binary search for a friend

gistfile1.c

#include <stdio.h>
#include <stdlib.h>

typedef unsigned char byte;

byte *memfnd(char *buffer, size_t buflen, char *pattern, size_t patlen) {
    if(!buffer || !pattern || !buflen || !patlen || patlen > buflen)
        return NULL;
    
    for(unsigned long i=0;i<buflen;++i) {
        if(!memcmp(&buffer[i], pattern, patlen))
            return (byte *)(buffer + i);
    }
    
    return NULL;
}

int main(int argc, const char **argv) {
    char mem[5] = { 0xFF, 0xFA, 0xaa, 0xaa, 0xbc };
    char pat[2] = { 0xfa, 0xaa };
    
    printf("Offset: 0x%x\n", memfnd(mem, sizeof(mem), pat, sizeof(pat)) - (byte *)&mem);
}