[Scummvm-cvs-logs] SF.net SVN: scummvm:[33419] scummvm/trunk
fingolfin at users.sourceforge.net
fingolfin at users.sourceforge.net
Tue Jul 29 19:42:20 CEST 2008
Revision: 33419
http://scummvm.svn.sourceforge.net/scummvm/?rev=33419&view=rev
Author: fingolfin
Date: 2008-07-29 17:42:19 +0000 (Tue, 29 Jul 2008)
Log Message:
-----------
Added two new classes, BufferedReadStream & BufferedSeekableReadStream, as proposed on scummvm-devel
Modified Paths:
--------------
scummvm/trunk/common/stream.cpp
scummvm/trunk/common/stream.h
scummvm/trunk/test/common/seekablesubreadstream.h
scummvm/trunk/test/common/subreadstream.h
Added Paths:
-----------
scummvm/trunk/test/common/bufferedreadstream.h
scummvm/trunk/test/common/bufferedseekablereadstream.h
Modified: scummvm/trunk/common/stream.cpp
===================================================================
--- scummvm/trunk/common/stream.cpp 2008-07-29 17:38:07 UTC (rev 33418)
+++ scummvm/trunk/common/stream.cpp 2008-07-29 17:42:19 UTC (rev 33419)
@@ -242,4 +242,85 @@
_parentStream->seek(_pos);
}
+BufferedReadStream::BufferedReadStream(ReadStream *parentStream, uint32 bufSize, bool disposeParentStream)
+ : _parentStream(parentStream),
+ _bufSize(bufSize),
+ _disposeParentStream(disposeParentStream) {
+
+ assert(parentStream);
+ _buf = new byte[_bufSize];
+ assert(_buf);
+ _pos = _bufSize = bufSize;
+}
+BufferedReadStream::~BufferedReadStream() {
+ if (_disposeParentStream)
+ delete _parentStream;
+ delete _buf;
+}
+
+uint32 BufferedReadStream::read(void *dataPtr, uint32 dataSize) {
+ uint32 alreadyRead = 0;
+ const uint32 bufBytesLeft = _bufSize - _pos;
+
+ // Check whether the data left in the buffer suffices....
+ if (dataSize > bufBytesLeft) {
+ // Nope, we need to read more data
+
+ // First, flush the buffer, if it is non-empty
+ if (0 < bufBytesLeft) {
+ memcpy(dataPtr, _buf + _pos, bufBytesLeft);
+ _pos = _bufSize;
+ alreadyRead += bufBytesLeft;
+ dataPtr = (byte *)dataPtr + bufBytesLeft;
+ dataSize -= bufBytesLeft;
+ }
+
+ // At this point the buffer is empty. Now if the read request
+ // exceeds the buffer size, just satisfy it directly.
+ if (dataSize > _bufSize)
+ return alreadyRead + _parentStream->read(dataPtr, dataSize);
+
+ // Refill the buffer.
+ uint32 bytesRead = _parentStream->read(_buf, _bufSize);
+ _pos = 0;
+
+ // If we didn't read as many bytes as requested, the reason
+ // is EOF or an error. In that case we truncate the buffer
+ // size, as well as the number of bytes we are going to
+ // return to the caller.
+ if (_bufSize > bytesRead) {
+ _bufSize = bytesRead;
+ if (dataSize > bytesRead)
+ dataSize = bytesRead;
+ }
+ }
+
+ // Satisfy the request from the buffer
+ memcpy(dataPtr, _buf + _pos, dataSize);
+ _pos += dataSize;
+ return alreadyRead + dataSize;
+}
+
+BufferedSeekableReadStream::BufferedSeekableReadStream(SeekableReadStream *parentStream, uint32 bufSize, bool disposeParentStream)
+ : BufferedReadStream(parentStream, bufSize, disposeParentStream),
+ _parentStream(parentStream) {
+}
+
+void BufferedSeekableReadStream::seek(int32 offset, int whence) {
+ // If it is a "local" seek, we may get away with "seeking" around
+ // in the buffer only.
+ // Note: We could try to handle SEEK_END and SEEK_SET, too, but
+ // since they are rarely used, it seems not worth the effort.
+ if (whence == SEEK_CUR && (int)_pos + offset >= 0 && _pos + offset <= _bufSize) {
+ _pos += offset;
+ } else {
+ // Seek was not local enough, so we reset the buffer and
+ // just seeks normally in the parent stream.
