Claw
1.7.3
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00001 /* 00002 CLAW - a C++ Library Absolutely Wonderful 00003 00004 CLAW is a free library without any particular aim but being useful to 00005 anyone. 00006 00007 Copyright (C) 2005-2011 Julien Jorge 00008 00009 This library is free software; you can redistribute it and/or 00010 modify it under the terms of the GNU Lesser General Public 00011 License as published by the Free Software Foundation; either 00012 version 2.1 of the License, or (at your option) any later version. 00013 00014 This library is distributed in the hope that it will be useful, 00015 but WITHOUT ANY WARRANTY; without even the implied warranty of 00016 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00017 Lesser General Public License for more details. 00018 00019 You should have received a copy of the GNU Lesser General Public 00020 License along with this library; if not, write to the Free Software 00021 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 00022 00023 contact: julien.jorge@gamned.org 00024 */ 00030 #include <climits> 00031 00032 /*----------------------------------------------------------------------------*/ 00037 template<typename Stream> 00038 claw::bit_istream<Stream>::bit_istream( stream_type& f ) 00039 : m_stream(f), m_pending(0), m_pending_length(0) 00040 { 00041 00042 } // bit_istream::bit_istream() 00043 00044 /*----------------------------------------------------------------------------*/ 00050 template<typename Stream> 00051 void claw::bit_istream<Stream>::read( char* buf, unsigned int n ) 00052 { 00053 if ( n == 0 ) 00054 return; 00055 00056 unsigned int cur_size = 0; 00057 00058 while ( (n != 0) && !!(*this) ) 00059 { 00060 while( (m_pending_length != 0) && (n!=0) && !!(*this) ) 00061 { 00062 unsigned int bits = std::min((unsigned int)m_pending_length, n); 00063 00064 if ( CHAR_BIT - cur_size < bits ) 00065 bits = CHAR_BIT - cur_size; 00066 00067 unsigned int mask = (1 << bits) - 1; 00068 00069 *buf |= (m_pending & mask) << cur_size; 00070 cur_size += bits; 00071 m_pending_length -= bits; 00072 m_pending >>= bits; 00073 n -= bits; 00074 00075 if ( cur_size == CHAR_BIT ) 00076 { 00077 ++buf; 00078 cur_size = 0; 00079 } 00080 } 00081 00082 if ( m_pending_length == 0 ) 00083 if ( m_stream.read( (char*)&m_pending, sizeof(m_pending) ) ) 00084 m_pending_length = CHAR_BIT; 00085 } 00086 } // bit_istream::read() 00087 00088 /*----------------------------------------------------------------------------*/ 00092 template<typename Stream> 00093 claw::bit_istream<Stream>::operator bool() const 00094 { 00095 return m_stream || (m_pending_length > 0); 00096 } // bit_istream::operator bool()