static int
queue_envelope_load_buffer(struct envelope *ep, char *evpbuf, size_t evpbufsize)
{
char evpbufcom[sizeof(struct envelope)];
char *evp;
size_t evplen;
evp = evpbuf;
evplen = evpbufsize;
if (env->sc_queue_flags & QUEUE_COMPRESS) {
evplen = uncompress_buffer(evp, evplen, evpbufcom, sizeof evpbufcom);
if (evplen == 0)
return (0);
evp = evpbufcom;
}
return (envelope_load_buffer(ep, evp, evplen));
}
int begin(char* base_file_name, unsigned char *png_buf, long long png_length) {
MY_PNG_READ_OFFSET = 0;
PNG_LENGTH = png_length;
ENTIRE_PNG_BUF = png_buf;
if (png_sig_cmp(ENTIRE_PNG_BUF, 0, 8) != 0) {
error(-1, "png_sig_cmp", E_INVALID);
return -1;
}
DEBUG_PRINT(("Initial png size is %lld bytes\n", PNG_LENGTH));
my_png_meta *pm = calloc(1, sizeof(my_png_meta));
my_init_libpng(pm);
//If libpng errors, we end up here
if (setjmp(png_jmpbuf(pm->read_ptr))) {
DEBUG_PRINT(("libpng called setjmp!\n"));
my_deinit_libpng(pm);
free(ENTIRE_PNG_BUF);
error(-1, "libpng", "libpng encountered an error\n");
return -1;
}
//Normally a file, but instead make it our buffer
void *read_io_ptr = png_get_io_ptr(pm->read_ptr);
png_set_read_fn(pm->read_ptr, read_io_ptr, my_png_read_fn);
//Transform all PNG image types to RGB
int transforms =
PNG_TRANSFORM_GRAY_TO_RGB |
PNG_TRANSFORM_STRIP_ALPHA |
PNG_TRANSFORM_EXPAND;
png_read_png(pm->read_ptr, pm->info_ptr, transforms, NULL);
//Now that it was read and transformed, its size will differ
PNG_LENGTH = 0;
//Lets collect our metadata
struct ihdr_infos_s ihdr_infos;
ihdr_infos.bit_depth = png_get_bit_depth(pm->read_ptr, pm->info_ptr);
ihdr_infos.color_type = png_get_color_type(pm->read_ptr, pm->info_ptr);
ihdr_infos.filter_method = png_get_filter_type(pm->read_ptr, pm->info_ptr);
ihdr_infos.compression_type = png_get_compression_type(pm->read_ptr, pm->info_ptr);
ihdr_infos.interlace_type = png_get_interlace_type(pm->read_ptr, pm->info_ptr);
ihdr_infos.height = png_get_image_height(pm->read_ptr, pm->info_ptr);
ihdr_infos.width = png_get_image_width(pm->read_ptr, pm->info_ptr);
if (ihdr_infos.color_type != 2) {
DEBUG_PRINT((E_INVALID));
free(ENTIRE_PNG_BUF);
my_deinit_libpng(pm);
DEBUG_PRINT(("Looks like libpng could not correctly convert to RGB\n"));
return -1;
}
//Just in case we want to enable alpha, etc
switch(ihdr_infos.color_type) {
case 0: //greyscale
case 3: //indexed
ihdr_infos.bytes_per_pixel = 1;
break;
case 4: ihdr_infos.bytes_per_pixel = 2; break; //greyscale w/ alpha
case 2: ihdr_infos.bytes_per_pixel = 3; break; //Truecolour (RGB)
case 6: ihdr_infos.bytes_per_pixel = 4; break; //Truecolour w/ alpha
default: error_fatal(1, "ihdr_infos", "Unknown image type"); //should never happen
}
ihdr_infos.scanline_len = (ihdr_infos.bytes_per_pixel * ihdr_infos.width) + 1;
DEBUG_PRINT(("HEIGHT: %u\n", ihdr_infos.height));
DEBUG_PRINT(("WIDTH: %u\n", ihdr_infos.width));
DEBUG_PRINT(("BIT_DEPTH: %u\n", ihdr_infos.bit_depth));
// Don't compress, since we are merely copying it to memory,
// we will be decompressing it again anyway
png_set_compression_level(pm->write_ptr, Z_NO_COMPRESSION);
void *write_io_ptr = png_get_io_ptr(pm->write_ptr);
png_set_write_fn(pm->write_ptr, write_io_ptr, my_png_write_fn, my_png_dummy_flush);
//Make sure we use all filters
png_set_filter(pm->write_ptr, 0,
PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE |
PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB |
PNG_FILTER_UP | PNG_FILTER_VALUE_UP |
PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG |
PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH);
//Set our comment
struct png_text_struct comment_struct;
comment_struct.compression = -1;
comment_struct.key = " Glitched by pnglitch.xyz ";
comment_struct.text = NULL;
comment_struct.text_length = 0;
png_set_text(pm->write_ptr, pm->info_ptr, &comment_struct, 1);
//Buffer is Written using callback my_png_write_fn to buffer
//ENTIRE_PNG_BUF. PNG_LENGTH will be updated automatically by it
png_write_png(pm->write_ptr, pm->info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
my_deinit_libpng(pm);
DEBUG_PRINT(("libpng output buf is %lld bytes\n", PNG_LENGTH));
//Now that libpng has converted the image
//and we have it in a buffer, we process it by hand with zlib
struct z_stream_s inflate_stream;
my_init_zlib(&inflate_stream);
inflateInit(&inflate_stream);
//Pointer to keep track of where we are
unsigned char *pngp = ENTIRE_PNG_BUF;
//Skip PNG Signature
pngp += 8;
//Get Header
unsigned char ihdr_bytes_buf[4+4+13+4]; // size + label + content + crc
buf_read(ihdr_bytes_buf, &pngp, 4+4+13+4);
//When we run into non-idat chunks, we will want to preserve them.
