Commit 25203222f55f8fc3a270620609ecfee2e151d76b
2022-02-05T11:01:25
optimize the SDL_str(case)cmp functions
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diff --git a/src/stdlib/SDL_string.c b/src/stdlib/SDL_string.c
index e23f14a..1331930 100644
--- a/src/stdlib/SDL_string.c
+++ b/src/stdlib/SDL_string.c
@@ -1070,13 +1070,16 @@ SDL_strcmp(const char *str1, const char *str2)
#if defined(HAVE_STRCMP)
return strcmp(str1, str2);
#else
- while (*str1 && *str2) {
- if (*str1 != *str2)
+ int result;
+
+ while(1) {
+ result = (int)((unsigned char) *str1 - (unsigned char) *str2);
+ if (result != 0 || (*str1 == '\0'/* && *str2 == '\0'*/))
break;
++str1;
++str2;
}
- return (int)((unsigned char) *str1 - (unsigned char) *str2);
+ return result;
#endif /* HAVE_STRCMP */
}
@@ -1086,17 +1089,20 @@ SDL_strncmp(const char *str1, const char *str2, size_t maxlen)
#if defined(HAVE_STRNCMP)
return strncmp(str1, str2, maxlen);
#else
- while (*str1 && *str2 && maxlen) {
- if (*str1 != *str2)
+ int result;
+
+ while (maxlen) {
+ result = (int) (unsigned char) *str1 - (unsigned char) *str2;
+ if (result != 0 || *str1 == '\0'/* && *str2 == '\0'*/)
break;
++str1;
++str2;
--maxlen;
}
if (!maxlen) {
- return 0;
+ result = 0;
}
- return (int) ((unsigned char) *str1 - (unsigned char) *str2);
+ return result;
#endif /* HAVE_STRNCMP */
}
@@ -1108,19 +1114,18 @@ SDL_strcasecmp(const char *str1, const char *str2)
#elif defined(HAVE__STRICMP)
return _stricmp(str1, str2);
#else
- char a = 0;
- char b = 0;
- while (*str1 && *str2) {
+ int a, b, result;
+
+ while (1) {
a = SDL_toupper((unsigned char) *str1);
b = SDL_toupper((unsigned char) *str2);
- if (a != b)
+ result = a - b;
+ if (result != 0 || a == 0 /*&& b == 0*/)
break;
++str1;
++str2;
}
- a = SDL_toupper((unsigned char) *str1);
- b = SDL_toupper((unsigned char) *str2);
- return (int) ((unsigned char) a - (unsigned char) b);
+ return result;
#endif /* HAVE_STRCASECMP */
}
@@ -1132,24 +1137,21 @@ SDL_strncasecmp(const char *str1, const char *str2, size_t maxlen)
#elif defined(HAVE__STRNICMP)
return _strnicmp(str1, str2, maxlen);
#else
- char a = 0;
- char b = 0;
- while (*str1 && *str2 && maxlen) {
+ int a, b, result;
+
+ while (maxlen) {
a = SDL_tolower((unsigned char) *str1);
b = SDL_tolower((unsigned char) *str2);
- if (a != b)
+ result = a - b;
+ if (result != 0 || a == 0 /*&& b == 0*/)
break;
++str1;
++str2;
--maxlen;
}
- if (maxlen == 0) {
- return 0;
- } else {
- a = SDL_tolower((unsigned char) *str1);
- b = SDL_tolower((unsigned char) *str2);
- return (int) ((unsigned char) a - (unsigned char) b);
- }
+ if (maxlen == 0)
+ result = 0;
+ return result;
#endif /* HAVE_STRNCASECMP */
}