mirror of
https://github.com/NationalSecurityAgency/ghidra.git
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100 lines
4 KiB
C++
100 lines
4 KiB
C++
/* ###
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* IP: GHIDRA
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/// \file compression.hh
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/// \brief The Compress and Decompress classes wrapping the deflate and inflate algorithms
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#ifndef __COMPRESSION__
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#define __COMPRESSION__
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#include "error.hh"
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#ifdef LOCAL_ZLIB
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#include "../zlib/zlib.h"
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#else
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#include <zlib.h>
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#endif
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namespace ghidra {
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/// \brief Wrapper for the deflate algorithm
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///
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/// Initialize/free algorithm resources. Provide successive arrays of bytes to compress via
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/// the input() method. Compute successive arrays of compressed bytes via the deflate() method.
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class Compress {
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z_stream compStream; ///< The zlib deflate algorithm state
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public:
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Compress(int4 level); ///< Initialize the deflate algorithm state
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~Compress(void); ///< Free algorithm state resources
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/// \brief Provide the next sequence of bytes to be compressed
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///
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/// \param buffer is a pointer to the bytes to compress
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/// \param sz is the number of bytes
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void input(uint1 *buffer,int4 sz) {
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compStream.avail_in = sz;
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compStream.next_in = buffer;
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}
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int4 deflate(uint1 *buffer,int4 sz,bool finish); ///< Deflate as much as possible into given buffer
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};
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/// \brief Wrapper for the inflate algorithm
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///
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/// Initialize/free algorithm resources. Provide successive arrays of compressed bytes via
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/// the input() method. Compute successive arrays of uncompressed bytes via the inflate() method.
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class Decompress {
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z_stream compStream; ///< The zlib inflate algorithm state
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bool streamFinished; ///< Set to \b true if the end of the compressed stream has been reached
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public:
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Decompress(void); ///< Initialize the inflate algorithm state
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~Decompress(void); ///< Free algorithm state resources
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/// \brief Provide the next sequence of compressed bytes
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///
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/// \param buffer is a pointer to the compressed bytes
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/// \param sz is the number of bytes
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void input(uint1 *buffer,int4 sz) {
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compStream.next_in = buffer;
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compStream.avail_in = sz;
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}
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bool isFinished(void) const { return streamFinished; } ///< Return \b if end of compressed stream is reached
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int4 inflate(uint1 *buffer,int4 sz); ///< Inflate as much as possible into given buffer
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};
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/// \brief Stream buffer that performs compression
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///
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/// Provides an ostream filter that compresses the stream using the \e deflate algorithm.
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/// The stream buffer is provided a backing stream that is the ultimate destination of the compressed bytes.
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/// A front-end stream is initialized with \b this stream buffer.
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/// After writing the full sequence of bytes to compressed to the front-end stream, make sure to
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/// call the stream's flush() method to emit the final compressed bytes to the backing stream.
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class CompressBuffer : public std::streambuf {
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static const int4 IN_BUFFER_SIZE; ///< Number of bytes in the \e input buffer
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static const int4 OUT_BUFFER_SIZE; ///< Number of bytes in the \e output buffer
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ostream &outStream; ///< The backing stream receiving compressed bytes
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uint1 *inBuffer; ///< The \e input buffer
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uint1 *outBuffer; ///< The \e output buffer
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Compress compressor; ///< Compressor state
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protected:
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void flushInput(bool lastBuffer); ///< Compress the current set of bytes in the \e input buffer
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virtual int overflow(int c); ///< Pass the filled input buffer to the compressor
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virtual int sync(void); ///< Pass remaining bytes in the input buffer to the compressor
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public:
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CompressBuffer(ostream &s,int4 level); ///< Constructor
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~CompressBuffer(void); ///< Destructor
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};
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}
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#endif
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