linux/sound/core/pcm_misc.c

/*
 *  PCM Interface - misc routines
 *  Copyright (c) 1998 by Jaroslav Kysela <perex@perex.cz>
 *
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library 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 Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */
  
#include <linux/time.h>
#include <linux/export.h>
#include <sound/core.h>
#include <sound/pcm.h>

#include "pcm_local.h"

#define SND_PCM_FORMAT_UNKNOWN (-1)

/* NOTE: "signed" prefix must be given below since the default char is
 *       unsigned on some architectures!
 */
struct pcm_format_data {
	unsigned char width;	/* bit width */
	unsigned char phys;	/* physical bit width */
	signed char le;	/* 0 = big-endian, 1 = little-endian, -1 = others */
	signed char signd;	/* 0 = unsigned, 1 = signed, -1 = others */
	unsigned char silence[8];	/* silence data to fill */
};

/* we do lots of calculations on snd_pcm_format_t; shut up sparse */
#define INT	__force int

static bool valid_format(snd_pcm_format_t format)
{
	return (INT)format >= 0 && (INT)format <= (INT)SNDRV_PCM_FORMAT_LAST;
}

static const struct pcm_format_data pcm_formats[(INT)SNDRV_PCM_FORMAT_LAST+1] = {
	[SNDRV_PCM_FORMAT_S8] = {
		.width = 8, .phys = 8, .le = -1, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_U8] = {
		.width = 8, .phys = 8, .le = -1, .signd = 0,
		.silence = { 0x80 },
	},
	[SNDRV_PCM_FORMAT_S16_LE] = {
		.width = 16, .phys = 16, .le = 1, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_S16_BE] = {
		.width = 16, .phys = 16, .le = 0, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_U16_LE] = {
		.width = 16, .phys = 16, .le = 1, .signd = 0,
		.silence = { 0x00, 0x80 },
	},
	[SNDRV_PCM_FORMAT_U16_BE] = {
		.width = 16, .phys = 16, .le = 0, .signd = 0,
		.silence = { 0x80, 0x00 },
	},
	[SNDRV_PCM_FORMAT_S24_LE] = {
		.width = 24, .phys = 32, .le = 1, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_S24_BE] = {
		.width = 24, .phys = 32, .le = 0, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_U24_LE] = {
		.width = 24, .phys = 32, .le = 1, .signd = 0,
		.silence = { 0x00, 0x00, 0x80 },
	},
	[SNDRV_PCM_FORMAT_U24_BE] = {
		.width = 24, .phys = 32, .le = 0, .signd = 0,
		.silence = { 0x00, 0x80, 0x00, 0x00 },
	},
	[SNDRV_PCM_FORMAT_S32_LE] = {
		.width = 32, .phys = 32, .le = 1, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_S32_BE] = {
		.width = 32, .phys = 32, .le = 0, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_U32_LE] = {
		.width = 32, .phys = 32, .le = 1, .signd = 0,
		.silence = { 0x00, 0x00, 0x00, 0x80 },
	},
	[SNDRV_PCM_FORMAT_U32_BE] = {
		.width = 32, .phys = 32, .le = 0, .signd = 0,
		.silence = { 0x80, 0x00, 0x00, 0x00 },
	},
	[SNDRV_PCM_FORMAT_FLOAT_LE] = {
		.width = 32, .phys = 32, .le = 1, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_FLOAT_BE] = {
		.width = 32, .phys = 32, .le = 0, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_FLOAT64_LE] = {
		.width = 64, .phys = 64, .le = 1, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_FLOAT64_BE] = {
		.width = 64, .phys = 64, .le = 0, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE] = {
		.width = 32, .phys = 32, .le = 1, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE] = {
		.width = 32, .phys = 32, .le = 0, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_MU_LAW] = {
		.width = 8, .phys = 8, .le = -1, .signd = -1,
