text: /* Spa
   *
   * Copyright © 2018 Wim Taymans
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  
  #include <errno.h>
  #include <string.h>
  #include <stdio.h>
  
  #include <spa/support/plugin.h>
  #include <spa/support/log.h>
  #include <spa/support/cpu.h>
  #include <spa/utils/list.h>
  #include <spa/utils/names.h>
  #include <spa/node/node.h>
  #include <spa/node/utils.h>
  #include <spa/node/io.h>
  #include <spa/param/audio/format-utils.h>
  #include <spa/param/param.h>
  #include <spa/pod/filter.h>
  
  #include "mix-ops.h"
  
  #define NAME "mixer-dsp"
  
  #define MAX_BUFFERS	64
  #define MAX_PORTS	128
  #define MAX_SAMPLES	8192
  #define MAX_ALIGN	64
  
  #define PORT_DEFAULT_VOLUME	1.0
  #define PORT_DEFAULT_MUTE	false
  
  struct port_props {
  	double volume;
  	int32_t mute;
  };
  
  static void port_props_reset(struct port_props *props)
  {
  	props->volume = PORT_DEFAULT_VOLUME;
  	props->mute = PORT_DEFAULT_MUTE;
  }
  
  struct buffer {
  	uint32_t id;
  #define BUFFER_FLAG_QUEUED	(1 << 0)
  	uint32_t flags;
  
  	struct spa_list link;
  	struct spa_buffer *buffer;
  	struct spa_meta_header *h;
  	struct spa_buffer buf;
          struct spa_data datas[1];
          struct spa_chunk chunk[1];
  };
  
  struct port {
  	uint32_t direction;
  	uint32_t id;
  
  	struct port_props props;
  
  	struct spa_io_buffers *io;
  
  	uint64_t info_all;
  	struct spa_port_info info;
  	struct spa_param_info params[8];
  
  	unsigned int valid:1;
  	unsigned int have_format:1;
  
  	struct buffer buffers[MAX_BUFFERS];
  	uint32_t n_buffers;
  
  	struct spa_list queue;
  	size_t queued_bytes;
  };
  
  struct impl {
  	struct spa_handle handle;
  	struct spa_node node;
  
  	struct spa_log *log;
  	struct spa_cpu *cpu;
  	uint32_t cpu_flags;
  
  	struct mix_ops ops;
  
  	uint64_t info_all;
  	struct spa_node_info info;
  	struct spa_param_info params[8];
  
  	struct spa_hook_list hooks;
  
  	uint32_t port_count;
  	uint32_t last_port;
  	struct port in_ports[MAX_PORTS];
  	struct port out_ports[1];
  
  	int n_formats;
  	struct spa_audio_info format;
  	uint32_t stride;
  
  	unsigned int have_format:1;
  	unsigned int started:1;
  
  	float empty[MAX_SAMPLES + MAX_ALIGN];
  };
  
  #define CHECK_FREE_IN_PORT(this,d,p) ((d) == SPA_DIRECTION_INPUT && (p) < MAX_PORTS && !this->in_ports[(p)].valid)
  #define CHECK_IN_PORT(this,d,p)      ((d) == SPA_DIRECTION_INPUT && (p) < MAX_PORTS && this->in_ports[(p)].valid)
  #define CHECK_OUT_PORT(this,d,p)     ((d) == SPA_DIRECTION_OUTPUT && (p) == 0)
  #define CHECK_PORT(this,d,p)         (CHECK_OUT_PORT(this,d,p) || CHECK_IN_PORT (this,d,p))
  #define GET_IN_PORT(this,p)          (&this->in_ports[p])
  #define GET_OUT_PORT(this,p)         (&this->out_ports[p])
  #define GET_PORT(this,d,p)           (d == SPA_DIRECTION_INPUT ? GET_IN_PORT(this,p) : GET_OUT_PORT(this,p))
  
