int PPMCompressor::CompressFile(BitFile &inputFile, BitFile &outputFile, bool paramVerbose) {
int result;
unsigned char curSymbol;
int curOrder,i;
std::string context;
ContextModel *CM;
Intervals curInterval;
RangeCoder RC;
unsigned int mask[256];
unsigned int cumFreq;
long int fSize, kSymb;
FILE *f = tmpfile();
RC.StartEncode(f);
CM = new ContextModel[ORDER+1];
for (i = 0; i <= ORDER; ++i) {
CM[i].SetOrder(i);
}
context = "";
fSize = inputFile.GetFileSize();
kSymb = 0;
if (paramVerbose) printProcentsBar(kSymb,fSize);
do {
inputFile.Read(&curSymbol,sizeof(char));
if ( !inputFile.FEOF() ) {
if (paramVerbose) printProcentsBar(++kSymb,fSize);
curOrder = ORDER;
for (i = 0; i < 256; ++i) {
mask[i] = 0;
}
do {
result = CM[curOrder].GetInterval(context, curSymbol, curInterval, &mask[0]);
if (result != 2) { // если контекст существует
RC.encode(curInterval.cumFreq,curInterval.curFreq,curInterval.totalFreq);
}
--curOrder;
} while ( result != 0 && curOrder>=0); //пока окончательно не закодировали символ и не зашли за границу порядка
if (result != 0) { //кодируем по равновероятностной модели
for (i = 0, cumFreq = 0; i < 256; ++i) {
if (mask[i] == 0) {
if (i == (int)curSymbol) {
curInterval.cumFreq = cumFreq;
curInterval.curFreq = 1;
}
cumFreq += 1;
}
}
curInterval.totalFreq = cumFreq + 1;
RC.encode(curInterval.cumFreq,curInterval.curFreq,curInterval.totalFreq);
}
for (curOrder=0; curOrder <= ORDER; ++curOrder) {
CM[curOrder].UpdateContextModel(context, curSymbol);
}
context.push_back(curSymbol);
context = cutString(context,ORDER);
}
} while ( !inputFile.FEOF() );
//записываем символ конца файла. Он кодируется как уход в модели -1 порядка
curOrder = ORDER;
for (i = 0; i < 256; ++i) {
mask[i] = 0;
}
do {
result = CM[curOrder].GetInterval(context, curSymbol, curInterval,&mask[0], true);
if (result != 2) { // если контекст существует
RC.encode(curInterval.cumFreq,curInterval.curFreq,curInterval.totalFreq);
}
--curOrder;
} while ( curOrder>=0); //пока окончательно не закодировали символ и не зашли за границу порядка
//кодируем по равновероятностной модели
for (i = 0, cumFreq = 0; i < 256; ++i) {
if (mask[i] == 0) {
cumFreq += 1;
}
}
curInterval.cumFreq = cumFreq;
curInterval.curFreq = 1;
curInterval.totalFreq = cumFreq + 1;
RC.encode(curInterval.cumFreq,curInterval.curFreq,curInterval.totalFreq);
RC.FinishEncode();
fseek(f,0,SEEK_SET);
while (!feof(f)) {
result = fread(&curSymbol, sizeof(curSymbol),1,f);
outputFile.Write(&curSymbol,sizeof(curSymbol));
}
fclose(f);
delete[] CM;
return 0;
}
int PPMCompressor::DecompressFile(BitFile &inputFile, BitFile &outputFile,bool paramVerbose) {
int result;
unsigned int i;
long int fSize;
int curOrder, curDecodeOrder;
unsigned int cum_freq=0, totFreq, CumFreqUnder;
unsigned int mask[256];
bool EndOfFile, found;
std::string context;
RangeCoder RC;
ContextModel *CM;
Intervals curInterval;
unsigned char curSymbol;
FILE *f;
f = tmpfile();
while (inputFile.FEOF() == false) {
result = inputFile.Read(&curSymbol, sizeof(curSymbol));
