moved code to crossfade.c

decode.c should be a lot smaller; start by moving all code which
handles cross-fading to crossfade.c.  Also includes camelCase
conversion.

src/crossfade.c

@@ -0,0 +1,62 @@
+/* the Music Player Daemon (MPD)
+ * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
+ * Copyright (C) 2008 Max Kellermann <max@duempel.org>
+ * This project's homepage is: 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 "crossfade.h"
+#include "audio.h"
+#include "pcm_utils.h"
+
+unsigned cross_fade_calc(float duration, float total_time,
+			 const AudioFormat * af,
+			 unsigned max_chunks)
+{
+	unsigned int chunks;
+
+	if (duration <= 0 || duration >= total_time ||
+	    !isCurrentAudioFormat(af))
+		return 0;
+
+	assert(duration > 0);
+	assert(af->bits > 0);
+	assert(af->channels > 0);
+	assert(af->sampleRate > 0);
+
+	chunks = audio_format_time_to_size(af) / CHUNK_SIZE;
+	chunks = (chunks * duration + 0.5);
+
+	if (chunks > max_chunks)
+		chunks = max_chunks;
+
+	return chunks;
+}
+
+void cross_fade_apply(ob_chunk * a, const ob_chunk * b,
+		      const AudioFormat * format,
+		      unsigned int current_chunk, unsigned int num_chunks)
+{
+	assert(current_chunk <= num_chunks);
+
+	pcm_mix(a->data,
+		b->data,
+		a->chunkSize,
+		b->chunkSize,
+		format,
+		((float)current_chunk) / num_chunks);
+	if (b->chunkSize > a->chunkSize)
+		a->chunkSize = b->chunkSize;
+}