  static int impl_node_enum_params(void *object, int seq,
  				 uint32_t id, uint32_t start, uint32_t num,
  				 const struct spa_pod *filter)
  {
  	return -ENOTSUP;
  }
  
  static int impl_node_set_param(void *object, uint32_t id, uint32_t flags,
  			       const struct spa_pod *param)
  {
  	return -ENOTSUP;
  }
  
  static int impl_node_set_io(void *object, uint32_t id, void *data, size_t size)
  {
  	return -ENOTSUP;
  }
  
  static int impl_node_send_command(void *object, const struct spa_command *command)
  {
  	struct impl *this = object;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(command != NULL, -EINVAL);
  
  	switch (SPA_NODE_COMMAND_ID(command)) {
  	case SPA_NODE_COMMAND_Start:
  		this->started = true;
  		break;
  	case SPA_NODE_COMMAND_Pause:
  		this->started = false;
  		break;
  	default:
  		return -ENOTSUP;
  	}
  	return 0;
  }
  
  static void emit_node_info(struct impl *this, bool full)
  {
  	if (full)
  		this->info.change_mask = this->info_all;
  	if (this->info.change_mask) {
  		spa_node_emit_info(&this->hooks, &this->info);
  		this->info.change_mask = 0;
  	}
  }
  
  static void emit_port_info(struct impl *this, struct port *port, bool full)
  {
  	if (full)
  		port->info.change_mask = port->info_all;
  	if (port->info.change_mask) {
  		spa_node_emit_port_info(&this->hooks,
  				port->direction, port->id, &port->info);
  		port->info.change_mask = 0;
  	}
  }
  
  static int impl_node_add_listener(void *object,
  		struct spa_hook *listener,
  		const struct spa_node_events *events,
  		void *data)
  {
  	struct impl *this = object;
  	struct spa_hook_list save;
  	uint32_t i;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	spa_hook_list_isolate(&this->hooks, &save, listener, events, data);
  
  	emit_node_info(this, true);
  	emit_port_info(this, GET_OUT_PORT(this, 0), true);
  	for (i = 0; i < this->last_port; i++) {
  		if (this->in_ports[i].valid)
  			emit_port_info(this, GET_IN_PORT(this, i), true);
  	}
  
  	spa_hook_list_join(&this->hooks, &save);
  
  	return 0;
  }
  
  static int
  impl_node_set_callbacks(void *object,
  			const struct spa_node_callbacks *callbacks,
  			void *user_data)
  {
  	return 0;
  }
  
  static int impl_node_add_port(void *object, enum spa_direction direction, uint32_t port_id,
  		const struct spa_dict *props)
  {
  	struct impl *this = object;
  	struct port *port;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(CHECK_FREE_IN_PORT(this, direction, port_id), -EINVAL);
  
  	port = GET_IN_PORT (this, port_id);
  	port->direction = direction;
  	port->id = port_id;
  
  	port_props_reset(&port->props);
  
  	spa_list_init(&port->queue);
  	port->info_all = SPA_PORT_CHANGE_MASK_FLAGS |
  			SPA_PORT_CHANGE_MASK_PARAMS;
  	port->info = SPA_PORT_INFO_INIT();
  	port->info.flags = SPA_PORT_FLAG_NO_REF |
  			   SPA_PORT_FLAG_DYNAMIC_DATA |
  			   SPA_PORT_FLAG_REMOVABLE |
  			   SPA_PORT_FLAG_OPTIONAL;
  	port->params[0] = SPA_PARAM_INFO(SPA_PARAM_EnumFormat, SPA_PARAM_INFO_READ);
  	port->params[1] = SPA_PARAM_INFO(SPA_PARAM_Meta, SPA_PARAM_INFO_READ);
  	port->params[2] = SPA_PARAM_INFO(SPA_PARAM_IO, SPA_PARAM_INFO_READ);
  	port->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
  	port->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
  	port->info.params = port->params;
  	port->info.n_params = 5;
  