//The spec says there's no chunk that needs to go after IDAT,
//so we can simply concatenate all of these chunks into a buffer
//then write them all at once after the IHDR
//ancillary chunks, eg comments
unsigned char *ancil_chunks_buf = calloc(1,1);
long long ancil_chunks_len = 0;
unsigned char *unzip_idats_buf = calloc(1, 1);
long unzip_buf_len = 1;
long unzip_buf_offset = 0;
long long zipped_idats_len = 0; //Length of all idats as we read them
unsigned long accum_png_len = 8 + (4+4+13+4);
int chunk_count = 0;
printf("Uncompressing image data...\n");
while (1) {
unsigned char chunk_label[4];
unsigned char chunk_len_buf[4];
buf_read(chunk_len_buf, &pngp, 4);
//first 4 bytes are the length of data section
long chunk_len = four_bytes_to_int(chunk_len_buf);
accum_png_len += chunk_len + 4 + 4 + 4; // plus len, crc, label
DEBUG_PRINT(("at %lu --> %lld\n", accum_png_len, PNG_LENGTH));
//leave at end of buffer
if (accum_png_len >= PNG_LENGTH)
break;
//read the chunk label (name of this header)
buf_read(chunk_label, &pngp, 4);
DEBUG_PRINT(("Reading chunk %d with label '%c%c%c%c', size %ld\n",
chunk_count, chunk_label[0], chunk_label[1], chunk_label[2],
chunk_label[3], chunk_len));
chunk_count += 1;
if (memcmp(chunk_label, "IDAT", 4) == 0) {
zipped_idats_len += chunk_len;
//read the chunk's data section
unsigned char *raw_chunk_buf = calloc(chunk_len, 1);
buf_read(raw_chunk_buf, &pngp, chunk_len);
//Tell inflate to uncompress it
inflate_stream.next_in = raw_chunk_buf;
inflate_stream.avail_in = chunk_len;
//Now uncompress it (resizes buffer automatically)
unsigned char *check_uncompress = uncompress_buffer(&inflate_stream,
unzip_idats_buf, &unzip_buf_len, &unzip_buf_offset);
//Stop if error
if (check_uncompress == NULL) {
DEBUG_PRINT((E_GLITCH));
free(ancil_chunks_buf);
free(raw_chunk_buf);
free(unzip_idats_buf);
free(ENTIRE_PNG_BUF);
return -1;
}
//Moving on
unzip_idats_buf = check_uncompress;
free(raw_chunk_buf);
pngp += 4; // skip CRC
} else { //This is not an idat
ancil_chunks_buf = realloc(ancil_chunks_buf,
ancil_chunks_len + 4 + 4 + chunk_len + 4); //make room for new data
//append length and label bytes
append_bytes(ancil_chunks_buf, chunk_len_buf, &ancil_chunks_len, 4);
append_bytes(ancil_chunks_buf, chunk_label, &ancil_chunks_len, 4);
//append chunk data
unsigned char *raw_chunk_buf = calloc(chunk_len, 1);
buf_read(raw_chunk_buf, &pngp, chunk_len);
append_bytes(ancil_chunks_buf, raw_chunk_buf, &ancil_chunks_len, chunk_len );
//append chunk crc
unsigned char chunk_crc_buf[4];
buf_read(chunk_crc_buf, &pngp, 4);
append_bytes(ancil_chunks_buf, chunk_crc_buf, &ancil_chunks_len, 4);
free(raw_chunk_buf);
DEBUG_PRINT(("ancillary chunks length: %lld\n", ancil_chunks_len));
}
}
//buf contains all idats uncompressed, concatenated
unsigned long unzipped_idats_len = inflate_stream.total_out;
unzip_idats_buf = realloc(unzip_idats_buf, unzipped_idats_len);
//we already have ancillary chunks and idats, don't need the original
free(ENTIRE_PNG_BUF);
inflateEnd(&inflate_stream);
printf("Uncompressed %lld bytes to %ld bytes\n", zipped_idats_len, unzipped_idats_len);
printf("Glitching image data...\n");
for (int g=0;g<NUM_OUTPUT_FILES;g++) {
//do glitches
switch(g) {
case 5:
glitch_random(unzip_idats_buf, unzipped_idats_len,
ihdr_infos.scanline_len, 0.0005);
break;
case 6:
glitch_random_filter(unzip_idats_buf, unzipped_idats_len,
ihdr_infos.scanline_len);
break;
default:
glitch_filter(unzip_idats_buf, unzipped_idats_len,
ihdr_infos.scanline_len, g);
}
//recompress so we can write them to file
long long glitched_idats_len = 0;
unsigned char *glitched_idats = zip_idats(unzip_idats_buf,
unzipped_idats_len, &glitched_idats_len);
if (glitched_idats == NULL) {
DEBUG_PRINT((E_GLITCH));
free (unzip_idats_buf);
free (ancil_chunks_buf);
return -1;
}
char path[MAX_PATH_LENGTH];
bzero(path, MAX_PATH_LENGTH);
snprintf(path, MAX_PATH_LENGTH, "%s%s%s-%d.png", OUTPUT_DIRECTORY, DIR_SEP,
base_file_name, g);
DEBUG_PRINT(("Output file name is %s\n", path));
FILE *outfp = fopen(path, "wb");
write_glitched_image(glitched_idats, glitched_idats_len, ihdr_bytes_buf,
ancil_chunks_buf, ancil_chunks_len, outfp);
printf("%s\n", path);
fflush(stdout);
fclose(outfp);
free(glitched_idats);
}
free(ancil_chunks_buf);
free(unzip_idats_buf);
return 0;
}
