diff options
Diffstat (limited to 'absl/strings/internal/memutil.h')
| -rw-r--r-- | absl/strings/internal/memutil.h | 116 |
1 files changed, 4 insertions, 112 deletions
diff --git a/absl/strings/internal/memutil.h b/absl/strings/internal/memutil.h index 9ad05358..b5911a01 100644 --- a/absl/strings/internal/memutil.h +++ b/absl/strings/internal/memutil.h @@ -14,51 +14,6 @@ // limitations under the License. // -// These routines provide mem versions of standard C string routines, -// such as strpbrk. They function exactly the same as the str versions, -// so if you wonder what they are, replace the word "mem" by -// "str" and check out the man page. I could return void*, as the -// strutil.h mem*() routines tend to do, but I return char* instead -// since this is by far the most common way these functions are called. -// -// The difference between the mem and str versions is the mem version -// takes a pointer and a length, rather than a '\0'-terminated string. -// The memcase* routines defined here assume the locale is "C" -// (they use absl::ascii_tolower instead of tolower). -// -// These routines are based on the BSD library. -// -// Here's a list of routines from string.h, and their mem analogues. -// Functions in lowercase are defined in string.h; those in UPPERCASE -// are defined here: -// -// strlen -- -// strcat strncat MEMCAT -// strcpy strncpy memcpy -// -- memccpy (very cool function, btw) -// -- memmove -// -- memset -// strcmp strncmp memcmp -// strcasecmp strncasecmp MEMCASECMP -// strchr memchr -// strcoll -- -// strxfrm -- -// strdup strndup MEMDUP -// strrchr MEMRCHR -// strspn MEMSPN -// strcspn MEMCSPN -// strpbrk MEMPBRK -// strstr MEMSTR MEMMEM -// (g)strcasestr MEMCASESTR MEMCASEMEM -// strtok -- -// strprefix MEMPREFIX (strprefix is from strutil.h) -// strcaseprefix MEMCASEPREFIX (strcaseprefix is from strutil.h) -// strsuffix MEMSUFFIX (strsuffix is from strutil.h) -// strcasesuffix MEMCASESUFFIX (strcasesuffix is from strutil.h) -// -- MEMIS -// -- MEMCASEIS -// strcount MEMCOUNT (strcount is from strutil.h) - #ifndef ABSL_STRINGS_INTERNAL_MEMUTIL_H_ #define ABSL_STRINGS_INTERNAL_MEMUTIL_H_ @@ -72,74 +27,11 @@ namespace absl { ABSL_NAMESPACE_BEGIN namespace strings_internal { -inline char* memcat(char* dest, size_t destlen, const char* src, - size_t srclen) { - return reinterpret_cast<char*>(memcpy(dest + destlen, src, srclen)); -} - +// Performs a byte-by-byte comparison of `len` bytes of the strings `s1` and +// `s2`, ignoring the case of the characters. It returns an integer less than, +// equal to, or greater than zero if `s1` is found, respectively, to be less +// than, to match, or be greater than `s2`. int memcasecmp(const char* s1, const char* s2, size_t len); -char* memdup(const char* s, size_t slen); -char* memrchr(const char* s, int c, size_t slen); -size_t memspn(const char* s, size_t slen, const char* accept); -size_t memcspn(const char* s, size_t slen, const char* reject); -char* mempbrk(const char* s, size_t slen, const char* accept); - -// This is for internal use only. Don't call this directly -template <bool case_sensitive> -const char* int_memmatch(const char* haystack, size_t haylen, - const char* needle, size_t neelen) { - if (0 == neelen) { - return haystack; // even if haylen is 0 - } - const char* hayend = haystack + haylen; - const char* needlestart = needle; - const char* needleend = needlestart + neelen; - - for (; haystack < hayend; ++haystack) { - char hay = case_sensitive - ? *haystack - : absl::ascii_tolower(static_cast<unsigned char>(*haystack)); - char nee = case_sensitive - ? *needle - : absl::ascii_tolower(static_cast<unsigned char>(*needle)); - if (hay == nee) { - if (++needle == needleend) { - return haystack + 1 - neelen; - } - } else if (needle != needlestart) { - // must back up haystack in case a prefix matched (find "aab" in "aaab") - haystack -= needle - needlestart; // for loop will advance one more - needle = needlestart; - } - } - return nullptr; -} - -// These are the guys you can call directly -inline const char* memstr(const char* phaystack, size_t haylen, - const char* pneedle) { - return int_memmatch<true>(phaystack, haylen, pneedle, strlen(pneedle)); -} - -inline const char* memcasestr(const char* phaystack, size_t haylen, - const char* pneedle) { - return int_memmatch<false>(phaystack, haylen, pneedle, strlen(pneedle)); -} - -inline const char* memmem(const char* phaystack, size_t haylen, - const char* pneedle, size_t needlelen) { - return int_memmatch<true>(phaystack, haylen, pneedle, needlelen); -} - -inline const char* memcasemem(const char* phaystack, size_t haylen, - const char* pneedle, size_t needlelen) { - return int_memmatch<false>(phaystack, haylen, pneedle, needlelen); -} - -// This is significantly faster for case-sensitive matches with very -// few possible matches. See unit test for benchmarks. -const char* memmatch(const char* phaystack, size_t haylen, const char* pneedle, - size_t neelen); } // namespace strings_internal ABSL_NAMESPACE_END |