  	this->port_count++;
  	if (this->last_port <= port_id)
  		this->last_port = port_id + 1;
  	port->valid = true;
  
  	spa_log_debug(this->log, NAME " %p: add port %d %d", this, port_id, this->last_port);
  	emit_port_info(this, port, true);
  
  	return 0;
  }
  
  static int
  impl_node_remove_port(void *object, enum spa_direction direction, uint32_t port_id)
  {
  	struct impl *this = object;
  	struct port *port;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(CHECK_IN_PORT(this, direction, port_id), -EINVAL);
  
  	port = GET_IN_PORT (this, port_id);
  
  	port->valid = false;
  	this->port_count--;
  	if (port->have_format && this->have_format) {
  		if (--this->n_formats == 0)
  			this->have_format = false;
  	}
  	spa_memzero(port, sizeof(struct port));
  
  	if (port_id == this->last_port - 1) {
  		int i;
  
  		for (i = this->last_port - 1; i >= 0; i--)
  			if (GET_IN_PORT (this, i)->valid)
  				break;
  
  		this->last_port = i + 1;
  	}
  	spa_log_debug(this->log, NAME " %p: remove port %d %d", this, port_id, this->last_port);
  
  	spa_node_emit_port_info(&this->hooks, direction, port_id, NULL);
  
  	return 0;
  }
  
  static int port_enum_formats(void *object,
  			     enum spa_direction direction, uint32_t port_id,
  			     uint32_t index,
  			     struct spa_pod **param,
  			     struct spa_pod_builder *builder)
  {
  	struct impl *this = object;
  
  	switch (index) {
  	case 0:
  		if (this->have_format) {
  			*param = spa_format_audio_dsp_build(builder, SPA_PARAM_EnumFormat,
  					&this->format.info.dsp);
  		} else {
  			*param = spa_pod_builder_add_object(builder,
  				SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat,
  				SPA_FORMAT_mediaType,      SPA_POD_Id(SPA_MEDIA_TYPE_audio),
  				SPA_FORMAT_mediaSubtype,   SPA_POD_Id(SPA_MEDIA_SUBTYPE_dsp),
  				SPA_FORMAT_AUDIO_format,   SPA_POD_Id(SPA_AUDIO_FORMAT_DSP_F32));
  		}
  		break;
  	default:
  		return 0;
  	}
  	return 1;
  }
  
  static int
  impl_node_port_enum_params(void *object, int seq,
  			   enum spa_direction direction, uint32_t port_id,
  			   uint32_t id, uint32_t start, uint32_t num,
  			   const struct spa_pod *filter)
  {
  	struct impl *this = object;
  	struct port *port;
  	struct spa_pod *param;
  	struct spa_pod_builder b = { 0 };
  	uint8_t buffer[1024];
  	struct spa_result_node_params result;
  	uint32_t count = 0;
  	int res;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(num != 0, -EINVAL);
  	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
  
  	port = GET_PORT(this, direction, port_id);
  
  	result.id = id;
  	result.next = start;
  next:
  	result.index = result.next++;
  
  	spa_pod_builder_init(&b, buffer, sizeof(buffer));
  
  	switch (id) {
  	case SPA_PARAM_EnumFormat:
  		if ((res = port_enum_formats(this, direction, port_id, result.index, &param, &b)) <= 0)
  			return res;
  		break;
  
  	case SPA_PARAM_Format:
  		if (!port->have_format)
  			return -EIO;
  		if (result.index > 0)
  			return 0;
  
  		param = spa_format_audio_dsp_build(&b, id, &this->format.info.dsp);
  		break;
  
  	case SPA_PARAM_Buffers:
  		if (!port->have_format)
  			return -EIO;
  		if (result.index > 0)
  			return 0;
  
