compress_gz.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_GZ_H
  17 #define SETUP_COMPRESS_GZ_H
  18
  19 #include "compress.h"
  20 #include <zlib.h>
  21
  22 class compress_gz:public compress
  23 {
  24 public:
  25   /* assumes decompression */
  26   compress_gz (io_stream *);
  27   /* the mode allows control, but this implementation only does compression */
  28   compress_gz (io_stream *, const char *);
  29   /* read data (duh!) */
  30   virtual ssize_t read (void *buffer, size_t len);
  31   /* provide data to (double duh!) */
  32   virtual ssize_t write (const void *buffer, size_t len);
  33   /* read data without removing it from the class's internal buffer */
  34   virtual ssize_t peek (void *buffer, size_t len);
  35   virtual off_t tell ();
  36   virtual off_t seek (off_t where, io_stream_seek_t whence);
  37   /* try guessing this one */
  38   virtual int error ();
  39   /* Find out the next stream name -
  40    * ie for foo.tar.gz, at offset 0, next_file_name = foo.tar
  41    * for foobar that is an compress, next_file_name is the next
  42    * extractable filename.
  43    */
  44   virtual const char *next_file_name ()
  45   {
  46     return NULL;
  47   };
  48   virtual int set_mtime (time_t);
  49   virtual time_t get_mtime ();
  50   virtual mode_t get_mode ();
  51   /* Use seek EOF, then tell (). get_size won't do this incase you are sucking down
  52    * over a WAN :} */
  53   virtual size_t get_size () {return 0;};
  54   virtual void release_original (); /* give up ownership of original io_stream */
  55   /* if you are still needing these hints... give up now! */
  56   virtual ~ compress_gz ();
  57 private:
  58     compress_gz ()
  59   {
  60   };
  61   char peekbuf[512];
  62   size_t peeklen;
  63   void construct ();
  64   void check_header ();
  65   int get_byte ();
  66   unsigned long getLong ();
  67   void putLong (unsigned long);
  68   void destroy ();
  69   int do_flush (int);
  70   io_stream *original;
  71   bool owns_original;
  72   const char *openmode;
  73   /* from zlib */
  74   z_stream stream;
  75   int z_err;                    /* error code for last stream operation */
  76   int z_eof;                    /* set if end of input file */
  77   unsigned char *inbuf;         /* input buffer */
  78   unsigned char *outbuf;        /* output buffer */
  79   uLong crc;                    /* crc32 of uncompressed data */
  80   char *msg;                    /* error message */
  81   int transparent;              /* 1 if input file is not a .gz file */
  82   char mode;                    /* 'w' or 'r' */
  83   off_t startpos;               /* start of compressed data in file (header skipped) */
  84 };
  85
  86 #endif /* SETUP_COMPRESS_GZ_H */