/*
 * Copyright (C) 2003-2011 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 "PcmFormat.hxx"
#include "PcmDither.hxx"
#include "pcm_buffer.h"
#include "pcm_pack.h"
#include "PcmUtils.hxx"

#include <type_traits>

template<typename S>
struct DefaultSampleBits {
	typedef decltype(*S()) T;
	typedef typename std::remove_reference<T>::type U;

	static constexpr auto value = sizeof(U) * 8;
};

static void
pcm_convert_8_to_16(int16_t *out, const int8_t *in, const int8_t *in_end)
{
	while (in < in_end) {
		*out++ = *in++ << 8;
	}
}

static void
pcm_convert_24_to_16(PcmDither &dither,
		     int16_t *out, const int32_t *in, const int32_t *in_end)
{
	dither.Dither24To16(out, in, in_end);
}

static void
pcm_convert_32_to_16(PcmDither &dither,
		     int16_t *out, const int32_t *in, const int32_t *in_end)
{
	dither.Dither32To16(out, in, in_end);
}

template<typename S, unsigned bits=DefaultSampleBits<S>::value>
static void
ConvertFromFloat(S dest, const float *src, const float *end)
{
	typedef decltype(*S()) T;
	typedef typename std::remove_reference<T>::type U;

	const float factor = 1 << (bits - 1);

	while (src != end) {
		int sample(*src++ * factor);
		*dest++ = PcmClamp<U, int, bits>(sample);
	}
}

template<typename S, unsigned bits=DefaultSampleBits<S>::value>
static void
ConvertFromFloat(S dest, const float *src, size_t size)
{
	ConvertFromFloat<S, bits>(dest, src, pcm_end_pointer(src, size));
}

template<typename S, unsigned bits=sizeof(S)*8>
static S *
AllocateFromFloat(pcm_buffer &buffer, const float *src, size_t src_size,
		  size_t *dest_size_r)
{
	constexpr size_t src_sample_size = sizeof(*src);
	assert(src_size % src_sample_size == 0);

	const size_t num_samples = src_size / src_sample_size;
	*dest_size_r = num_samples * sizeof(S);
	S *dest = (S *)pcm_buffer_get(&buffer, *dest_size_r);
	ConvertFromFloat<S *, bits>(dest, src, src_size);
	return dest;
}

static int16_t *
pcm_allocate_8_to_16(struct pcm_buffer *buffer,
		     const int8_t *src, size_t src_size, size_t *dest_size_r)
{
	int16_t *dest;
	*dest_size_r = src_size / sizeof(*src) * sizeof(*dest);
	dest = (int16_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_8_to_16(dest, src, pcm_end_pointer(src, src_size));
	return dest;
}

static int16_t *
pcm_allocate_24p32_to_16(struct pcm_buffer *buffer, PcmDither &dither,
			 const int32_t *src, size_t src_size,
			 size_t *dest_size_r)
{
	int16_t *dest;
	*dest_size_r = src_size / 2;
	assert(*dest_size_r == src_size / sizeof(*src) * sizeof(*dest));
	dest = (int16_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_24_to_16(dither, dest, src,
			     pcm_end_pointer(src, src_size));
	return dest;
}

static int16_t *
pcm_allocate_32_to_16(struct pcm_buffer *buffer, PcmDither &dither,
		      const int32_t *src, size_t src_size,
		      size_t *dest_size_r)
{
	int16_t *dest;
	*dest_size_r = src_size / 2;
	assert(*dest_size_r == src_size / sizeof(*src) * sizeof(*dest));
	dest = (int16_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_32_to_16(dither, dest, src,
			     pcm_end_pointer(src, src_size));
	return dest;
}

static int16_t *
pcm_allocate_float_to_16(struct pcm_buffer *buffer,
			 const float *src, size_t src_size,
			 size_t *dest_size_r)
{
	return AllocateFromFloat<int16_t>(*buffer, src, src_size, dest_size_r);
}

const int16_t *
pcm_convert_to_16(struct pcm_buffer *buffer, PcmDither &dither,
		  enum sample_format src_format, const void *src,
		  size_t src_size, size_t *dest_size_r)
{
	assert(src_size % sample_format_size(src_format) == 0);

	switch (src_format) {
	case SAMPLE_FORMAT_UNDEFINED:
	case SAMPLE_FORMAT_DSD:
		break;

	case SAMPLE_FORMAT_S8:
		return pcm_allocate_8_to_16(buffer,
					    (const int8_t *)src, src_size,
					    dest_size_r);

	case SAMPLE_FORMAT_S16:
		*dest_size_r = src_size;
		return (const int16_t *)src;

	case SAMPLE_FORMAT_S24_P32:
		return pcm_allocate_24p32_to_16(buffer, dither,
						(const int32_t *)src, src_size,
						dest_size_r);

	case SAMPLE_FORMAT_S32:
		return pcm_allocate_32_to_16(buffer, dither,
					     (const int32_t *)src, src_size,
					     dest_size_r);

	case SAMPLE_FORMAT_FLOAT:
		return pcm_allocate_float_to_16(buffer,
						(const float *)src, src_size,
						dest_size_r);
	}

