root/GPXSee
1
0
Fork 0
mirror of https://github.com/tumic0/GPXSee.git synced 2025-07-22 14:54:24 +02:00
Code Issues Projects Releases Activity

Reuse the stream logic in the text decoder

Browse Source
This commit is contained in:
Martin Tůma
2021-11-02 21:15:22 +01:00
parent 21cda471cc
commit 3972bb25e0
3 changed files with 26 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files

68
src/map/IMG/huffmantext.cpp
View File

@ -1,65 +1,33 @@
#include "subfile.h"
#include "huffmanstream.h"
#include "huffmantext.h"
using namespace IMG;
bool HuffmanText::fetch(const SubFile *file, SubFile::Handle &hdl,
quint32 &data, quint32 &bits, quint32 &usedBits, quint32 &usedData) const
bool HuffmanText::load(const RGNFile *rgn, SubFile::Handle &rgnHdl)
{
quint32 rs, ls, old;
if (!_table.load(rgn, rgnHdl))
return false;
bits = _table.symBits() - bits;
if (usedBits < bits) {
old = usedBits ? usedData >> (32 - usedBits) : 0;
if (!file->readVUInt32SW(hdl, 4, usedData))
return false;
ls = bits - usedBits;
rs = 32 - (bits - usedBits);
old = usedData >> rs | old << ls;
} else {
ls = bits;
rs = usedBits - bits;
old = usedData >> (32 - bits);
}
usedData = usedData << ls;
data = data | old << (32 - _table.symBits());
usedBits = rs;
return true;
Q_ASSERT(!(_table.symbolBits() & 7));
return !(_table.symbolBits() & 7);
}
bool HuffmanText::decode(const SubFile *file, SubFile::Handle &hdl,
QVector<quint8> &str) const
quint32 size, QVector<quint8> &str) const
{
quint32 bits = 0;
quint32 data = 0;
quint32 usedBits = 0;
quint32 usedData = 0;
BitStream4F bs(*file, hdl, size);
HuffmanStream<BitStream4F> hs(bs, _table);
quint32 sym;
while (true) {
if (!fetch(file, hdl, data, bits, usedBits, usedData))
return false;
quint8 size;
quint32 sym = _table.symbol(data, size);
if (_table.symBits() < size)
return false;
data = data << size;
bits = _table.symBits() - size;
if (!(_table.symbolBits() & 7)) {
for (quint32 i = 0; i < (_table.symbolBits() >> 3); i++) {
str.append((quint8)sym);
if (((quint8)sym == '\0'))
return true;
sym = sym >> 8;
}
} else {
Q_ASSERT(false);
return false;
while (hs.readSymbol(sym)) {
for (quint32 i = 0; i < (_table.symbolBits() >> 3); i++) {
str.append((quint8)sym);
if (((quint8)sym == '\0'))
return true;
sym = sym >> 8;
}
}
return false;
}