result = fwrite(&curSymbol, sizeof(curSymbol),1, f);
}
fseek(f,0,SEEK_SET);
//инициализация
RC.StartDecode(f);
CM = new ContextModel[ORDER+1];
for (curOrder = 0; curOrder <= ORDER; ++curOrder) {
CM[curOrder].SetOrder(curOrder);
}
context = "";
curDecodeOrder = -1;
totFreq = 257;
EndOfFile = false;
for (i = 0; i < 256; ++i) {
mask[i] = 0;
}
fSize = inputFile.GetFileSize();
if (paramVerbose) printProcentsBar(0,fSize);
do {
cum_freq = RC.get_freq(totFreq);
if (curDecodeOrder == -1) {
for (i = 0, found = false, CumFreqUnder = 0; i < 256; ++i) {
if (mask[i] == 0) {
if ( found == false && (CumFreqUnder + 1) > cum_freq ) {
curSymbol = (unsigned char)i;
curInterval.cumFreq = CumFreqUnder;
curInterval.curFreq = 1;
found = true;
}
CumFreqUnder += 1;
mask[i] = 1;
}
}
curInterval.totalFreq = CumFreqUnder + 1;
if (found == false) {
EndOfFile = true;
curInterval.curFreq = 1;
curInterval.cumFreq = CumFreqUnder;
}
RC.decode_update(curInterval.cumFreq,curInterval.curFreq, curInterval.totalFreq);
if (found == true) {
outputFile.Write(&curSymbol, sizeof(curSymbol));
for (curOrder=0; curOrder <= ORDER; ++curOrder) {
CM[curOrder].UpdateContextModel(context, curSymbol);
}
if (paramVerbose) printProcentsBar(ftell(f),fSize);
context.push_back(curSymbol);
context = cutString(context,ORDER);
for (i = 0; i < 256; ++i) {
mask[i] = 0;
}
//находим значение максимального порядка, по которому будем декодировать
curDecodeOrder = ORDER;
for (curOrder = curDecodeOrder, totFreq = 0; curOrder >= 0 && totFreq == 0; --curOrder) {
totFreq = CM[curOrder].GetTotalFreq( cutString(context, curOrder));
curDecodeOrder = curOrder;
}
if (totFreq == 0) {
totFreq = 257;
curDecodeOrder = -1;
}
}
}
else {
result = CM[curDecodeOrder].GetSymbol( cutString(context, curDecodeOrder) , cum_freq,curSymbol,curInterval, &mask[0]);
RC.decode_update(curInterval.cumFreq,curInterval.curFreq, curInterval.totalFreq);
if (result == 0) {
outputFile.Write(&curSymbol, sizeof(curSymbol));
for (curOrder=0; curOrder <= ORDER; ++curOrder) {
CM[curOrder].UpdateContextModel(context, curSymbol);
}
if (paramVerbose) printProcentsBar(ftell(f),fSize);
context.push_back(curSymbol);
context = cutString(context,ORDER);
for (i = 0; i < 256; ++i) {
mask[i] = 0;
}
//находим значение максимального порядка, по которому можно декодировать
curDecodeOrder = ORDER;
for (curOrder = curDecodeOrder, totFreq = 0; curOrder >= 0 && totFreq == 0; --curOrder) {
totFreq = CM[curOrder].GetTotalFreq( cutString(context, curOrder));
curDecodeOrder = curOrder;
}
if (totFreq == 0) {
totFreq = 257;
curDecodeOrder = -1;
}
}
else {
--curDecodeOrder;
if (curDecodeOrder>=0) {
totFreq = CM[curDecodeOrder].GetTotalFreq( cutString(context, curDecodeOrder) , &mask[0]);
} else {
for (i = 0, CumFreqUnder = 0; i<256; ++i) {
if (mask[i] == 0) {
CumFreqUnder += 1;
}
}
totFreq = CumFreqUnder + 1;
}
}
}
}while (!feof(f) && !EndOfFile);
if (paramVerbose) printProcentsBar(fSize,fSize);
RC.FinishDecode();
fclose(f);
delete[] CM;
return 0;
}