100 lines
2 KiB
C++
100 lines
2 KiB
C++
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#include "eyd_compressor.hh"
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namespace EydLib {
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/*
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class BitCompressor {
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private:
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BitGroup _last_group;
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int _last_count;
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std::list<BitGroup> _compressed;
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public:
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BitCompressor();
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void clear();
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void append(BitGroup bg);
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std::list<BitGroup> flush();
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bool hasContent();
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};
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*/
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BitCompressor::BitCompressor(int size) : _rle(size) {
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_group_size = size;
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}
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void BitCompressor::clear(){
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// we clear everything
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_last_count = 0;
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_compressed.clear();
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}
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void BitCompressor::flushRleData(){
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BitGroup len(_group_size);
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_compressed.push_back(_rle);
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len.setValue(_last_count);
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_compressed.push_back(len);
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_compressed.push_back(_last_group);
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_last_count = 0;
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}
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void BitCompressor::flushRawData(){
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int i;
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for (i=0; i<_last_count; i++){
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// on duplique les RLE trouvés
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if (_last_group == _rle) {
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_compressed.push_back(_last_group);
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}
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_compressed.push_back(_last_group);
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}
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_last_count = 0;
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}
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void BitCompressor::append(BitGroup data){
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// take the data and make it smaller...
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if (_last_count > 0) {
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// there are data in the compressor
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if (data != _last_group){
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// we have to empty the compressed list
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if (_last_count < 4){
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// not efficient
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if ((_last_count > 1) && (_last_group == _rle)) {
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// 1 RLE gives 2 RLE
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// 2 RLE gives 4 RLE... let compress it...
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this->flushRleData();
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} else {
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this->flushRawData();
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}
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} else {
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// efficient ! lets compress it !
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this->flushRleData();
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}
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} else {
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// nothing to do... wait for another different data...
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// maybe the count is bigger than the len-cell can store ?
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if (_last_count >= _rle.maxValue()){
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this->flushRleData();
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}
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}
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} else {
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// it is the first bitgroup
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}
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_last_group = data;
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_last_count++;
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}
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std::list<BitGroup> BitCompressor::flush(){
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// we add the data from _last* to the outlist
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std::list<BitGroup> result;
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result = _compressed;
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_compressed.clear();
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return result;
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}
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bool BitCompressor::hasContent(){
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return (!_compressed.empty());
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}
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}
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