  		param = spa_pod_builder_add_object(&b,
  			SPA_TYPE_OBJECT_ParamBuffers, id,
  			SPA_PARAM_BUFFERS_buffers, SPA_POD_CHOICE_RANGE_Int(1, 1, MAX_BUFFERS),
  			SPA_PARAM_BUFFERS_blocks,  SPA_POD_Int(1),
  			SPA_PARAM_BUFFERS_size,    SPA_POD_CHOICE_RANGE_Int(
  								MAX_SAMPLES * this->stride,
  								16 * this->stride,
  								INT32_MAX),
  			SPA_PARAM_BUFFERS_stride,  SPA_POD_Int(this->stride),
  			SPA_PARAM_BUFFERS_align,   SPA_POD_Int(16));
  		break;
  
  	case SPA_PARAM_Meta:
  		switch (result.index) {
  		case 0:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_ParamMeta, id,
  				SPA_PARAM_META_type, SPA_POD_Id(SPA_META_Header),
  				SPA_PARAM_META_size, SPA_POD_Int(sizeof(struct spa_meta_header)));
  			break;
  		default:
  			return 0;
  		}
  		break;
  
  	case SPA_PARAM_IO:
  		switch (result.index) {
  		case 0:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_ParamIO, id,
  				SPA_PARAM_IO_id,   SPA_POD_Id(SPA_IO_Buffers),
  				SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_buffers)));
  			break;
  		default:
  			return 0;
  		}
  		break;
  	default:
  		return -ENOENT;
  	}
  
  	if (spa_pod_filter(&b, &result.param, param, filter) < 0)
  		goto next;
  
  	spa_node_emit_result(&this->hooks, seq, 0, SPA_RESULT_TYPE_NODE_PARAMS, &result);
  
  	if (++count != num)
  		goto next;
  
  	return 0;
  }
  
  static int clear_buffers(struct impl *this, struct port *port)
  {
  	if (port->n_buffers > 0) {
  		spa_log_debug(this->log, NAME " %p: clear buffers %p", this, port);
  		port->n_buffers = 0;
  		spa_list_init(&port->queue);
  	}
  	return 0;
  }
  
  static int queue_buffer(struct impl *this, struct port *port, struct buffer *b)
  {
  	if (SPA_FLAG_IS_SET(b->flags, BUFFER_FLAG_QUEUED))
  		return -EINVAL;
  
  	spa_list_append(&port->queue, &b->link);
  	SPA_FLAG_SET(b->flags, BUFFER_FLAG_QUEUED);
  	spa_log_trace_fp(this->log, NAME " %p: queue buffer %d", this, b->id);
  	return 0;
  }
  
  static struct buffer *dequeue_buffer(struct impl *this, struct port *port)
  {
  	struct buffer *b;
  
  	if (spa_list_is_empty(&port->queue))
  		return NULL;
  
  	b = spa_list_first(&port->queue, struct buffer, link);
  	spa_list_remove(&b->link);
  	SPA_FLAG_CLEAR(b->flags, BUFFER_FLAG_QUEUED);
  	spa_log_trace_fp(this->log, NAME " %p: dequeue buffer %d", this, b->id);
  	return b;
  }
  
  static int port_set_format(void *object,
  			   enum spa_direction direction,
  			   uint32_t port_id,
  			   uint32_t flags,
  			   const struct spa_pod *format)
  {
  	struct impl *this = object;
  	struct port *port;
  	int res;
  
  	port = GET_PORT(this, direction, port_id);
  
  	if (format == NULL) {
  		if (port->have_format) {
  			port->have_format = false;
  			if (--this->n_formats == 0)
  				this->have_format = false;
  			clear_buffers(this, port);
  		}
  	} else {
  		struct spa_audio_info info = { 0 };
  
  		if ((res = spa_format_parse(format, &info.media_type, &info.media_subtype)) < 0)
  			return res;
  
  		if (info.media_type != SPA_MEDIA_TYPE_audio ||
  		    info.media_subtype != SPA_MEDIA_SUBTYPE_dsp)
  			return -EINVAL;
  
