本文整理汇总了C++中AsyncFio::fioAvail方法的典型用法代码示例。如果您正苦于以下问题：C++ AsyncFio::fioAvail方法的具体用法？C++ AsyncFio::fioAvail怎么用？C++ AsyncFio::fioAvail使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类AsyncFio的用法示例。
在下文中一共展示了AsyncFio::fioAvail方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1:
void Ps2File::cacheReadAhead() {
if (_cacheOpRunning) {
// there's already some cache read running
if (fio.poll(_fd)) // did it finish?
cacheReadSync(); // yes.
}
if ((!_cacheOpRunning) && ((_readBytesBlock >= CACHE_READ_THRESHOLD) || _stream) && fio.fioAvail()) {
// the engine seems to do sequential reads and there are no other I/Os going on. read ahead.
uint32 cachePosEnd = _cachePos + _bytesInCache;
if (_cachePos > _filePos)
return; // there was a seek in the meantime, don't cache.
if (cachePosEnd - _filePos >= CACHE_FILL_MIN)
return; // cache is full enough.
if (cachePosEnd == _fileSize)
return; // can't read beyond EOF.
assert(cachePosEnd < _fileSize);
if (_cachePos + _bytesInCache <= _filePos) {
_cacheOfs = _bytesInCache = 0;
_cachePos = cachePosEnd = _filePos & ~READ_ALIGN_MASK;
assert(_filePos == _physFilePos);
} else {
uint32 cacheDiff = _filePos - _cachePos;
assert(_bytesInCache >= cacheDiff);
cacheDiff &= ~READ_ALIGN_MASK;
_bytesInCache -= cacheDiff;
_cachePos += cacheDiff;
_cacheOfs = (_cacheOfs + cacheDiff) % CACHE_SIZE;
}
if (_physFilePos != cachePosEnd) {
sioprintf("unexpected _physFilePos %d cache %d %d\n", _physFilePos, _cacheOfs, _bytesInCache);
// assert(!(cachePosEnd & READ_ALIGN_MASK)); // romeo
_physFilePos = fio.seek(_fd, cachePosEnd, SEEK_SET);
if (_physFilePos != cachePosEnd) {
sioprintf("cache seek error: seek to %d instead of %d, fs = %d\n", _physFilePos, cachePosEnd, _fileSize);
return;
}
}
uint32 cacheDest = (_cacheOfs + _bytesInCache) % CACHE_SIZE;
uint32 cacheRead = CACHE_SIZE - _bytesInCache;
if (cacheDest + cacheRead > CACHE_SIZE)
cacheRead = CACHE_SIZE - cacheDest;
if (cacheRead > MAX_READ_STEP)
cacheRead = MAX_READ_STEP;
assert((!(cacheRead & READ_ALIGN_MASK)) && cacheRead);
_cacheOpRunning = true;
fio.read(_fd, _cacheBuf + cacheDest, cacheRead);
}
}