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# bmgamma.h

Go to the documentation of this file.

    00001 /*
    00002 Copyright(c) 2002-2009 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
    00003
    00004 Permission is hereby granted, free of charge, to any person
    00005 obtaining a copy of this software and associated documentation
    00006 files (the "Software"), to deal in the Software without restriction,
    00007 including without limitation the rights to use, copy, modify, merge,
    00008 publish, distribute, sublicense, and/or sell copies of the Software,
    00009 and to permit persons to whom the Software is furnished to do so,
    00010 subject to the following conditions:
    00011
    00012 The above copyright notice and this permission notice shall be included
    00013 in all copies or substantial portions of the Software.
    00014
    00015 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    00016 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
    00017 OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
    00018 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
    00019 DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
    00020 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    00021 OTHER DEALINGS IN THE SOFTWARE.
    00022
    00023 For more information please visit:  http://bmagic.sourceforge.net
    00024
    00025 */
    00026
    00027 #ifndef BMGAMMAENC__H__INCLUDED__
    00028 #define BMGAMMAENC__H__INCLUDED__
    00029
    00030
    00031 namespace bm
    00032 {
    00033
    00034
    00035 /**
    00036     Elias Gamma decoder
    00037 */
    00038 template<typename T, typename TBitIO>
    00039 class gamma_decoder
    00040 {
    00041 public:
    00042     gamma_decoder(TBitIO& bin) : bin_(bin)
    00043     {}
    00044
    00045     /**
    00046         Start encoding sequence
    00047     */
    00048     void start()
    00049     {}
    00050
    00051     /**
    00052         Stop decoding sequence
    00053     */
    00054     void stop()
    00055     {}
    00056
    00057     /**
    00058         Decode word
    00059     */
    00060     T operator()(void)
    00061     {
    00062         unsigned l = bin_.eat_zero_bits();
    00063         bin_.get_bit(); // get border bit
    00064         T current = 0;
    00065         for (unsigned i = 0; i < l; ++i)
    00066         {
    00067             if (bin_.get_bit())
    00068             {
    00069                 current += 1 << i;
    00070             }
    00071         }
    00072         current |= (1 << l);
    00073         return current;
    00074     }
    00075 private:
    00076     gamma_decoder(const gamma_decoder&);
    00077     gamma_decoder& operator=(const gamma_decoder&);
    00078 private:
    00079     TBitIO&  bin_;
    00080 };
    00081
    00082
    00083
    00084 } // bm
    00085
    00086 #endif
    00087