1 files changed, 135 insertions, 0 deletions
diff --git a/src/pcm_export.c b/src/pcm_export.c
new file mode 100644
index 000000000..e586b51d2
--- /dev/null
+++ b/src/pcm_export.c
@@ -0,0 +1,135 @@
+/*
+ * Copyright (C) 2003-2012 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 "pcm_export.h"
+#include "pcm_dsd_usb.h"
+#include "pcm_pack.h"
+#include "util/byte_reverse.h"
+
+void
+pcm_export_init(struct pcm_export_state *state)
+{
+	pcm_buffer_init(&state->reverse_buffer);
+	pcm_buffer_init(&state->pack_buffer);
+	pcm_buffer_init(&state->dsd_buffer);
+}
+
+void pcm_export_deinit(struct pcm_export_state *state)
+{
+	pcm_buffer_deinit(&state->reverse_buffer);
+	pcm_buffer_deinit(&state->pack_buffer);
+	pcm_buffer_deinit(&state->dsd_buffer);
+}
+
+void
+pcm_export_open(struct pcm_export_state *state,
+		enum sample_format sample_format, unsigned channels,
+		bool dsd_usb, bool shift8, bool pack, bool reverse_endian)
+{
+	assert(audio_valid_sample_format(sample_format));
+	assert(!dsd_usb || audio_valid_channel_count(channels));
+
+	state->channels = channels;
+	state->dsd_usb = dsd_usb && sample_format == SAMPLE_FORMAT_DSD;
+	if (state->dsd_usb)
+		/* after the conversion to DSD-over-USB, the DSD
+		   samples are stuffed inside fake 24 bit samples */
+		sample_format = SAMPLE_FORMAT_S24_P32;
+
+	state->shift8 = shift8 && sample_format == SAMPLE_FORMAT_S24_P32;
+	state->pack24 = pack && sample_format == SAMPLE_FORMAT_S24_P32;
+
+	assert(!state->shift8 || !state->pack24);
+
+	state->reverse_endian = 0;
+	if (reverse_endian) {
+		size_t sample_size = state->pack24
+			? 3
+			: sample_format_size(sample_format);
+		assert(sample_size <= 0xff);
+
+		if (sample_size > 1)
+			state->reverse_endian = sample_size;
+	}
+}
+
+const void *
+pcm_export(struct pcm_export_state *state, const void *data, size_t size,
+	   size_t *dest_size_r)
+{
+	if (state->dsd_usb)
+		data = pcm_dsd_to_usb(&state->dsd_buffer, state->channels,
+				      data, size, &size);
+
+	if (state->pack24) {
+		assert(size % 4 == 0);
+
+		const size_t num_samples = size / 4;
+		const size_t dest_size = num_samples * 3;
+
+		const uint8_t *src8 = data, *src_end8 = src8 + size;
+		uint8_t *dest = pcm_buffer_get(&state->pack_buffer, dest_size);
+		assert(dest != NULL);
+
+		pcm_pack_24(dest, (const int32_t *)src8,
+			    (const int32_t *)src_end8);
+
+		data = dest;
+		size = dest_size;
+	} else if (state->shift8) {
+		assert(size % 4 == 0);
+
+		const uint8_t *src8 = data, *src_end8 = src8 + size;
+		const uint32_t *src = (const uint32_t *)src8;
+		const uint32_t *const src_end = (const uint32_t *)src_end8;
+
+		uint32_t *dest = pcm_buffer_get(&state->pack_buffer, size);
+		data = dest;
+
+		while (src < src_end)
+			*dest++ = *src++ << 8;
+	}
+
+
+	if (state->reverse_endian > 0) {
+		assert(state->reverse_endian >= 2);
+
+		void *dest = pcm_buffer_get(&state->reverse_buffer, size);
+		assert(dest != NULL);
+
+		const uint8_t *src = data, *src_end = src + size;
+		reverse_bytes(dest, src, src_end, state->reverse_endian);
+
+		data = dest;
+	}
+
+	*dest_size_r = size;
+	return data;
+}
+
+size_t
+pcm_export_source_size(const struct pcm_export_state *state, size_t size)
+{
+	if (state->dsd_usb)
+		/* DSD over USB doubles the transport size */
+		size /= 2;
+
+	return size;
+}