  		if (spa_format_audio_dsp_parse(format, &info.info.dsp) < 0)
  			return -EINVAL;
  
  		if (info.info.dsp.format != SPA_AUDIO_FORMAT_DSP_F32)
  			return -EINVAL;
  
  		if (!this->have_format) {
  			this->ops.fmt = info.info.dsp.format;
  			this->ops.n_channels = 1;
  			this->ops.cpu_flags = this->cpu_flags;
  
  			if ((res = mix_ops_init(&this->ops)) < 0)
  				return res;
  
  			this->stride = sizeof(float);
  			this->have_format = true;
  			this->format = info;
  		}
  		if (!port->have_format) {
  			this->n_formats++;
  			port->have_format = true;
  			spa_log_debug(this->log, NAME " %p: set format on port %d:%d",
  					this, direction, port_id);
  		}
  	}
  	port->info.change_mask |= SPA_PORT_CHANGE_MASK_PARAMS;
  	if (port->have_format) {
  		port->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_READWRITE);
  		port->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, SPA_PARAM_INFO_READ);
  	} else {
  		port->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
  		port->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
  	}
  	emit_port_info(this, port, false);
  
  	return 0;
  }
  
  
  static int
  impl_node_port_set_param(void *object,
  			 enum spa_direction direction, uint32_t port_id,
  			 uint32_t id, uint32_t flags,
  			 const struct spa_pod *param)
  {
  	struct impl *this = object;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
  
  	if (id == SPA_PARAM_Format) {
  		return port_set_format(this, direction, port_id, flags, param);
  	}
  	else
  		return -ENOENT;
  }
  
  static int
  impl_node_port_use_buffers(void *object,
  			   enum spa_direction direction,
  			   uint32_t port_id,
  			   uint32_t flags,
  			   struct spa_buffer **buffers,
  			   uint32_t n_buffers)
  {
  	struct impl *this = object;
  	struct port *port;
  	uint32_t i;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
  
  	port = GET_PORT(this, direction, port_id);
  
  	spa_log_debug(this->log, NAME " %p: use buffers %d on port %d:%d",
  			this, n_buffers, direction, port_id);
  
  	spa_return_val_if_fail(port->have_format, -EIO);
  
  	clear_buffers(this, port);
  
  	for (i = 0; i < n_buffers; i++) {
  		struct buffer *b;
  		struct spa_data *d = buffers[i]->datas;
  
  		b = &port->buffers[i];
  		b->buffer = buffers[i];
  		b->flags = 0;
  		b->id = i;
  		b->h = spa_buffer_find_meta_data(buffers[i], SPA_META_Header, sizeof(*b->h));
  
  		if (d[0].data == NULL) {
  			spa_log_error(this->log, NAME " %p: invalid memory on buffer %d", this, i);
  			return -EINVAL;
  		}
  		if (!SPA_IS_ALIGNED(d[0].data, 16)) {
  			spa_log_warn(this->log, NAME " %p: memory on buffer %d not aligned", this, i);
  		}
  		if (direction == SPA_DIRECTION_OUTPUT)
  			queue_buffer(this, port, b);
  
  		spa_log_debug(this->log, NAME " %p: port %d.%d buffer %d n_data:%d data:%p maxsize:%d",
  				this, i, direction, port_id,
  				buffers[i]->n_datas, d[0].data, d[0].maxsize);
  	}
  	port->n_buffers = n_buffers;
  
  	return 0;
  }
  
  static int
  impl_node_port_set_io(void *object,
  		      enum spa_direction direction, uint32_t port_id,
  		      uint32_t id, void *data, size_t size)
  {
  	struct impl *this = object;
  	struct port *port;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
  
  	port = GET_PORT(this, direction, port_id);
  
  	spa_log_debug(this->log, NAME " %p: port %d:%d io %d %p/%zd", this,
  			direction, port_id, id, data, size);
  
