Find And Replace hex

Question

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

int main()
{

FILE *file,*fileout;
unsigned char data[1];

    uint8_t what[] = {0x00, 0xEB, 0x00, 0x00, 0x50, 0xE3, 0x02};
uint8_t repl[] = {0x00, 0xEB, 0x01, 0x00, 0x37, 0xB3, 0x02};

  uint8_t *buf_find(uint8_t *p, uint8_t *end, uint8_t *needle, int len)
    {
        end = end - len + 1;

    while (p < end) {
        if (memcmp(p, needle, len) == 0) return p;
        p++;
    }
    return NULL;
}



file=fopen("test.bin","rb");
fileout=fopen("test.bin.bak","wb");

while (!feof(file)) {
if (fread(data, 1, 1, file) > 0) {      

    char *p = data;
        char *end = data + 1;    
        for (;;) {
            uint8_t *q = buf_find(p, end, what, sizeof(what));
            if (q == NULL) break;
                memcpy(q, repl, sizeof(repl));
                p = q + sizeof(data[0]);
        }

    printf("%02X ",data[0]);
    fwrite(&data,1,1,fileout);
}
}

fclose(file);
fclose(fileout);
return 0;
}

How to change a binary file hexadecimal character in a binary file? reading hex = "00 EB 00 00 50 E3 02" replace hex = "00 EB 01 00 37 E3 02"

my problem answered but it's wery slowly. Hexadecimal find and replace

Answer 1

try this

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


size_t replace(FILE *fi, FILE *fo, uint8_t *what, uint8_t *repl, size_t size){
    size_t i, index = 0, count = 0;
    int ch;
    while(EOF!=(ch=fgetc(fi))){
        if(ch == what[index]){
            if(++index == size){
                for(i = 0; i < size ; ++i){
                    fputc(repl[i], fo);
                }
                index = 0;
                ++count;
            }
        } else {
            for(i = 0; i < index ; ++i){
                fputc(what[i], fo);
            }
            index =0;
            fputc(ch, fo);
        }
    }
    for(i = 0; i < index ; ++i){
        fputc(what[i], fo);
    }

    return count;
}

int main(void){
    FILE *file,*fileout;
    uint8_t what[] = {0x00, 0xEB, 0x00, 0x00, 0x50, 0xE3, 0x02};
    uint8_t repl[] = {0x00, 0xEB, 0x01, 0x00, 0x37, 0xB3, 0x02};
    size_t count;

    file=fopen("test.bin","rb");
    fileout=fopen("test.bin.bak","wb");
    count = replace(file, fileout, what, repl, sizeof(what));
    printf("number of replace count is %zu\n", count);
    fclose(fileout);
    fclose(file);
    return 0;
}