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Added basic table data sanity checks

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+ some more code cleanup
This commit is contained in:
Martin Tůma 2021-10-23 07:41:27 +02:00
parent ccfda7ca7f
commit a531b7859b
1 changed files with 5 additions and 11 deletions
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14
src/map/IMG/huffmantable.cpp
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@ -28,12 +28,12 @@ bool HuffmanTable::load(const RGNFile *rgn, SubFile::Handle &rgnHdl)
_symbolBytes = bs(_symbolBits); _symbolBytes = bs(_symbolBits);
_aclEntryBytes = _symbolBytes + 1; _aclEntryBytes = _symbolBytes + 1;
_indexBytes = vs(_buffer.at(4)); _indexBytes = vs(_buffer.at(4));
_bsrchEntryBytes = _symBytes + 1 + _indexBytes; _bsrchEntryBytes = _symBytes + _indexBytes + 1;
_bsrchTable = (quint8*)(_buffer.data()) + 4 + _indexBytes; _bsrchTable = (quint8*)(_buffer.data()) + 4 + _indexBytes;
_aclTable = _bsrchTable + _bsrchEntryBytes * _bsrchEntries; _aclTable = _bsrchTable + _bsrchEntryBytes * _bsrchEntries;
_huffmanTable = _aclTable + (_aclEntryBytes << _aclBits); _huffmanTable = _aclTable + (_aclEntryBytes << _aclBits);
return true; return (_symBits <= 32 && _symbolBits <= 32 && _symbolBits >= 8);
} }
quint32 HuffmanTable::symbol(quint32 data, quint8 &size) const quint32 HuffmanTable::symbol(quint32 data, quint8 &size) const
@ -89,17 +89,11 @@ quint32 HuffmanTable::symbol(quint32 data, quint8 &size) const
quint32 bi = readVUint32(tp + 1, _indexBytes); quint32 bi = readVUint32(tp + 1, _indexBytes);
quint32 ci = (data - i) >> (_symBits - size); quint32 ci = (data - i) >> (_symBits - size);
quint32 si = (ci + bi) * _symbolBits; quint32 si = (ci + bi) * _symbolBits;
quint32 sby = si >> 3;
quint32 sbi = si & 7; quint32 sbi = si & 7;
quint32 shift = 8 - sbi; quint32 shift = 8 - sbi;
quint32 sym = *(_huffmanTable + sby) >> sbi; tp = _huffmanTable + (si >> 3);
if (shift < _symbolBits) {
tp = _huffmanTable + sby;
quint32 val = readVUint32(tp + 1, bs(_symbolBits - shift)); quint32 val = readVUint32(tp + 1, bs(_symbolBits - shift));
sym = (val << shift) | sym;
}
return sym; return (val << shift) | (*tp >> sbi);
} }
} }