metaforce/hecl/lib/winsupport.cpp

37 lines
946 B
C++

#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <string>
#include "HECL/winsupport.hpp"
/*
* The memmem() function finds the start of the first occurrence of the
* substring 'needle' of length 'nlen' in the memory area 'haystack' of
* length 'hlen'.
*
* The return value is a pointer to the beginning of the sub-string, or
* NULL if the substring is not found.
*/
void *memmem(const void *haystack, size_t hlen, const void *needle, size_t nlen)
{
int needle_first;
const uint8_t *p = static_cast<const uint8_t*>(haystack);
size_t plen = hlen;
if (!nlen)
return NULL;
needle_first = *(unsigned char *)needle;
while (plen >= nlen && (p = static_cast<const uint8_t*>(memchr(p, needle_first, plen - nlen + 1))))
{
if (!memcmp(p, needle, nlen))
return (void *)p;
p++;
plen = hlen - (p - static_cast<const uint8_t*>(haystack));
}
return NULL;
}