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Documentation                       Search   bit_mem_stream.cpp Go to the documentation of this file. /* Copyright, 2000, 2001 Nevrax Ltd. * * This file is part of NEVRAX NEL. * NEVRAX NEL is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * NEVRAX NEL is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * You should have received a copy of the GNU General Public License * along with NEVRAX NEL; see the file COPYING. If not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, * MA 02111-1307, USA. */ #include "stdmisc.h" #include "nel/misc/bit_mem_stream.h" using namespace std; namespace NLMISC { /* * Constructor */ CBitMemStream::CBitMemStream( bool inputStream, uint32 defaultcapacity ) : CMemStream( inputStream, false, defaultcapacity ), _FreeBits( 8 ) { _BufPos--; } /* * Copy constructor */ CBitMemStream::CBitMemStream( const CBitMemStream& other ) : CMemStream( other ), _FreeBits( other._FreeBits ) { } /* * Serialize a buffer */ void CBitMemStream::serialBuffer( uint8 *buf, uint len ) { uint i; uint32 v; if ( isReading() ) { for ( i=0; i!=len; ++i ) { serial( v, 8 ); buf[i] = (uint8)v; } } else { for ( i=0; i!=len; ++i ) { v = (uint32)buf[i]; serial( v, 8 ); } } } /* * Serialize one bit */ void CBitMemStream::serialBit( bool& bit ) { uint32 ubit=0; if ( isReading() ) { serial( ubit, 1 ); bit = ( ubit!=0 ); } else { ubit = bit; serial( ubit, 1 ); } } //sint32 CBitMemStream::getPosInBit () #define displayByteBits(a,b,c) /*void displayByteBits( uint8 b, uint nbits, sint beginpos ) { string s1, s2; sint i; for ( i=nbits-1; i!=-1; --i ) { s1 += ( (b >> i) & 1 ) ? "1" : "0"; } nlinfo( "%s", s1.c_str() ); for ( i=nbits; i>beginpos+1; --i ) { s2 += " "; } s2 += "^"; nlinfo( "%s beginpos=%u", s2.c_str(), beginpos ); }*/ #define displayDwordBits(a,b,c) /*void displayDwordBits( uint32 b, uint nbits, sint beginpos ) { string s1, s2; sint i; for ( i=nbits-1; i!=-1; --i ) { s1 += ( (b >> i) & 1 ) ? "1" : "0"; } nlinfo( "%s", s1.c_str() ); for ( i=nbits; i>beginpos+1; --i ) { s2 += " "; } s2 += "^"; nlinfo( "%s beginpos=%u", s2.c_str(), beginpos ); }*/ /* * Serialize only the nbits lower bits of value */ void CBitMemStream::serial( uint32& value, uint nbits, bool resetvalue ) { //nlassert( (nbits <= 32) && (nbits != 0) ); if (nbits>32 || nbits==0) throw EMemStream (string("trying to serial ")+toString(nbits)+string(" %d bits")); if ( isReading() ) { // Check that we don't read more than there is to read if (getPosInBit() + nbits > lengthR() * 8) { throw EStreamOverflow(); } if ( resetvalue ) { value = 0; } // Clear high-order bits after _FreeBits uint8 v = *_BufPos & ((1 << _FreeBits) - 1); if ( nbits > _FreeBits ) { //nldebug( "Reading byte %u from %u free bits (%u remaining bits)", lengthS(), _FreeBits, nbits ); value |= (v << (nbits-_FreeBits)); ++_BufPos; uint readbits = _FreeBits; displayByteBits( *_BufPos, 8, readbits-1 ); _FreeBits = 8; serial( value, nbits - readbits, false ); // read without resetting value } else { //nlinfo( "Reading last byte %u from %u free bits (%u remaining bits)", lengthS(), _FreeBits, nbits ); //displayByteBits( *_BufPos, 8, _FreeBits-1 ); value |= (v >> (_FreeBits-nbits)); displayByteBits( *_BufPos, 