libyelp/yelp-magic-decompressor.c

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * Copyright (C) 2009 Red Hat, Inc.
   4  * Copyright (C) 2009 Shaun McCance <shaunm@gnome.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General
  17  * Public License along with this library; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  19  * Boston, MA 02111-1307, USA.
  20  *
  21  * Author: Shaun McCance <shaunm@gnome.org>
  22  */
  23
  24 #include "config.h"
  25
  26 #include <glib/gi18n.h>
  27 #include <string.h>
  28
  29 #include "yelp-magic-decompressor.h"
  30
  31 #ifdef ENABLE_BZ2
  32 #include "yelp-bz2-decompressor.h"
  33 #endif
  34
  35 #ifdef ENABLE_LZMA
  36 #include "yelp-lzma-decompressor.h"
  37 #endif
  38
  39
  40 static void yelp_magic_decompressor_iface_init          (GConverterIface *iface);
  41
  42 struct _YelpMagicDecompressor
  43 {
  44     GObject parent_instance;
  45
  46     GConverter *magic_decoder_ring;
  47
  48     gboolean first;
  49 };
  50
  51 G_DEFINE_TYPE_WITH_CODE (YelpMagicDecompressor, yelp_magic_decompressor, G_TYPE_OBJECT,
  52                          G_IMPLEMENT_INTERFACE (G_TYPE_CONVERTER,
  53                                                 yelp_magic_decompressor_iface_init))
  54
  55 static void
  56 yelp_magic_decompressor_dispose (GObject *object)
  57 {
  58     YelpMagicDecompressor *decompressor = YELP_MAGIC_DECOMPRESSOR (object);
  59
  60     if (decompressor->magic_decoder_ring) {
  61         g_object_unref (decompressor->magic_decoder_ring);
  62         decompressor->magic_decoder_ring = NULL;
  63     }
  64
  65     G_OBJECT_CLASS (yelp_magic_decompressor_parent_class)->dispose (object);
  66 }
  67
  68 static void
  69 yelp_magic_decompressor_init (YelpMagicDecompressor *decompressor)
  70 {
  71     decompressor->magic_decoder_ring = NULL;
  72     decompressor->first = TRUE;
  73 }
  74
  75 static void
  76 yelp_magic_decompressor_class_init (YelpMagicDecompressorClass *klass)
  77 {
  78     GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
  79
  80     gobject_class->dispose = yelp_magic_decompressor_dispose;
  81 }
  82
  83 YelpMagicDecompressor *
  84 yelp_magic_decompressor_new (void)
  85 {
  86     YelpMagicDecompressor *decompressor;
  87
  88     decompressor = g_object_new (YELP_TYPE_MAGIC_DECOMPRESSOR, NULL);
  89
  90     return decompressor;
  91 }
  92
  93 static void
  94 yelp_magic_decompressor_reset (GConverter *converter)
  95 {
  96     YelpMagicDecompressor *decompressor = YELP_MAGIC_DECOMPRESSOR (converter);
  97
  98     if (decompressor->magic_decoder_ring)
  99         g_converter_reset (decompressor->magic_decoder_ring);
 100 }
 101
 102 static GConverter*
 103 yelp_magic_decompressor_choose (const void *inbuf, gsize inbuf_size)
 104 {
 105     /* If input_size is less than two the first time, we end up
 106      * not getting detection.  Might be worth addressing.  Not
 107      * sure I care.
 108      *
 109      * The two-byte magic we're doing here is not sufficient in
 110      * the general case.  It is sufficient for the specific data
 111      * Yelp deals with.
 112      */
 113     if (inbuf_size <= 2)
 114         return NULL;
 115
 116 #ifdef ENABLE_BZ2
 117     if (((gchar *) inbuf)[0] == 'B' && ((gchar *) inbuf)[1] == 'Z') {
 118         return (GConverter *) yelp_bz2_decompressor_new ();
 119     }
 120 #endif
 121 #ifdef ENABLE_LZMA
 122     if (((gchar *) inbuf)[0] == ']' && ((gchar *) inbuf)[1] == '\0') {
 123         return (GConverter *) yelp_lzma_decompressor_new ();
 124     }
 125 #endif
 126     if (((guint8*) inbuf)[0] == 0x1F && ((guint8*) inbuf)[1] == 0x8B) {
 127         return (GConverter *) g_zlib_decompressor_new (G_ZLIB_COMPRESSOR_FORMAT_GZIP);
 128     }
 129
 130     return NULL;
 131 }
 132
 133 static GConverterResult
 134 yelp_magic_decompressor_convert (GConverter *converter,
 135                                  const void *inbuf,
 136                                  gsize       inbuf_size,
 137                                  void       *outbuf,
 138                                  gsize       outbuf_size,
 139                                  GConverterFlags flags,
 140                                  gsize      *bytes_read,
 141                                  gsize      *bytes_written,
 142                                  GError    **error)
 143 {
 144     YelpMagicDecompressor *decompressor;
 145     gsize txfer_size;
 146
 147     decompressor = YELP_MAGIC_DECOMPRESSOR (converter);
 148
 149     if (decompressor->first) {
 150         decompressor->magic_decoder_ring =
 151             yelp_magic_decompressor_choose (inbuf, inbuf_size);
 152         decompressor->first = FALSE;
 153     }
 154
 155     if (decompressor->magic_decoder_ring) {
 156         return g_converter_convert (decompressor->magic_decoder_ring,
 157                                     inbuf, inbuf_size,
 158                                     outbuf, outbuf_size,
 159                                     flags,
 160                                     bytes_read, bytes_written,
 161                                     error);
 162     }
 163
 164     /* If there's no magic_decoder_ring, we just copy the data
 165      * straight through. */
 166     txfer_size = MIN (inbuf_size, outbuf_size);
 167     memcpy (outbuf, inbuf, txfer_size);
 168     *bytes_read = txfer_size;
 169     *bytes_written = txfer_size;
 170
 171     return G_CONVERTER_CONVERTED;
 172 }
 173
 174 static void
 175 yelp_magic_decompressor_iface_init (GConverterIface *iface)
 176 {
 177   iface->convert = yelp_magic_decompressor_convert;
 178   iface->reset = yelp_magic_decompressor_reset;
 179 }