Load up input buffer and set eof flag if last data loaded -- return -1 on error, 0 otherwise. Note that the eof flag is set when the end of the input file is reached, even though there may be unused data in the buffer. Once that data has been used, no more attempts will be made to read the file. If strm->avail_in != 0, then the current data is moved to the beginning of the input b
(state)