void MemoryMappedFile::PrefetchRange( Range<const char*> memoryRange ) const {
# if( WIN8_MEMORY_MAPPED_FILE_AVAILABLE )
WIN32_MEMORY_RANGE_ENTRY ranges[] = { { const_cast<char*>( memoryRange.first ), memoryRange.GetSize() } };
PrefetchVirtualMemory( GetCurrentProcess(), _countof( ranges ), ranges, 0 );
# else
for( auto temp( memoryRange.Begin() ); temp < memoryRange.End(); temp += PrefetchStride ) {
// TODO: Is it possible to use prefetch instructions to avoid polluting the processor caches?
register int readTarget = *reinterpret_cast<const int*>(temp);
}
# endif
}
/*! \brief Looks for a pattern match in the given data stream, starting from
each offset withing the given range. Returns true is a match is found,
false if not.
*/
bool
Pattern::Sniff(Range range, BPositionIO *data, bool caseInsensitive) const {
int32 start = range.Start();
int32 end = range.End();
off_t size = data->Seek(0, SEEK_END);
if (end >= size)
end = size-1; // Don't bother searching beyond the end of the stream
for (int i = start; i <= end; i++) {
if (Sniff(i, size, data, caseInsensitive))
return true;
}
return false;
}
bool
ChunkSet::HasSubrange(const Range& aSubrange) const
{
for (const Range& range : mRanges) {
if (range.Contains(aSubrange)) {
return true;
} else if (!(aSubrange.Begin() > range.End() ||
range.Begin() > aSubrange.End())) {
// In this case, aSubrange overlaps this range but is not a subrange.
// because the ChunkSet implementation ensures that there are no
// overlapping ranges, this means that aSubrange cannot be a subrange of
// any of the following ranges
return false;
}
}
return false;
}