size_t StandardFile::readData(File::Byte* buffer,size_t bufferSize)
{
/* Check if file needs to be repositioned: */
if(filePos!=readPos)
if(lseek64(fd,readPos,SEEK_SET)<0)
throw SeekError(readPos);
/* Read more data from source: */
ssize_t readResult;
do
{
readResult=::read(fd,buffer,bufferSize);
}
while(readResult<0&&(errno==EAGAIN||errno==EWOULDBLOCK||errno==EINTR));
/* Handle the result from the read call: */
if(readResult<0)
{
/* Unknown error; probably a bad thing: */
throw Error(Misc::printStdErrMsg("IO::StandardFile: Fatal error %d while reading from file",int(errno)));
}
/* Advance the read pointer: */
readPos+=readResult;
filePos=readPos;
return size_t(readResult);
}
void StandardFile::writeData(const File::Byte* buffer,size_t bufferSize)
{
/* Check if file needs to be repositioned: */
if(filePos!=writePos)
if(lseek64(fd,writePos,SEEK_SET)<0)
throw SeekError(writePos);
/* Invalidate the read buffer to prevent reading stale data: */
flushReadBuffer();
/* Write all data in the given buffer: */
while(bufferSize>0)
{
ssize_t writeResult=::write(fd,buffer,bufferSize);
if(writeResult>0)
{
/* Prepare to write more data: */
buffer+=writeResult;
bufferSize-=writeResult;
/* Advance the write pointer: */
writePos+=writeResult;
filePos=writePos;
}
else if(writeResult<0&&(errno==EAGAIN||errno==EWOULDBLOCK||errno==EINTR))
{
/* Do nothing */
}
else if(writeResult==0)
{
/* Sink has reached end-of-file: */
throw WriteError(bufferSize);
}
else
{
/* Unknown error; probably a bad thing: */
throw Error(Misc::printStdErrMsg("IO::StandardFile: Fatal error %d while writing to file",int(errno)));
}
}
}
size_t SeekableFilter::readData(File::Byte* buffer,size_t bufferSize)
{
/* Check if the file position needs to be moved to the read position: */
if(filePos!=readPos)
{
if(readPos>filePos)
{
/* Skip forward in buffer chain from the current position: */
currentPos+=(readPos-filePos);
/* Skip buffers until the current buffer offset is within the current buffer: */
while(currentPos>Offset(current->size))
{
/* Check if there is a next buffer: */
if(current->succ!=0)
{
/* Go to the next buffer: */
currentPos-=current->size;
current=current->succ;
}
else
{
/* Check for end-of-file: */
if(source->eof())
throw SeekError(readPos);
/* Read more data: */
readFromSource();
}
}
}
else
{
/* Skip from the beginning of the buffer chain: */
current=head;
currentPos=readPos;
/* Skip buffers until the current buffer offset is within the current buffer: */
while(currentPos>Offset(current->size))
{
/* Go to the next buffer: */
currentPos-=current->size;
current=current->succ;
}
}
/* Update the file position: */
filePos=readPos;
}
/* Check if the file position is at the end of the read data: */
if(filePos==totalReadSize)
{
/* Check for end-of-file: */
if(source->eof())
return 0;
/* Read more data: */
readFromSource();
}
/* Read from the current file position: */
if(currentPos==Offset(current->size))
{
/* Go to the next buffer: */
current=current->succ;
currentPos=0;
}
size_t copySize=current->size-size_t(currentPos);
setReadBuffer(copySize,reinterpret_cast<Byte*>(current+1)+currentPos,false);
readPos+=copySize;
filePos+=copySize;
currentPos+=copySize;
return copySize;
}