		.silence = { 0x7f },
	},
	[SNDRV_PCM_FORMAT_A_LAW] = {
		.width = 8, .phys = 8, .le = -1, .signd = -1,
		.silence = { 0x55 },
	},
	[SNDRV_PCM_FORMAT_IMA_ADPCM] = {
		.width = 4, .phys = 4, .le = -1, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_G723_24] = {
		.width = 3, .phys = 3, .le = -1, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_G723_40] = {
		.width = 5, .phys = 5, .le = -1, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_DSD_U8] = {
		.width = 8, .phys = 8, .le = 1, .signd = 0,
		.silence = { 0x69 },
	},
	[SNDRV_PCM_FORMAT_DSD_U16_LE] = {
		.width = 16, .phys = 16, .le = 1, .signd = 0,
		.silence = { 0x69, 0x69 },
	},
	[SNDRV_PCM_FORMAT_DSD_U32_LE] = {
		.width = 32, .phys = 32, .le = 1, .signd = 0,
		.silence = { 0x69, 0x69, 0x69, 0x69 },
	},
	[SNDRV_PCM_FORMAT_DSD_U16_BE] = {
		.width = 16, .phys = 16, .le = 0, .signd = 0,
		.silence = { 0x69, 0x69 },
	},
	[SNDRV_PCM_FORMAT_DSD_U32_BE] = {
		.width = 32, .phys = 32, .le = 0, .signd = 0,
		.silence = { 0x69, 0x69, 0x69, 0x69 },
	},
	/* FIXME: the following two formats are not defined properly yet */
	[SNDRV_PCM_FORMAT_MPEG] = {
		.le = -1, .signd = -1,
	},
	[SNDRV_PCM_FORMAT_GSM] = {
		.le = -1, .signd = -1,
	},
	[SNDRV_PCM_FORMAT_S20_LE] = {
		.width = 20, .phys = 32, .le = 1, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_S20_BE] = {
		.width = 20, .phys = 32, .le = 0, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_U20_LE] = {
		.width = 20, .phys = 32, .le = 1, .signd = 0,
		.silence = { 0x00, 0x00, 0x08, 0x00 },
	},
	[SNDRV_PCM_FORMAT_U20_BE] = {
		.width = 20, .phys = 32, .le = 0, .signd = 0,
		.silence = { 0x00, 0x08, 0x00, 0x00 },
	},
	/* FIXME: the following format is not defined properly yet */
	[SNDRV_PCM_FORMAT_SPECIAL] = {
		.le = -1, .signd = -1,
	},
	[SNDRV_PCM_FORMAT_S24_3LE] = {
		.width = 24, .phys = 24, .le = 1, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_S24_3BE] = {
		.width = 24, .phys = 24, .le = 0, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_U24_3LE] = {
		.width = 24, .phys = 24, .le = 1, .signd = 0,
		.silence = { 0x00, 0x00, 0x80 },
	},
	[SNDRV_PCM_FORMAT_U24_3BE] = {
		.width = 24, .phys = 24, .le = 0, .signd = 0,
		.silence = { 0x80, 0x00, 0x00 },
	},
	[SNDRV_PCM_FORMAT_S20_3LE] = {
		.width = 20, .phys = 24, .le = 1, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_S20_3BE] = {
		.width = 20, .phys = 24, .le = 0, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_U20_3LE] = {
		.width = 20, .phys = 24, .le = 1, .signd = 0,
		.silence = { 0x00, 0x00, 0x08 },
	},
	[SNDRV_PCM_FORMAT_U20_3BE] = {
		.width = 20, .phys = 24, .le = 0, .signd = 0,
		.silence = { 0x08, 0x00, 0x00 },
	},
	[SNDRV_PCM_FORMAT_S18_3LE] = {
		.width = 18, .phys = 24, .le = 1, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_S18_3BE] = {
		.width = 18, .phys = 24, .le = 0, .signd = 1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_U18_3LE] = {
		.width = 18, .phys = 24, .le = 1, .signd = 0,
		.silence = { 0x00, 0x00, 0x02 },
	},
	[SNDRV_PCM_FORMAT_U18_3BE] = {
		.width = 18, .phys = 24, .le = 0, .signd = 0,
		.silence = { 0x02, 0x00, 0x00 },
	},
	[SNDRV_PCM_FORMAT_G723_24_1B] = {
		.width = 3, .phys = 8, .le = -1, .signd = -1,
		.silence = {},
	},
	[SNDRV_PCM_FORMAT_G723_40_1B] = {
		.width = 5, .phys = 8, .le = -1, .signd = -1,
		.silence = {},
	},
};


