lily_png/lily_png.cpp

294 lines
8.2 KiB
C++

#include "lily_png.h"
#include <math.h>
static metadata parse_metadata(buffer &data)
{
std::tuple<unsigned int, unsigned int, char, char, char, char, char> meta;
constexpr std::size_t size = std::tuple_size_v<decltype(meta)>;
parsing_buffer par_buf(data);
par_buf.point = par_buf.buf.data;
par_buf.consumed_size = 0;
read_comp(size, par_buf, meta);
std::println("Width {} height {}", std::get<0>(meta), std::get<1>(meta));
metadata m{0};
m.width = std::get<0>(meta);
m.height = std::get<1>(meta);
m.bit_depth = std::get<2>(meta);
m.color_type = std::get<3>(meta);
m.compression = std::get<4>(meta);
m.filter = std::get<5>(meta);
m.interface = std::get<6>(meta);
std::println("metadata{{ width: {}, height: {}, bit_depth: {}, color_type: {}, compression: {}, filter: {}, interface: {} }}", m.width, m.height, (int)m.bit_depth, (int)m.color_type, (int)m.compression, (int)m.filter, (int)m.interface);
return m;
}
static size_t get_pixel_bit_size(const metadata &meta)
{
size_t ret = 0;
switch (meta.color_type)
{
case 0:
if (meta.bit_depth == 1 || meta.bit_depth == 2 || meta.bit_depth == 4 || meta.bit_depth == 8 || meta.bit_depth == 16)
{
ret = meta.bit_depth;
}
else
throw std::runtime_error("Invalid bit depht");
break;
case 2:
if (meta.bit_depth == 8 || meta.bit_depth == 16)
{
ret = meta.bit_depth * 3;
}
else
throw std::runtime_error("Invalid bit depht");
break;
case 3:
if (meta.bit_depth == 1 || meta.bit_depth == 2 || meta.bit_depth == 4 || meta.bit_depth == 8)
{
ret = meta.bit_depth;
}
else
throw std::runtime_error("Invalid bit depht");
break;
case 4:
if (meta.bit_depth == 8 || meta.bit_depth == 16)
{
ret = meta.bit_depth * 2;
}
else
throw std::runtime_error("Invalid bit depht");
break;
case 6:
if (meta.bit_depth == 8 || meta.bit_depth == 16)
{
ret = meta.bit_depth * 4;
}
else
throw std::runtime_error("Invalid bit depht");
break;
default:
throw std::runtime_error("Invalid color type");
}
return ret;
}
static size_t get_uncompressed_size(const metadata meta)
{
size_t ret = 0;
switch (meta.color_type)
{
case 0:
if (meta.bit_depth == 1 || meta.bit_depth == 2 || meta.bit_depth == 4 || meta.bit_depth == 8 || meta.bit_depth == 16)
{
size_t size_per_row = ceil((meta.width * (meta.bit_depth))/8) + 1;
ret = size_per_row * meta.height;
}
else
throw std::runtime_error("Invalid bit depht");
break;
case 2:
if (meta.bit_depth == 8 || meta.bit_depth == 16)
{
size_t size_per_row = ceil((meta.width * (meta.bit_depth * 3))/8) + 1;
ret = size_per_row * meta.height;
}
else
throw std::runtime_error("Invalid bit depht");
break;
case 3:
if (meta.bit_depth == 1 || meta.bit_depth == 2 || meta.bit_depth == 4 || meta.bit_depth == 8)
{
size_t size_per_row = ceil((meta.width * (meta.bit_depth))/8) + 1;
ret = size_per_row * meta.height;
}
else
throw std::runtime_error("Invalid bit depht");
break;
case 4:
if (meta.bit_depth == 8 || meta.bit_depth == 16)
{
size_t size_per_row = ceil((meta.width * (meta.bit_depth * 2))/8) + 1;
ret = size_per_row * meta.height;
}
else
throw std::runtime_error("Invalid bit depht");
break;
case 6:
if (meta.bit_depth == 8 || meta.bit_depth == 16)
{
size_t size_per_row = ceil((meta.width * (meta.bit_depth * 4))/8) + 1;
ret = size_per_row * meta.height;
}
else
throw std::runtime_error("Invalid bit depht");
break;
default:
throw std::runtime_error("Invalid color type");
}
std::println("Uncompressed size {}", ret);
return ret;
}
static void read_raw_data(const std::string &file_path, buffer_unsigned &data, metadata &meta)
{
unsigned char magic[9] = {137, 80, 78, 71, 13, 10, 26, 10};
file_reader reader(file_path);
char file_magic[9] = {0};
reader.read_buffer(file_magic, 8);
if (memcmp(magic, file_magic, 8) != 0)
{
std::println("File is not a png!");
return ;
}
buffer_unsigned raw_dat{};
while (true)
{
std::tuple<unsigned int, buffer> chunk_header;
