| From | "Paul E. McKenney" <> | Subject | [PATCH nolibc 46/61] tools/nolibc/string: add strcmp() and strncmp() | Date | Mon, 18 Apr 2022 17:42:10 -0700 |
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From: Willy Tarreau <w@1wt.eu>
We need these functions all the time, including when checking environment variables and parsing command-line arguments. These implementations were optimized to show optimal code size on a wide range of compilers (22 bytes return included for strcmp(), 33 for strncmp()).
Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- tools/include/nolibc/string.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)
diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h index 4554b6fcb400..0d5e870c7c0b 100644 --- a/tools/include/nolibc/string.h +++ b/tools/include/nolibc/string.h @@ -102,6 +102,17 @@ char *strchr(const char *s, int c) return NULL; } +static __attribute__((unused)) +int strcmp(const char *a, const char *b) +{ + unsigned int c; + int diff; + + while (!(diff = (unsigned char)*a++ - (c = (unsigned char)*b++)) && c) + ; + return diff; +} + static __attribute__((unused)) char *strcpy(char *dst, const char *src) { @@ -184,6 +195,18 @@ char *strncat(char *dst, const char *src, size_t size) return orig; } +static __attribute__((unused)) +int strncmp(const char *a, const char *b, size_t size) +{ + unsigned int c; + int diff = 0; + + while (size-- && + !(diff = (unsigned char)*a++ - (c = (unsigned char)*b++)) && c) + ; + + return diff; +} static __attribute__((unused)) char *strncpy(char *dst, const char *src, size_t size) -- 2.31.1.189.g2e36527f23
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