zzip_entry_fread(3) open a file within a zip disk for reading

Other Alias

zzip_entry_fopen, zzip_entry_ffile, zzip_entry_fclose, zzip_entry_feof

SYNOPSIS


#include <zzip/fseeko.h>

zzip__new__ ZZIP_ENTRY_FILE * zzip_entry_fopen((ZZIP_ENTRY * entry, int takeover));
zzip__new__ ZZIP_ENTRY_FILE * zzip_entry_ffile((FILE * disk, char *filename));
zzip_size_t zzip_entry_fread((void *ptr, zzip_size_t sized, zzip_size_t nmemb, ZZIP_ENTRY_FILE * file));
int zzip_entry_fclose((ZZIP_ENTRY_FILE * file));
int zzip_entry_feof((ZZIP_ENTRY_FILE * file));

DESCRIPTION

The zzip_entry_fopen function does take an "entry" argument and copies it (or just takes it over as owner) to a new ZZIP_ENTRY_FILE handle structure. That structure contains also a zlib buffer for decoding. The zzip_entry_fopen function does seek to the file_header of the given "entry" and validates it for the data buffer following it. We do also prefetch some data from the data buffer thereby trying to match the disk pagesize for faster access later. The zzip_entry_fread will then read in chunks of pagesizes which is the size of the internal readahead buffer. If an error occurs then null is returned.

The zzip_entry_ffile function opens a file found by name, so it does a search into the zip central directory with zzip_entry_findfile and whatever is found first is given to zzip_entry_fopen

The zzip_entry_fread function reads more bytes into the output buffer specified as arguments. The return value is null on eof or error, the stdio-like interface can not distinguish between these so you need to check with zzip_entry_feof for the difference.

The zzip_entry_fclose function releases any zlib decoder info needed for decompression and dumps the ZZIP_ENTRY_FILE struct then.

The zzip_entry_feof function allows to distinguish an error from an eof condition. Actually, if we found an error but we did already reach eof then we just keep on saying that it was an eof, so the app can just continue.

AUTHOR

• Guido Draheim <[email protected]>

COPYRIGHT

Copyright (c) 2003,2004 Guido Draheim All rights reserved, use under the restrictions of the Lesser GNU General Public License or alternatively the restrictions of the Mozilla Public License 1.1

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