL_LE32_GET(p, v) \
+do { \
+	unsigned char const *__p = (unsigned char const *) (p); \
+	(v) = (unsigned long) __p[0] | ((unsigned long) __p[1]) << 8 | \
+		((unsigned long) __p[2]) << 16 | ((unsigned long) __p[3]) << 24; \
+} while (0)
+
+
+#endif /* #if !defined(XMACROS_H) */
+
diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
new file mode 100644
index 0000000..27a0879
--- /dev/null
+++ b/xdiff/xprepare.c
@@ -0,0 +1,436 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+
+
+#define XDL_KPDIS_RUN 4
+
+
+
+typedef struct s_xdlclass {
+	struct s_xdlclass *next;
+	unsigned long ha;
+	char const *line;
+	long size;
+	long idx;
+} xdlclass_t;
+
+typedef struct s_xdlclassifier {
+	unsigned int hbits;
+	long hsize;
+	xdlclass_t **rchash;
+	chastore_t ncha;
+	long count;
+} xdlclassifier_t;
+
+
+
+
+static int xdl_init_classifier(xdlclassifier_t *cf, long size);
+static void xdl_free_classifier(xdlclassifier_t *cf);
+static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits,
+			       xrecord_t *rec);
+static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
+			   xdlclassifier_t *cf, xdfile_t *xdf);
+static void xdl_free_ctx(xdfile_t *xdf);
+static int xdl_clean_mmatch(char const *dis, long i, long s, long e);
+static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2);
+static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2);
+static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2);
+
+
+
+
+static int xdl_init_classifier(xdlclassifier_t *cf, long size) {
+	long i;
+
+	cf->hbits = xdl_hashbits((unsigned int) size);
+	cf->hsize = 1 << cf->hbits;
+
+	if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) {
+
+		return -1;
+	}
+	if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) {
+
+		xdl_cha_free(&cf->ncha);
+		return -1;
+	}
+	for (i = 0; i < cf->hsize; i++)
+		cf->rchash[i] = NULL;
+
+	cf->count = 0;
+
+	return 0;
+}
+
+
+static void xdl_free_classifier(xdlclassifier_t *cf) {
+
+	xdl_free(cf->rchash);
+	xdl_cha_free(&cf->ncha);
+}
+
+
+static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits,
+			       xrecord_t *rec) {
+	long hi;
+	char const *line;
+	xdlclass_t *rcrec;
+
+	line = rec->ptr;
+	hi = (long) XDL_HASHLONG(rec->ha, cf->hbits);
+	for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next)
+		if (rcrec->ha == rec->ha && rcrec->size == rec->size &&
+		    !memcmp(line, rcrec->line, rec->size))
+			break;
+
+	if (!rcrec) {
+		if (!(rcrec = xdl_cha_alloc(&cf->ncha))) {
+
+			return -1;
+		}
+		rcrec->idx = cf->count++;
+		rcrec->line = line;
+		rcrec->size = rec->size;
+		rcrec->ha = rec->ha;
+		rcrec->next = cf->rchash[hi];
+		cf->rchash[hi] = rcrec;
+	}
+
+	rec->ha = (unsigned long) rcrec->idx;
+
+	hi = (long) XDL_HASHLONG(rec->ha, hbits);
+	rec->next = rhash[hi];
+	rhash[hi] = rec;
+
+	return 0;
+}
+
+
+static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
+			   xdlclassifier_t *cf, xdfile_t *xdf) {
+	unsigned int hbits;
+	long i, nrec, hsize, bsize;
+	unsigned long hav;
+	char const *blk, *cur, *top, *prev;
+	xrecord_t *crec;
+	xrecord_t **recs, **rrecs;
+	xrecord_t **rhash;
+	unsigned long *ha;
+	char *rchg;
+	long *rindex;
+
+	if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) {
+
+		return -1;
+	}
+	if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *)))) {
+
+		xdl_cha_free(&xdf->rcha);
+		return -1;
+	}
+
+	hbits = xdl_hashbits((unsigned int) narec);
+	hsize = 1 << hbits;
+	if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *)))) {
+
+		xdl_free(recs);
