static bool png_parse_ihdr(FILE *file, struct png_chunk *chunk, struct png_ihdr *ihdr)
{
unsigned i;
bool ret = true;
if (!png_read_chunk(file, chunk))
return false;
if (chunk->size != 13)
GOTO_END_ERROR();
ihdr->width = dword_be(chunk->data + 0);
ihdr->height = dword_be(chunk->data + 4);
ihdr->depth = chunk->data[8];
ihdr->color_type = chunk->data[9];
ihdr->compression = chunk->data[10];
ihdr->filter = chunk->data[11];
ihdr->interlace = chunk->data[12];
if (ihdr->width == 0 || ihdr->height == 0)
GOTO_END_ERROR();
if (ihdr->color_type == 2 || ihdr->color_type == 4 || ihdr->color_type == 6)
{
if (ihdr->depth != 8 && ihdr->depth != 16)
GOTO_END_ERROR();
}
else if (ihdr->color_type == 0)
{
static const unsigned valid_bpp[] = { 1, 2, 4, 8, 16 };
bool correct_bpp = false;
for (i = 0; i < ARRAY_SIZE(valid_bpp); i++)
{
if (valid_bpp[i] == ihdr->depth)
{
correct_bpp = true;
break;
}
}
if (!correct_bpp)
GOTO_END_ERROR();
}
else if (ihdr->color_type == 3)
{
static const unsigned valid_bpp[] = { 1, 2, 4, 8 };
bool correct_bpp = false;
for (i = 0; i < ARRAY_SIZE(valid_bpp); i++)
{
if (valid_bpp[i] == ihdr->depth)
{
correct_bpp = true;
break;
}
}
if (!correct_bpp)
GOTO_END_ERROR();
}
else
GOTO_END_ERROR();
#ifdef RPNG_TEST
fprintf(stderr, "IHDR: (%u x %u), bpc = %u, palette = %s, color = %s, alpha = %s, adam7 = %s.\n",
ihdr->width, ihdr->height,
ihdr->depth, ihdr->color_type == 3 ? "yes" : "no",
ihdr->color_type & 2 ? "yes" : "no",
ihdr->color_type & 4 ? "yes" : "no",
ihdr->interlace == 1 ? "yes" : "no");
#endif
if (ihdr->compression != 0)
GOTO_END_ERROR();
//if (ihdr->interlace != 0) // No Adam7 supported.
// GOTO_END_ERROR();
end:
png_free_chunk(chunk);
return ret;
}
static bool rpng_load_image_argb_iterate(FILE **fd, rpng_t *rpng)
{
struct png_chunk chunk = {0};
FILE *file = *fd;
if (!read_chunk_header_fio(fd, &chunk))
return false;
switch (png_chunk_type(&chunk))
{
case PNG_CHUNK_NOOP:
default:
if (fseek(file, chunk.size + sizeof(uint32_t), SEEK_CUR) < 0)
return false;
break;
case PNG_CHUNK_ERROR:
return false;
case PNG_CHUNK_IHDR:
if (rpng_is_valid(rpng))
return false;
if (!png_parse_ihdr_fio(fd, &chunk, &rpng->ihdr))
{
png_free_chunk(&chunk);
return false;
}
if (!png_process_ihdr(&rpng->ihdr))
{
png_free_chunk(&chunk);
return false;
}
png_free_chunk(&chunk);
rpng->has_ihdr = true;
break;
case PNG_CHUNK_PLTE:
{
uint8_t buf[256 * 3];
unsigned entries = chunk.size / 3;
if (!rpng->has_ihdr || rpng->has_plte || rpng->has_iend || rpng->has_idat)
return false;
if (chunk.size % 3)
return false;
if (entries > 256)
return false;
if (fread(rpng->palette, 3, entries, *fd) != entries)
return false;
if (!png_read_plte(&buf[0], rpng->palette, entries))
return false;
if (fseek(*fd, sizeof(uint32_t), SEEK_CUR) < 0)
return false;
rpng->has_plte = true;
}
break;
case PNG_CHUNK_IDAT:
if (!rpng->has_ihdr || rpng->has_iend || (rpng->ihdr.color_type == PNG_IHDR_COLOR_PLT && !rpng->has_plte))
return false;
if (!png_realloc_idat(&chunk, &rpng->idat_buf))
return false;
if (fread(rpng->idat_buf.data + rpng->idat_buf.size, 1, chunk.size, file) != chunk.size)
return false;
if (fseek(file, sizeof(uint32_t), SEEK_CUR) < 0)
return false;
rpng->idat_buf.size += chunk.size;
rpng->has_idat = true;
break;
case PNG_CHUNK_IEND:
if (!rpng->has_ihdr || !rpng->has_idat)
return false;
if (fseek(file, sizeof(uint32_t), SEEK_CUR) < 0)
return false;
rpng->has_iend = true;
break;
}
return true;
}