compression.cpp

#include "prism/compression.h"

#include <zstd.h>

#include "prism/log.h"
#include "prism/system.h"
#include "prism/memoryhandler.h"

namespace prism {

	static const int COMPRESSION_BUFFER = 400;

	void compressBufferZSTD(Buffer* tBuffer)
	{
		if (!tBuffer->mIsOwned) {
			logError("Unable to compress unowned Buffer");
			recoverFromError();
		}

		char* src = (char*)tBuffer->mData;
		auto dstBufferSize = size_t(tBuffer->mLength + COMPRESSION_BUFFER);
		char* dst = (char*)allocMemory(int(dstBufferSize));
		auto dstLength = ZSTD_compress(dst, dstBufferSize, src, tBuffer->mLength, 1);
		dst = (char*)reallocMemory(dst, int(dstLength));

		freeBuffer(*tBuffer);
		*tBuffer = makeBufferOwned(dst, int(dstLength));
	}

	void decompressBufferZSTD(Buffer* tBuffer)
	{
		if (!tBuffer->mIsOwned) {
			logError("Unable to decompress unowned Buffer");
			recoverFromError();
		}

		char* src = (char*)tBuffer->mData;
		size_t uncompressedLength = (size_t)ZSTD_getFrameContentSize(src, tBuffer->mLength);

		char* dst = (char*)allocMemory(int(uncompressedLength));
		auto dstLength = ZSTD_decompress(dst, uncompressedLength, src, size_t(tBuffer->mLength));
		dst = (char*)reallocMemory(dst, int(dstLength));

		freeBuffer(*tBuffer);
		*tBuffer = makeBufferOwned(dst, uint32_t(dstLength));
	}

}