diff options
Diffstat (limited to 'src/userspace/mlibc/string')
-rw-r--r-- | src/userspace/mlibc/string/strlen.c | 32 |
1 files changed, 29 insertions, 3 deletions
diff --git a/src/userspace/mlibc/string/strlen.c b/src/userspace/mlibc/string/strlen.c index 133ee3d..f6a06a4 100644 --- a/src/userspace/mlibc/string/strlen.c +++ b/src/userspace/mlibc/string/strlen.c @@ -2,7 +2,33 @@ size_t strlen(const char *str) { - size_t len = 0; - while (str[len]) len++; - return len; + const char *char_ptr; + const unsigned long int *longword_ptr; + unsigned long int longword, himagic, lomagic; + + for (char_ptr = str; ((unsigned long int) char_ptr & (sizeof(longword) - 1)) != 0; ++char_ptr) + if (*char_ptr == '\0') + return char_ptr - str; + + longword_ptr = (unsigned long int *) char_ptr; + + himagic = 0x80808080L; + lomagic = 0x01010101L; + + for (;;) { + longword = *longword_ptr++; + + if (((longword - lomagic) & himagic) != 0) { + const char *cp = (const char *) (longword_ptr - 1); + + if (cp[0] == 0) + return cp - str; + if (cp[1] == 0) + return cp - str + 1; + if (cp[2] == 0) + return cp - str + 2; + if (cp[3] == 0) + return cp - str + 3; + } + } }
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