[Scummvm-cvs-logs] scummvm master -> 83f4565fe21e59afa3651413134a2ecfa613b84d
m-kiewitz
m_kiewitz at users.sourceforge.net
Sun Jul 5 11:30:00 CEST 2015
This automated email contains information about 1 new commit which have been
pushed to the 'scummvm' repo located at https://github.com/scummvm/scummvm .
Summary:
83f4565fe2 ACCESS: fix valgrind errors in decompressor
Commit: 83f4565fe21e59afa3651413134a2ecfa613b84d
https://github.com/scummvm/scummvm/commit/83f4565fe21e59afa3651413134a2ecfa613b84d
Author: Martin Kiewitz (m_kiewitz at users.sourceforge.net)
Date: 2015-07-05T11:29:35+02:00
Commit Message:
ACCESS: fix valgrind errors in decompressor
Changed paths:
engines/access/decompress.cpp
engines/access/decompress.h
diff --git a/engines/access/decompress.cpp b/engines/access/decompress.cpp
index c5656af..3de376c 100644
--- a/engines/access/decompress.cpp
+++ b/engines/access/decompress.cpp
@@ -46,7 +46,7 @@ void LzwDecompressor::decompress(byte *source, byte *dest) {
maxCodeValue = 512;
copyLength = 0;
- _bitPos = 0;
+ _sourceBitsLeft = 8;
while (1) {
@@ -97,17 +97,39 @@ uint16 LzwDecompressor::getCode() {
const byte bitMasks[9] = {
0x00, 0x01, 0x03, 0x07, 0x0F, 0x1F, 0x3F, 0x7F, 0x0FF
};
- uint16 bits, loCode, hiCode;
- loCode = (READ_LE_UINT16(_source) >> _bitPos) & 0xFF;
- _source++;
- bits = _codeLength - 8;
- hiCode = (READ_LE_UINT16(_source) >> _bitPos) & bitMasks[bits];
- _bitPos += bits;
- if (_bitPos > 8) {
- _source++;
- _bitPos -= 8;
+
+ byte resultBitsLeft = _codeLength;
+ byte resultBitsPos = 0;
+ uint16 result = 0;
+ byte currentByte = *_source;
+ byte currentBits = 0;
+
+ // Get bits of current byte
+ while (resultBitsLeft) {
+ if (resultBitsLeft < _sourceBitsLeft) {
+ // we need less than we have left
+ currentBits = (currentByte >> (8 - _sourceBitsLeft)) & bitMasks[resultBitsLeft];
+ result |= (currentBits << resultBitsPos);
+ _sourceBitsLeft -= resultBitsLeft;
+ resultBitsLeft = 0;
+
+ } else {
+ // we need as much as we have left or more
+ resultBitsLeft -= _sourceBitsLeft;
+ currentBits = currentByte >> (8 - _sourceBitsLeft);
+ result |= (currentBits << resultBitsPos);
+ resultBitsPos += _sourceBitsLeft;
+
+ // Go to next byte
+ _source++;
+
+ _sourceBitsLeft = 8;
+ if (resultBitsLeft) {
+ currentByte = *_source;
+ }
+ }
}
- return (hiCode << 8) | loCode;
+ return result;
}
uint32 decompressDBE(byte *source, byte **dest) {
diff --git a/engines/access/decompress.h b/engines/access/decompress.h
index eea4500..bea9a1d 100644
--- a/engines/access/decompress.h
+++ b/engines/access/decompress.h
@@ -32,7 +32,8 @@ public:
void decompress(byte *source, byte *dest);
private:
byte *_source;
- byte _codeLength, _bitPos;
+ byte _sourceBitsLeft;
+ byte _codeLength;
uint16 getCode();
};
More information about the Scummvm-git-logs
mailing list