pcm_lib.c

linux 内核源代码

 *
 * c = a * k / b
 *
 * Returns non-zero if the value is changed, zero if not changed.
 */
void snd_interval_mulkdiv(const struct snd_interval *a, unsigned int k,
		      const struct snd_interval *b, struct snd_interval *c)
{
	unsigned int r;
	if (a->empty || b->empty) {
		snd_interval_none(c);
		return;
	}
	c->empty = 0;
	c->min = muldiv32(a->min, k, b->max, &r);
	c->openmin = (r || a->openmin || b->openmax);
	if (b->min > 0) {
		c->max = muldiv32(a->max, k, b->min, &r);
		if (r) {
			c->max++;
			c->openmax = 1;
		} else
			c->openmax = (a->openmax || b->openmin);
	} else {
		c->max = UINT_MAX;
		c->openmax = 0;
	}
	c->integer = 0;
}

/* ---- */


/**
 * snd_interval_ratnum - refine the interval value
 * @i: interval to refine
 * @rats_count: number of ratnum_t 
 * @rats: ratnum_t array
 * @nump: pointer to store the resultant numerator
 * @denp: pointer to store the resultant denominator
 *
 * Returns non-zero if the value is changed, zero if not changed.
 */
int snd_interval_ratnum(struct snd_interval *i,
			unsigned int rats_count, struct snd_ratnum *rats,
			unsigned int *nump, unsigned int *denp)
{
	unsigned int best_num, best_diff, best_den;
	unsigned int k;
	struct snd_interval t;
	int err;

	best_num = best_den = best_diff = 0;
	for (k = 0; k < rats_count; ++k) {
		unsigned int num = rats[k].num;
		unsigned int den;
		unsigned int q = i->min;
		int diff;
		if (q == 0)
			q = 1;
		den = div_down(num, q);
		if (den < rats[k].den_min)
			continue;
		if (den > rats[k].den_max)
			den = rats[k].den_max;
		else {
			unsigned int r;
			r = (den - rats[k].den_min) % rats[k].den_step;
			if (r != 0)
				den -= r;
		}
		diff = num - q * den;
		if (best_num == 0 ||
		    diff * best_den < best_diff * den) {
			best_diff = diff;
			best_den = den;
			best_num = num;
		}
	}
	if (best_den == 0) {
		i->empty = 1;
		return -EINVAL;
	}
	t.min = div_down(best_num, best_den);
	t.openmin = !!(best_num % best_den);
	
	best_num = best_den = best_diff = 0;
	for (k = 0; k < rats_count; ++k) {
		unsigned int num = rats[k].num;
		unsigned int den;
		unsigned int q = i->max;
		int diff;
		if (q == 0) {
			i->empty = 1;
			return -EINVAL;
		}
		den = div_up(num, q);
		if (den > rats[k].den_max)
			continue;
		if (den < rats[k].den_min)
			den = rats[k].den_min;
		else {
			unsigned int r;
			r = (den - rats[k].den_min) % rats[k].den_step;
			if (r != 0)
				den += rats[k].den_step - r;
		}
		diff = q * den - num;
		if (best_num == 0 ||
		    diff * best_den < best_diff * den) {
			best_diff = diff;
			best_den = den;
			best_num = num;
		}
	}
	if (best_den == 0) {
		i->empty = 1;
		return -EINVAL;
	}
	t.max = div_up(best_num, best_den);
	t.openmax = !!(best_num % best_den);
	t.integer = 0;
	err = snd_interval_refine(i, &t);
	if (err < 0)
		return err;

	if (snd_interval_single(i)) {
		if (nump)
			*nump = best_num;
		if (denp)
			*denp = best_den;
	}
	return err;
}

EXPORT_SYMBOL(snd_interval_ratnum);

