133 lines
1.8 KiB
C
133 lines
1.8 KiB
C
/*
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* Copyright (c) 2013-2014 Stanford University
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* Copyright (c) 2006-2008 Ali Mashtizadeh
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* All rights reserved.
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*/
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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char *
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strchr(const char *s, int c)
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{
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int i;
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for (i = 0; ; i++)
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{
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if (s[i] == c)
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return (char *)s + i;
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if (s[i] == '\0')
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return NULL;
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}
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}
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char *
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strcpy(char *to, const char *from)
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{
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char *save = to;
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for (; (*to = *from); ++from, ++to);
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return save;
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}
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char *
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strncpy(char *to, const char *from, size_t length)
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{
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char *save = to;
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for (; (*to = *from) != '\0' && length > 0; ++from, ++to, length--);
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*to = '\0';
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return save;
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}
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int
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strcmp(const char *s1, const char *s2)
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{
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while (*s1 == *s2++)
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if (*s1++ == 0)
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return 0;
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return (*(const uint8_t *)s1 - *(const uint8_t *)(s2 - 1));
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}
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int
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strncmp(const char *s1, const char *s2, size_t len)
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{
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if (len == 0)
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return 0;
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while (*s1 == *s2) {
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if (*s1 == 0)
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return 0;
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s1++;
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s2++;
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len--;
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if (len == 0)
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return 0;
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}
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return (*(const uint8_t *)s1 - *(const uint8_t *)s2);
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}
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size_t
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strlen(const char *str)
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{
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const char *s;
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for (s = str; *s; ++s);
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return (s - str);
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}
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void *
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memset(void *dst, int c, size_t length)
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{
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uint8_t *p = (uint8_t *)dst;
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while (length-- != 0) {
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*p = c;
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p += 1;
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};
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return dst;
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}
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void *
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memcpy(void *dst, const void *src, size_t length)
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{
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uint8_t *d = (uint8_t *)dst;
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const uint8_t *s = (const uint8_t *)src;
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while (length-- != 0) {
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*d = *s;
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d += 1;
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s += 1;
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};
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return dst;
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}
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int
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memcmp(const void *b1, const void *b2, size_t length)
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{
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int i;
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const char *c1 = (const char *)b1;
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const char *c2 = (const char *)b2;
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for (i = 0; i < length; i++)
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{
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if (*c1 != *c2)
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return *c2 - *c1;
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c1++;
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c2++;
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}
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return 0;
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}
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