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1 /* GStreamer |
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2 * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de> |
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3 * |
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4 * gsttypefind.c: typefinding subsystem |
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5 * |
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6 * This library is free software; you can redistribute it and/or |
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7 * modify it under the terms of the GNU Library General Public |
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8 * License as published by the Free Software Foundation; either |
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9 * version 2 of the License, or (at your option) any later version. |
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10 * |
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11 * This library is distributed in the hope that it will be useful, |
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 * Library General Public License for more details. |
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15 * |
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16 * You should have received a copy of the GNU Library General Public |
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17 * License along with this library; if not, write to the |
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18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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19 * Boston, MA 02111-1307, USA. |
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20 */ |
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21 |
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22 /** |
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23 * SECTION:gsttypefind |
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24 * @short_description: Stream type detection |
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25 * |
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26 * The following functions allow you to detect the media type of an unknown |
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27 * stream. |
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28 * |
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29 * Last reviewed on 2005-11-09 (0.9.4) |
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30 */ |
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31 |
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32 #include "gst_private.h" |
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33 #include "gstinfo.h" |
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34 #include "gsttypefind.h" |
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35 #include "gstregistry.h" |
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36 #include "gsttypefindfactory.h" |
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37 |
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38 GST_DEBUG_CATEGORY_EXTERN (type_find_debug); |
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39 #define GST_CAT_DEFAULT type_find_debug |
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40 |
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41 #ifdef __SYMBIAN32__ |
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42 EXPORT_C |
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43 #endif |
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44 GType |
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45 gst_type_find_get_type (void) |
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46 { |
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47 static GType typefind_type = 0; |
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48 |
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49 if (G_UNLIKELY (typefind_type == 0)) { |
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50 typefind_type = g_pointer_type_register_static ("GstTypeFind"); |
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51 } |
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52 return typefind_type; |
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53 } |
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54 |
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55 /** |
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56 * gst_type_find_register: |
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57 * @plugin: A #GstPlugin, or NULL for a static typefind function (note that |
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58 * passing NULL only works in GStreamer 0.10.16 and later) |
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59 * @name: The name for registering |
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60 * @rank: The rank (or importance) of this typefind function |
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61 * @func: The #GstTypeFindFunction to use |
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62 * @extensions: Optional extensions that could belong to this type |
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63 * @possible_caps: Optionally the caps that could be returned when typefinding |
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64 * succeeds |
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65 * @data: Optional user data. This user data must be available until the plugin |
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66 * is unloaded. |
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67 * @data_notify: a #GDestroyNotify that will be called on @data when the plugin |
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68 * is unloaded. |
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69 * |
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70 * Registers a new typefind function to be used for typefinding. After |
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71 * registering this function will be available for typefinding. |
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72 * This function is typically called during an element's plugin initialization. |
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73 * |
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74 * Returns: TRUE on success, FALSE otherwise |
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75 */ |
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76 #ifdef __SYMBIAN32__ |
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77 EXPORT_C |
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78 #endif |
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79 |
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80 gboolean |
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81 gst_type_find_register (GstPlugin * plugin, const gchar * name, guint rank, |
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82 GstTypeFindFunction func, gchar ** extensions, |
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83 const GstCaps * possible_caps, gpointer data, GDestroyNotify data_notify) |
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84 { |
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85 GstTypeFindFactory *factory; |
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86 |
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87 g_return_val_if_fail (name != NULL, FALSE); |
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88 g_return_val_if_fail (func != NULL, FALSE); |
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89 |
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90 GST_INFO ("registering typefind function for %s", name); |
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91 |
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92 factory = g_object_new (GST_TYPE_TYPE_FIND_FACTORY, NULL); |
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93 GST_DEBUG_OBJECT (factory, "using new typefind factory for %s", name); |
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94 g_assert (GST_IS_TYPE_FIND_FACTORY (factory)); |
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95 gst_plugin_feature_set_name (GST_PLUGIN_FEATURE (factory), name); |
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96 |
