C++ (Cpp) cacheReadAhead Beispiele

Beispiel #1

Datei: fileio.cpp Projekt: iPodLinux-Community/iScummVM

uint32 Ps2ReadFile::read(void *dest, uint32 len) {
	WaitSema(_sema);
	uint8 *destBuf = (uint8*)dest;
	if ((_filePos < _cachePos) || (_filePos + len > _cachePos + _bytesInCache))
		cacheReadSync(); // we have to read from CD, sync cache.

	while (len && (_filePos != _fileSize)) {
		if ((_filePos >= _cachePos) && (_filePos < _cachePos + _bytesInCache)) { // read from cache
			uint32 staPos = (_cacheOfs + (_filePos - _cachePos)) % CACHE_SIZE;
			uint32 cpyLen = _bytesInCache - (_filePos - _cachePos);
			if (cpyLen > len)
				cpyLen = len;
			if (staPos + cpyLen > CACHE_SIZE)
				cpyLen = CACHE_SIZE - staPos;

			assert(cpyLen);
			memcpy(destBuf, _cacheBuf + staPos, cpyLen);
			_filePos += cpyLen;
			destBuf += cpyLen;
			_readBytesBlock += len;
			len -= cpyLen;
		} else { // cache miss
			assert(!_cacheOpRunning);
			if (_physFilePos != _filePos) {
				if ((_filePos < _physFilePos) || (_filePos > _physFilePos + (CACHE_SIZE / 2)))
					_readBytesBlock = 0; // reset cache hit count

				_physFilePos = _filePos & ~READ_ALIGN_MASK;
				if (fio.seek(_fd, _physFilePos, SEEK_SET) != (int)_physFilePos)
					break; // read beyond EOF
			}

			int doRead = len + (_filePos - _physFilePos);
			doRead = (doRead + READ_ALIGN_MASK) & ~READ_ALIGN_MASK;

			if (doRead > MAX_READ_STEP)
				doRead = MAX_READ_STEP;
			if (doRead < 2048)
				doRead = 2048;

			fio.read(_fd, _cacheBuf, doRead);
			_cachePos = _physFilePos;
			_cacheOfs = 0;
			_bytesInCache = fio.sync(_fd);
			_physFilePos += _bytesInCache;
			if (!_bytesInCache)
				break; // EOF
		}
	}
	cacheReadAhead();
	SignalSema(_sema);
	return destBuf - (uint8*)dest;
}

Beispiel #2

Datei: fileio.cpp Projekt: project-cabal/cabal

uint32 Ps2File::read(void *dest, uint32 len) {
	// uint32 r=0, d=0, ds=0, sz=0;
#ifdef __PS2_FILE_SEMA__
	WaitSema(_sema);
#endif

#ifdef __PS2_FILE_DEBUG__
	dbg_printf("read (1) : _filePos = %d\n", _filePos);
	dbg_printf("read (1) : _cachePos = %d\n", _cachePos);
#endif

	if (len == 0) {
#ifdef __PS2_FILE_SEMA__
		SignalSema(_sema);
#endif
		return 0;
	}

	if (_filePos >= _fileSize) {
		_eof = true;
#ifdef __PS2_FILE_SEMA__
		SignalSema(_sema);
#endif
		return 0;
	}

	if ((_filePos+len) > _fileSize) {
		len = _fileSize-_filePos;
		_eof = true;
	}

	uint8 *destBuf = (uint8 *)dest;
	if ((_filePos < _cachePos) || (_filePos + len > _cachePos + _bytesInCache))
		cacheReadSync(); // we have to read from CD, sync cache.

	while (len && (_filePos != _fileSize)) {
		if ((_filePos >= _cachePos) && (_filePos < _cachePos + _bytesInCache)) { // read from cache
			uint32 staPos = (_cacheOfs + (_filePos - _cachePos)) % CACHE_SIZE;
			uint32 cpyLen = _bytesInCache - (_filePos - _cachePos);
			if (cpyLen > len)
				cpyLen = len;
			if (staPos + cpyLen > CACHE_SIZE)
				cpyLen = CACHE_SIZE - staPos;

			assert(cpyLen);
			memcpy(destBuf, _cacheBuf + staPos, cpyLen);
			_filePos += cpyLen;
			destBuf += cpyLen;
			_readBytesBlock += len;
			len -= cpyLen;
		} else { // cache miss
			assert(!_cacheOpRunning);
			if (_physFilePos != _filePos) {
				if ((_filePos < _physFilePos) || (_filePos > _physFilePos + (CACHE_SIZE / 2)))
					_readBytesBlock = 0; // reset cache hit count

				_physFilePos = _filePos & ~READ_ALIGN_MASK;
				if (fio.seek(_fd, _physFilePos, SEEK_SET) != (int)_physFilePos)
					break; // read beyond EOF
			}

			int doRead = len + (_filePos - _physFilePos);
			doRead = (doRead + READ_ALIGN_MASK) & ~READ_ALIGN_MASK;

			if (doRead > MAX_READ_STEP)
				doRead = MAX_READ_STEP;
			if (doRead < 2048)
				doRead = 2048;

			fio.read(_fd, _cacheBuf, doRead);
			_cachePos = _physFilePos;
			_cacheOfs = 0;
			_bytesInCache = fio.sync(_fd);
			_physFilePos += _bytesInCache;
			if (!_bytesInCache)
				break; // EOF
		}
	}
#ifndef ENABLE_PROFILING
	// doesn't play nice with -pg
	cacheReadAhead();
#endif
#ifdef __PS2_FILE_SEMA__
	SignalSema(_sema);
#endif
	return destBuf - (uint8 *)dest;
}