+ if (whence == SEEK_CUR)
+ offset -= (_bufSize - _pos);
+ _pos = _bufSize;
+ _parentStream->seek(offset, whence);
+ }
+}
+
} // End of namespace Common
Modified: scummvm/trunk/common/stream.h
===================================================================
--- scummvm/trunk/common/stream.h 2008-07-29 17:38:07 UTC (rev 33418)
+++ scummvm/trunk/common/stream.h 2008-07-29 17:42:19 UTC (rev 33419)
@@ -350,15 +350,17 @@
class SubReadStream : virtual public ReadStream {
protected:
ReadStream *_parentStream;
+ bool _disposeParentStream;
uint32 _pos;
uint32 _end;
- bool _disposeParentStream;
public:
SubReadStream(ReadStream *parentStream, uint32 end, bool disposeParentStream = false)
: _parentStream(parentStream),
_pos(0),
_end(end),
- _disposeParentStream(disposeParentStream) {}
+ _disposeParentStream(disposeParentStream) {
+ assert(parentStream);
+ }
~SubReadStream() {
if (_disposeParentStream) delete _parentStream;
}
@@ -414,8 +416,49 @@
}
};
+/**
+ * Wrapper class which adds buffering to any given ReadStream.
+ * Users can specify how big the buffer should be, and whether the
+ * wrapped stream should be disposed when the wrapper is disposed.
+ */
+class BufferedReadStream : virtual public ReadStream {
+protected:
+ ReadStream *_parentStream;
+ bool _disposeParentStream;
+ byte *_buf;
+ uint32 _pos;
+ uint32 _bufSize;
+public:
+ BufferedReadStream(ReadStream *parentStream, uint32 bufSize, bool disposeParentStream = false);
+ ~BufferedReadStream();
+
+ virtual bool eos() const { return (_pos == _bufSize) && _parentStream->eos(); }
+ virtual bool ioFailed() const { return _parentStream->ioFailed(); }
+ virtual void clearIOFailed() { _parentStream->clearIOFailed(); }
+
+ virtual uint32 read(void *dataPtr, uint32 dataSize);
+};
+
/**
+ * Wrapper class which adds buffering to any given SeekableReadStream.
+ * @see BufferedReadStream
+ */
+class BufferedSeekableReadStream : public BufferedReadStream, public SeekableReadStream {
+protected:
+ SeekableReadStream *_parentStream;
+public:
+ BufferedSeekableReadStream(SeekableReadStream *parentStream, uint32 bufSize, bool disposeParentStream = false);
+
+ virtual uint32 pos() const { return _parentStream->pos() - (_bufSize - _pos); }
+ virtual uint32 size() const { return _parentStream->size(); }
+
+ virtual void seek(int32 offset, int whence = SEEK_SET);
+};
+
+
+
+/**
* Simple memory based 'stream', which implements the ReadStream interface for
* a plain memory block.
*/
Added: scummvm/trunk/test/common/bufferedreadstream.h
===================================================================
--- scummvm/trunk/test/common/bufferedreadstream.h (rev 0)
+++ scummvm/trunk/test/common/bufferedreadstream.h 2008-07-29 17:42:19 UTC (rev 33419)
@@ -0,0 +1,27 @@
+#include <cxxtest/TestSuite.h>
+
+#include "common/stream.h"
+
+class BufferedReadStreamTestSuite : public CxxTest::TestSuite {
+ public:
+ void test_traverse(void) {
+ byte contents[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+ Common::MemoryReadStream ms(contents, 10);
+
+ // Use a buffer size of 4 -- note that 10 % 4 != 0,
+ // so we test what happens if the cache can't be completly
+ // refilled.
+ Common::BufferedReadStream srs(&ms, 4);
+
+ int i;
+ byte b;
+ for (i = 0; i < 10; ++i) {
+ TS_ASSERT( !srs.eos() );
+
+ b = srs.readByte();
+ TS_ASSERT_EQUALS( i, b );
+ }
+
+ TS_ASSERT( srs.eos() );
+ }
+};
Property changes on: scummvm/trunk/test/common/bufferedreadstream.h
___________________________________________________________________
Added: svn:mime-type
+ text/plain
Added: svn:keywords
+ Date Rev Author URL Id
Added: svn:eol-style
+ native
Added: scummvm/trunk/test/common/bufferedseekablereadstream.h
===================================================================
--- scummvm/trunk/test/common/bufferedseekablereadstream.h (rev 0)
+++ scummvm/trunk/test/common/bufferedseekablereadstream.h 2008-07-29 17:42:19 UTC (rev 33419)
@@ -0,0 +1,65 @@
+#include <cxxtest/TestSuite.h>
+
+#include "common/stream.h"
+
+class BufferedSeekableReadStreamTestSuite : public CxxTest::TestSuite {
+ public:
+ void test_traverse(void) {