/**
 * snd_pcm_format_signed - Check the PCM format is signed linear
 * @format: the format to check
 *
 * Return: 1 if the given PCM format is signed linear, 0 if unsigned
 * linear, and a negative error code for non-linear formats.
 */
int snd_pcm_format_signed(snd_pcm_format_t format)
{
	int val;
	if (!valid_format(format))
		return -EINVAL;
	val = pcm_formats[(INT)format].signd;
	if (val < 0)
		return -EINVAL;
	return val;
}
EXPORT_SYMBOL(snd_pcm_format_signed);

/**
 * snd_pcm_format_unsigned - Check the PCM format is unsigned linear
 * @format: the format to check
 *
 * Return: 1 if the given PCM format is unsigned linear, 0 if signed
 * linear, and a negative error code for non-linear formats.
 */
int snd_pcm_format_unsigned(snd_pcm_format_t format)
{
	int val;

	val = snd_pcm_format_signed(format);
	if (val < 0)
		return val;
	return !val;
}
EXPORT_SYMBOL(snd_pcm_format_unsigned);

/**
 * snd_pcm_format_linear - Check the PCM format is linear
 * @format: the format to check
 *
 * Return: 1 if the given PCM format is linear, 0 if not.
 */
int snd_pcm_format_linear(snd_pcm_format_t format)
{
	return snd_pcm_format_signed(format) >= 0;
}
EXPORT_SYMBOL(snd_pcm_format_linear);

/**
 * snd_pcm_format_little_endian - Check the PCM format is little-endian
 * @format: the format to check
 *
 * Return: 1 if the given PCM format is little-endian, 0 if
 * big-endian, or a negative error code if endian not specified.
 */
int snd_pcm_format_little_endian(snd_pcm_format_t format)
{
	int val;
	if (!valid_format(format))
		return -EINVAL;
	val = pcm_formats[(INT)format].le;
	if (val < 0)
		return -EINVAL;
	return val;
}
EXPORT_SYMBOL(snd_pcm_format_little_endian);

/**
 * snd_pcm_format_big_endian - Check the PCM format is big-endian
 * @format: the format to check
 *
 * Return: 1 if the given PCM format is big-endian, 0 if
 * little-endian, or a negative error code if endian not specified.
 */
int snd_pcm_format_big_endian(snd_pcm_format_t format)
{
	int val;

	val = snd_pcm_format_little_endian(format);
	if (val < 0)
		return val;
	return !val;
}
EXPORT_SYMBOL(snd_pcm_format_big_endian);

/**
 * snd_pcm_format_width - return the bit-width of the format
 * @format: the format to check
 *
 * Return: The bit-width of the format, or a negative error code
 * if unknown format.
 */
int snd_pcm_format_width(snd_pcm_format_t format)
{
	int val;
	if (!valid_format(format))
		return -EINVAL;
	val = pcm_formats[(INT)format].width;
	if (!val)
		return -EINVAL;
	return val;
}
EXPORT_SYMBOL(snd_pcm_format_width);

/**
 * snd_pcm_format_physical_width - return the physical bit-width of the format
 * @format: the format to check
 *
 * Return: The physical bit-width of the format, or a negative error code
 * if unknown format.
 */
int snd_pcm_format_physical_width(snd_pcm_format_t format)
{
	int val;
	if (!valid_format(format))
		return -EINVAL;
	val = pcm_formats[(INT)format].phys;
	if (!val)
		return -EINVAL;
	return val;
}
EXPORT_SYMBOL(snd_pcm_format_physical_width);

