86 lines
2.4 KiB
C++
86 lines
2.4 KiB
C++
#include <sp/extensions/Compress.h>
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#include <cassert>
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#include <sp/common/VarInt.h>
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#include <zlib.h>
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namespace sp {
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namespace zlib {
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static DataBuffer Inflate(const std::uint8_t* source, std::size_t size, std::size_t uncompressedSize) {
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DataBuffer result;
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result.Resize(uncompressedSize);
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uncompress(static_cast<Bytef*>(result.data()), reinterpret_cast<uLongf*>(&uncompressedSize), static_cast<const Bytef*>(source),
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static_cast<uLong>(size));
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assert(result.GetSize() == uncompressedSize);
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return result;
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}
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static DataBuffer Deflate(const std::uint8_t* source, std::size_t size) {
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DataBuffer result;
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uLongf compressedSize = size;
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result.Resize(size); // Resize for the compressed data to fit into
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compress(static_cast<Bytef*>(result.data()), &compressedSize, static_cast<const Bytef*>(source), static_cast<uLong>(size));
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result.Resize(compressedSize); // Resize to cut useless data
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return result;
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}
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DataBuffer Compress(const DataBuffer& buffer, std::size_t a_CompressionThreshold) {
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DataBuffer packet;
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if (buffer.GetSize() < a_CompressionThreshold) {
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// Don't compress since it's a small packet
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packet << VarInt{0};
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packet << buffer;
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return packet;
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}
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DataBuffer compressedData = Deflate(buffer.data(), buffer.GetSize());
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VarInt uncompressedDataLength = buffer.GetSize();
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if (compressedData.GetSize() >= buffer.GetSize()) {
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// the compression is overkill so we don't send the compressed buffer
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packet << VarInt{0};
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packet << buffer;
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} else {
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packet << uncompressedDataLength;
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packet << compressedData;
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}
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return packet;
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}
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DataBuffer Decompress(DataBuffer& buffer, std::uint64_t packetLength) {
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VarInt uncompressedLength;
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buffer >> uncompressedLength;
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std::uint64_t compressedLength = packetLength - uncompressedLength.GetSerializedLength();
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if (uncompressedLength.GetValue() == 0) {
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// Data already uncompressed. Nothing to do
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DataBuffer ret;
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buffer.ReadSome(ret, compressedLength);
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return ret;
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}
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assert(buffer.GetReadOffset() + compressedLength <= buffer.GetSize());
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return Inflate(buffer.data() + buffer.GetReadOffset(), compressedLength, uncompressedLength.GetValue());
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}
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} // namespace zlib
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DataBuffer ZlibCompress::EncapsulateImpl(const DataBuffer& a_Data) {
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return zlib::Compress(a_Data, m_CompressionThreshold);
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}
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DataBuffer ZlibCompress::DecapsulateImpl(DataBuffer& a_Data) {
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return zlib::Decompress(a_Data, a_Data.GetSize());
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}
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} // namespace sp
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