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Fix for bug : Various SeekableReadStream::seek() implementations (as well as our unit tests, ouch) handled SEEK_END incorrectly (using -offset instead of offset), contrary to what the docs said and what fseek does. Hopefully I found and fixed all affected parts, but still watch out for regressions

Browse Source 
svn-id: r39135
This commit is contained in:
Max Horn 2009-03-05 20:37:53 +00:00
parent 2017d1c9ea
commit 05b4370c21
9 changed files with 72 additions and 11 deletions

2
backends/platform/ds/arm9/source/ramsave.cpp

@ -205,7 +205,7 @@ bool DSSaveFile::seek(int32 pos, int whence) {
break;
}
case SEEK_END: {
ptr = save.size - pos;
ptr = save.size + pos;
break;
}
}

4
common/stream.cpp

@ -69,7 +69,7 @@ bool MemoryReadStream::seek(int32 offs, int whence) {
case SEEK_END:
// SEEK_END works just like SEEK_SET, only 'reversed',
// i.e. from the end.
offs = _size - offs;
offs = _size + offs;
// Fall through
case SEEK_SET:
_ptr = _ptrOrig + offs;
@ -204,7 +204,7 @@ bool SeekableSubReadStream::seek(int32 offset, int whence) {
switch(whence) {
case SEEK_END:
offset = size() - offset;
offset = size() + offset;
// fallthrough
case SEEK_SET:
_pos = _begin + offset;

2
engines/gob/inter_v1.cpp

@ -2222,7 +2222,7 @@ bool Inter_v1::o1_readData(OpFuncParams &params) {
_vm->_draw->animateCursor(4);
if (offset < 0)
stream->seek(-offset - 1, SEEK_END);
stream->seek(offset + 1, SEEK_END);
else
stream->seek(offset);

2
engines/gob/inter_v2.cpp

@ -1979,7 +1979,7 @@ bool Inter_v2::o2_readData(OpFuncParams &params) {
_vm->_draw->animateCursor(4);
if (offset < 0)
stream->seek(-offset - 1, SEEK_END);
stream->seek(offset + 1, SEEK_END);
else
stream->seek(offset);

2
engines/parallaction/disk_ns.cpp

@ -661,7 +661,7 @@ public:
return;
}
stream.seek(4, SEEK_END);
stream.seek(-4, SEEK_END);
uint32 decrlen = stream.readUint32BE() >> 8;
byte *dest = (byte*)malloc(decrlen);

2
engines/scumm/file.cpp

@ -142,7 +142,7 @@ bool ScummFile::seek(int32 offs, int whence) {
// Constrain the seek to the subfile
switch (whence) {
case SEEK_END:
offs = _subFileStart + _subFileLen - offs;
offs = _subFileStart + _subFileLen + offs;
break;
case SEEK_SET:
offs += _subFileStart;

4
test/common/bufferedseekablereadstream.h

@ -56,13 +56,13 @@ class BufferedSeekableReadStreamTestSuite : public CxxTest::TestSuite {
b = ssrs.readByte();
TS_ASSERT( ssrs.eos() );
ssrs.seek(3, SEEK_END);
ssrs.seek(-3, SEEK_END);
TS_ASSERT( !ssrs.eos() );
TS_ASSERT_EQUALS( ssrs.pos(), 7 );
b = ssrs.readByte();
TS_ASSERT_EQUALS( b, 7 );
ssrs.seek(8, SEEK_END);
ssrs.seek(-8, SEEK_END);
TS_ASSERT_EQUALS( ssrs.pos(), 2 );
b = ssrs.readByte();
TS_ASSERT_EQUALS( b, 2 );

61
test/common/memoryreadstream.h Normal file

@ -0,0 +1,61 @@
#include <cxxtest/TestSuite.h>
#include "common/stream.h"
class MemoryReadStreamTestSuite : public CxxTest::TestSuite {
public:
void test_seek_set(void) {
byte contents[] = { 'a', 'b', '\n', '\n', 'c', '\n' };
Common::MemoryReadStream ms(contents, sizeof(contents));
ms.seek(0, SEEK_SET);
TS_ASSERT_EQUALS(ms.pos(), 0);
TS_ASSERT(!ms.eos());
ms.seek(1, SEEK_SET);
TS_ASSERT_EQUALS(ms.pos(), 1);
TS_ASSERT(!ms.eos());
ms.seek(5, SEEK_SET);
TS_ASSERT_EQUALS(ms.pos(), 5);
TS_ASSERT(!ms.eos());
}
void test_seek_cur(void) {
byte contents[] = { 'a', 'b', '\n', '\n', 'c' };
Common::MemoryReadStream ms(contents, sizeof(contents));
ms.seek(3, SEEK_CUR);
TS_ASSERT_EQUALS(ms.pos(), 3);
TS_ASSERT(!ms.eos());
ms.seek(-1, SEEK_CUR);
TS_ASSERT_EQUALS(ms.pos(), 2);
TS_ASSERT(!ms.eos());
ms.seek(3, SEEK_CUR);
TS_ASSERT_EQUALS(ms.pos(), 5);
TS_ASSERT(!ms.eos());
ms.seek(-1, SEEK_CUR);
TS_ASSERT_EQUALS(ms.pos(), 4);
TS_ASSERT(!ms.eos());
}
void test_seek_end(void) {
byte contents[] = { 'a', 'b', '\n', '\n', 'c' };
Common::MemoryReadStream ms(contents, sizeof(contents));
ms.seek(0, SEEK_END);
TS_ASSERT_EQUALS(ms.pos(), 5);
TS_ASSERT(!ms.eos());
ms.seek(-1, SEEK_END);
TS_ASSERT_EQUALS(ms.pos(), 4);
TS_ASSERT(!ms.eos());
ms.seek(-5, SEEK_END);
TS_ASSERT_EQUALS(ms.pos(), 0);
TS_ASSERT(!ms.eos());
}
};

4
test/common/seekablesubreadstream.h

@ -58,13 +58,13 @@ class SeekableSubReadStreamTestSuite : public CxxTest::TestSuite {
b = ssrs.readByte();
TS_ASSERT( ssrs.eos() );
ssrs.seek(3, SEEK_END);
ssrs.seek(-3, SEEK_END);
TS_ASSERT( !ssrs.eos() );
TS_ASSERT_EQUALS( ssrs.pos(), 5 );
b = ssrs.readByte();
TS_ASSERT_EQUALS( b, 6 );
ssrs.seek(8, SEEK_END);
ssrs.seek(-8, SEEK_END);
TS_ASSERT_EQUALS( ssrs.pos(), 0 );
b = ssrs.readByte();
TS_ASSERT_EQUALS( b, 1 );