/**
 * snd_interval_ratden - refine the interval value
 * @i: interval to refine
 * @rats_count: number of struct ratden
 * @rats: struct ratden array
 * @nump: pointer to store the resultant numerator
 * @denp: pointer to store the resultant denominator
 *
 * Returns non-zero if the value is changed, zero if not changed.
 */
static int snd_interval_ratden(struct snd_interval *i,
			       unsigned int rats_count, struct snd_ratden *rats,
			       unsigned int *nump, unsigned int *denp)
{
	unsigned int best_num, best_diff, best_den;
	unsigned int k;
	struct snd_interval t;
	int err;

	best_num = best_den = best_diff = 0;
	for (k = 0; k < rats_count; ++k) {
		unsigned int num;
		unsigned int den = rats[k].den;
		unsigned int q = i->min;
		int diff;
		num = mul(q, den);
		if (num > rats[k].num_max)
			continue;
		if (num < rats[k].num_min)
			num = rats[k].num_max;
		else {
			unsigned int r;
			r = (num - rats[k].num_min) % rats[k].num_step;
			if (r != 0)
				num += rats[k].num_step - r;
		}
		diff = num - q * den;
		if (best_num == 0 ||
		    diff * best_den < best_diff * den) {
			best_diff = diff;
			best_den = den;
			best_num = num;
		}
	}
	if (best_den == 0) {
		i->empty = 1;
		return -EINVAL;
	}
	t.min = div_down(best_num, best_den);
	t.openmin = !!(best_num % best_den);
	
	best_num = best_den = best_diff = 0;
	for (k = 0; k < rats_count; ++k) {
		unsigned int num;
		unsigned int den = rats[k].den;
		unsigned int q = i->max;
		int diff;
		num = mul(q, den);
		if (num < rats[k].num_min)
			continue;
		if (num > rats[k].num_max)
			num = rats[k].num_max;
		else {
			unsigned int r;
			r = (num - rats[k].num_min) % rats[k].num_step;
			if (r != 0)
				num -= r;
		}
		diff = q * den - num;
		if (best_num == 0 ||
		    diff * best_den < best_diff * den) {
			best_diff = diff;
			best_den = den;
			best_num = num;
		}
	}
	if (best_den == 0) {
		i->empty = 1;
		return -EINVAL;
	}
	t.max = div_up(best_num, best_den);
	t.openmax = !!(best_num % best_den);
	t.integer = 0;
	err = snd_interval_refine(i, &t);
	if (err < 0)
		return err;

	if (snd_interval_single(i)) {
		if (nump)
			*nump = best_num;
		if (denp)
			*denp = best_den;
	}
	return err;
}

/**
 * snd_interval_list - refine the interval value from the list
 * @i: the interval value to refine
 * @count: the number of elements in the list
 * @list: the value list
 * @mask: the bit-mask to evaluate
 *
 * Refines the interval value from the list.
 * When mask is non-zero, only the elements corresponding to bit 1 are
 * evaluated.
 *
 * Returns non-zero if the value is changed, zero if not changed.
 */
int snd_interval_list(struct snd_interval *i, unsigned int count, unsigned int *list, unsigned int mask)
{
        unsigned int k;
	int changed = 0;

	if (!count) {
		i->empty = 1;
		return -EINVAL;
	}
        for (k = 0; k < count; k++) {
		if (mask && !(mask & (1 << k)))
			continue;
                if (i->min == list[k] && !i->openmin)
                        goto _l1;
                if (i->min < list[k]) {
                        i->min = list[k];
			i->openmin = 0;
			changed = 1;
                        goto _l1;
                }
        }
        i->empty = 1;
        return -EINVAL;
 _l1:
        for (k = count; k-- > 0;) {
		if (mask && !(mask & (1 << k)))
			continue;
                if (i->max == list[k] && !i->openmax)
                        goto _l2;
                if (i->max > list[k]) {
                        i->max = list[k];
			i->openmax = 0;
			changed = 1;
                        goto _l2;
                }
        }
        i->empty = 1;
        return -EINVAL;
 _l2:
	if (snd_interval_checkempty(i)) {
		i->empty = 1;
		return -EINVAL;
	}
        return changed;
}

