archive_tar_file.cc

   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 /* An individual stream from a tar archive. */
  17
  18 #if 0
  19 static const char *cvsid = "\n%%% $Id$\n";
  20 #endif
  21
  22 #include "win32.h"
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <sys/types.h>
  26 #include <sys/fcntl.h>
  27 #include <errno.h>
  28
  29 #include "zlib/zlib.h"
  30 #include "io_stream.h"
  31 #include "compress.h"
  32 #include "archive.h"
  33 #include "archive_tar.h"
  34 #include "log.h"
  35 #include "concat.h"
  36
  37 #include "port.h"
  38
  39 archive_tar_file::archive_tar_file (tar_state & newstate):state (newstate)
  40 {
  41 }
  42
  43 archive_tar_file::~archive_tar_file ()
  44 {
  45   state.header_read = 0;
  46   destroyed = 1;
  47 }
  48
  49 /* Virtual memebrs */
  50 ssize_t archive_tar_file::read (void *buffer, size_t len)
  51 {
  52   /* how many bytes do we want to give the user */
  53   int
  54     want = min (len, state.file_length - state.file_offset);
  55   /* how many do we need to read after that to line up the file pointer */
  56   int
  57     roundup = (512 - (want % 512)) % 512;
  58   if (want)
  59     {
  60       ssize_t
  61         got = state.parent->read (buffer, want);
  62       char
  63         throwaway[512];
  64       ssize_t
  65         got2 = state.parent->read (throwaway, roundup);
  66       if (got == want && got2 == roundup)
  67         {
  68           state.file_offset += got;
  69           return got;
  70         }
  71       else
  72         {
  73           /* unexpected EOF or read error in the tar parent stream */
  74           /* the user can query the parent for the error */
  75           state.lasterr = EIO;
  76           return EIO;
  77         }
  78     }
  79   return 0;
  80 }
  81
  82 /* provide data to (double duh!) */
  83 ssize_t archive_tar_file::write (const void *buffer, size_t len)
  84 {
  85   /* write not supported */
  86   return EBADF;
  87 }
  88
  89 /* read data without removing it from the class's internal buffer */
  90 ssize_t archive_tar_file::peek (void *buffer, size_t len)
  91 {
  92   int
  93     want = min (len, state.file_length - state.file_offset);
  94   if (want)
  95     {
  96       ssize_t
  97         got = state.parent->peek (buffer, want);
  98       if (got == want)
  99         {
 100           return got;
 101         }
 102       else
 103         {
 104           /* unexpected EOF or read error in the tar parent stream */
 105           /* the user can query the parent for the error */
 106           state.lasterr = EIO;
 107           return EIO;
 108         }
 109     }
 110   return 0;
 111 }
 112
 113 long
 114 archive_tar_file::tell ()
 115 {
 116   return state.file_offset;
 117 }
 118
 119 int
 120 archive_tar_file::seek (long where, io_stream_seek_t whence)
 121 {
 122   /* nothing needs seeking here yet. Implement when needed
 123    */
 124   return -1;
 125 }
 126
 127 /* try guessing this one */
 128 int
 129 archive_tar_file::error ()
 130 {
 131   return state.lasterr;
 132 }
 133
 134 int
 135 archive_tar_file::get_mtime ()
 136 {
 137   int mtime;
 138   sscanf (state.tar_header.mtime, "%o", &mtime);
 139   return mtime;
 140 }