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 }
  47
  48 /* Virtual memebrs */
  49 ssize_t archive_tar_file::read (void *buffer, size_t len)
  50 {
  51   /* how many bytes do we want to give the user */
  52   int
  53     want = min (len, state.file_length - state.file_offset);
  54   /* how many do we need to read after that to line up the file pointer */
  55   int
  56     roundup = (512 - (want % 512)) % 512;
  57   if (want)
  58     {
  59       ssize_t
  60         got = state.parent->read (buffer, want);
  61       char
  62         throwaway[512];
  63       ssize_t
  64         got2 = state.parent->read (throwaway, roundup);
  65       if (got == want && got2 == roundup)
  66         {
  67           state.file_offset += got;
  68           return got;
  69         }
  70       else
  71         {
  72           /* unexpected EOF or read error in the tar parent stream */
  73           /* the user can query the parent for the error */
  74           state.lasterr = EIO;
  75           return EIO;
  76         }
  77     }
  78   return 0;
  79 }
  80
  81 /* provide data to (double duh!) */
  82 ssize_t archive_tar_file::write (void *buffer, size_t len)
  83 {
  84   /* write not supported */
  85   return EBADF;
  86 }
  87
  88 /* read data without removing it from the class's internal buffer */
  89 ssize_t archive_tar_file::peek (void *buffer, size_t len)
  90 {
  91   int
  92     want = min (len, state.file_length - state.file_offset);
  93   if (want)
  94     {
  95       ssize_t
  96         got = state.parent->peek (buffer, want);
  97       if (got == want)
  98         {
  99           return got;
 100         }
 101       else
 102         {
 103           /* unexpected EOF or read error in the tar parent stream */
 104           /* the user can query the parent for the error */
 105           state.lasterr = EIO;
 106           return EIO;
 107         }
 108     }
 109   return 0;
 110 }
 111
 112 long
 113 archive_tar_file::tell ()
 114 {
 115   return state.file_offset;
 116 }
 117
 118 /* try guessing this one */
 119 int
 120 archive_tar_file::error ()
 121 {
 122   return state.lasterr;
 123 }
 124
 125 int
 126 archive_tar_file::get_mtime ()
 127 {
 128   int mtime;
 129   sscanf (state.tar_header.mtime, "%o", &mtime);
 130   return mtime;
 131 }