void dng_memory_stream::DoRead (void *data,
uint32 count,
uint64 offset)
{
if (offset + count > fMemoryStreamLength)
{
ThrowEndOfFile ();
}
uint64 baseOffset = offset;
while (count)
{
uint32 pageIndex = (uint32) (offset / fPageSize);
uint32 pageOffset = (uint32) (offset % fPageSize);
uint32 blockCount = Min_uint32 (fPageSize - pageOffset, count);
const uint8 *sPtr = fPageList [pageIndex]->Buffer_uint8 () +
pageOffset;
uint8 *dPtr = ((uint8 *) data) + (uint32) (offset - baseOffset);
DoCopyBytes (sPtr, dPtr, blockCount);
offset += blockCount;
count -= blockCount;
}
}
void dng_stream::SetReadPosition (uint64 offset)
{
fPosition = offset;
if (fPosition > Length ())
{
ThrowEndOfFile ();
}
}
void dng_memory_stream::CopyToStream (dng_stream &dstStream,
uint64 count)
{
if (count < kBigBufferSize)
{
dng_stream::CopyToStream (dstStream, count);
}
else
{
Flush ();
uint64 offset = Position ();
if (offset + count > Length ())
{
ThrowEndOfFile ();
}
while (count)
{
uint32 pageIndex = (uint32) (offset / fPageSize);
uint32 pageOffset = (uint32) (offset % fPageSize);
uint32 blockCount = (uint32) Min_uint64 (fPageSize - pageOffset, count);
const uint8 *sPtr = fPageList [pageIndex]->Buffer_uint8 () +
pageOffset;
dstStream.Put (sPtr, blockCount);
offset += blockCount;
count -= blockCount;
}
SetReadPosition (offset);
}
}
void dng_stream::Get (void *data, uint32 count)
{
while (count)
{
// See if the request is totally inside buffer.
if (fPosition >= fBufferStart && fPosition + count <= fBufferEnd)
{
DoCopyBytes (fBuffer + (uint32) (fPosition - fBufferStart),
data,
count);
fPosition += count;
return;
}
// See if first part of request is inside buffer.
if (fPosition >= fBufferStart && fPosition < fBufferEnd)
{
uint32 block = (uint32) (fBufferEnd - fPosition);
DoCopyBytes (fBuffer + (fPosition - fBufferStart),
data,
block);
count -= block;
data = (void *) (((char *) data) + block);
fPosition += block;
}
// Flush buffer if dirty.
Flush ();
// Do large reads unbuffered.
if (count > fBufferSize)
{
if (fPosition + count > Length ())
{
ThrowEndOfFile ();
}
DoRead (data,
count,
fPosition);
fPosition += count;
return;
}
// Figure out new buffer range.
fBufferStart = fPosition;
if (fBufferSize >= 4096)
{
// Align to a 4K file block.
fBufferStart &= (uint64) ~((int64) 4095);
}
fBufferEnd = Min_uint64 (fBufferStart + fBufferSize, Length ());
if (fBufferEnd <= fPosition)
{
ThrowEndOfFile ();
}
// Read data into buffer.
dng_abort_sniffer::SniffForAbort (fSniffer);
DoRead (fBuffer,
(uint32) (fBufferEnd - fBufferStart),
fBufferStart);
}
}