+		xdl_cha_free(&xdf->rcha);
+		return -1;
+	}
+	for (i = 0; i < hsize; i++)
+		rhash[i] = NULL;
+
+	nrec = 0;
+	if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) {
+		for (top = blk + bsize;;) {
+			if (cur >= top) {
+				if (!(cur = blk = xdl_mmfile_next(mf, &bsize)))
+					break;
+				top = blk + bsize;
+			}
+			prev = cur;
+			hav = xdl_hash_record(&cur, top);
+			if (nrec >= narec) {
+				narec *= 2;
+				if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *)))) {
+
+					xdl_free(rhash);
+					xdl_free(recs);
+					xdl_cha_free(&xdf->rcha);
+					return -1;
+				}
+				recs = rrecs;
+			}
+			if (!(crec = xdl_cha_alloc(&xdf->rcha))) {
+
+				xdl_free(rhash);
+				xdl_free(recs);
+				xdl_cha_free(&xdf->rcha);
+				return -1;
+			}
+			crec->ptr = prev;
+			crec->size = (long) (cur - prev);
+			crec->ha = hav;
+			recs[nrec++] = crec;
+
+			if (xdl_classify_record(cf, rhash, hbits, crec) < 0) {
+
+				xdl_free(rhash);
+				xdl_free(recs);
+				xdl_cha_free(&xdf->rcha);
+				return -1;
+			}
+		}
+	}
+
+	if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char)))) {
+
+		xdl_free(rhash);
+		xdl_free(recs);
+		xdl_cha_free(&xdf->rcha);
+		return -1;
+	}
+	memset(rchg, 0, (nrec + 2) * sizeof(char));
+
+	if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long)))) {
+
+		xdl_free(rchg);
+		xdl_free(rhash);
+		xdl_free(recs);
+		xdl_cha_free(&xdf->rcha);
+		return -1;
+	}
+	if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long)))) {
+
+		xdl_free(rindex);
+		xdl_free(rchg);
+		xdl_free(rhash);
+		xdl_free(recs);
+		xdl_cha_free(&xdf->rcha);
+		return -1;
+	}
+
+	xdf->nrec = nrec;
+	xdf->recs = recs;
+	xdf->hbits = hbits;
+	xdf->rhash = rhash;
+	xdf->rchg = rchg + 1;
+	xdf->rindex = rindex;
+	xdf->nreff = 0;
+	xdf->ha = ha;
+	xdf->dstart = 0;
+	xdf->dend = nrec - 1;
+
+	return 0;
+}
+
+
+static void xdl_free_ctx(xdfile_t *xdf) {
+
+	xdl_free(xdf->rhash);
+	xdl_free(xdf->rindex);
+	xdl_free(xdf->rchg - 1);
+	xdl_free(xdf->ha);
+	xdl_free(xdf->recs);
+	xdl_cha_free(&xdf->rcha);
+}
+
+
+int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+		    xdfenv_t *xe) {
+	long enl1, enl2;
+	xdlclassifier_t cf;
+
+	enl1 = xdl_guess_lines(mf1) + 1;
+	enl2 = xdl_guess_lines(mf2) + 1;
+
+	if (xdl_init_classifier(&cf, enl1 + enl2 + 1) < 0) {
+
+		return -1;
+	}
+
+	if (xdl_prepare_ctx(mf1, enl1, xpp, &cf, &xe->xdf1) < 0) {
+
+		xdl_free_classifier(&cf);
+		return -1;
+	}
+	if (xdl_prepare_ctx(mf2, enl2, xpp, &cf, &xe->xdf2) < 0) {
+
+		xdl_free_ctx(&xe->xdf1);
+		xdl_free_classifier(&cf);
+		return -1;
+	}
+
+	xdl_free_classifier(&cf);
+
+	if (xdl_optimize_ctxs(&xe->xdf1, &xe->xdf2) < 0) {
+
+		xdl_free_ctx(&xe->xdf2);
+		xdl_free_ctx(&xe->xdf1);
+		return -1;
+	}
+
+	return 0;
+}
+
+
+void xdl_free_env(xdfenv_t *xe) {
+
+	xdl_free_ctx(&xe->xdf2);
+	xdl_free_ctx(&xe->xdf1);
+}
+
+
+static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
+	long r, rdis, rpdis;
+
+	for (r = 1, rdis = 0, rpdis = 1; (i - r) >= s; r++) {
+		if (!dis[i - r])
+			rdis++;
+		else if (dis[i - r] == 2)
+			rpdis++;
+		else
+			break;
+	}
+	for (r = 1; (i + r) <= e; r++) {
+		if (!dis[i + r])
+			rdis++;
+		else if (dis[i + r] == 2)
+			rpdis++;
+		else
+			break;
+	}
+
+	return rpdis * XDL_KPDIS_RUN < (rpdis + rdis);
+}
+
+
+/*
+ * Try to reduce the problem complexity, discard records that have no
+ * matches on the other file. Also, lines that have multiple matches
+ * might be potentially discarded if they happear in a run of discardable.
