util/SplitString: new utility class

To replace g_strdup().

Makefile.am

@@ -253,6 +253,7 @@ libutil_a_SOURCES = \
 	src/util/CharUtil.hxx \
 	src/util/NumberParser.hxx \
 	src/util/StringUtil.cxx src/util/StringUtil.hxx \
+	src/util/SplitString.cxx src/util/SplitString.hxx \
 	src/util/FormatString.cxx src/util/FormatString.hxx \
 	src/util/Tokenizer.cxx src/util/Tokenizer.hxx \
 	src/util/UriUtil.cxx src/util/UriUtil.hxx \

src/decoder/FlacMetadata.cxx

@@ -26,6 +26,7 @@
 #include "tag/TagBuilder.hxx"
 #include "ReplayGainInfo.hxx"
 #include "util/ASCII.hxx"
+#include "util/SplitString.hxx"
 
 #include <glib.h>
 
@@ -165,16 +166,12 @@ flac_scan_comment(const FLAC__StreamMetadata_VorbisComment_Entry *entry,
 		  const struct tag_handler *handler, void *handler_ctx)
 {
 	if (handler->pair != nullptr) {
-		char *name = g_strdup((const char*)entry->entry);
-		char *value = strchr(name, '=');
-
-		if (value != nullptr && value > name) {
-			*value++ = 0;
+		const char *comment = (const char *)entry->entry;
+		const SplitString split(comment, '=');
+		if (split.IsDefined() && !split.IsEmpty())
 			tag_handler_invoke_pair(handler, handler_ctx,
-						name, value);
-		}
-
-		g_free(name);
+						split.GetFirst(),
+						split.GetSecond());
 	}
 
 	for (const struct tag_table *i = xiph_tags; i->name != nullptr; ++i)

src/decoder/VorbisComments.cxx

@@ -25,8 +25,7 @@
 #include "tag/TagBuilder.hxx"
 #include "ReplayGainInfo.hxx"
 #include "util/ASCII.hxx"
-
-#include <glib.h>
+#include "util/SplitString.hxx"
 
 #include <stddef.h>
 #include <string.h>
@@ -102,16 +101,11 @@ vorbis_scan_comment(const char *comment,
 		    const struct tag_handler *handler, void *handler_ctx)
 {
 	if (handler->pair != nullptr) {
-		char *name = g_strdup(comment);
-		char *value = strchr(name, '=');
-
-		if (value != nullptr && value > name) {
-			*value++ = 0;
+		const SplitString split(comment, '=');
+		if (split.IsDefined() && !split.IsEmpty())
 			tag_handler_invoke_pair(handler, handler_ctx,
-						name, value);
-		}
-
-		g_free(name);
+						split.GetFirst(),
+						split.GetSecond());
 	}
 
 	for (const struct tag_table *i = xiph_tags; i->name != nullptr; ++i)

src/util/SplitString.cxx

@@ -0,0 +1,37 @@
+/*
+ * 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.
+ */
+
+#include "SplitString.hxx"
+
+#include <string.h>
+
+SplitString::SplitString(const char *s, char separator)
+	:first(nullptr)
+{
+	const char *x = strchr(s, separator);
+	if (x == nullptr)
+		return;
+
+	size_t length = x - s;
+	second = x + 1;
+
+	first = new char[length + 1];
+	memcpy(first, s, length);
+	first[length] = 0;
+}

src/util/SplitString.hxx

@@ -0,0 +1,71 @@
+/*
+ * 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_SPLIT_STRING_HXX
+#define MPD_SPLIT_STRING_HXX
+
+#include "Compiler.h"
+
+#include <assert.h>
+
+/**
+ * Split a given constant string at a separator character.  Duplicates
+ * the first part to be able to null-terminate it.
+ */
+class SplitString {
+	char *first;
+	const char *second;
+
+public:
+	SplitString(const char *s, char separator);
+
+	~SplitString() {
+		delete[] first;
+	}
+
+	/**
+	 * Was the separator found?
+	 */
+	bool IsDefined() const {
+		return first != nullptr;
+	}
+
+	/**
+	 * Is the first part empty?
+	 */
+	bool IsEmpty() const {
+		assert(IsDefined());
+
+		return *first == 0;
+	}
+
+	const char *GetFirst() const {
+		assert(IsDefined());
+
+		return first;
+	}
+
+	const char *GetSecond() const {
+		assert(IsDefined());
+
+		return second;
+	}
+};
+
+#endif