m2.enlarge-your-data/src/lib/eyd_compressor.cpp

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2005-10-29 22:51:22 +00:00
#include "eyd_compressor.hh"
namespace EydLib {
/*
class BitCompressor {
private:
BitGroup _last_group;
int _last_count;
std::list<BitGroup> _compressed;
public:
BitCompressor();
void clear();
void append(BitGroup bg);
std::list<BitGroup> flush();
bool hasContent();
};
*/
BitCompressor::BitCompressor(){
}
void BitCompressor::clear(){
// we clear everything
_last_count = 0;
_compressed.clear();
}
void BitCompressor::flushRleData(){
BitGroup len;
_compressed.push_back(_rle);
len.setValue(_last_count);
_compressed.push_back(len);
_compressed.push_back(_last_group);
_last_count = 0;
}
void BitCompressor::flushRawData(){
int i;
for (i=0; i<_last_count; i++){
// FIXME: on duplique les RLE trouv<75>s
_compressed.push_back(_last_group);
}
_last_count = 0;
}
void BitCompressor::append(BitGroup data){
// take the data and make it smaller...
if (_last_count > 0) {
// there are data in the compressor
if (data != _last_group){
// we have to empty the compressed list
if (_last_count < 4){
// not efficient
if ((_last_count > 1) && (_last_group == _rle)) {
// 1 RLE gives 2 RLE
// 2 RLE gives 4 RLE... let compress it...
this->flushRleData();
} else {
this->flushRawData();
}
} else {
// efficient ! lets compress it !
this->flushRleData();
}
} else {
// nothing to do... wait for another different data...
}
} else {
// it is the first bitgroup
}
_last_group = data;
_last_count++;
}
std::list<BitGroup> BitCompressor::flush(){
// we add the data from _last* to the outlist
std::list<BitGroup> result;
result = _compressed;
_compressed.clear();
return result;
}
bool BitCompressor::hasContent(){
return (!_compressed.empty());
}
}