+ */
+static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2) {
+	long i, rhi, nreff;
+	unsigned long hav;
+	xrecord_t **recs;
+	xrecord_t *rec;
+	char *dis, *dis1, *dis2;
+
+	if (!(dis = (char *) xdl_malloc((xdf1->nrec + xdf2->nrec + 2) * sizeof(char)))) {
+
+		return -1;
+	}
+	memset(dis, 0, (xdf1->nrec + xdf2->nrec + 2) * sizeof(char));
+	dis1 = dis;
+	dis2 = dis1 + xdf1->nrec + 1;
+
+	for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) {
+		hav = (*recs)->ha;
+		rhi = (long) XDL_HASHLONG(hav, xdf2->hbits);
+		for (rec = xdf2->rhash[rhi]; rec; rec = rec->next)
+			if (rec->ha == hav && ++dis1[i] == 2)
+				break;
+	}
+
+	for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) {
+		hav = (*recs)->ha;
+		rhi = (long) XDL_HASHLONG(hav, xdf1->hbits);
+		for (rec = xdf1->rhash[rhi]; rec; rec = rec->next)
+			if (rec->ha == hav && ++dis2[i] == 2)
+				break;
+	}
+
+	for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart];
+	     i <= xdf1->dend; i++, recs++) {
+		if (dis1[i] == 1 ||
+		    (dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) {
+			xdf1->rindex[nreff] = i;
+			xdf1->ha[nreff] = (*recs)->ha;
+			nreff++;
+		} else
+			xdf1->rchg[i] = 1;
+	}
+	xdf1->nreff = nreff;
+
+	for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart];
+	     i <= xdf2->dend; i++, recs++) {
+		if (dis2[i] == 1 ||
+		    (dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) {
+			xdf2->rindex[nreff] = i;
+			xdf2->ha[nreff] = (*recs)->ha;
+			nreff++;
+		} else
+			xdf2->rchg[i] = 1;
+	}
+	xdf2->nreff = nreff;
+
+	xdl_free(dis);
+
+	return 0;
+}
+
+
+/*
+ * Early trim initial and terminal matching records.
+ */
+static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) {
+	long i, lim;
+	xrecord_t **recs1, **recs2;
+
+	recs1 = xdf1->recs;
+	recs2 = xdf2->recs;
+	for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim;
+	     i++, recs1++, recs2++)
+		if ((*recs1)->ha != (*recs2)->ha)
+			break;
+
+	xdf1->dstart = xdf2->dstart = i;
+
+	recs1 = xdf1->recs + xdf1->nrec - 1;
+	recs2 = xdf2->recs + xdf2->nrec - 1;
+	for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--)
+		if ((*recs1)->ha != (*recs2)->ha)
+			break;
+
+	xdf1->dend = xdf1->nrec - i - 1;
+	xdf2->dend = xdf2->nrec - i - 1;
+
+	return 0;
+}
+
+
+static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2) {
+
+	if (xdl_trim_ends(xdf1, xdf2) < 0 ||
+	    xdl_cleanup_records(xdf1, xdf2) < 0) {
+
+		return -1;
+	}
+
+	return 0;
+}
+
diff --git a/xdiff/xprepare.h b/xdiff/xprepare.h
new file mode 100644
index 0000000..344c569
--- /dev/null
+++ b/xdiff/xprepare.h
@@ -0,0 +1,35 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XPREPARE_H)
+#define XPREPARE_H
+
+
+
+int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+		    xdfenv_t *xe);
+void xdl_free_env(xdfenv_t *xe);
+
+
+
+#endif /* #if !defined(XPREPARE_H) */
+
diff --git a/xdiff/xtypes.h b/xdiff/xtypes.h
new file mode 100644
index 0000000..3593a66
--- /dev/null
+++ b/xdiff/xtypes.h
@@ -0,0 +1,68 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XTYPES_H)
+#define XTYPES_H
+
+
+
+typedef struct s_chanode {
+	struct s_chanode *next;
+	long icurr;
