typefind: add smoothstreaming manifest typefinding

Checks if the received XML is a smoothstreaming manifest
in both UTF8 and UTF16 formats. The check is made for a
SmoothStreamingMedia top level element.

Conflicts:
	gst/typefind/gsttypefindfunctions.c

gst/typefind/gsttypefindfunctions.c

@@ -477,6 +477,67 @@ hls_type_find (GstTypeFind * tf, gpointer unused)
   }                                                                     \
 }
 
+#define XML_INC_BUFFER_DATA {                                           \
+  pos++;                                                                \
+  if (pos >= length) {                                                  \
+    return FALSE;                                                       \
+  } else {                                                              \
+    data++;                                                             \
+  }                                                                     \
+}
+
+static gboolean
+xml_check_first_element_from_data (const guint8 * data, guint length,
+    const gchar * element, guint elen, gboolean strict)
+{
+  gboolean got_xmldec;
+  guint pos = 0;
+
+  g_return_val_if_fail (data != NULL, FALSE);
+
+  if (length <= 5)
+    return FALSE;
+
+  /* look for the XMLDec
+   * see XML spec 2.8, Prolog and Document Type Declaration
+   * http://www.w3.org/TR/2004/REC-xml-20040204/#sec-prolog-dtd */
+  got_xmldec = (memcmp (data, "<?xml", 5) == 0);
+
+  if (strict && !got_xmldec)
+    return FALSE;
+
+  /* skip XMLDec in any case if we've got one */
+  if (got_xmldec) {
+    if (pos + 5 >= length)
+      return FALSE;
+    pos += 5;
+    data += 5;
+  }
+
+  /* look for the first element, it has to be the requested element. Bail
+   * out if it is not within the first 4kB. */
+  while (data && pos < MIN (4096, length)) {
+    while (*data != '<' && pos < MIN (4096, length)) {
+      XML_INC_BUFFER_DATA;
+    }
+
+    XML_INC_BUFFER_DATA;
+    if (!g_ascii_isalpha (*data)) {
+      /* if not alphabetic, it's a PI or an element / attribute declaration
+       * like <?xxx or <!xxx */
+      XML_INC_BUFFER_DATA;
+      continue;
+    }
+
+    /* the first normal element, check if it's the one asked for */
+    if (pos + elen + 1 >= length)
+      return FALSE;
+    return (data && element && strncmp ((char *) data, element, elen) == 0);
+  }
+
+  return FALSE;
+}
+
 static gboolean
 xml_check_first_element (GstTypeFind * tf, const gchar * element, guint elen,
     gboolean strict)
@@ -3199,6 +3260,64 @@ swf_type_find (GstTypeFind * tf, gpointer unused)
   }
 }
 
+/*** application/vnd.ms-sstr+xml ***/
+
+static GstStaticCaps mss_manifest_caps =
+GST_STATIC_CAPS ("application/vnd.ms-sstr+xml");
+#define MSS_MANIFEST_CAPS (gst_static_caps_get(&mss_manifest_caps))
+static void
+mss_manifest_type_find (GstTypeFind * tf, gpointer unused)
+{
+  if (xml_check_first_element (tf, "SmoothStreamingMedia", 20, TRUE)) {
+    gst_type_find_suggest (tf, GST_TYPE_FIND_MAXIMUM, MSS_MANIFEST_CAPS);
+  } else {
+    const guint8 *data;
+    gboolean utf16_le, utf16_be;
+    const gchar *convert_from = NULL;
+    guint8 *converted_data;
+
+    /* try detecting the charset */
+    data = gst_type_find_peek (tf, 0, 2);
+
+    /* look for a possible BOM */
+    utf16_le = data[0] == 0xFF && data[1] == 0xFE;
+    utf16_be = data[0] == 0xFE && data[1] == 0xFF;
+    if (utf16_le) {
+      convert_from = "UTF-16LE";
+    } else if (utf16_be) {
+      convert_from = "UTF-16BE";
+    }
+
+    if (convert_from) {
+      gsize new_size = 0;
+      guint length = gst_type_find_get_length (tf);
+
+      /* try a default that should be enough */
+      if (length == 0)
+        length = 512;
+      data = gst_type_find_peek (tf, 0, length);
+
+      if (data) {
+        /* skip the BOM */
+        data += 2;
+        length -= 2;
+
+        converted_data =
+            (guint8 *) g_convert ((gchar *) data, length, "UTF-8", convert_from,
+            NULL, &new_size, NULL);
+        if (converted_data) {
+          if (xml_check_first_element_from_data (converted_data, new_size,
+                  "SmoothStreamingMedia", 20, TRUE))
+            gst_type_find_suggest (tf, GST_TYPE_FIND_MAXIMUM,
+                MSS_MANIFEST_CAPS);
+
+          g_free (converted_data);
+        }
+      }
+    }
+  }
+}
+
 /*** image/jpeg ***/
 
 #define JPEG_MARKER_IS_START_OF_FRAME(x) \
@@ -5058,6 +5177,9 @@ plugin_init (GstPlugin * plugin)
       GST_TYPE_FIND_MAXIMUM);
   TYPE_FIND_REGISTER (plugin, "application/x-shockwave-flash",
       GST_RANK_SECONDARY, swf_type_find, "swf,swfl", SWF_CAPS, NULL, NULL);
+  TYPE_FIND_REGISTER (plugin, "application/vnd.ms-sstr+xml",
+      GST_RANK_PRIMARY, mss_manifest_type_find, NULL, MSS_MANIFEST_CAPS, NULL,
+      NULL);
   TYPE_FIND_REGISTER_START_WITH (plugin, "video/x-flv", GST_RANK_SECONDARY,
       "flv", "FLV", 3, GST_TYPE_FIND_MAXIMUM);
   TYPE_FIND_REGISTER (plugin, "text/plain", GST_RANK_MARGINAL, utf8_type_find,