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- #include <string.h>
- #include <stdlib.h>
- #ifdef __USE_GNU
- size_t strnlen (const char *str, size_t maxlen)
- {
- const char *char_ptr, *end_ptr = str + maxlen;
- const unsigned long int *longword_ptr;
- unsigned long int longword, himagic, lomagic;
- if (maxlen == 0)
- return 0;
- if (__builtin_expect (end_ptr < str, 0))
- end_ptr = (const char *) ~0UL;
-
- for (char_ptr = str; ((unsigned long int) char_ptr
- & (sizeof (longword) - 1)) != 0;
- ++char_ptr)
- if (*char_ptr == '\0')
- {
- if (char_ptr > end_ptr)
- char_ptr = end_ptr;
- return char_ptr - str;
- }
-
- longword_ptr = (unsigned long int *) char_ptr;
-
- himagic = 0x80808080L;
- lomagic = 0x01010101L;
- if (sizeof (longword) > 4)
- {
-
-
- himagic = ((himagic << 16) << 16) | himagic;
- lomagic = ((lomagic << 16) << 16) | lomagic;
- }
- if (sizeof (longword) > 8)
- abort ();
-
- while (longword_ptr < (unsigned long int *) end_ptr)
- {
-
- longword = *longword_ptr++;
- if ((longword - lomagic) & himagic)
- {
-
- const char *cp = (const char *) (longword_ptr - 1);
- char_ptr = cp;
- if (cp[0] == 0)
- break;
- char_ptr = cp + 1;
- if (cp[1] == 0)
- break;
- char_ptr = cp + 2;
- if (cp[2] == 0)
- break;
- char_ptr = cp + 3;
- if (cp[3] == 0)
- break;
- if (sizeof (longword) > 4)
- {
- char_ptr = cp + 4;
- if (cp[4] == 0)
- break;
- char_ptr = cp + 5;
- if (cp[5] == 0)
- break;
- char_ptr = cp + 6;
- if (cp[6] == 0)
- break;
- char_ptr = cp + 7;
- if (cp[7] == 0)
- break;
- }
- }
- char_ptr = end_ptr;
- }
- if (char_ptr > end_ptr)
- char_ptr = end_ptr;
- return char_ptr - str;
- }
- libc_hidden_def(strnlen)
- #endif
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