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97 gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE (factory), rank); |
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98 if (factory->extensions) |
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99 g_strfreev (factory->extensions); |
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100 |
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101 factory->extensions = g_strdupv (extensions); |
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102 gst_caps_replace (&factory->caps, (GstCaps *) possible_caps); |
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103 factory->function = func; |
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104 factory->user_data = data; |
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105 factory->user_data_notify = data_notify; |
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106 if (plugin && plugin->desc.name) { |
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107 GST_PLUGIN_FEATURE (factory)->plugin_name = plugin->desc.name; /* interned string */ |
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108 } else { |
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109 GST_PLUGIN_FEATURE (factory)->plugin_name = "NULL"; |
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110 } |
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111 GST_PLUGIN_FEATURE (factory)->loaded = TRUE; |
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112 |
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113 gst_registry_add_feature (gst_registry_get_default (), |
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114 GST_PLUGIN_FEATURE (factory)); |
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115 |
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116 return TRUE; |
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117 } |
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118 |
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119 /*** typefind function interface **********************************************/ |
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120 |
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121 /** |
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122 * gst_type_find_peek: |
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123 * @find: The #GstTypeFind object the function was called with |
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124 * @offset: The offset |
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125 * @size: The number of bytes to return |
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126 * |
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127 * Returns the @size bytes of the stream to identify beginning at offset. If |
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128 * offset is a positive number, the offset is relative to the beginning of the |
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129 * stream, if offset is a negative number the offset is relative to the end of |
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130 * the stream. The returned memory is valid until the typefinding function |
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131 * returns and must not be freed. |
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132 * |
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133 * Returns: the requested data, or NULL if that data is not available. |
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134 */ |
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135 #ifdef __SYMBIAN32__ |
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136 EXPORT_C |
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137 #endif |
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138 |
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139 guint8 * |
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140 gst_type_find_peek (GstTypeFind * find, gint64 offset, guint size) |
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141 { |
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142 g_return_val_if_fail (find->peek != NULL, NULL); |
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143 |
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144 return find->peek (find->data, offset, size); |
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145 } |
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146 |
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147 /** |
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148 * gst_type_find_suggest: |
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149 * @find: The #GstTypeFind object the function was called with |
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150 * @probability: The probability in percent that the suggestion is right |
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151 * @caps: The fixed #GstCaps to suggest |
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152 * |
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153 * If a #GstTypeFindFunction calls this function it suggests the caps with the |
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154 * given probability. A #GstTypeFindFunction may supply different suggestions |
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155 * in one call. |
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156 * It is up to the caller of the #GstTypeFindFunction to interpret these values. |
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157 */ |
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158 #ifdef __SYMBIAN32__ |
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159 EXPORT_C |
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160 #endif |
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161 |
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162 void |
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163 gst_type_find_suggest (GstTypeFind * find, guint probability, |
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164 const GstCaps * caps) |
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165 { |
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166 g_return_if_fail (find->suggest != NULL); |
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167 g_return_if_fail (probability <= 100); |
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168 g_return_if_fail (caps != NULL); |
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169 g_return_if_fail (gst_caps_is_fixed (caps)); |
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170 |
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171 find->suggest (find->data, probability, caps); |
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172 } |
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173 |
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174 /** |
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175 * gst_type_find_get_length: |
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176 * @find: The #GstTypeFind the function was called with |
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177 * |
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178 * Get the length of the data stream. |
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179 * |
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180 * Returns: The length of the data stream, or 0 if it is not available. |
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181 */ |
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182 #ifdef __SYMBIAN32__ |
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183 EXPORT_C |
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184 #endif |
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185 |
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186 guint64 |
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187 gst_type_find_get_length (GstTypeFind * find) |
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188 { |
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189 if (find->get_length == NULL) |
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190 return 0; |
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191 |
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192 return find->get_length (find->data); |
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193 } |