8, _FreeBits-1 ); if ( _FreeBits == nbits ) { _FreeBits = 8; ++_BufPos; } else { _FreeBits -= nbits; } } } else { // Resize if necessary if ( _FreeBits == 8 ) // _FreeBits is from 7 downto 1, then 8 { if (_BufPos == _Buffer.getPtr()+_Buffer.size() - 1) { // need to resize _Buffer.resize(_Buffer.size()*2+1); _BufPos = _Buffer.getPtr() + ((_Buffer.size()-1)/2); } else { _BufPos++; } // _Buffer.push_back(0); // _BufPos = _Buffer.end() - 1; *_BufPos = 0; } // Clear high-order bits after nbits //displayDwordBits( value, 32, nbits-1 ); //uint32 mask = (-1 >> (32-nbits)); // does not work uint32 v; if ( nbits != 32 ) // arg of shl/sal/shr/sal ranges from 0 to 31 { uint32 mask = (1 << nbits) - 1; v = value & mask; } else { v = value; } // Set if ( nbits > _FreeBits ) { // Longer than the room in the current byte //nldebug( "Writing byte %u into %u free bits (%u remaining bits)", lengthS(), _FreeBits, nbits ); displayDwordBits( value, 32, nbits-1 ); *_BufPos |= (v >> (nbits - _FreeBits)); uint filledbits = _FreeBits; displayByteBits( *_BufPos, 8, filledbits-1 ); _FreeBits = 8; serial( v, nbits - filledbits ); } else { // Shorter or equal //nldebug( "Writing last byte %u into %u free bits (%u remaining bits)", lengthS(), _FreeBits, nbits ); displayByteBits( *_BufPos, 8, 7 ); *_BufPos |= (v << (_FreeBits-nbits)); displayByteBits( *_BufPos, 8, _FreeBits-1 ); _FreeBits = ((_FreeBits-1 - nbits) % 8) + 1; // ((uint)-1) % 8 equals 7 } } } /* * Serial float */ void CBitMemStream::serial(float &b) { uint32 uf=0; if ( isReading() ) { serial( uf ); b = *(float*)&uf; } else { uf = *(uint32*)&b; serial( uf ); } } /* * Serial string */ void CBitMemStream::serial(std::string &b) { uint32 len=0; // Serialize length if ( isReading() ) { serial( len ); if (len > length()-getPos()) { nlwarning("string maximum length reached, perhaps invalid string size (%d)", len); throw NLMISC::EInvalidDataStream(); } b.resize( len ); } else { len = b.size(); serial( len ); } // Serialize buffer if ( len != 0 ) { serialBuffer( (uint8*)(&*b.begin()), len ); } } /* * Serial string */ void CBitMemStream::serial(CBitMemStream &b) { uint32 len=0; // Serialize length if ( isReading() ) { // fill b with data from this serial (len); if (len > length()-getPos()) { nlwarning("bitmemstream maximum length reached, perhaps invalid bitmemstream size (%d)", len); throw NLMISC::EInvalidDataStream(); } serialBuffer (b.bufferToFill (len), len); b.resetBufPos (); } else { // fill this with data from b len = b.length(); serial( len ); serialBuffer( (uint8*) b.buffer (), len ); } } /* * Specialisation of serialCont() for vector<bool> */ void CBitMemStream::serialCont(std::vector<bool> &cont) { sint32 len=0; if(isReading()) { serial(len); if (len/8 > (sint32)(length()-getPos())) { nlwarning("stl container maximum length reached, perhaps invalid container size (%d)", len); throw NLMISC::EInvalidDataStream(); } // special version for vector: adjut good size. contReset(cont); cont.reserve(len); for(sint i=0;i<len;i++) { bool v; serialBit(v); cont.insert(cont.end(), v); } } else { len= cont.size(); serial(len); std::vector<bool>::iterator it= cont.begin(); for(sint i=0;i<len;i++, it++) { bool b = *it; serialBit( b ); } } } } // NLMISC