+} chanode_t;
+
+typedef struct s_chastore {
+	chanode_t *head, *tail;
+	long isize, nsize;
+	chanode_t *ancur;
+	chanode_t *sncur;
+	long scurr;
+} chastore_t;
+
+typedef struct s_xrecord {
+	struct s_xrecord *next;
+	char const *ptr;
+	long size;
+	unsigned long ha;
+} xrecord_t;
+
+typedef struct s_xdfile {
+	chastore_t rcha;
+	long nrec;
+	unsigned int hbits;
+	xrecord_t **rhash;
+	long dstart, dend;
+	xrecord_t **recs;
+	char *rchg;
+	long *rindex;
+	long nreff;
+	unsigned long *ha;
+} xdfile_t;
+
+typedef struct s_xdfenv {
+	xdfile_t xdf1, xdf2;
+} xdfenv_t;
+
+
+
+#endif /* #if !defined(XTYPES_H) */
+
diff --git a/xdiff/xutils.c b/xdiff/xutils.c
new file mode 100644
index 0000000..8221806
--- /dev/null
+++ b/xdiff/xutils.c
@@ -0,0 +1,277 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003	Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+
+
+#define XDL_GUESS_NLINES 256
+
+
+
+
+int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
+		     xdemitcb_t *ecb) {
+	mmbuffer_t mb[3];
+	int i;
+
+	mb[0].ptr = (char *) pre;
+	mb[0].size = psize;
+	mb[1].ptr = (char *) rec;
+	mb[1].size = size;
+	i = 2;
+
+	if (!size || rec[size-1] != '\n') {
+		mb[2].ptr = "\n\\ No newline at end of file\n";
+		mb[2].size = strlen(mb[2].ptr);
+		i = 3;
+	}
+
+	if (ecb->outf(ecb->priv, mb, i) < 0) {
+
+		return -1;
+	}
+
+	return 0;
+}
+
+void *xdl_mmfile_first(mmfile_t *mmf, long *size)
+{
+	*size = mmf->size;
+	return mmf->ptr;
+}
+
+
+void *xdl_mmfile_next(mmfile_t *mmf, long *size)
+{
+	return NULL;
+}
+
+
+long xdl_mmfile_size(mmfile_t *mmf)
+{
+	return mmf->size;
+}
+
+
+int xdl_cha_init(chastore_t *cha, long isize, long icount) {
+
+	cha->head = cha->tail = NULL;
+	cha->isize = isize;
+	cha->nsize = icount * isize;
+	cha->ancur = cha->sncur = NULL;
+	cha->scurr = 0;
+
+	return 0;
+}
+
+
+void xdl_cha_free(chastore_t *cha) {
+	chanode_t *cur, *tmp;
+
+	for (cur = cha->head; (tmp = cur) != NULL;) {
+		cur = cur->next;
+		xdl_free(tmp);
+	}
+}
+
+
+void *xdl_cha_alloc(chastore_t *cha) {
+	chanode_t *ancur;
+	void *data;
+
+	if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
+		if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
+
+			return NULL;
+		}
+		ancur->icurr = 0;
+		ancur->next = NULL;
+		if (cha->tail)
+			cha->tail->next = ancur;
+		if (!cha->head)
+			cha->head = ancur;
+		cha->tail = ancur;
+		cha->ancur = ancur;
+	}
+
+	data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
+	ancur->icurr += cha->isize;
+
+	return data;
+}
+
+
+void *xdl_cha_first(chastore_t *cha) {
+	chanode_t *sncur;
+
+	if (!(cha->sncur = sncur = cha->head))
+		return NULL;
+
+	cha->scurr = 0;
+
+	return (char *) sncur + sizeof(chanode_t) + cha->scurr;
+}
+
+
+void *xdl_cha_next(chastore_t *cha) {
+	chanode_t *sncur;
+
+	if (!(sncur = cha->sncur))
+		return NULL;
+	cha->scurr += cha->isize;
+	if (cha->scurr == sncur->icurr) {
+		if (!(sncur = cha->sncur = sncur->next))
+			return NULL;
+		cha->scurr = 0;
+	}
+
+	return (char *) sncur + sizeof(chanode_t) + cha->scurr;
+}
+
+
+long xdl_guess_lines(mmfile_t *mf) {
+	long nl = 0, size, tsize = 0;
+	char const *data, *cur, *top;
+
