Luna/lily_png
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now it has crc checks and uncompression is good now

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Luna 2025-07-06 14:28:35 +02:00
parent 2fbdd1e43d
commit a1f2a6d1af
4 changed files with 41 additions and 12 deletions
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3
CMakeLists.txt
View file

@ -4,7 +4,8 @@ project(lily_png)
set(CMAKE_CXX_STANDARD 23)
add_subdirectory(file_reader)
find_package(ZLIB)
add_library(lily_png STATIC lily_png.cpp)
target_link_libraries(lily_png file_read ZLIB::ZLIB)
target_link_libraries(lily_png file_read)

2
file_reader

@ -1 +1 @@
Subproject commit 35c95790edb62100e8f05d27f2cbe52ee11109df
Subproject commit 238f9a9b975ab97195b0982a08c8939e4eee2251

45
lily_png.cpp
View file

@ -1,7 +1,5 @@
#include "lily_png.h"
#include <iostream>
static metadata parse_metadata(buffer &data)
{
std::tuple<unsigned int, unsigned int, char, char, char, char, char> meta;
@ -23,7 +21,7 @@ static metadata parse_metadata(buffer &data)
return m;
}
buffer read_png(const std::string &file_path)
buffer_unsigned read_png(const std::string &file_path)
{
unsigned char magic[9] = {137, 80, 78, 71, 13, 10, 26, 10};
file_reader reader(file_path);
@ -36,7 +34,8 @@ buffer read_png(const std::string &file_path)
if (memcmp(magic, std::get<0>(head_tup).data, 8) != 0)
throw std::runtime_error("File is not a png");
metadata meta{0};
buffer image_data{0};
buffer_unsigned image_data_concat{0};
buffer_unsigned image_data{0};
while (true)
{
buffer chunk_type{0};
@ -50,21 +49,49 @@ buffer read_png(const std::string &file_path)
std::println("Header stats size {} type {}", std::get<0>(chunk_head), std::get<1>(chunk_head).data);
buffer data_body{0};
data_body.size = std::get<0>(chunk_head);
auto data = std::make_tuple(data_body, chunk_type);
auto data = std::make_tuple(data_body, (unsigned int)0);
auto ree = reader.read_from_tuple(data);
unsigned long crc = crc32(0, reinterpret_cast<unsigned char *>(std::get<1>(chunk_head).data), std::get<1>(chunk_head).size);
crc = crc32(crc, reinterpret_cast<unsigned char *>(std::get<0>(data).data), std::get<0>(data).size);
if (crc != std::get<1>(data))
throw std::runtime_error("Crc check failed");
std::println("Size received {}", ree.first);
if (strcmp("IHDR", std::get<1>(chunk_head).data) == 0)
meta = parse_metadata(std::get<0>(data));
else if (strcmp("IDAT", std::get<1>(chunk_head).data) == 0)
{
buffer &temp_buf = std::get<0>(data);
image_data.write(temp_buf.data, temp_buf.size);
image_data_concat.write(reinterpret_cast<unsigned char *>(temp_buf.data), temp_buf.size);
}
else if (strcmp("IEND",std::get<1>(chunk_head).data) == 0)
break;
}
std::println("Image data size {}", image_data.size);
std::println("Image data allocated {}", image_data.allocated);
std::println("Allocations {}", image_data.allocations);
std::println("Image data size {}", image_data_concat.size);
std::println("Image data allocated {}", image_data_concat.allocated);
std::println("Allocations {}", image_data_concat.allocations);
image_data.allocate(image_data_concat.allocated);
uncompress(image_data.data, &image_data.allocated, image_data_concat.data, image_data_concat.size);
std::println("Filter {}", (int)meta.filter);
switch (meta.filter)
{
case 0:
break;
case 1:
std::println("sub filter now implemented");
break;
case 2:
std::println("up filter now implemented");
break;
case 3:
std::println("average filter now implemented");
break;
case 4:
std::println("paeth filter now implemented");
break;
default:
std::println("Filter not recognised");
break;
}
return image_data;
}

3
lily_png.h
View file

@ -2,6 +2,7 @@
#include "file_reader/src/file_read.h"
#include <string>
#include <zlib.h>
struct metadata
{
@ -14,4 +15,4 @@ struct metadata
char interface;
};
buffer read_png(const std::string &file_path);
buffer_unsigned read_png(const std::string &file_path);