Implemented basic icy support for the httpd output

[mk: folded with patch "Put icy related functions in extra source
files"; moved icy_server.c from HAVE_CURL to ENABLE_HTTPD_OUTPUT;
removed an unused variable]

src/icy_server.c

@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "icy_server.h"
+
+#include <glib.h>
+
+#include <assert.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "icy_server"
+
+char*
+icy_server_metadata_header(const char *name,
+			   const char *genre, const char *url,
+			   const char *content_type, int metaint)
+{
+	return g_strdup_printf("ICY 200 OK\r\n"
+			       "icy-notice1:<BR>This stream requires an audio player!<BR>\r\n" /* TODO */
+			       "icy-notice2:MPD - The music player daemon<BR>\r\n"
+			       "icy-name: %s\r\n"             /* TODO */
+			       "icy-genre: %s\r\n"            /* TODO */
+			       "icy-url: %s\r\n"              /* TODO */
+			       "icy-pub:1\r\n"
+			       "icy-metaint:%d\r\n"
+			       /* TODO "icy-br:%d\r\n" */
+			       "Content-Type: %s\r\n"
+			       "Connection: close\r\n"
+			       "Pragma: no-cache\r\n"
+			       "Cache-Control: no-cache, no-store\r\n"
+			       "\r\n",
+			       name,
+			       genre,
+			       url,
+			       metaint,
+			       /* bitrate, */
+			       content_type);
+}
+
+char*
+icy_server_metadata_string(const char *stream_title, const char* stream_url)
+{
+	gchar *icy_metadata;
+	guint meta_length;
+
+	// The leading n is a placeholder for the length information
+	icy_metadata = g_strdup_printf("nStreamTitle='%s';"
+				       "StreamUrl='%s';",
+				       stream_title,
+				       stream_url);
+
+	g_return_val_if_fail(icy_metadata, NULL);
+
+	meta_length = strlen(icy_metadata);
+
+	meta_length--; // substract placeholder
+
+	meta_length = ((int)meta_length / 16) + 1;
+
+	icy_metadata[0] = meta_length;
+
+	if (meta_length > 255) {
+		g_free(icy_metadata);
+		return NULL;
+	}
+
+	return icy_metadata;
+}
+
+struct page*
+icy_server_metadata_page(const struct tag *tag, ...)
+{
+	va_list args;
+	const gchar *tag_items[TAG_NUM_OF_ITEM_TYPES];
+	gint last_item, item;
+	guint position;
+	gchar *icy_string;
+	struct page *icy_metadata;
+	gchar stream_title[(1 + 255 - 28) * 16]; // Length + Metadata -
+						 // "StreamTitle='';StreamUrl='';"
+						 // = 4081 - 28
+
+	last_item = -1;
+
+	va_start(args, tag);
+	while (1) {
+		enum tag_type type;
+		const gchar *tag_item;
+
+		type = va_arg(args, enum tag_type);
+
+		if (type == TAG_NUM_OF_ITEM_TYPES)
+			break;
+
+		tag_item = tag_get_value(tag, type);
+
+		if (tag_item)
+			tag_items[++last_item] = tag_item;
+	}
+	va_end(args);
+
+	position = item = 0;
+	while (position < sizeof(stream_title) && item <= last_item) {
+		gint length = 0;
+
+		length = g_strlcpy(stream_title + position,
+				   tag_items[item++],
+				   sizeof(stream_title) - position);
+
+		position += length;
+
+		if (item <= last_item) {
+			length = g_strlcpy(stream_title + position,
+					   " - ",
+					   sizeof(stream_title) - position);
+
+			position += length;
+		}
+	}
+
+	icy_string = icy_server_metadata_string(stream_title, "");
+
+	if (icy_string == NULL)
+		return NULL;
+
+	icy_metadata = page_new_copy(icy_string, (icy_string[0] * 16) + 1);
+
+	g_free(icy_string);
+
+	return icy_metadata;
+}