static int png_reverse_filter_iterate(rpng_t *rpng, uint32_t **data)
{
if (!rpng)
return false;
if (rpng->ihdr.interlace)
return png_reverse_filter_adam7(data, &rpng->ihdr, rpng->process);
return png_reverse_filter_regular_iterate(data, &rpng->ihdr, rpng->process);
}
bool rpng_load_image_argb(const char *path, uint32_t **data, unsigned *width, unsigned *height)
{
long pos;
*data = NULL;
*width = 0;
*height = 0;
bool ret = true;
FILE *file = fopen(path, "rb");
if (!file)
return false;
fseek(file, 0, SEEK_END);
long file_len = ftell(file);
rewind(file);
bool has_ihdr = false;
bool has_idat = false;
bool has_iend = false;
bool has_plte = false;
uint8_t *inflate_buf = NULL;
size_t inflate_buf_size = 0;
z_stream stream = {0};
struct idat_buffer idat_buf = {0};
struct png_ihdr ihdr = {0};
uint32_t palette[256] = {0};
char header[8];
if (fread(header, 1, sizeof(header), file) != sizeof(header))
GOTO_END_ERROR();
if (memcmp(header, png_magic, sizeof(png_magic)) != 0)
GOTO_END_ERROR();
// feof() apparently isn't triggered after a seek (IEND).
for (pos = ftell(file); pos < file_len && pos >= 0; pos = ftell(file))
{
struct png_chunk chunk = {0};
if (!read_chunk_header(file, &chunk))
GOTO_END_ERROR();
switch (png_chunk_type(&chunk))
{
case PNG_CHUNK_NOOP:
default:
if (fseek(file, chunk.size + sizeof(uint32_t), SEEK_CUR) < 0)
GOTO_END_ERROR();
break;
case PNG_CHUNK_ERROR:
GOTO_END_ERROR();
case PNG_CHUNK_IHDR:
if (has_ihdr || has_idat || has_iend)
GOTO_END_ERROR();
if (!png_parse_ihdr(file, &chunk, &ihdr))
GOTO_END_ERROR();
has_ihdr = true;
break;
case PNG_CHUNK_PLTE:
if (!has_ihdr || has_plte || has_iend || has_idat)
GOTO_END_ERROR();
if (chunk.size % 3)
GOTO_END_ERROR();
if (!png_read_plte(file, palette, chunk.size / 3))
GOTO_END_ERROR();
has_plte = true;
break;
case PNG_CHUNK_IDAT:
if (!has_ihdr || has_iend || (ihdr.color_type == 3 && !has_plte))
GOTO_END_ERROR();
if (!png_append_idat(file, &chunk, &idat_buf))
GOTO_END_ERROR();
has_idat = true;
break;
case PNG_CHUNK_IEND:
if (!has_ihdr || !has_idat)
GOTO_END_ERROR();
if (fseek(file, sizeof(uint32_t), SEEK_CUR) < 0)
GOTO_END_ERROR();
has_iend = true;
break;
}
}
if (!has_ihdr || !has_idat || !has_iend)
GOTO_END_ERROR();
if (inflateInit(&stream) != Z_OK)
GOTO_END_ERROR();
png_pass_geom(&ihdr, ihdr.width, ihdr.height, NULL, NULL, &inflate_buf_size);
if (ihdr.interlace == 1) // To be sure.
inflate_buf_size *= 2;
inflate_buf = (uint8_t*)malloc(inflate_buf_size);
if (!inflate_buf)
GOTO_END_ERROR();
stream.next_in = idat_buf.data;
stream.avail_in = idat_buf.size;
stream.avail_out = inflate_buf_size;
stream.next_out = inflate_buf;
if (inflate(&stream, Z_FINISH) != Z_STREAM_END)
{
inflateEnd(&stream);
GOTO_END_ERROR();
}
inflateEnd(&stream);
*width = ihdr.width;
*height = ihdr.height;
*data = (uint32_t*)malloc(ihdr.width * ihdr.height * sizeof(uint32_t));
if (!*data)
GOTO_END_ERROR();
if (ihdr.interlace == 1)
{
if (!png_reverse_filter_adam7(*data, &ihdr, inflate_buf, stream.total_out, palette))
GOTO_END_ERROR();
}
else if (!png_reverse_filter(*data, &ihdr, inflate_buf, stream.total_out, palette))
GOTO_END_ERROR();
end:
if (file)
fclose(file);
if (!ret)
free(*data);
free(idat_buf.data);
free(inflate_buf);
return ret;
}
