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/***************************************************************************
* Copyright (C) 2008 by Jakub Stachowski <qbast@go2.pl> *
* *
* RLE decompressor based on FBReader *
* Copyright (C) 2004-2008 Geometer Plus <contact@geometerplus.com> *
* *
* Huffdic decompressor based on Python code by Igor Skochinsky *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
***************************************************************************/
#include "decompressor.h"
#include "mobipocket.h"
#include <QList>
static const unsigned char TOKEN_CODE[256] = {
0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
};
namespace Mobipocket {
class NOOPDecompressor : public Decompressor
{
public:
NOOPDecompressor(const PDB& p) : Decompressor(p) {}
QByteArray decompress(const QByteArray& data) override { return data; }
};
class RLEDecompressor : public Decompressor
{
public:
RLEDecompressor(const PDB& p) : Decompressor(p) {}
QByteArray decompress(const QByteArray& data) override;
};
class BitReader
{
public:
BitReader(const QByteArray& d) : pos(0), len(d.size() * 8), data(d) {
data.append(4, '\0');
}
quint32 read() {
quint32 g=0;
quint64 r=0;
while (g<32) {
r=(r << 8) | (quint8)data[(pos+g)>>3];
g=g+8 - ((pos+g) & 7);
}
return (r >> (g-32));
}
bool eat(int n) {
pos+=n;
return pos <= len;
}
int left() {
return len - pos;
}
private:
int pos;
int len;
QByteArray data;
};
class HuffdicDecompressor : public Decompressor
{
public:
HuffdicDecompressor(const PDB& p);
QByteArray decompress(const QByteArray& data) override;
private:
void unpack(BitReader reader, int depth = 0);
QList<QByteArray> dicts;
quint32 entry_bits;
quint32 dict1[256];
quint32 dict2[64];
QByteArray buf;
};
QByteArray RLEDecompressor::decompress(const QByteArray& data)
{
QByteArray ret;
ret.reserve(8192);
unsigned char token;
unsigned short copyLength, N, shift;
unsigned short shifted;
int i=0;
int maxIndex=data.size()-1;
while (i<data.size()) {
token = data.at(i++);
switch (TOKEN_CODE[token]) {
case 0:
ret.append(token);
break;
case 1:
if ((i + token > maxIndex) ) {
goto endOfLoop;
}
ret.append(data.mid(i,token));
i+=token;
break;
case 2:
ret.append(' ');
ret.append(token ^ 0x80);
break;
case 3:
if (i + 1 > maxIndex) {
goto endOfLoop;
}
N = token;
N<<=8;
N+=(unsigned char)data.at(i++);
copyLength = (N & 7) + 3;
shift = (N & 0x3fff) / 8;
if ((shift < 1) || (shift > ret.size())) {
return ret;
}
shifted = ret.size() - shift;
for (int i = shifted; i < shifted + copyLength; i++) {
ret.append(ret.at(i));
}
break;
}
}
endOfLoop:
return ret;
}
quint32 readBELong(const QByteArray& data, int offset)
{
quint32 ret=0;
for (int i=0;i<4;i++) { ret<<=8; ret+=(unsigned char)data[offset+i]; }
return ret;
}
HuffdicDecompressor::HuffdicDecompressor(const PDB& p) : Decompressor(p)
{
QByteArray header=p.getRecord(0);
quint32 huff_ofs=readBELong(header,0x70);
quint32 huff_num=readBELong(header,0x74);
quint32 off1,off2;
QByteArray huff1=p.getRecord(huff_ofs);
if (huff1.isNull()) goto fail;
for (unsigned int i=1;i<huff_num;i++) {
QByteArray h=p.getRecord(huff_ofs+i);
if (h.isNull()) goto fail;
dicts.append(h);
}
off1=readBELong(huff1,16);
off2=readBELong(huff1,20);
if (!huff1.startsWith("HUFF")) goto fail; //krazy:exclude=strings
if (!dicts[0].startsWith("CDIC")) goto fail; //krazy:exclude=strings
entry_bits=readBELong(dicts[0],12);
memcpy(dict1,huff1.data()+off1, 256*4);
memcpy(dict2,huff1.data()+off2, 64*4);
return;
fail:
valid=false;
}
QByteArray HuffdicDecompressor::decompress(const QByteArray& data)
{
buf.clear();
unpack(BitReader(data));
return buf;
}
void HuffdicDecompressor::unpack(BitReader reader,int depth)
{
if (depth>32) goto fail;
while (reader.left()) {
quint32 dw=reader.read();
quint32 v=dict1[dw>>24];
quint8 codelen = v & 0x1F;
if (!codelen) goto fail;
quint32 code = dw >> (32 - codelen);
quint32 r=(v >> 8);
if (!( v & 0x80)) {
while (code < dict2[(codelen-1)*2]) {
codelen++;
code = dw >> (32 - codelen);
}
r = dict2[(codelen-1)*2+1];
}
r-=code;
if (!codelen) goto fail;
if (!reader.eat(codelen)) return;
quint32 dict_no = r >> entry_bits;
quint32 off1 = 16 + (r - (dict_no << entry_bits))*2;
QByteArray dict=dicts[dict_no];
quint32 off2 = 16 + (unsigned char)dict[off1]*256 + (unsigned char)dict[off1+1];
quint32 blen = (unsigned char)dict[off2]*256 + (unsigned char)dict[off2+1];
QByteArray slice=dict.mid(off2+2,(blen & 0x7fff));
if (blen & 0x8000) buf+=slice;
else unpack(BitReader(slice),depth+1);
}
return;
fail:
valid=false;
}
std::unique_ptr<Decompressor> Decompressor::create(quint8 type, const PDB& pdb)
{
switch (type) {
case 1 : return std::make_unique<NOOPDecompressor>(pdb);
case 2 : return std::make_unique<RLEDecompressor>(pdb);
case 'H' : return std::make_unique<HuffdicDecompressor>(pdb);
default : return nullptr;
}
}
}
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