compress.h

   1 /*
   2  * Copyright (c) 2001, Robert Collins.
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     A copy of the GNU General Public License can be found at
  10  *     http://www.gnu.org/
  11  *
  12  * Written by Robert Collins  <rbtcollins@hotmail.com>
  13  *
  14  */
  15
  16 #ifndef SETUP_COMPRESS_H
  17 #define SETUP_COMPRESS_H
  18
  19 #include "io_stream.h"
  20
  21 class compress:public io_stream
  22 {
  23 public:
  24   /* Get a decompressed stream from a normal stream. If this function returns non-null
  25    * a valid compress header was found. The io_stream pointer passed to decompress
  26    * should be discarded. The old io_stream will be automatically closed when the
  27    * decompression stream is closed
  28    */
  29   static io_stream *decompress (io_stream *);
  30   /*
  31    * To create a stream that will be compressed, you should open the url, and then get a new stream
  32    * from compress::compress.
  33    */
  34   /* read data (duh!) */
  35   virtual ssize_t read (void *buffer, size_t len) = 0;
  36   /* provide data to (double duh!) */
  37   virtual ssize_t write (const void *buffer, size_t len) = 0;
  38   /* read data without removing it from the class's internal buffer */
  39   virtual ssize_t peek (void *buffer, size_t len) = 0;
  40   virtual off_t tell () = 0;
  41   /* try guessing this one */
  42   virtual int error () = 0;
  43   /* Find out the next stream name -
  44    * ie for foo.tar.gz, at offset 0, next_file_name = foo.tar
  45    * for foobar that is an compress, next_file_name is the next
  46    * extractable filename.
  47    */
  48   virtual const char *next_file_name () = 0;
  49   /* if you are still needing these hints... give up now! */
  50   virtual ~compress () = 0;
  51 };
  52
  53 #endif /* SETUP_COMPRESS_H */