contrib/libarchive-1.3.1/libarchive/archive_read_open_memory.c

   1 /*-
   2  * Copyright (c) 2003-2006 Tim Kientzle
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "archive_platform.h"
  27 __FBSDID("$FreeBSD: src/lib/libarchive/archive_read_open_fd.c,v 1.5 2006/01/17 04:49:04 kientzle Exp $");
  28
  29 #include <errno.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include "archive.h"
  34
  35 /*
  36  * Glue to read an archive from a block of memory.
  37  *
  38  * This is mostly a huge help in building test harnesses;
  39  * test programs can build archives in memory and read them
  40  * back again without having to mess with files on disk.
  41  */
  42
  43 struct read_memory_data {
  44         unsigned char   *buffer;
  45         unsigned char   *end;
  46         ssize_t  read_size;
  47 };
  48
  49 static int      memory_read_close(struct archive *, void *);
  50 static int      memory_read_open(struct archive *, void *);
  51 static ssize_t  memory_read_skip(struct archive *, void *, size_t request);
  52 static ssize_t  memory_read(struct archive *, void *, const void **buff);
  53
  54 int
  55 archive_read_open_memory(struct archive *a, void *buff, size_t size)
  56 {
  57         return archive_read_open_memory2(a, buff, size, size);
  58 }
  59
  60 /*
  61  * Don't use this in production code; the archive_read_open_memory()
  62  * version is the one you really want.  This is just here so that
  63  * test harnesses can exercise block operations inside the library.
  64  */
  65 int
  66 archive_read_open_memory2(struct archive *a, void *buff,
  67     size_t size, size_t read_size)
  68 {
  69         struct read_memory_data *mine;
  70
  71         mine = malloc(sizeof(*mine));
  72         if (mine == NULL) {
  73                 archive_set_error(a, ENOMEM, "No memory");
  74                 return (ARCHIVE_FATAL);
  75         }
  76         memset(mine, 0, sizeof(*mine));
  77         mine->buffer = buff;
  78         mine->end = mine->buffer + size;
  79         mine->read_size = read_size;
  80         return (archive_read_open2(a, mine, memory_read_open,
  81                     memory_read, memory_read_skip, memory_read_close));
  82 }
  83
  84 /*
  85  * There's nothing to open.
  86  */
  87 static int
  88 memory_read_open(struct archive *a, void *client_data)
  89 {
  90         (void)a; /* UNUSED */
  91         (void)client_data; /* UNUSED */
  92         return (ARCHIVE_OK);
  93 }
  94
  95 /*
  96  * This is scary simple:  Just advance a pointer.  Limiting
  97  * to read_size is not technically necessary, but it exercises
  98  * more of the internal logic when used with a small block size
  99  * in a test harness.  Production use should not specify a block
 100  * size; then this is much faster.
 101  */
 102 static ssize_t
 103 memory_read(struct archive *a, void *client_data, const void **buff)
 104 {
 105         struct read_memory_data *mine = client_data;
 106         ssize_t size;
 107
 108         (void)a; /* UNUSED */
 109         *buff = mine->buffer;
 110         size = mine->end - mine->buffer;
 111         if (size > mine->read_size)
 112                 size = mine->read_size;
 113         mine->buffer += size;
 114         return (size);
 115 }
 116
 117 /*
 118  * Advancing is just as simple.  Again, this is doing more than
 119  * necessary in order to better exercise internal code when used
 120  * as a test harness.
 121  */
 122 static ssize_t
 123 memory_read_skip(struct archive *a, void *client_data, size_t skip)
 124 {
 125         struct read_memory_data *mine = client_data;
 126
 127         (void)a; /* UNUSED */
 128         if (mine->buffer + skip > mine->end)
 129                 skip = mine->end - mine->buffer;
 130         /* Round down to block size. */
 131         skip /= mine->read_size;
 132         skip *= mine->read_size;
 133         mine->buffer += skip;
 134         return (skip);
 135 }
 136
 137 /*
 138  * Close is just cleaning up our one small bit of data.
 139  */
 140 static int
 141 memory_read_close(struct archive *a, void *client_data)
 142 {
 143         struct read_memory_data *mine = client_data;
 144         (void)a; /* UNUSED */
 145         free(mine);
 146         return (ARCHIVE_OK);
 147 }