EXPORT_SYMBOL(snd_interval_list);

static int snd_interval_step(struct snd_interval *i, unsigned int min, unsigned int step)
{
	unsigned int n;
	int changed = 0;
	n = (i->min - min) % step;
	if (n != 0 || i->openmin) {
		i->min += step - n;
		changed = 1;
	}
	n = (i->max - min) % step;
	if (n != 0 || i->openmax) {
		i->max -= n;
		changed = 1;
	}
	if (snd_interval_checkempty(i)) {
		i->empty = 1;
		return -EINVAL;
	}
	return changed;
}

/* Info constraints helpers */

/**
 * snd_pcm_hw_rule_add - add the hw-constraint rule
 * @runtime: the pcm runtime instance
 * @cond: condition bits
 * @var: the variable to evaluate
 * @func: the evaluation function
 * @private: the private data pointer passed to function
 * @dep: the dependent variables
 *
 * Returns zero if successful, or a negative error code on failure.
 */
int snd_pcm_hw_rule_add(struct snd_pcm_runtime *runtime, unsigned int cond,
			int var,
			snd_pcm_hw_rule_func_t func, void *private,
			int dep, ...)
{
	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
	struct snd_pcm_hw_rule *c;
	unsigned int k;
	va_list args;
	va_start(args, dep);
	if (constrs->rules_num >= constrs->rules_all) {
		struct snd_pcm_hw_rule *new;
		unsigned int new_rules = constrs->rules_all + 16;
		new = kcalloc(new_rules, sizeof(*c), GFP_KERNEL);
		if (!new)
			return -ENOMEM;
		if (constrs->rules) {
			memcpy(new, constrs->rules,
			       constrs->rules_num * sizeof(*c));
			kfree(constrs->rules);
		}
		constrs->rules = new;
		constrs->rules_all = new_rules;
	}
	c = &constrs->rules[constrs->rules_num];
	c->cond = cond;
	c->func = func;
	c->var = var;
	c->private = private;
	k = 0;
	while (1) {
		snd_assert(k < ARRAY_SIZE(c->deps), return -EINVAL);
		c->deps[k++] = dep;
		if (dep < 0)
			break;
		dep = va_arg(args, int);
	}
	constrs->rules_num++;
	va_end(args);
	return 0;
}				    

EXPORT_SYMBOL(snd_pcm_hw_rule_add);

/**
 * snd_pcm_hw_constraint_mask
 * @runtime: PCM runtime instance
 * @var: hw_params variable to apply the mask
 * @mask: the bitmap mask
 *
 * Apply the constraint of the given bitmap mask to a mask parameter.
 */
int snd_pcm_hw_constraint_mask(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
			       u_int32_t mask)
{
	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
	struct snd_mask *maskp = constrs_mask(constrs, var);
	*maskp->bits &= mask;
	memset(maskp->bits + 1, 0, (SNDRV_MASK_MAX-32) / 8); /* clear rest */
	if (*maskp->bits == 0)
		return -EINVAL;
	return 0;
}

/**
 * snd_pcm_hw_constraint_mask64
 * @runtime: PCM runtime instance
 * @var: hw_params variable to apply the mask
 * @mask: the 64bit bitmap mask
 *
 * Apply the constraint of the given bitmap mask to a mask parameter.
 */
int snd_pcm_hw_constraint_mask64(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
				 u_int64_t mask)
{
	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
	struct snd_mask *maskp = constrs_mask(constrs, var);
	maskp->bits[0] &= (u_int32_t)mask;
	maskp->bits[1] &= (u_int32_t)(mask >> 32);
	memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
	if (! maskp->bits[0] && ! maskp->bits[1])
		return -EINVAL;
	return 0;
}

/**
 * snd_pcm_hw_constraint_integer
 * @runtime: PCM runtime instance
 * @var: hw_params variable to apply the integer constraint
 *
 * Apply the constraint of integer to an interval parameter.
 */
int snd_pcm_hw_constraint_integer(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var)
{
	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
	return snd_interval_setinteger(constrs_interval(constrs, var));
}

