pcm/PcmVolume: rename to Volume.cxx

src/pcm/Volume.cxx

@@ -0,0 +1,178 @@
+/*
+ * 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 "config.h"
+#include "Volume.hxx"
+#include "PcmUtils.hxx"
+#include "Traits.hxx"
+#include "AudioFormat.hxx"
+
+#include <stdint.h>
+#include <string.h>
+
+template<SampleFormat F, class Traits=SampleTraits<F>>
+static void
+pcm_volume_change(typename Traits::pointer_type buffer,
+		  typename Traits::const_pointer_type end,
+		  int volume)
+{
+	while (buffer < end) {
+		typename Traits::long_type sample = *buffer;
+
+		sample = (sample * volume + pcm_volume_dither() +
+			  PCM_VOLUME_1S / 2)
+			>> PCM_VOLUME_BITS;
+
+		*buffer++ = PcmClamp<F, Traits>(sample);
+	}
+}
+
+static void
+pcm_volume_change_8(int8_t *buffer, const int8_t *end, int volume)
+{
+	pcm_volume_change<SampleFormat::S8>(buffer, end, volume);
+}
+
+static void
+pcm_volume_change_16(int16_t *buffer, const int16_t *end, int volume)
+{
+	pcm_volume_change<SampleFormat::S16>(buffer, end, volume);
+}
+
+#ifdef __i386__
+/**
+ * Optimized volume function for i386.  Use the EDX:EAX 2*32 bit
+ * multiplication result instead of emulating 64 bit multiplication.
+ */
+static inline int32_t
+pcm_volume_sample_24(int32_t sample, int32_t volume, gcc_unused int32_t dither)
+{
+	int32_t result;
+
+	asm(/* edx:eax = sample * volume */
+	    "imul %2\n"
+
+	    /* "add %3, %1\n"  dithering disabled for now, because we
+	       have no overflow check - is dithering really important
+	       here? */
+
+	    /* eax = edx:eax / PCM_VOLUME_1 */
+	    "sal $22, %%edx\n"
+	    "shr $10, %1\n"
+	    "or %%edx, %1\n"
+
+	    : "=a"(result)
+	    : "0"(sample), "r"(volume) /* , "r"(dither) */
+	    : "edx"
+	    );
+
+	return result;
+}
+#endif
+
+static void
+pcm_volume_change_24(int32_t *buffer, const int32_t *end, int volume)
+{
+#ifdef __i386__
+	while (buffer < end) {
+		/* assembly version for i386 */
+		int32_t sample = *buffer;
+
+		sample = pcm_volume_sample_24(sample, volume,
+					      pcm_volume_dither());
+	}
+#else
+	pcm_volume_change<SampleFormat::S24_P32>(buffer, end, volume);
+#endif
+}
+
+static void
+pcm_volume_change_32(int32_t *buffer, const int32_t *end, int volume)
+{
+#ifdef __i386__
+	while (buffer < end) {
+		/* assembly version for i386 */
+		int32_t sample = *buffer;
+
+		*buffer++ = pcm_volume_sample_24(sample, volume, 0);
+	}
+#else
+	pcm_volume_change<SampleFormat::S32>(buffer, end, volume);
+#endif
+}
+
+static void
+pcm_volume_change_float(float *buffer, const float *end, float volume)
+{
+	while (buffer < end) {
+		float sample = *buffer;
+		sample *= volume;
+		*buffer++ = sample;
+	}
+}
+
+bool
+pcm_volume(void *buffer, size_t length,
+	   SampleFormat format,
+	   int volume)
+{
+	if (volume == PCM_VOLUME_1S)
+		return true;
+
+	if (volume <= 0) {
+		memset(buffer, 0, length);
+		return true;
+	}
+
+	const void *end = pcm_end_pointer(buffer, length);
+	switch (format) {
+	case SampleFormat::UNDEFINED:
+	case SampleFormat::DSD:
+		/* not implemented */
+		return false;
+
+	case SampleFormat::S8:
+		pcm_volume_change_8((int8_t *)buffer, (const int8_t *)end,
+				    volume);
+		return true;
+
+	case SampleFormat::S16:
+		pcm_volume_change_16((int16_t *)buffer, (const int16_t *)end,
+				     volume);
+		return true;
+
+	case SampleFormat::S24_P32:
+		pcm_volume_change_24((int32_t *)buffer, (const int32_t *)end,
+				     volume);
+		return true;
+
+	case SampleFormat::S32:
+		pcm_volume_change_32((int32_t *)buffer, (const int32_t *)end,
+				     volume);
+		return true;
+
+	case SampleFormat::FLOAT:
+		pcm_volume_change_float((float *)buffer, (const float *)end,
+					pcm_volume_to_float(volume));
+		return true;
+	}
+
+	assert(false);
+	gcc_unreachable();
+}