std::get<1>(chunk_header).size = 4;
auto ret = reader.read_from_tuple(chunk_header);
if (ret.second == READ_FILE_ENDED || ret.second == READ_INCOMPLETE)
{
std::println("Chunk incomplete!");
return ;
}
std::println("Chunk type {} Size {}", std::get<1>(chunk_header).data, std::get<0>(chunk_header));
buffer_unsigned raw_data{};
raw_data.size = std::get<0>(chunk_header);
std::tuple<buffer, unsigned> dat;
std::get<0>(dat).size = std::get<0>(chunk_header);
ret = reader.read_from_tuple(dat);
if (ret.second == READ_FILE_ENDED || ret.second == READ_INCOMPLETE)
{
std::println("Chunk incomplete!");
return ;
}
unsigned long crc = crc32(0, reinterpret_cast<unsigned char *>(std::get<1>(chunk_header).data), 4);
crc = crc32(crc, reinterpret_cast<unsigned char *>(std::get<0>(dat).data), std::get<0>(chunk_header));
if (crc != std::get<1>(dat))
throw std::runtime_error("Crc check failed");
if (strncmp(std::get<1>(chunk_header).data, "IDAT", 4) == 0)
{
raw_dat.write(reinterpret_cast<unsigned char *>(std::get<0>(dat).data), std::get<0>(chunk_header));
}
else if (strncmp(std::get<1>(chunk_header).data, "IHDR", 4) == 0)
{
meta = parse_metadata(std::get<0>(dat));
}
else if (strncmp(std::get<1>(chunk_header).data, "IEND", 4) == 0)
break;
}
data.allocate(get_uncompressed_size(meta));
size_t prev_allocated = data.allocated;
int r = uncompress(data.data, &prev_allocated, raw_dat.data, raw_dat.allocated);
if (r != Z_OK)
{
std::println("Uncompress failed {}", r);
throw std::runtime_error("Uncompress fail");
}
}
template <typename T>
T paeth_predict(T a, T b, T c)
{
T pred = a+b-c;
T pred1 = abs(pred - a);
T pred2 = abs(pred - b);
T pred3 = abs(pred - c);
if (pred1 <= pred2 && pred1 <= pred3)
return a;
if (pred2 <= pred3)
return b;
return c;
}
static void filter(buffer_unsigned &data, buffer_unsigned &dest ,metadata &meta)
{
unsigned long index = 0;
unsigned long index_dest = 0;
size_t pixel_size = get_pixel_bit_size(meta);
unsigned long scanlines = 0;
dest.allocate(get_uncompressed_size(meta));
while (scanlines < meta.height)
{
unsigned char filter = 0;
for (int i = 0; i < (pixel_size/8) * meta.width + 1; i++)
{
if (i == 0)
{
filter = data.data[index + i];
continue;
}
long index_before = 0;
long index_before2 = 0;
long index_before3 = 0;
switch (filter)
{
case 0:
dest.data[index_dest] = data.data[index + i];
break;
case 1:
if (pixel_size < 8)
index_before = index + i - 1;
else
index_before = index + i - pixel_size/8;
if (index_before <= 0)
break;
dest.data[index_dest] = data.data[index + i] + dest.data[index_before];
break;
case 2:
index_before = (index + i) - (meta.width * (pixel_size/8));
if (index_before <= 0)
break;
dest.data[index_dest] = data.data[index + i] + dest.data[index_before];
break;
case 3:
if (pixel_size < 8)
index_before = index + i - 1;
else
index_before = index + i - pixel_size/8;
if (index_before <= 0)
break;
index_before2 = (index + i) - (meta.width * (pixel_size/8));
dest.data[index_dest] = data.data[index + i] + floor((dest.data[index_before] + dest.data[index_before2])/2);
break;
case 4:
if (pixel_size < 8)
index_before = index + i - 1;
else
index_before = index + i - pixel_size/8;
if (index_before <= 0)
break;
index_before2 = (index + i) - (meta.width * (pixel_size/8));
index_before3 = 0;
if (pixel_size < 8)
index_before3 = index_before2 + i - 1;
else
index_before3 = index_before2 + i - pixel_size/8;
if (index_before3 <= 0)
break;
dest.data[index_dest] = data.data[index + i] + paeth_predict(dest.data[index_before], dest.data[index_before2], dest.data[index_before3]);
break;
default:
std::println("Non standard filter");
break;
}
index_dest++;
}
index += (pixel_size/8) * meta.width + 1;
scanlines++;
}
}
void read_png(const std::string &file_path, buffer_unsigned &data)
{
buffer_unsigned tmp_data{};
metadata meta{0};
read_raw_data(file_path, tmp_data, meta);
filter(tmp_data, data, meta);
}