EXPORT_SYMBOL(snd_pcm_hw_constraint_integer);

/**
 * snd_pcm_hw_constraint_minmax
 * @runtime: PCM runtime instance
 * @var: hw_params variable to apply the range
 * @min: the minimal value
 * @max: the maximal value
 * 
 * Apply the min/max range constraint to an interval parameter.
 */
int snd_pcm_hw_constraint_minmax(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
				 unsigned int min, unsigned int max)
{
	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
	struct snd_interval t;
	t.min = min;
	t.max = max;
	t.openmin = t.openmax = 0;
	t.integer = 0;
	return snd_interval_refine(constrs_interval(constrs, var), &t);
}

EXPORT_SYMBOL(snd_pcm_hw_constraint_minmax);

static int snd_pcm_hw_rule_list(struct snd_pcm_hw_params *params,
				struct snd_pcm_hw_rule *rule)
{
	struct snd_pcm_hw_constraint_list *list = rule->private;
	return snd_interval_list(hw_param_interval(params, rule->var), list->count, list->list, list->mask);
}		


/**
 * snd_pcm_hw_constraint_list
 * @runtime: PCM runtime instance
 * @cond: condition bits
 * @var: hw_params variable to apply the list constraint
 * @l: list
 * 
 * Apply the list of constraints to an interval parameter.
 */
int snd_pcm_hw_constraint_list(struct snd_pcm_runtime *runtime,
			       unsigned int cond,
			       snd_pcm_hw_param_t var,
			       struct snd_pcm_hw_constraint_list *l)
{
	return snd_pcm_hw_rule_add(runtime, cond, var,
				   snd_pcm_hw_rule_list, l,
				   var, -1);
}

EXPORT_SYMBOL(snd_pcm_hw_constraint_list);

static int snd_pcm_hw_rule_ratnums(struct snd_pcm_hw_params *params,
				   struct snd_pcm_hw_rule *rule)
{
	struct snd_pcm_hw_constraint_ratnums *r = rule->private;
	unsigned int num = 0, den = 0;
	int err;
	err = snd_interval_ratnum(hw_param_interval(params, rule->var),
				  r->nrats, r->rats, &num, &den);
	if (err >= 0 && den && rule->var == SNDRV_PCM_HW_PARAM_RATE) {
		params->rate_num = num;
		params->rate_den = den;
	}
	return err;
}

/**
 * snd_pcm_hw_constraint_ratnums
 * @runtime: PCM runtime instance
 * @cond: condition bits
 * @var: hw_params variable to apply the ratnums constraint
 * @r: struct snd_ratnums constriants
 */
int snd_pcm_hw_constraint_ratnums(struct snd_pcm_runtime *runtime, 
				  unsigned int cond,
				  snd_pcm_hw_param_t var,
				  struct snd_pcm_hw_constraint_ratnums *r)
{
	return snd_pcm_hw_rule_add(runtime, cond, var,
				   snd_pcm_hw_rule_ratnums, r,
				   var, -1);
}

EXPORT_SYMBOL(snd_pcm_hw_constraint_ratnums);

static int snd_pcm_hw_rule_ratdens(struct snd_pcm_hw_params *params,
				   struct snd_pcm_hw_rule *rule)
{
	struct snd_pcm_hw_constraint_ratdens *r = rule->private;
	unsigned int num = 0, den = 0;
	int err = snd_interval_ratden(hw_param_interval(params, rule->var),
				  r->nrats, r->rats, &num, &den);
	if (err >= 0 && den && rule->var == SNDRV_PCM_HW_PARAM_RATE) {
		params->rate_num = num;
		params->rate_den = den;
	}
	return err;
}

/**
 * snd_pcm_hw_constraint_ratdens
 * @runtime: PCM runtime instance
 * @cond: condition bits
 * @var: hw_params variable to apply the ratdens constraint