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openmw/components/misc/compression.cpp

49 lines
1.9 KiB
C++

#include "compression.hpp"
#include <lz4.h>
#include <cstddef>
#include <cstring>
#include <stdexcept>
#include <string>
#include <vector>
namespace Misc
{
std::vector<std::byte> compress(const std::vector<std::byte>& data)
{
const std::size_t originalSize = data.size();
std::vector<std::byte> result(static_cast<std::size_t>(LZ4_compressBound(static_cast<int>(originalSize)) + sizeof(originalSize)));
const int size = LZ4_compress_default(
reinterpret_cast<const char*>(data.data()),
reinterpret_cast<char*>(result.data()) + sizeof(originalSize),
static_cast<int>(data.size()),
static_cast<int>(result.size() - sizeof(originalSize))
);
if (size == 0)
throw std::runtime_error("Failed to compress");
std::memcpy(result.data(), &originalSize, sizeof(originalSize));
result.resize(static_cast<std::size_t>(size) + sizeof(originalSize));
return result;
}
std::vector<std::byte> decompress(const std::vector<std::byte>& data)
{
std::size_t originalSize;
std::memcpy(&originalSize, data.data(), sizeof(originalSize));
std::vector<std::byte> result(originalSize);
const int size = LZ4_decompress_safe(
reinterpret_cast<const char*>(data.data()) + sizeof(originalSize),
reinterpret_cast<char*>(result.data()),
static_cast<int>(data.size() - sizeof(originalSize)),
static_cast<int>(result.size())
);
if (size < 0)
throw std::runtime_error("Failed to decompress");
if (originalSize != static_cast<std::size_t>(size))
throw std::runtime_error("Size of decompressed data (" + std::to_string(size)
+ ") doesn't match stored (" + std::to_string(originalSize) + ")");
return result;
}
}