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Prevent erroneous access of negative array indices

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svn-id: r35633
This commit is contained in:
Filippos Karapetis 2008-12-31 14:49:53 +00:00
parent 9f0a401047
commit a8a4ba3a98
1 changed files with 17 additions and 5 deletions
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22
sound/shorten.cpp
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@ -26,6 +26,8 @@
// Based on etree's Shorten tool, version 3.6.1
// http://etree.org/shnutils/shorten/
// FIXME: This doesn't work yet correctly
#include "common/endian.h"
#include "common/util.h"
#include "common/stream.h"
@ -335,15 +337,21 @@ byte *loadShortenFromStream(Common::ReadStream &stream, int &size, int &rate, by
buffer[curChannel][i] = gReader->getSRice(energy) + channelOffset;
break;
case kCmdDiff1:
for (i = 0; i < blockSize; i++)
gReader->getSRice(energy); // i = 0 (to fix invalid table/memory access)
for (i = 1; i < blockSize; i++)
buffer[curChannel][i] = gReader->getSRice(energy) + buffer[curChannel][i - 1];
break;
case kCmdDiff2:
for (i = 0; i < blockSize; i++)
gReader->getSRice(energy); // i = 0 (to fix invalid table/memory access)
gReader->getSRice(energy); // i = 1 (to fix invalid table/memory access)
for (i = 2; i < blockSize; i++)
buffer[curChannel][i] = gReader->getSRice(energy) + 2 * buffer[curChannel][i - 1] - buffer[curChannel][i - 2];
break;
case kCmdDiff3:
for (i = 0; i < blockSize; i++)
gReader->getSRice(energy); // i = 0 (to fix invalid table/memory access)
gReader->getSRice(energy); // i = 1 (to fix invalid table/memory access)
gReader->getSRice(energy); // i = 2 (to fix invalid table/memory access)
for (i = 3; i < blockSize; i++)
buffer[curChannel][i] = gReader->getSRice(energy) + 3 * (buffer[curChannel][i - 1] - buffer[curChannel][i - 2]) + buffer[curChannel][i - 3];
break;
case kCmdQLPC:
@ -364,8 +372,11 @@ byte *loadShortenFromStream(Common::ReadStream &stream, int &size, int &rate, by
for (i = 0; i < blockSize; i++) {
int32 sum = lpcqOffset;
for (j = 0; j < lpcNum; j++)
for (j = 0; j < lpcNum; j++) {
if (i - j - 1 < 0) // ignore invalid table/memory access
continue;
sum += lpc[j] * buffer[curChannel][i - j - 1];
}
buffer[curChannel][i] = gReader->getSRice(energy) + (sum >> 5);
}
@ -393,7 +404,8 @@ byte *loadShortenFromStream(Common::ReadStream &stream, int &size, int &rate, by
// Do the wrap
// FIXME: removed for now, as this corrupts the heap
// FIXME: removed for now, as this corrupts the heap, because it
// accesses negative array indices
//for (int32 k = -wrap; k < 0; k++)
// buffer[curChannel][k] = buffer[curChannel][k + blockSize];