Spencer/PNG_CC
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2021-10-14 01:27:38 -04:00
parent 7534150326
commit 6166af2b41
4 changed files with 104 additions and 9 deletions
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71
src/crc_util.c
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@@ -27,6 +27,77 @@ int check_file_header(char *addr) {
}
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)));
}
printf("\n%ld\n", cur_idat_length);
}
void populate_start_png(unsigned char *addr, struct PNG_START_FILE_STRUCT *png_data) {
for(int i = 0; i < 8; i++) {
png_data->file_sig[i] = addr[i];
printf("%02X ", png_data->file_sig[i]);
}
printf("\n");
for(int i = 0; i < 4; i++) {
png_data->ihdr_length[i] = addr[i+8];
printf("%02X ", png_data->ihdr_length[i]);
}
printf("\n");
for(int i = 0; i < 4; i++) {
png_data->ihdr_header[i] = addr[i+12];
printf("%02X ", png_data->ihdr_header[i]);
}
printf("\n");
for(int i = 0; i < 4; i++) {
png_data->file_width[i] = addr[i+16];
printf("%02X ", png_data->file_width[i]);
}
printf("\n");
for(int i = 0; i < 4; i++) {
png_data->file_height[i] = addr[i+20];
printf("%02X ", png_data->file_height[i]);
}
printf("\n");
for(int i = 0; i < 1; i++) {
png_data->bit_depth[i] = addr[i+24];
printf("%02X ", png_data->bit_depth[i]);
}
printf("\n");
for(int i = 0; i < 1; i++) {
png_data->color_type[i] = addr[i+25];
printf("%02X ", png_data->color_type[i]);
}
printf("\n");
for(int i = 0; i < 1; i++) {
png_data->compression_method[i] = addr[i+26];
printf("%02X ", png_data->compression_method[i]);
}
printf("\n");
for(int i = 0; i < 1; i++) {
png_data->filter_method[i] = addr[i+27];
printf("%02X ", png_data->filter_method[i]);
}
printf("\n");
for(int i = 0; i < 1; i++) {
png_data->interlace_method[i] = addr[i+28];
printf("%02X ", png_data->interlace_method[i]);
}
printf("\n");
for(int i = 0; i < 4; i++) {
png_data->ihdr_crc[i] = addr[i+29];
printf("%02X ", png_data->ihdr_crc[i]);
}
printf("\n");
}
int create_cc_file(unsigned char *addr, unsigned long file_length) {
FILE *fp;
fp = fopen("png2.png", "w");