From a6db3fbb6e4ec11695e2a3af8bc2cb9119cb1941 Mon Sep 17 00:00:00 2001 From: Jeff Hostetler Date: Fri, 14 Apr 2017 19:12:28 +0000 Subject: 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 Signed-off-by: Junio C Hamano --- Makefile | 1 + cache.h | 1 + read-cache.c | 20 ++++++++++++++++++++ t/helper/.gitignore | 1 + t/helper/test-strcmp-offset.c | 22 ++++++++++++++++++++++ t/t0065-strcmp-offset.sh | 21 +++++++++++++++++++++ 6 files changed, 66 insertions(+) create mode 100644 t/helper/test-strcmp-offset.c create mode 100755 t/t0065-strcmp-offset.sh diff --git a/Makefile b/Makefile index 9b36068ac..0a4fb9de8 100644 --- a/Makefile +++ b/Makefile @@ -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 diff --git a/cache.h b/cache.h index 5c8078291..2aea7caf4 100644 --- a/cache.h +++ b/cache.h @@ -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); diff --git a/read-cache.c b/read-cache.c index e44775182..11823f5db 100644 --- a/read-cache.c +++ b/read-cache.c @@ -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? diff --git a/t/helper/.gitignore b/t/helper/.gitignore index 758ed2e8f..e7fe7ff59 100644 --- a/t/helper/.gitignore +++ b/t/helper/.gitignore @@ -26,6 +26,7 @@ /test-sha1 /test-sha1-array /test-sigchain +/test-strcmp-offset /test-string-list /test-submodule-config /test-subprocess diff --git a/t/helper/test-strcmp-offset.c b/t/helper/test-strcmp-offset.c new file mode 100644 index 000000000..4a45a54e9 --- /dev/null +++ b/t/helper/test-strcmp-offset.c @@ -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 ", 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; +} diff --git a/t/t0065-strcmp-offset.sh b/t/t0065-strcmp-offset.sh new file mode 100755 index 000000000..7d6d21425 --- /dev/null +++ b/t/t0065-strcmp-offset.sh @@ -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 -- cgit v1.2.1