  	switch (id) {
  	case SPA_IO_Buffers:
  		port->io = data;
  		break;
  	default:
  		return -ENOENT;
  	}
  	return 0;
  }
  
  static int impl_node_port_reuse_buffer(void *object, uint32_t port_id, uint32_t buffer_id)
  {
  	struct impl *this = object;
  	struct port *port;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(CHECK_PORT(this, SPA_DIRECTION_OUTPUT, port_id), -EINVAL);
  	port = GET_OUT_PORT(this, 0);
  
  	if (buffer_id >= port->n_buffers)
  		return -EINVAL;
  
  	return queue_buffer(this, port, &port->buffers[buffer_id]);
  }
  
  static int impl_node_process(void *object)
  {
  	struct impl *this = object;
  	struct port *outport;
  	struct spa_io_buffers *outio;
  	uint32_t n_samples, n_buffers, i, maxsize;
          struct buffer **buffers;
          struct buffer *outb;
  	const void **datas;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	outport = GET_OUT_PORT(this, 0);
  	outio = outport->io;
  	spa_return_val_if_fail(outio != NULL, -EIO);
  
  	spa_log_trace_fp(this->log, NAME " %p: status %p %d %d",
  			this, outio, outio->status, outio->buffer_id);
  
  	if (outio->status == SPA_STATUS_HAVE_DATA)
  		return outio->status;
  
  	/* recycle */
  	if (outio->buffer_id < outport->n_buffers) {
  		queue_buffer(this, outport, &outport->buffers[outio->buffer_id]);
  		outio->buffer_id = SPA_ID_INVALID;
  	}
  
          buffers = alloca(MAX_PORTS * sizeof(struct buffer *));
          datas = alloca(MAX_PORTS * sizeof(void *));
          n_buffers = 0;
  
  	maxsize = MAX_SAMPLES * sizeof(float);
  
  	for (i = 0; i < this->last_port; i++) {
  		struct port *inport = GET_IN_PORT(this, i);
  		struct spa_io_buffers *inio = NULL;
  		struct buffer *inb;
  
  		if (!inport->valid ||
  		    (inio = inport->io) == NULL ||
  		    inio->buffer_id >= inport->n_buffers ||
  		    inio->status != SPA_STATUS_HAVE_DATA) {
  			spa_log_trace_fp(this->log, NAME " %p: skip input idx:%d valid:%d "
  					"io:%p status:%d buf_id:%d n_buffers:%d", this,
  				i, inport->valid, inio,
  				inio ? inio->status : -1,
  				inio ? inio->buffer_id : SPA_ID_INVALID,
  				inport->n_buffers);
  			continue;
  		}
  
  		inb = &inport->buffers[inio->buffer_id];
  		maxsize = SPA_MIN(inb->buffer->datas[0].chunk->size, maxsize);
  
  		spa_log_trace_fp(this->log, NAME " %p: mix input %d %p->%p %d %d %d", this,
  				i, inio, outio, inio->status, inio->buffer_id, maxsize);
  
  		datas[n_buffers] = inb->buffer->datas[0].data;
  		buffers[n_buffers++] = inb;
  		inio->status = SPA_STATUS_NEED_DATA;
  	}
  
  	outb = dequeue_buffer(this, outport);
          if (outb == NULL) {
                  spa_log_trace(this->log, NAME " %p: out of buffers", this);
                  return -EPIPE;
          }
  
  	n_samples = maxsize / sizeof(float);
  
  	if (n_buffers == 1) {
  		*outb->buffer = *buffers[0]->buffer;
  	}
  	else {
  		outb->buffer->n_datas = 1;
  		outb->buffer->datas = outb->datas;
  		outb->datas[0].data = SPA_PTR_ALIGN(this->empty, MAX_ALIGN, void);
  		outb->datas[0].chunk = outb->chunk;
  		outb->datas[0].chunk->offset = 0;
  		outb->datas[0].chunk->size = n_samples * sizeof(float);
  		outb->datas[0].chunk->stride = sizeof(float);
  
