199 lines
6.1 KiB
C++
Executable File
199 lines
6.1 KiB
C++
Executable File
/*===========================================================================
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FILE:
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BitParser.h
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DESCRIPTION:
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Declaration of cBitParser class
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PUBLIC CLASSES AND METHODS:
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cBitParser
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This class extracts bits from a buffer
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Copyright (c) 2011, Code Aurora Forum. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of Code Aurora Forum nor
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the names of its contributors may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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===========================================================================*/
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//---------------------------------------------------------------------------
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// Pragmas
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//---------------------------------------------------------------------------
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#pragma once
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//---------------------------------------------------------------------------
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// Definitions
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//---------------------------------------------------------------------------
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// Number of bits in a byte
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const ULONG BITS_PER_BYTE = 8;
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// Maximum number of bits we will parse for any supported type
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const ULONG MAX_TYPE_BITS = (ULONG)sizeof(ULONGLONG) * BITS_PER_BYTE;
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/*===========================================================================
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METHOD:
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ByteSwap (Inline Public Method)
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DESCRIPTION:
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Changes little-endian values to big-endian, and vice versa
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PARAMETERS:
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data [ I ] - Data being byte-swapped
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RETURN VALUE:
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None
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===========================================================================*/
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template <class T>
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void ByteSwap( T & data )
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{
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// Just reverse the order of the bytes
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PBYTE pL;
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PBYTE pR;
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for (pL = (PBYTE)&data, pR = pL + sizeof( T ) - 1; pL < pR; ++pL, --pR)
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{
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*pL = *pL ^ *pR;
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*pR = *pL ^ *pR;
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*pL = *pL ^ *pR;
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}
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};
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/*=========================================================================*/
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// Class cBitParser
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//
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// Class to assist in parsing a buffer into bit/byte specified fields
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/*=========================================================================*/
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class cBitParser
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{
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public:
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// Constructor (default)
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cBitParser();
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// Constructor (from a buffer)
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cBitParser(
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const BYTE * pData,
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ULONG dataBitSize );
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// Destructor
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~cBitParser();
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// (Inline) Returns the number of bits left in the buffer (from the
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// current working bit offset)
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ULONG GetNumBitsLeft() const
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{
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return (mMaxOffset - mOffset);
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};
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// (Inline) Returns the number of bits in the buffer that have been
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// processed (essentially the current working bit offset)
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ULONG GetNumBitsParsed() const
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{
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return (mOffset);
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};
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// (Inline) Set current working bit offset
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void SetOffset( ULONG offset )
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{
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mOffset = offset;
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if (mOffset > mMaxOffset)
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{
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mOffset = mMaxOffset;
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}
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};
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// (Inline) Are we parsing LSB -> MSB (the default)?
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bool GetLSBMode()
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{
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return mbLSB;
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};
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// (Inline) Parse LSB -> MSB (if true) or MSB -> LSB
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void SetLSBMode( bool bLSB )
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{
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mbLSB = bLSB;
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};
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// Return 'numBits' as a CHAR (advances offset)
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DWORD Get(
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ULONG numBits,
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CHAR & dataOut );
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// Return 'numBits' as a SHORT (advances offset)
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DWORD Get(
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ULONG numBits,
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SHORT & dataOut );
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// Return 'numBits' as a LONG (advances offset)
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DWORD Get(
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ULONG numBits,
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LONG & dataOut );
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// Return 'numBits' as a LONGLONG (advances offset)
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DWORD Get(
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ULONG numBits,
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LONGLONG & dataOut );
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// Return 'numBits' as a UCHAR (advances offset)
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DWORD Get(
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ULONG numBits,
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UCHAR & dataOut );
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// Return 'numBits' as a USHORT (advances offset)
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DWORD Get(
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ULONG numBits,
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USHORT & dataOut );
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// Return 'numBits' as a ULONG (advances offset)
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DWORD Get(
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ULONG numBits,
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ULONG & dataOut );
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// Return 'numBits' as a ULONGLONG (advances offset)
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DWORD Get(
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ULONG numBits,
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ULONGLONG & dataOut );
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// Release the data being parsed
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void ReleaseData();
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// Set the data being parsed
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void SetData(
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const BYTE * pData,
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ULONG dataBitSize );
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protected:
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/* Data buffer */
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const BYTE * mpData;
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/* Current bit-specified offset */
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ULONG mOffset;
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/* Maximum bit-specified offset */
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ULONG mMaxOffset;
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/* Are we parsing LSB -> MSB (the default)? */
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bool mbLSB;
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};
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