read-cache: add strcmp_offset function

Add strcmp_offset() function to also return the offset of the
first change.

Add unit test and helper to verify.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff Hostetler 2017-04-14 19:12:28 +00:00 коммит произвёл Junio C Hamano
Родитель cf11a67975
Коммит a6db3fbb6e
6 изменённых файлов: 66 добавлений и 0 удалений

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@ -637,6 +637,7 @@ TEST_PROGRAMS_NEED_X += test-scrap-cache-tree
TEST_PROGRAMS_NEED_X += test-sha1
TEST_PROGRAMS_NEED_X += test-sha1-array
TEST_PROGRAMS_NEED_X += test-sigchain
TEST_PROGRAMS_NEED_X += test-strcmp-offset
TEST_PROGRAMS_NEED_X += test-string-list
TEST_PROGRAMS_NEED_X += test-submodule-config
TEST_PROGRAMS_NEED_X += test-subprocess

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@ -595,6 +595,7 @@ extern int write_locked_index(struct index_state *, struct lock_file *lock, unsi
extern int discard_index(struct index_state *);
extern int unmerged_index(const struct index_state *);
extern int verify_path(const char *path);
extern int strcmp_offset(const char *s1, const char *s2, size_t *first_change);
extern int index_dir_exists(struct index_state *istate, const char *name, int namelen);
extern void adjust_dirname_case(struct index_state *istate, char *name);
extern struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int igncase);

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@ -887,6 +887,26 @@ static int has_file_name(struct index_state *istate,
return retval;
}
/*
* Like strcmp(), but also return the offset of the first change.
* If strings are equal, return the length.
*/
int strcmp_offset(const char *s1, const char *s2, size_t *first_change)
{
size_t k;
if (!first_change)
return strcmp(s1, s2);
for (k = 0; s1[k] == s2[k]; k++)
if (s1[k] == '\0')
break;
*first_change = k;
return (unsigned char)s1[k] - (unsigned char)s2[k];
}
/*
* Do we have another file with a pathname that is a proper
* subset of the name we're trying to add?

1
t/helper/.gitignore поставляемый
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@ -26,6 +26,7 @@
/test-sha1
/test-sha1-array
/test-sigchain
/test-strcmp-offset
/test-string-list
/test-submodule-config
/test-subprocess

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@ -0,0 +1,22 @@
#include "cache.h"
int cmd_main(int argc, const char **argv)
{
int result;
size_t offset;
if (!argv[1] || !argv[2])
die("usage: %s <string1> <string2>", argv[0]);
result = strcmp_offset(argv[1], argv[2], &offset);
/*
* Because differnt CRTs behave differently, only rely on signs
* of the result values.
*/
result = (result < 0 ? -1 :
result > 0 ? 1 :
0);
printf("%d %"PRIuMAX"\n", result, (uintmax_t)offset);
return 0;
}

21
t/t0065-strcmp-offset.sh Executable file
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@ -0,0 +1,21 @@
#!/bin/sh
test_description='Test strcmp_offset functionality'
. ./test-lib.sh
while read s1 s2 expect
do
test_expect_success "strcmp_offset($s1, $s2)" '
echo "$expect" >expect &&
test-strcmp-offset "$s1" "$s2" >actual &&
test_cmp expect actual
'
done <<-EOF
abc abc 0 3
abc def -1 0
abc abz -1 2
abc abcdef -1 3
EOF
test_done