+ byte contents[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+ Common::MemoryReadStream ms(contents, 10);
+
+ Common::BufferedSeekableReadStream ssrs(&ms, 4);
+
+ int i;
+ byte b;
+ for (i = 0; i < 10; ++i) {
+ TS_ASSERT( !ssrs.eos() );
+
+ TS_ASSERT_EQUALS( i, ssrs.pos() );
+
+ ssrs.read(&b, 1);
+ TS_ASSERT_EQUALS( i, b );
+ }
+
+ TS_ASSERT( ssrs.eos() );
+ }
+
+ void test_seek(void) {
+ byte contents[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+ Common::MemoryReadStream ms(contents, 10);
+
+ Common::BufferedSeekableReadStream ssrs(&ms, 4);
+ byte b;
+
+ TS_ASSERT_EQUALS( ssrs.pos(), (uint32)0 );
+
+ ssrs.seek(1, SEEK_SET);
+ TS_ASSERT_EQUALS( ssrs.pos(), (uint32)1 );
+ b = ssrs.readByte();
+ TS_ASSERT_EQUALS( b, 1 );
+
+ ssrs.seek(5, SEEK_CUR);
+ TS_ASSERT_EQUALS( ssrs.pos(), (uint32)7 );
+ b = ssrs.readByte();
+ TS_ASSERT_EQUALS( b, 7 );
+
+ ssrs.seek(-3, SEEK_CUR);
+ TS_ASSERT_EQUALS( ssrs.pos(), (uint32)5 );
+ b = ssrs.readByte();
+ TS_ASSERT_EQUALS( b, 5 );
+
+ ssrs.seek(0, SEEK_END);
+ TS_ASSERT_EQUALS( ssrs.pos(), (uint32)10 );
+ TS_ASSERT( ssrs.eos() );
+
+ ssrs.seek(3, SEEK_END);
+ TS_ASSERT_EQUALS( ssrs.pos(), (uint32)7 );
+ b = ssrs.readByte();
+ TS_ASSERT_EQUALS( b, 7 );
+
+ ssrs.seek(8, SEEK_END);
+ TS_ASSERT_EQUALS( ssrs.pos(), (uint32)2 );
+ b = ssrs.readByte();
+ TS_ASSERT_EQUALS( b, 2 );
+ }
+};
Property changes on: scummvm/trunk/test/common/bufferedseekablereadstream.h
___________________________________________________________________
Added: svn:mime-type
+ text/plain
Added: svn:keywords
+ Date Rev Author URL Id
Added: svn:eol-style
+ native
Modified: scummvm/trunk/test/common/seekablesubreadstream.h
===================================================================
--- scummvm/trunk/test/common/seekablesubreadstream.h 2008-07-29 17:38:07 UTC (rev 33418)
+++ scummvm/trunk/test/common/seekablesubreadstream.h 2008-07-29 17:42:19 UTC (rev 33419)
@@ -2,22 +2,19 @@
#include "common/stream.h"
-class SeekableSubReadStreamTestSuite : public CxxTest::TestSuite
-{
+class SeekableSubReadStreamTestSuite : public CxxTest::TestSuite {
public:
- void test_traverse( void )
- {
+ void test_traverse(void) {
byte contents[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
- Common::MemoryReadStream ms = Common::MemoryReadStream(contents, 10);
+ Common::MemoryReadStream ms(contents, 10);
int start = 2, end = 8;
- Common::SeekableSubReadStream ssrs = Common::SeekableSubReadStream(&ms, start, end);
+ Common::SeekableSubReadStream ssrs(&ms, start, end);
int i;
byte b;
- for (i = start; i < end; ++i)
- {
+ for (i = start; i < end; ++i) {
TS_ASSERT( !ssrs.eos() );
TS_ASSERT_EQUALS( uint32(i - start), ssrs.pos() );
@@ -29,12 +26,11 @@
TS_ASSERT( ssrs.eos() );
}
- void test_seek( void )
- {
+ void test_seek(void) {
byte contents[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
- Common::MemoryReadStream ms = Common::MemoryReadStream(contents, 10);
+ Common::MemoryReadStream ms(contents, 10);
- Common::SeekableSubReadStream ssrs = Common::SeekableSubReadStream(&ms, 1, 9);
+ Common::SeekableSubReadStream ssrs(&ms, 1, 9);
byte b;
TS_ASSERT_EQUALS( ssrs.pos(), (uint32)0 );
Modified: scummvm/trunk/test/common/subreadstream.h
===================================================================
--- scummvm/trunk/test/common/subreadstream.h 2008-07-29 17:38:07 UTC (rev 33418)
+++ scummvm/trunk/test/common/subreadstream.h 2008-07-29 17:42:19 UTC (rev 33419)
@@ -2,25 +2,22 @@
#include "common/stream.h"
-class SubReadStreamTestSuite : public CxxTest::TestSuite
-{
+class SubReadStreamTestSuite : public CxxTest::TestSuite {
public:
- void test_traverse( void )
- {
+ void test_traverse(void) {
byte contents[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
- Common::MemoryReadStream ms = Common::MemoryReadStream(contents, 10);
+ Common::MemoryReadStream ms(contents, 10);
int end = 5;
- Common::SubReadStream srs = Common::SubReadStream(&ms, end);
+ Common::SubReadStream srs(&ms, end);
int i;
byte b;
- for (i = 0; i < end; ++i)
- {
+ for (i = 0; i < end; ++i) {
TS_ASSERT( !srs.eos() );
- srs.read(&b, 1);
+ b = srs.readByte();
TS_ASSERT_EQUALS( i, b );
}
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