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#include <exception>
#include "grey.hpp"
#include <arpa/inet.h>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"
static void push_in_network_order(std::uint32_t input, std::vector<std::uint8_t>& output)
{
input = htonl(input);
auto pointer_range = reinterpret_cast<std::uint8_t *>(&input);
std::copy(pointer_range, pointer_range + 4, std::back_inserter(output));
}
static std::uint32_t pop_in_native_order(std::string::const_iterator& input)
{
std::uint32_t in_native = ntohl(*reinterpret_cast<const std::uint32_t *>(&*input));
input += 4;
return in_native;
}
std::vector<std::uint8_t> to_rle(const std::filesystem::path& input)
{
int x, y, n;
unsigned char *data = stbi_load(input.native().data(), &x, &y, &n, 1);
if (data == nullptr)
{
throw std::runtime_error(stbi_failure_reason());
}
unsigned char *original_data = data;
std::uint8_t current_color = 255;
std::uint32_t current_count = 0;
std::vector<std::uint8_t> rle_stream;
push_in_network_order(x, rle_stream);
push_in_network_order(y, rle_stream);
push_in_network_order(1, rle_stream);
for (std::size_t i = 0; i < x; ++i)
{
for (std::size_t j = 0; j < y; ++j)
{
if (current_color == *data)
{
++current_count;
}
else
{
current_color = current_color == 255 ? 0 : 255;
push_in_network_order(current_count, rle_stream);
current_count = 1;
}
++data;
}
}
stbi_image_free(original_data);
if (current_count != 0)
{
push_in_network_order(current_count, rle_stream);
}
return rle_stream;
}
void from_rle(const std::string& input, const std::filesystem::path& output)
{
std::vector<std::uint8_t> buffer;
auto input_position = std::cbegin(input);
int x = pop_in_native_order(input_position);
int y = pop_in_native_order(input_position);
int comp = pop_in_native_order(input_position);
std::uint8_t current_color = 255;
std::uint32_t current_count = 0;
while (input_position != std::cend(input))
{
auto in_native = pop_in_native_order(input_position);
for (; in_native > 0; --in_native)
{
buffer.push_back(current_color);
}
current_color = current_color == 255 ? 0 : 255;
}
stbi_write_jpg(output.native().data(), x, y, comp, buffer.data(), 100);
}
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