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#include <stdio.h>
#include <stdlib.h>
#include "crc_util.h"
const long png_signature[8] = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
int check_header_length(unsigned char *addr, long offset) {
unsigned int res = 0;
for( int i = 0; i < 4; i++ ) {
res |= addr[offset+i];
if (i < 3) {
res <<= 8;
}
}
return res;
}
int check_file_header(char *addr) {
int signature_match = 0;
for( int i = 0; i < 8; i++ ) {
if (addr[i] != png_signature[i]) {
signature_match = 1;
}
}
printf("Sig Match: %d\n", signature_match);
return signature_match;
}
void populate_idat_png(unsigned char *addr, struct PNG_IDAT_FILE_STRUCT *png_data, unsigned long offset) {
unsigned long cur_idat_length = 0;
for(int i = 0; i < 4; i++){
png_data->idat_length[i] = addr[i+offset];
}
for(int i = 0; i < 4; i++){
cur_idat_length += (png_data->idat_length[i] << (24-(8*i)));
}
for(int i = 0; i < 4; i++){
png_data->idat_header[i] = addr[i+offset+4];
}
}
void populate_start_png(unsigned char *addr, struct PNG_START_FILE_STRUCT *png_data) {
union{
unsigned char *data;
struct PNG_START_FILE_STRUCT *png_data;
}png;
png.png_data = png_data;
for(int i = 0; i < sizeof(struct PNG_START_FILE_STRUCT); i++) {
png.data[i] = addr[i];
}
}
int create_cc_file(unsigned char *addr, unsigned long file_length) {
FILE *fp;
fp = fopen("png2.png", "w");
if(fp == NULL) {
return EXIT_FAILURE;
}
for(int i = 0; i < file_length; i++){
fputc(addr[i], fp);
}
fclose(fp);
return 0;
}
unsigned char* file_to_char_array(FILE *in_file, size_t* size) {
unsigned int c;
unsigned long file_data_cap = 8;
unsigned char* file_data = calloc(file_data_cap, sizeof(unsigned char));
for(size_t i = 0;(c = fgetc(in_file)) != EOF; i++) {
if(i == file_data_cap) {
file_data_cap *= 2;
file_data = reallocarray(file_data, file_data_cap, sizeof(unsigned char));
if(file_data == NULL) {
perror("FAILED ARRAY RESIZE");
return NULL;
}
}
file_data[i] = c;
*size += 1;
}
return file_data;
}
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