pcm_export: convert to C++

src/pcm/PcmExport.hxx

@@ -0,0 +1,139 @@
+/*
+ * 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 PCM_EXPORT_HXX
+#define PCM_EXPORT_HXX
+
+#include "check.h"
+#include "pcm_buffer.h"
+#include "audio_format.h"
+
+struct audio_format;
+
+/**
+ * An object that handles export of PCM samples to some instance
+ * outside of MPD.  It has a few more options to tweak the binary
+ * representation which are not supported by the pcm_convert library.
+ */
+struct PcmExport {
+	/**
+	 * The buffer is used to convert DSD samples to the
+	 * DSD-over-USB format.
+	 *
+	 * @see #dsd_usb
+	 */
+	struct pcm_buffer dsd_buffer;
+
+	/**
+	 * The buffer is used to pack samples, removing padding.
+	 *
+	 * @see #pack24
+	 */
+	struct pcm_buffer pack_buffer;
+
+	/**
+	 * The buffer is used to reverse the byte order.
+	 *
+	 * @see #reverse_endian
+	 */
+	struct pcm_buffer reverse_buffer;
+
+	/**
+	 * The number of channels.
+	 */
+	uint8_t channels;
+
+	/**
+	 * Convert DSD to DSD-over-USB?  Input format must be
+	 * SAMPLE_FORMAT_DSD and output format must be
+	 * SAMPLE_FORMAT_S24_P32.
+	 */
+	bool dsd_usb;
+
+	/**
+	 * Convert (padded) 24 bit samples to 32 bit by shifting 8
+	 * bits to the left?
+	 */
+	bool shift8;
+
+	/**
+	 * Pack 24 bit samples?
+	 */
+	bool pack24;
+
+	/**
+	 * Export the samples in reverse byte order?  A non-zero value
+	 * means the option is enabled and represents the size of each
+	 * sample (2 or bigger).
+	 */
+	uint8_t reverse_endian;
+
+	PcmExport() {
+		pcm_buffer_init(&reverse_buffer);
+		pcm_buffer_init(&pack_buffer);
+		pcm_buffer_init(&dsd_buffer);
+	}
+
+	~PcmExport() {
+		pcm_buffer_deinit(&reverse_buffer);
+		pcm_buffer_deinit(&pack_buffer);
+		pcm_buffer_deinit(&dsd_buffer);
+	}
+
+	/**
+	 * Open the #pcm_export_state object.
+	 *
+	 * There is no "close" method.  This function may be called multiple
+	 * times to reuse the object, until pcm_export_deinit() is called.
+	 *
+	 * This function cannot fail.
+	 *
+	 * @param channels the number of channels; ignored unless dsd_usb is set
+	 */
+	void Open(enum sample_format sample_format, unsigned channels,
+		  bool dsd_usb, bool shift8, bool pack, bool reverse_endian);
+
+	/**
+	 * Calculate the size of one output frame.
+	 */
+	gcc_pure
+	size_t GetFrameSize(const struct audio_format &audio_format) const;
+
+	/**
+	 * Export a PCM buffer.
+	 *
+	 * @param state an initialized and open pcm_export_state object
+	 * @param src the source PCM buffer
+	 * @param src_size the size of #src in bytes
+	 * @param dest_size_r returns the number of bytes of the destination buffer
+	 * @return the destination buffer (may be a pointer to the source buffer)
+	 */
+	const void *Export(const void *src, size_t src_size,
+			   size_t &dest_size_r);
+
+	/**
+	 * Converts the number of consumed bytes from the pcm_export()
+	 * destination buffer to the according number of bytes from the
+	 * pcm_export() source buffer.
+	 */
+	gcc_pure
+	size_t CalcSourceSize(size_t dest_size) const;
+};
+
+#endif