added library for parsing icy-metadata

src/Makefile.am

@@ -37,6 +37,7 @@ mpd_headers = \
 	input_stream.h \
 	input_file.h \
 	input_curl.h \
+	icy_metadata.h \
 	client.h \
 	dlist.h \
 	listen.h \
@@ -264,7 +265,7 @@ endif
 
 
 if HAVE_CURL
-mpd_SOURCES += input_curl.c
+mpd_SOURCES += input_curl.c icy_metadata.c
 endif
 
 

src/icy_metadata.c

+/*
+ * Copyright (C) 2003-2008 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "icy_metadata.h"
+#include "tag.h"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <string.h>
+
+void
+icy_deinit(struct icy_metadata *im)
+{
+	if (!icy_defined(im))
+		return;
+
+	if (im->data_rest == 0 && im->meta_size > 0)
+		g_free(im->meta_data);
+
+	if (im->tag != NULL)
+		tag_free(im->tag);
+}
+
+void
+icy_reset(struct icy_metadata *im)
+{
+	if (!icy_defined(im))
+		return;
+
+	icy_deinit(im);
+
+	im->data_rest = im->data_size;
+	im->meta_size = 0;
+}
+
+size_t
+icy_data(struct icy_metadata *im, size_t length)
+{
+	assert(icy_defined(im));
+	assert(length > 0);
+
+	if (im->data_rest == 0)
+		return 0;
+
+	if (length >= im->data_rest) {
+		length = im->data_rest;
+		im->data_rest = 0;
+	} else
+		im->data_rest -= length;
+
+	return length;
+}
+
+static void
+icy_add_item(struct tag *tag, enum tag_type type, const char *value)
+{
+	size_t length = strlen(value);
+
+	if (length >= 2 && value[0] == '\'' && value[length - 1] == '\'') {
+		/* strip the single quotes */
+		++value;
+		length -= 2;
+	}
+
+	if (length > 0)
+		tag_add_item_n(tag, type, value, length);
+}
+
+static void
+icy_parse_tag_item(struct tag *tag, const char *item)
+{
+	gchar **p = g_strsplit(item, "=", 0);
+
+	if (p[0] != NULL && p[1] != NULL) {
+		if (strcmp(p[0], "StreamTitle") == 0)
+			icy_add_item(tag, TAG_ITEM_TITLE, p[1]);
+		else
+			g_debug("unknown icy-tag: '%s'", p[0]);
+	}
+
+	g_strfreev(p);
+}
+
+static struct tag *
+icy_parse_tag(const char *p)
+{
+	struct tag *tag = tag_new();
+	gchar **items = g_strsplit(p, ";", 0);
+
+	for (unsigned i = 0; items[i] != NULL; ++i)
+		icy_parse_tag_item(tag, items[i]);
+
+	g_strfreev(items);
+
+	return tag;
+}
+
+size_t
+icy_meta(struct icy_metadata *im, const void *data, size_t length)
+{
+	const unsigned char *p = data;
+
+	assert(icy_defined(im));
+	assert(im->data_rest == 0);
+	assert(length > 0);
+
+	if (im->meta_size == 0) {
+		/* read meta_size from the first byte of a meta
+		   block */
+		im->meta_size = *p++ * 16;
+		if (im->meta_size == 0) {
+			/* special case: no metadata */
+			im->data_rest = im->data_size;
+			return 1;
+		}
+
+		/* 1 byte was consumed (must be re-added later for the
+		   return value */
+		--length;
+
+		/* initialize metadata reader, allocate enough
+		   memory (+1 for the null terminator) */
+		im->meta_position = 0;
+		im->meta_data = g_malloc(im->meta_size + 1);
+	}
+
+	assert(im->meta_position < im->meta_size);
+
+	if (length > im->meta_size - im->meta_position)
+		length = im->meta_size - im->meta_position;
+
+	memcpy(im->meta_data + im->meta_position, data, length);
+	im->meta_position += length;
+
+	if (p != data)
+		/* re-add the first byte (which contained meta_size) */
+		++length;
+
+	if (im->meta_position == im->meta_size) {
+		/* null-terminate the string */
+
+		im->meta_data[im->meta_size] = 0;
+
+		/* parse */
+
+		if (im->tag != NULL)
+			tag_free(im->tag);
+
+		im->tag = icy_parse_tag(im->meta_data);
+		g_free(im->meta_data);
+
+		/* change back to normal data mode */
+
+		im->meta_size = 0;
+		im->data_rest = im->data_size;
+	}
+
+	return length;
+}

src/icy_metadata.h

+/*
+ * Copyright (C) 2003-2008 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef ICY_METADATA_H
+#define ICY_METADATA_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+struct icy_metadata {
+	size_t data_size, data_rest;
+
+	size_t meta_size, meta_position;
+	char *meta_data;
+
+	struct tag *tag;
+};
+
+/**
+ * Initialize a disabled icy_metadata object.
+ */
+static inline void
+icy_clear(struct icy_metadata *im)
+{
+	im->data_size = 0;
+}
+
+/**
+ * Initialize an enabled icy_metadata object with the specified
+ * data_size (from the icy-metaint HTTP response header).
+ */
+static inline void
+icy_start(struct icy_metadata *im, size_t data_size)
+{
+	im->data_size = im->data_rest = data_size;
+	im->meta_size = 0;
+	im->tag = NULL;
+}
+
+/**
+ * Resets the icy_metadata.  Call this after rewinding the stream.
+ */
+void
+icy_reset(struct icy_metadata *im);
+
+void
+icy_deinit(struct icy_metadata *im);
+
+/**
+ * Checks whether the icy_metadata object is enabled.
+ */
+static inline bool
+icy_defined(const struct icy_metadata *im)
+{
+	return im->data_size > 0;
+}
+
+/**
+ * Evaluates data.  Returns the number of bytes of normal data which
+ * can be read by the caller, but not more than "length".  If the
+ * return value is smaller than "length", the caller should invoke
+ * icy_meta().
+ */
+size_t
+icy_data(struct icy_metadata *im, size_t length);
+
+/**
+ * Reads metadata from the stream.  Returns the number of bytes
+ * consumed.  If the return value is smaller than "length", the caller
+ * should invoke icy_data().
+ */
+size_t
+icy_meta(struct icy_metadata *im, const void *data, size_t length);
+
+static inline struct tag *
+icy_tag(struct icy_metadata *im)
+{
+	struct tag *tag = im->tag;
+	im->tag = NULL;
+	return tag;
+}
+
+#endif