+	if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
+		for (top = data + size; nl < XDL_GUESS_NLINES;) {
+			if (cur >= top) {
+				tsize += (long) (cur - data);
+				if (!(cur = data = xdl_mmfile_next(mf, &size)))
+					break;
+				top = data + size;
+			}
+			nl++;
+			if (!(cur = memchr(cur, '\n', top - cur)))
+				cur = top;
+			else
+				cur++;
+		}
+		tsize += (long) (cur - data);
+	}
+
+	if (nl && tsize)
+		nl = xdl_mmfile_size(mf) / (tsize / nl);
+
+	return nl + 1;
+}
+
+
+unsigned long xdl_hash_record(char const **data, char const *top) {
+	unsigned long ha = 5381;
+	char const *ptr = *data;
+
+	for (; ptr < top && *ptr != '\n'; ptr++) {
+		ha += (ha << 5);
+		ha ^= (unsigned long) *ptr;
+	}
+	*data = ptr < top ? ptr + 1: ptr;
+
+	return ha;
+}
+
+
+unsigned int xdl_hashbits(unsigned int size) {
+	unsigned int val = 1, bits = 0;
+
+	for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
+	return bits ? bits: 1;
+}
+
+
+int xdl_num_out(char *out, long val) {
+	char *ptr, *str = out;
+	char buf[32];
+
+	ptr = buf + sizeof(buf) - 1;
+	*ptr = '\0';
+	if (val < 0) {
+		*--ptr = '-';
+		val = -val;
+	}
+	for (; val && ptr > buf; val /= 10)
+		*--ptr = "0123456789"[val % 10];
+	if (*ptr)
+		for (; *ptr; ptr++, str++)
+			*str = *ptr;
+	else
+		*str++ = '0';
+	*str = '\0';
+
+	return str - out;
+}
+
+
+long xdl_atol(char const *str, char const **next) {
+	long val, base;
+	char const *top;
+
+	for (top = str; XDL_ISDIGIT(*top); top++);
+	if (next)
+		*next = top;
+	for (val = 0, base = 1, top--; top >= str; top--, base *= 10)
+		val += base * (long)(*top - '0');
+	return val;
+}
+
+
+int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2, xdemitcb_t *ecb) {
+	int nb = 0;
+	mmbuffer_t mb;
+	char buf[128];
+
+	memcpy(buf, "@@ -", 4);
+	nb += 4;
+
+	nb += xdl_num_out(buf + nb, c1 ? s1: 0);
+
+	if (c1 != 1) {
+		memcpy(buf + nb, ",", 1);
+		nb += 1;
+
+		nb += xdl_num_out(buf + nb, c1);
+	}
+
+	memcpy(buf + nb, " +", 2);
+	nb += 2;
+
+	nb += xdl_num_out(buf + nb, c2 ? s2: 0);
+
+	if (c2 != 1) {
+		memcpy(buf + nb, ",", 1);
+		nb += 1;
+
+		nb += xdl_num_out(buf + nb, c2);
+	}
+
+	memcpy(buf + nb, " @@\n", 4);
+	nb += 4;
+
+	mb.ptr = buf;
+	mb.size = nb;
+	if (ecb->outf(ecb->priv, &mb, 1) < 0)
+		return -1;
+
+	return 0;
+}
+
diff --git a/xdiff/xutils.h b/xdiff/xutils.h
new file mode 100644
index 0000000..428a4bb
--- /dev/null
+++ b/xdiff/xutils.h
@@ -0,0 +1,44 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XUTILS_H)
+#define XUTILS_H
+
+
+int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
+		     xdemitcb_t *ecb);
+int xdl_cha_init(chastore_t *cha, long isize, long icount);
+void xdl_cha_free(chastore_t *cha);
+void *xdl_cha_alloc(chastore_t *cha);
+void *xdl_cha_first(chastore_t *cha);
+void *xdl_cha_next(chastore_t *cha);
+long xdl_guess_lines(mmfile_t *mf);
+unsigned long xdl_hash_record(char const **data, char const *top);
+unsigned int xdl_hashbits(unsigned int size);
+int xdl_num_out(char *out, long val);
+long xdl_atol(char const *str, char const **next);
+int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2, xdemitcb_t *ecb);
+
+
+
+#endif /* #if !defined(XUTILS_H) */
+