tag: convert to C++

1 files changed, 218 insertions, 0 deletions

diff --git a/src/Tag.hxx b/src/Tag.hxx
new file mode 100644
index 000000000..5f1702994
--- /dev/null
+++ b/src/Tag.hxx
@@ -0,0 +1,218 @@
+/*
+ * Copyright (C) 2003-2013 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.
+ */
+
+#ifndef MPD_TAG_HXX
+#define MPD_TAG_HXX
+
+#include "TagType.h"
+#include "gcc.h"
+
+#include <algorithm>
+
+#include <stddef.h>
+
+/**
+ * One tag value.  It is a mapping of #tag_type to am arbitrary string
+ * value.  Each tag can have multiple items of one tag type (although
+ * few clients support that).
+ */
+struct TagItem {
+	/** the type of this item */
+	enum tag_type type;
+
+	/**
+	 * the value of this tag; this is a variable length string
+	 */
+	char value[sizeof(long)];
+} gcc_packed;
+
+/**
+ * The meta information about a song file.  It is a MPD specific
+ * subset of tags (e.g. from ID3, vorbis comments, ...).
+ */
+struct Tag {
+	/**
+	 * The duration of the song (in seconds).  A value of zero
+	 * means that the length is unknown.  If the duration is
+	 * really between zero and one second, you should round up to
+	 * 1.
+	 */
+	int time;
+
+	/**
+	 * Does this file have an embedded playlist (e.g. embedded CUE
+	 * sheet)?
+	 */
+	bool has_playlist;
+
+	/** an array of tag items */
+	TagItem **items;
+
+	/** the total number of tag items in the #items array */
+	unsigned num_items;
+
+	/**
+	 * Create an empty tag.
+	 */
+	Tag():time(-1), has_playlist(false),
+	      items(nullptr), num_items(0) {}
+
+	Tag(const Tag &other);
+
+	Tag(Tag &&other)
+		:time(other.time), has_playlist(other.has_playlist),
+		 items(other.items), num_items(other.num_items) {
+		other.items = nullptr;
+		other.num_items = 0;
+	}
+
+	/**
+	 * Free the tag object and all its items.
+	 */
+	~Tag();
+
+	Tag &operator=(const Tag &other) = delete;
+
+	Tag &operator=(Tag &&other) {
+		time = other.time;
+		has_playlist = other.has_playlist;
+		std::swap(items, other.items);
+		std::swap(num_items, other.num_items);
+		return *this;
+	}
+
+	/**
+	 * Returns true if the tag contains no items.  This ignores the "time"
+	 * attribute.
+	 */
+	bool IsEmpty() const {
+		return num_items == 0;
+	}
+
+	/**
+	 * Returns true if the tag contains any information.
+	 */
+	bool IsDefined() const {
+		return !IsEmpty() || time >= 0;
+	}
+
+	void DeleteItem(unsigned i);
+
+	/**
+	 * Clear all tag items with the specified type.
+	 */
+	void ClearItemsByType(tag_type type);
+
+	/**
+	 * Gives an optional hint to the tag library that we will now
+	 * add several tag items; this is used by the library to
+	 * optimize memory allocation.  Only one tag may be in this
+	 * state, and this tag must not have any items yet.  You must
+	 * call tag_end_add() when you are done.
+	 */
+	void BeginAdd();
+
+	/**
+	 * Finishes the operation started with tag_begin_add().
+	 */
+	void EndAdd();
+
+	/**
+	 * Appends a new tag item.
+	 *
+	 * @param type the type of the new tag item
+	 * @param value the value of the tag item (not null-terminated)
+	 * @param len the length of #value
+	 */
+	void AddItem(tag_type type, const char *value, size_t len);
+
+	/**
+	 * Appends a new tag item.
+	 *
+	 * @param tag the #tag object
+	 * @param type the type of the new tag item
+	 * @param value the value of the tag item (null-terminated)
+	 */
+	void AddItem(tag_type type, const char *value);
+
+	/**
+	 * Merges the data from two tags.  If both tags share data for the
+	 * same tag_type, only data from "add" is used.
+	 *
+	 * @return a newly allocated tag
+	 */
+	gcc_malloc
+	static Tag *Merge(const Tag &base, const Tag &add);
+
+	/**
+	 * Merges the data from two tags.  Any of the two may be NULL.  Both
+	 * are freed by this function.
+	 *
+	 * @return a newly allocated tag
+	 */
+	gcc_malloc
+	static Tag *MergeReplace(Tag *base, Tag *add);
+
+	/**
+	 * Returns the first value of the specified tag type, or NULL if none
+	 * is present in this tag object.
+	 */
+	gcc_pure
+	const char *GetValue(tag_type type) const;
+
+	/**
+	 * Checks whether the tag contains one or more items with
+	 * the specified type.
+	 */
+	bool HasType(tag_type type) const;
+
+	/**
+	 * Compares two tags, including the duration and all tag items.  The
+	 * order of the tag items matters.
+	 */
+	gcc_pure
+	bool Equals(const Tag &other) const;
+
+private:
+	void AddItemInternal(tag_type type, const char *value, size_t len);
+};
+
+/**
+ * Parse the string, and convert it into a #tag_type.  Returns
+ * #TAG_NUM_OF_ITEM_TYPES if the string could not be recognized.
+ */
+enum tag_type
+tag_name_parse(const char *name);
+
+/**
+ * Parse the string, and convert it into a #tag_type.  Returns
+ * #TAG_NUM_OF_ITEM_TYPES if the string could not be recognized.
+ *
+ * Case does not matter.
+ */
+enum tag_type
+tag_name_parse_i(const char *name);
+
+/**
+ * Initializes the tag library.
+ */
+void
+tag_lib_init();
+
+#endif