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#include "string.h"
unsigned long strlen(const char *buf)
{
unsigned long len = 0;
while (*buf++)
++len;
return len;
}
char *strcat(char *dest, const char *src)
{
char *p = dest;
while (*p)
++p;
while ((*p++ = *src++) != 0)
;
return dest;
}
char *strcpy(char *dest, const char *src)
{
*dest = 0;
return strcat(dest, src);
}
int strcmp(const char *a, const char *b)
{
while (*a == *b) {
if (*a == '\0') {
break;
}
++a, ++b;
}
return *a - *b;
}
char *strchr(const char *s, int c)
{
while (*s != (char)c)
if (*s++ == '\0')
return NULL;
return (char *)s;
}
char *strstr(const char *s1, const char *s2)
{
size_t l1, l2;
l2 = strlen(s2);
if (!l2)
return (char *)s1;
l1 = strlen(s1);
while (l1 >= l2) {
l1--;
if (!memcmp(s1, s2, l2))
return (char *)s1;
s1++;
}
return NULL;
}
int memcmp(const void *s1, const void *s2, size_t n)
{
const unsigned char *a = s1, *b = s2;
int ret = 0;
while (n--) {
ret = *a - *b;
if (ret)
break;
++a, ++b;
}
return ret;
}
void *memmove(void *dest, const void *src, size_t n)
{
const unsigned char *s = src;
unsigned char *d = dest;
if (d <= s) {
while (n--)
*d++ = *s++;
} else {
d += n, s += n;
while (n--)
*--d = *--s;
}
return dest;
}
void *memchr(const void *s, int c, size_t n)
{
const unsigned char *str = s, chr = (unsigned char)c;
while (n--)
if (*str++ == chr)
return (void *)(str - 1);
return NULL;
}
long atol(const char *ptr)
{
long acc = 0;
const char *s = ptr;
int neg, c;
while (*s == ' ' || *s == '\t')
s++;
if (*s == '-'){
neg = 1;
s++;
} else {
neg = 0;
if (*s == '+')
s++;
}
while (*s) {
if (*s < '0' || *s > '9')
break;
c = *s - '0';
acc = acc * 10 + c;
s++;
}
if (neg)
acc = -acc;
return acc;
}
uint8_t csum8(uint8_t *buf, uint32_t len)
{
uint32_t s = 0;
while (len-- > 0)
s += *buf++;
return s;
}
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