// Truncate the buffer by deleting the end segments
NS_IMETHODIMP
nsStorageStream::SetLength(uint32_t aLength)
{
if (NS_WARN_IF(!mSegmentedBuffer))
return NS_ERROR_NOT_INITIALIZED;
if (mWriteInProgress)
return NS_ERROR_NOT_AVAILABLE;
if (aLength > mLogicalLength)
return NS_ERROR_INVALID_ARG;
int32_t newLastSegmentNum = SegNum(aLength);
int32_t segmentOffset = SegOffset(aLength);
if (segmentOffset == 0)
newLastSegmentNum--;
while (newLastSegmentNum < mLastSegmentNum) {
mSegmentedBuffer->DeleteLastSegment();
mLastSegmentNum--;
}
mLogicalLength = aLength;
return NS_OK;
}
NS_METHOD
nsStorageStream::Seek(int32_t aPosition)
{
if (NS_WARN_IF(!mSegmentedBuffer))
return NS_ERROR_NOT_INITIALIZED;
// An argument of -1 means "seek to end of stream"
if (aPosition == -1)
aPosition = mLogicalLength;
// Seeking beyond the buffer end is illegal
if ((uint32_t)aPosition > mLogicalLength)
return NS_ERROR_INVALID_ARG;
// Seeking backwards in the write stream results in truncation
SetLength(aPosition);
// Special handling for seek to start-of-buffer
if (aPosition == 0) {
mWriteCursor = 0;
mSegmentEnd = 0;
LOG(("nsStorageStream [%p] Seek mWriteCursor=%x mSegmentEnd=%x\n",
this, mWriteCursor, mSegmentEnd));
return NS_OK;
}
// Segment may have changed, so reset pointers
mWriteCursor = mSegmentedBuffer->GetSegment(mLastSegmentNum);
NS_ASSERTION(mWriteCursor, "null mWriteCursor");
mSegmentEnd = mWriteCursor + mSegmentSize;
// Adjust write cursor for current segment offset. This test is necessary
// because SegNum may reference the next-to-be-allocated segment, in which
// case we need to be pointing at the end of the last segment.
int32_t segmentOffset = SegOffset(aPosition);
if (segmentOffset == 0 && (SegNum(aPosition) > (uint32_t) mLastSegmentNum))
mWriteCursor = mSegmentEnd;
else
mWriteCursor += segmentOffset;
LOG(("nsStorageStream [%p] Seek mWriteCursor=%x mSegmentEnd=%x\n",
this, mWriteCursor, mSegmentEnd));
return NS_OK;
}
// Truncate the buffer by deleting the end segments
NS_IMETHODIMP
nsStorageStream::SetLength(PRUint32 aLength)
{
if (mWriteInProgress)
return NS_ERROR_NOT_AVAILABLE;
if (aLength > mLogicalLength)
return NS_ERROR_INVALID_ARG;
PRInt32 newLastSegmentNum = SegNum(aLength);
PRInt32 segmentOffset = SegOffset(aLength);
if (segmentOffset == 0)
newLastSegmentNum--;
while (newLastSegmentNum < mLastSegmentNum) {
mSegmentedBuffer->DeleteLastSegment();
mLastSegmentNum--;
}
mLogicalLength = aLength;
return NS_OK;
}