	return NULL;
}

static void
pcm_convert_8_to_24(int32_t *out, const int8_t *in, const int8_t *in_end)
{
	while (in < in_end)
		*out++ = *in++ << 16;
}

static void
pcm_convert_16_to_24(int32_t *out, const int16_t *in, const int16_t *in_end)
{
	while (in < in_end)
		*out++ = *in++ << 8;
}

static void
pcm_convert_32_to_24(int32_t *restrict out,
		     const int32_t *restrict in,
		     const int32_t *restrict in_end)
{
	while (in < in_end)
		*out++ = *in++ >> 8;
}

static int32_t *
pcm_allocate_8_to_24(struct pcm_buffer *buffer,
		     const int8_t *src, size_t src_size, size_t *dest_size_r)
{
	int32_t *dest;
	*dest_size_r = src_size / sizeof(*src) * sizeof(*dest);
	dest = (int32_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_8_to_24(dest, src, pcm_end_pointer(src, src_size));
	return dest;
}

static int32_t *
pcm_allocate_16_to_24(struct pcm_buffer *buffer,
		      const int16_t *src, size_t src_size, size_t *dest_size_r)
{
	int32_t *dest;
	*dest_size_r = src_size * 2;
	assert(*dest_size_r == src_size / sizeof(*src) * sizeof(*dest));
	dest = (int32_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_16_to_24(dest, src, pcm_end_pointer(src, src_size));
	return dest;
}

static int32_t *
pcm_allocate_32_to_24(struct pcm_buffer *buffer,
		      const int32_t *src, size_t src_size, size_t *dest_size_r)
{
	*dest_size_r = src_size;
	int32_t *dest = (int32_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_32_to_24(dest, src, pcm_end_pointer(src, src_size));
	return dest;
}

static int32_t *
pcm_allocate_float_to_24(struct pcm_buffer *buffer,
			 const float *src, size_t src_size,
			 size_t *dest_size_r)
{
	return AllocateFromFloat<int32_t, 24>(*buffer, src, src_size,
					      dest_size_r);
}

const int32_t *
pcm_convert_to_24(struct pcm_buffer *buffer,
		  enum sample_format src_format, const void *src,
		  size_t src_size, size_t *dest_size_r)
{
	assert(src_size % sample_format_size(src_format) == 0);

	switch (src_format) {
	case SAMPLE_FORMAT_UNDEFINED:
	case SAMPLE_FORMAT_DSD:
		break;

	case SAMPLE_FORMAT_S8:
		return pcm_allocate_8_to_24(buffer,
					    (const int8_t *)src, src_size,
					    dest_size_r);

	case SAMPLE_FORMAT_S16:
		return pcm_allocate_16_to_24(buffer,
					     (const int16_t *)src, src_size,
					     dest_size_r);

	case SAMPLE_FORMAT_S24_P32:
		*dest_size_r = src_size;
		return (const int32_t *)src;

	case SAMPLE_FORMAT_S32:
		return pcm_allocate_32_to_24(buffer,
					     (const int32_t *)src, src_size,
					     dest_size_r);

	case SAMPLE_FORMAT_FLOAT:
		return pcm_allocate_float_to_24(buffer,
						(const float *)src, src_size,
						dest_size_r);
	}

	return NULL;
}

static void
pcm_convert_8_to_32(int32_t *out, const int8_t *in, const int8_t *in_end)
{
	while (in < in_end)
		*out++ = *in++ << 24;
}

static void
pcm_convert_16_to_32(int32_t *out, const int16_t *in, const int16_t *in_end)
{
	while (in < in_end)
		*out++ = *in++ << 16;
}

static void
pcm_convert_24_to_32(int32_t *restrict out,
		     const int32_t *restrict in,
		     const int32_t *restrict in_end)
{
	while (in < in_end)
		*out++ = *in++ << 8;
}

static int32_t *
pcm_allocate_8_to_32(struct pcm_buffer *buffer,
		     const int8_t *src, size_t src_size, size_t *dest_size_r)
{
	int32_t *dest;
	*dest_size_r = src_size / sizeof(*src) * sizeof(*dest);
	dest = (int32_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_8_to_32(dest, src, pcm_end_pointer(src, src_size));
	return dest;
}

static int32_t *
pcm_allocate_16_to_32(struct pcm_buffer *buffer,
		      const int16_t *src, size_t src_size, size_t *dest_size_r)
{
	int32_t *dest;
	*dest_size_r = src_size * 2;
	assert(*dest_size_r == src_size / sizeof(*src) * sizeof(*dest));
	dest = (int32_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_16_to_32(dest, src, pcm_end_pointer(src, src_size));
	return dest;
}

static int32_t *
pcm_allocate_24p32_to_32(struct pcm_buffer *buffer,
			 const int32_t *src, size_t src_size,
			 size_t *dest_size_r)
{
	*dest_size_r = src_size;
	int32_t *dest = (int32_t *)pcm_buffer_get(buffer, *dest_size_r);
	pcm_convert_24_to_32(dest, src, pcm_end_pointer(src, src_size));
	return dest;
}

static int32_t *
pcm_allocate_float_to_32(struct pcm_buffer *buffer,
			 const float *src, size_t src_size,
			 size_t *dest_size_r)
{
	/* convert to S24_P32 first */
	int32_t *dest = pcm_allocate_float_to_24(buffer, src, src_size,
						 dest_size_r);

