pack-bitmap: do not use gcc packed attribute
The "__attribute__" flag may be a noop on some compilers.
That's OK as long as the code is correct without the
attribute, but in this case it is not. We would typically
end up with a struct that is 2 bytes too long due to struct
padding, breaking both reading and writing of bitmaps.
Instead of marshalling the data in a struct, let's just
provide helpers for reading and writing the appropriate
types. Besides being correct on all platforms, the result is
more efficient and simpler to read.
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/csum-file.h b/csum-file.h
index 9dedb03..da612c5 100644
--- a/csum-file.h
+++ b/csum-file.h
@@ -39,4 +39,15 @@
extern void crc32_begin(struct sha1file *);
extern uint32_t crc32_end(struct sha1file *);
+static inline void sha1write_u8(struct sha1file *f, uint8_t data)
+{
+ sha1write(f, &data, sizeof(data));
+}
+
+static inline void sha1write_be32(struct sha1file *f, uint32_t data)
+{
+ data = htonl(data);
+ sha1write(f, &data, sizeof(data));
+}
+
#endif
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index 1218bef..5d353ad 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -473,7 +473,6 @@
for (i = 0; i < writer.selected_nr; ++i) {
struct bitmapped_commit *stored = &writer.selected[i];
- struct bitmap_disk_entry on_disk;
int commit_pos =
sha1_pos(stored->commit->object.sha1, index, index_nr, sha1_access);
@@ -481,11 +480,10 @@
if (commit_pos < 0)
die("BUG: trying to write commit not in index");
- on_disk.object_pos = htonl(commit_pos);
- on_disk.xor_offset = stored->xor_offset;
- on_disk.flags = stored->flags;
+ sha1write_be32(f, commit_pos);
+ sha1write_u8(f, stored->xor_offset);
+ sha1write_u8(f, stored->flags);
- sha1write(f, &on_disk, sizeof(on_disk));
dump_bitmap(f, stored->write_as);
}
}
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 91e4101..9f8b909 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -197,13 +197,24 @@
return stored;
}
+static inline uint32_t read_be32(const unsigned char *buffer, size_t *pos)
+{
+ uint32_t result = get_be32(buffer + *pos);
+ (*pos) += sizeof(result);
+ return result;
+}
+
+static inline uint8_t read_u8(const unsigned char *buffer, size_t *pos)
+{
+ return buffer[(*pos)++];
+}
+
static int load_bitmap_entries_v1(struct bitmap_index *index)
{
static const size_t MAX_XOR_OFFSET = 160;
uint32_t i;
struct stored_bitmap **recent_bitmaps;
- struct bitmap_disk_entry *entry;
recent_bitmaps = xcalloc(MAX_XOR_OFFSET, sizeof(struct stored_bitmap));
@@ -214,15 +225,12 @@
uint32_t commit_idx_pos;
const unsigned char *sha1;
- entry = (struct bitmap_disk_entry *)(index->map + index->map_pos);
- index->map_pos += sizeof(struct bitmap_disk_entry);
+ commit_idx_pos = read_be32(index->map, &index->map_pos);
+ xor_offset = read_u8(index->map, &index->map_pos);
+ flags = read_u8(index->map, &index->map_pos);
- commit_idx_pos = ntohl(entry->object_pos);
sha1 = nth_packed_object_sha1(index->pack, commit_idx_pos);
- xor_offset = (int)entry->xor_offset;
- flags = (int)entry->flags;
-
bitmap = read_bitmap_1(index);
if (!bitmap)
return -1;
diff --git a/pack-bitmap.h b/pack-bitmap.h
index 8b7f4e9..487600b 100644
--- a/pack-bitmap.h
+++ b/pack-bitmap.h
@@ -5,12 +5,6 @@
#include "khash.h"
#include "pack-objects.h"
-struct bitmap_disk_entry {
- uint32_t object_pos;
- uint8_t xor_offset;
- uint8_t flags;
-} __attribute__((packed));
-
struct bitmap_disk_header {
char magic[4];
uint16_t version;