/**
 * snd_pcm_format_size - return the byte size of samples on the given format
 * @format: the format to check
 * @samples: sampling rate
 *
 * Return: The byte size of the given samples for the format, or a
 * negative error code if unknown format.
 */
ssize_t snd_pcm_format_size(snd_pcm_format_t format, size_t samples)
{
	int phys_width = snd_pcm_format_physical_width(format);
	if (phys_width < 0)
		return -EINVAL;
	return samples * phys_width / 8;
}
EXPORT_SYMBOL(snd_pcm_format_size);

/**
 * snd_pcm_format_silence_64 - return the silent data in 8 bytes array
 * @format: the format to check
 *
 * Return: The format pattern to fill or %NULL if error.
 */
const unsigned char *snd_pcm_format_silence_64(snd_pcm_format_t format)
{
	if (!valid_format(format))
		return NULL;
	if (! pcm_formats[(INT)format].phys)
		return NULL;
	return pcm_formats[(INT)format].silence;
}
EXPORT_SYMBOL(snd_pcm_format_silence_64);

/**
 * snd_pcm_format_set_silence - set the silence data on the buffer
 * @format: the PCM format
 * @data: the buffer pointer
 * @samples: the number of samples to set silence
 *
 * Sets the silence data on the buffer for the given samples.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
int snd_pcm_format_set_silence(snd_pcm_format_t format, void *data, unsigned int samples)
{
	int width;
	unsigned char *dst;
	const unsigned char *pat;

	if (!valid_format(format))
		return -EINVAL;
	if (samples == 0)
		return 0;
	width = pcm_formats[(INT)format].phys; /* physical width */
	pat = pcm_formats[(INT)format].silence;
	if (!width || !pat)
		return -EINVAL;
	/* signed or 1 byte data */
	if (pcm_formats[(INT)format].signd == 1 || width <= 8) {
		unsigned int bytes = samples * width / 8;
		memset(data, *pat, bytes);
		return 0;
	}
	/* non-zero samples, fill using a loop */
	width /= 8;
	dst = data;
#if 0
	while (samples--) {
		memcpy(dst, pat, width);
		dst += width;
	}
#else
	/* a bit optimization for constant width */
	switch (width) {
	case 2:
		while (samples--) {
			memcpy(dst, pat, 2);
			dst += 2;
		}
		break;
	case 3:
		while (samples--) {
			memcpy(dst, pat, 3);
			dst += 3;
		}
		break;
	case 4:
		while (samples--) {
			memcpy(dst, pat, 4);
			dst += 4;
		}
		break;
	case 8:
		while (samples--) {
			memcpy(dst, pat, 8);
			dst += 8;
		}
		break;
	}
#endif
	return 0;
}
EXPORT_SYMBOL(snd_pcm_format_set_silence);

/**
 * snd_pcm_hw_limit_rates - determine rate_min/rate_max fields
 * @hw: the pcm hw instance
 *
 * Determines the rate_min and rate_max fields from the rates bits of
 * the given hw.
 *
 * Return: Zero if successful.
 */
int snd_pcm_hw_limit_rates(struct snd_pcm_hardware *hw)
{
	int i;
	for (i = 0; i < (int)snd_pcm_known_rates.count; i++) {
		if (hw->rates & (1 << i)) {
			hw->rate_min = snd_pcm_known_rates.list[i];
			break;
		}
	}
	for (i = (int)snd_pcm_known_rates.count - 1; i >= 0; i--) {
		if (hw->rates & (1 << i)) {
			hw->rate_max = snd_pcm_known_rates.list[i];
			break;
		}
	}
	return 0;
}
EXPORT_SYMBOL(snd_pcm_hw_limit_rates);

