1 /* 2 =============================================================================== 3 4 FILE: integercompressor.hpp 5 6 CONTENTS: 7 8 This compressor provides three different contexts for encoding integer 9 numbers whose range may lie anywhere between 1 and 31 bits, which is 10 specified with the SetPrecision function. 11 12 The compressor encodes two things: 13 14 (1) the number k of miss-predicted low-order bits and 15 (2) the k-bit number that corrects the missprediction 16 17 The k-bit number is usually coded broken in two chunks. The highest 18 bits are compressed using an arithmetic range table. The lower bits 19 are stored raw without predicive coding. How many of the higher bits 20 are compressed can be specified with bits_high. The default is 8. 21 22 PROGRAMMERS: 23 24 martin.isenburg@rapidlasso.com - http://rapidlasso.com 25 26 COPYRIGHT: 27 28 (c) 2005-2014, martin isenburg, rapidlasso - fast tools to catch reality 29 30 This is free software; you can redistribute and/or modify it under the 31 terms of the GNU Lesser General Licence as published by the Free Software 32 Foundation. See the COPYING file for more information. 33 34 This software is distributed WITHOUT ANY WARRANTY and without even the 35 implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 36 37 CHANGE HISTORY: 38 39 6 September 2014 -- removed inheritance of EntropyEncoder and EntropyDecoder 40 10 January 2011 -- licensing change for LGPL release and liblas integration 41 10 December 2010 -- unified for all entropy coders at Baeckerei Schaefer 42 31 October 2009 -- switched from the Rangecoder to the Entropycoder 43 30 September 2005 -- now splitting the corrector into raw and compressed bits 44 13 July 2005 -- created after returning with many mosquito bites from OBX 45 46 =============================================================================== 47 */ 48 #ifndef INTEGER_COMPRESSOR_HPP 49 #define INTEGER_COMPRESSOR_HPP 50 51 #include "arithmeticencoder.hpp" 52 #include "arithmeticdecoder.hpp" 53 54 class IntegerCompressor 55 { 56 public: 57 58 // Constructor & Deconstructor 59 IntegerCompressor(ArithmeticEncoder* enc, U32 bits=16, U32 contexts=1, U32 bits_high=8, U32 range=0); 60 IntegerCompressor(ArithmeticDecoder* dec, U32 bits=16, U32 contexts=1, U32 bits_high=8, U32 range=0); 61 ~IntegerCompressor(); 62 63 // Manage Compressor 64 void initCompressor(); 65 void compress(I32 iPred, I32 iReal, U32 context=0); 66 67 // Manage Decompressor 68 void initDecompressor(); 69 I32 decompress(I32 iPred, U32 context=0); 70 71 // Get the k corrector bits from the last compress/decompress call getK() const72 U32 getK() const {return k;}; 73 74 private: 75 void writeCorrector(I32 c, ArithmeticModel* model); 76 I32 readCorrector(ArithmeticModel* model); 77 78 U32 k; 79 80 U32 contexts; 81 U32 bits_high; 82 83 U32 bits; 84 U32 range; 85 86 U32 corr_bits; 87 U32 corr_range; 88 I32 corr_min; 89 I32 corr_max; 90 91 ArithmeticEncoder* enc; 92 ArithmeticDecoder* dec; 93 94 ArithmeticModel** mBits; 95 96 ArithmeticModel** mCorrector; 97 98 #ifdef CREATE_HISTOGRAMS 99 int** corr_histogram; 100 #endif 101 }; 102 103 #endif 104