use skip_prefix to avoid repeating strings
It's a common idiom to match a prefix and then skip past it
with strlen, like:
if (starts_with(foo, "bar"))
foo += strlen("bar");
This avoids magic numbers, but means we have to repeat the
string (and there is no compiler check that we didn't make a
typo in one of the strings).
We can use skip_prefix to handle this case without repeating
ourselves.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/diff.c b/diff.c
index 97db932..2378ae4 100644
--- a/diff.c
+++ b/diff.c
@@ -3395,12 +3395,10 @@
const char **optarg)
{
const char *arg = argv[0];
- if (arg[0] != '-' || arg[1] != '-')
+ if (!skip_prefix(arg, "--", &arg))
return 0;
- arg += strlen("--");
- if (!starts_with(arg, opt))
+ if (!skip_prefix(arg, opt, &arg))
return 0;
- arg += strlen(opt);
if (*arg == '=') { /* stuck form: --option=value */
*optarg = arg + 1;
return 1;
@@ -3429,8 +3427,7 @@
switch (*arg) {
case '-':
- if (starts_with(arg, "-width")) {
- arg += strlen("-width");
+ if (skip_prefix(arg, "-width", &arg)) {
if (*arg == '=')
width = strtoul(arg + 1, &end, 10);
else if (!*arg && !av[1])
@@ -3439,8 +3436,7 @@
width = strtoul(av[1], &end, 10);
argcount = 2;
}
- } else if (starts_with(arg, "-name-width")) {
- arg += strlen("-name-width");
+ } else if (skip_prefix(arg, "-name-width", &arg)) {
if (*arg == '=')
name_width = strtoul(arg + 1, &end, 10);
else if (!*arg && !av[1])
@@ -3449,8 +3445,7 @@
name_width = strtoul(av[1], &end, 10);
argcount = 2;
}
- } else if (starts_with(arg, "-graph-width")) {
- arg += strlen("-graph-width");
+ } else if (skip_prefix(arg, "-graph-width", &arg)) {
if (*arg == '=')
graph_width = strtoul(arg + 1, &end, 10);
else if (!*arg && !av[1])
@@ -3459,8 +3454,7 @@
graph_width = strtoul(av[1], &end, 10);
argcount = 2;
}
- } else if (starts_with(arg, "-count")) {
- arg += strlen("-count");
+ } else if (skip_prefix(arg, "-count", &arg)) {
if (*arg == '=')
count = strtoul(arg + 1, &end, 10);
else if (!*arg && !av[1])
@@ -3905,16 +3899,13 @@
cmd = *opt++;
if (cmd == '-') {
/* convert the long-form arguments into short-form versions */
- if (starts_with(opt, "break-rewrites")) {
- opt += strlen("break-rewrites");
+ if (skip_prefix(opt, "break-rewrites", &opt)) {
if (*opt == 0 || *opt++ == '=')
cmd = 'B';
- } else if (starts_with(opt, "find-copies")) {
- opt += strlen("find-copies");
+ } else if (skip_prefix(opt, "find-copies", &opt)) {
if (*opt == 0 || *opt++ == '=')
cmd = 'C';
- } else if (starts_with(opt, "find-renames")) {
- opt += strlen("find-renames");
+ } else if (skip_prefix(opt, "find-renames", &opt)) {
if (*opt == 0 || *opt++ == '=')
cmd = 'M';
}