/**
 * snd_pcm_rate_to_rate_bit - converts sample rate to SNDRV_PCM_RATE_xxx bit
 * @rate: the sample rate to convert
 *
 * Return: The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or
 * SNDRV_PCM_RATE_KNOT for an unknown rate.
 */
unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate)
{
	unsigned int i;

	for (i = 0; i < snd_pcm_known_rates.count; i++)
		if (snd_pcm_known_rates.list[i] == rate)
			return 1u << i;
	return SNDRV_PCM_RATE_KNOT;
}
EXPORT_SYMBOL(snd_pcm_rate_to_rate_bit);

/**
 * snd_pcm_rate_bit_to_rate - converts SNDRV_PCM_RATE_xxx bit to sample rate
 * @rate_bit: the rate bit to convert
 *
 * Return: The sample rate that corresponds to the given SNDRV_PCM_RATE_xxx flag
 * or 0 for an unknown rate bit.
 */
unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit)
{
	unsigned int i;

	for (i = 0; i < snd_pcm_known_rates.count; i++)
		if ((1u << i) == rate_bit)
			return snd_pcm_known_rates.list[i];
	return 0;
}
EXPORT_SYMBOL(snd_pcm_rate_bit_to_rate);

static unsigned int snd_pcm_rate_mask_sanitize(unsigned int rates)
{
	if (rates & SNDRV_PCM_RATE_CONTINUOUS)
		return SNDRV_PCM_RATE_CONTINUOUS;
	else if (rates & SNDRV_PCM_RATE_KNOT)
		return SNDRV_PCM_RATE_KNOT;
	return rates;
}

/**
 * snd_pcm_rate_mask_intersect - computes the intersection between two rate masks
 * @rates_a: The first rate mask
 * @rates_b: The second rate mask
 *
 * This function computes the rates that are supported by both rate masks passed
 * to the function. It will take care of the special handling of
 * SNDRV_PCM_RATE_CONTINUOUS and SNDRV_PCM_RATE_KNOT.
 *
 * Return: A rate mask containing the rates that are supported by both rates_a
 * and rates_b.
 */
unsigned int snd_pcm_rate_mask_intersect(unsigned int rates_a,
	unsigned int rates_b)
{
	rates_a = snd_pcm_rate_mask_sanitize(rates_a);
	rates_b = snd_pcm_rate_mask_sanitize(rates_b);

	if (rates_a & SNDRV_PCM_RATE_CONTINUOUS)
		return rates_b;
	else if (rates_b & SNDRV_PCM_RATE_CONTINUOUS)
		return rates_a;
	else if (rates_a & SNDRV_PCM_RATE_KNOT)
		return rates_b;
	else if (rates_b & SNDRV_PCM_RATE_KNOT)
		return rates_a;
	return rates_a & rates_b;
}
EXPORT_SYMBOL_GPL(snd_pcm_rate_mask_intersect);

/**
 * snd_pcm_rate_range_to_bits - converts rate range to SNDRV_PCM_RATE_xxx bit
 * @rate_min: the minimum sample rate
 * @rate_max: the maximum sample rate
 *
 * This function has an implicit assumption: the rates in the given range have
 * only the pre-defined rates like 44100 or 16000.
 *
 * Return: The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate range,
 * or SNDRV_PCM_RATE_KNOT for an unknown range.
 */
unsigned int snd_pcm_rate_range_to_bits(unsigned int rate_min,
	unsigned int rate_max)
{
	unsigned int rates = 0;
	int i;

	for (i = 0; i < snd_pcm_known_rates.count; i++) {
		if (snd_pcm_known_rates.list[i] >= rate_min
			&& snd_pcm_known_rates.list[i] <= rate_max)
			rates |= 1 << i;
	}

	if (!rates)
		rates = SNDRV_PCM_RATE_KNOT;

	return rates;
}
EXPORT_SYMBOL_GPL(snd_pcm_rate_range_to_bits);