diff options
Diffstat (limited to 'plugins/CryptoPP/crypto/zlib.cpp')
| -rw-r--r-- | plugins/CryptoPP/crypto/zlib.cpp | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/plugins/CryptoPP/crypto/zlib.cpp b/plugins/CryptoPP/crypto/zlib.cpp new file mode 100644 index 0000000000..528f809122 --- /dev/null +++ b/plugins/CryptoPP/crypto/zlib.cpp @@ -0,0 +1,90 @@ +// zlib.cpp - written and placed in the public domain by Wei Dai
+
+// "zlib" is the name of a well known C language compression library
+// (http://www.zlib.org) and also the name of a compression format
+// (RFC 1950) that the library implements. This file is part of a
+// complete reimplementation of the zlib compression format.
+
+#include "pch.h"
+#include "zlib.h"
+#include "zdeflate.h"
+#include "zinflate.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+static const byte DEFLATE_METHOD = 8;
+static const byte FDICT_FLAG = 1 << 5;
+
+// *************************************************************
+
+void ZlibCompressor::WritePrestreamHeader()
+{
+ m_adler32.Restart();
+ byte cmf = DEFLATE_METHOD | ((GetLog2WindowSize()-8) << 4);
+ byte flags = GetCompressionLevel() << 6;
+ AttachedTransformation()->PutWord16(RoundUpToMultipleOf(cmf*256+flags, 31));
+}
+
+void ZlibCompressor::ProcessUncompressedData(const byte *inString, size_t length)
+{
+ m_adler32.Update(inString, length);
+}
+
+void ZlibCompressor::WritePoststreamTail()
+{
+ FixedSizeSecBlock<byte, 4> adler32;
+ m_adler32.Final(adler32);
+ AttachedTransformation()->Put(adler32, 4);
+}
+
+unsigned int ZlibCompressor::GetCompressionLevel() const
+{
+ static const unsigned int deflateToCompressionLevel[] = {0, 1, 1, 1, 2, 2, 2, 2, 2, 3};
+ return deflateToCompressionLevel[GetDeflateLevel()];
+}
+
+// *************************************************************
+
+ZlibDecompressor::ZlibDecompressor(BufferedTransformation *attachment, bool repeat, int propagation)
+ : Inflator(attachment, repeat, propagation)
+{
+}
+
+void ZlibDecompressor::ProcessPrestreamHeader()
+{
+ m_adler32.Restart();
+
+ byte cmf;
+ byte flags;
+
+ if (!m_inQueue.Get(cmf) || !m_inQueue.Get(flags))
+ throw HeaderErr();
+
+ if ((cmf*256+flags) % 31 != 0)
+ throw HeaderErr(); // if you hit this exception, you're probably trying to decompress invalid data
+
+ if ((cmf & 0xf) != DEFLATE_METHOD)
+ throw UnsupportedAlgorithm();
+
+ if (flags & FDICT_FLAG)
+ throw UnsupportedPresetDictionary();
+
+ m_log2WindowSize = 8 + (cmf >> 4);
+}
+
+void ZlibDecompressor::ProcessDecompressedData(const byte *inString, size_t length)
+{
+ AttachedTransformation()->Put(inString, length);
+ m_adler32.Update(inString, length);
+}
+
+void ZlibDecompressor::ProcessPoststreamTail()
+{
+ FixedSizeSecBlock<byte, 4> adler32;
+ if (m_inQueue.Get(adler32, 4) != 4)
+ throw Adler32Err();
+ if (!m_adler32.Verify(adler32))
+ throw Adler32Err();
+}
+
+NAMESPACE_END
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