	/* convert to 32 bit in-place */
	pcm_convert_24_to_32(dest, dest, pcm_end_pointer(dest, *dest_size_r));
	return dest;
}

const int32_t *
pcm_convert_to_32(struct pcm_buffer *buffer,
		  enum sample_format src_format, const void *src,
		  size_t src_size, size_t *dest_size_r)
{
	assert(src_size % sample_format_size(src_format) == 0);

	switch (src_format) {
	case SAMPLE_FORMAT_UNDEFINED:
	case SAMPLE_FORMAT_DSD:
		break;

	case SAMPLE_FORMAT_S8:
		return pcm_allocate_8_to_32(buffer,
					    (const int8_t *)src, src_size,
					    dest_size_r);

	case SAMPLE_FORMAT_S16:
		return pcm_allocate_16_to_32(buffer,
					     (const int16_t *)src, src_size,
					     dest_size_r);

	case SAMPLE_FORMAT_S24_P32:
		return pcm_allocate_24p32_to_32(buffer,
						(const int32_t *)src, src_size,
						dest_size_r);

	case SAMPLE_FORMAT_S32:
		*dest_size_r = src_size;
		return (const int32_t *)src;

	case SAMPLE_FORMAT_FLOAT:
		return pcm_allocate_float_to_32(buffer,
						(const float *)src, src_size,
						dest_size_r);
	}

	return NULL;
}

template<typename S, unsigned bits=DefaultSampleBits<S>::value>
static void
ConvertToFloat(float *dest, S src, S end)
{
	constexpr float factor = 0.5 / (1 << (bits - 2));
	while (src != end)
		*dest++ = float(*src++) * factor;

}

template<typename S, unsigned bits=DefaultSampleBits<S>::value>
static void
ConvertToFloat(float *dest, S src, size_t size)
{
	ConvertToFloat<S, bits>(dest, src, pcm_end_pointer(src, size));
}

template<typename S, unsigned bits=DefaultSampleBits<S>::value>
static float *
AllocateToFloat(pcm_buffer &buffer, S src, size_t src_size,
		size_t *dest_size_r)
{
	constexpr size_t src_sample_size = sizeof(*S());
	assert(src_size % src_sample_size == 0);

	const size_t num_samples = src_size / src_sample_size;
	*dest_size_r = num_samples * sizeof(float);
	float *dest = (float *)pcm_buffer_get(&buffer, *dest_size_r);
	ConvertToFloat<S, bits>(dest, src, src_size);
	return dest;
}

static float *
pcm_allocate_8_to_float(struct pcm_buffer *buffer,
			const int8_t *src, size_t src_size,
			size_t *dest_size_r)
{
	return AllocateToFloat(*buffer, src, src_size, dest_size_r);
}

static float *
pcm_allocate_16_to_float(struct pcm_buffer *buffer,
			 const int16_t *src, size_t src_size,
			 size_t *dest_size_r)
{
	return AllocateToFloat(*buffer, src, src_size, dest_size_r);
}

static float *
pcm_allocate_24p32_to_float(struct pcm_buffer *buffer,
			    const int32_t *src, size_t src_size,
			    size_t *dest_size_r)
{
	return AllocateToFloat<decltype(src), 24>
		(*buffer, src, src_size, dest_size_r);
}

static float *
pcm_allocate_32_to_float(struct pcm_buffer *buffer,
			 const int32_t *src, size_t src_size,
			 size_t *dest_size_r)
{
	return AllocateToFloat(*buffer, src, src_size, dest_size_r);
}

const float *
pcm_convert_to_float(struct pcm_buffer *buffer,
		     enum sample_format src_format, const void *src,
		     size_t src_size, size_t *dest_size_r)
{
	switch (src_format) {
	case SAMPLE_FORMAT_UNDEFINED:
	case SAMPLE_FORMAT_DSD:
		break;

	case SAMPLE_FORMAT_S8:
		return pcm_allocate_8_to_float(buffer,
					       (const int8_t *)src, src_size,
					       dest_size_r);

	case SAMPLE_FORMAT_S16:
		return pcm_allocate_16_to_float(buffer,
						(const int16_t *)src, src_size,
						dest_size_r);

	case SAMPLE_FORMAT_S24_P32:
		return pcm_allocate_24p32_to_float(buffer,
						   (const int32_t *)src, src_size,
						   dest_size_r);

	case SAMPLE_FORMAT_S32:
		return pcm_allocate_32_to_float(buffer,
						(const int32_t *)src, src_size,
						dest_size_r);

	case SAMPLE_FORMAT_FLOAT:
		*dest_size_r = src_size;
		return (const float *)src;
	}

	return NULL;
}