  		mix_ops_process(&this->ops, outb->datas[0].data, datas, n_buffers, n_samples);
  	}
  
  	outio->buffer_id = outb->id;
  	outio->status = SPA_STATUS_HAVE_DATA;
  
  	return SPA_STATUS_HAVE_DATA | SPA_STATUS_NEED_DATA;
  }
  
  static const struct spa_node_methods impl_node = {
  	SPA_VERSION_NODE_METHODS,
  	.add_listener = impl_node_add_listener,
  	.set_callbacks = impl_node_set_callbacks,
  	.enum_params = impl_node_enum_params,
  	.set_param = impl_node_set_param,
  	.set_io = impl_node_set_io,
  	.send_command = impl_node_send_command,
  	.add_port = impl_node_add_port,
  	.remove_port = impl_node_remove_port,
  	.port_enum_params = impl_node_port_enum_params,
  	.port_set_param = impl_node_port_set_param,
  	.port_use_buffers = impl_node_port_use_buffers,
  	.port_set_io = impl_node_port_set_io,
  	.port_reuse_buffer = impl_node_port_reuse_buffer,
  	.process = impl_node_process,
  };
  
  static int impl_get_interface(struct spa_handle *handle, const char *type, void **interface)
  {
  	struct impl *this;
  
  	spa_return_val_if_fail(handle != NULL, -EINVAL);
  	spa_return_val_if_fail(interface != NULL, -EINVAL);
  
  	this = (struct impl *) handle;
  
  	if (strcmp(type, SPA_TYPE_INTERFACE_Node) == 0)
  		*interface = &this->node;
  	else
  		return -ENOENT;
  
  	return 0;
  }
  
  static int impl_clear(struct spa_handle *handle)
  {
  	return 0;
  }
  
  static size_t
  impl_get_size(const struct spa_handle_factory *factory,
  	      const struct spa_dict *params)
  {
  	return sizeof(struct impl);
  }
  
  static int
  impl_init(const struct spa_handle_factory *factory,
  	  struct spa_handle *handle,
  	  const struct spa_dict *info,
  	  const struct spa_support *support,
  	  uint32_t n_support)
  {
  	struct impl *this;
  	struct port *port;
  
  	spa_return_val_if_fail(factory != NULL, -EINVAL);
  	spa_return_val_if_fail(handle != NULL, -EINVAL);
  
  	handle->get_interface = impl_get_interface;
  	handle->clear = impl_clear;
  
  	this = (struct impl *) handle;
  
  	this->log = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_Log);
  	this->cpu = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_CPU);
  
  	if (this->cpu)
  		this->cpu_flags = spa_cpu_get_flags(this->cpu);
  
  	spa_hook_list_init(&this->hooks);
  
  	this->node.iface = SPA_INTERFACE_INIT(
  			SPA_TYPE_INTERFACE_Node,
  			SPA_VERSION_NODE,
  			&impl_node, this);
  	this->info = SPA_NODE_INFO_INIT();
  	this->info.max_input_ports = MAX_PORTS;
  	this->info.max_output_ports = 1;
  	this->info.change_mask |= SPA_NODE_CHANGE_MASK_FLAGS;
  	this->info.flags = SPA_NODE_FLAG_RT | SPA_NODE_FLAG_IN_DYNAMIC_PORTS;
  
  	port = GET_OUT_PORT(this, 0);
  	port->valid = true;
  	port->direction = SPA_DIRECTION_OUTPUT;
  	port->id = 0;
  	port->info = SPA_PORT_INFO_INIT();
  	port->info.change_mask |= SPA_PORT_CHANGE_MASK_FLAGS;
  	port->info.flags = SPA_PORT_FLAG_DYNAMIC_DATA;
  	port->info.change_mask |= SPA_PORT_CHANGE_MASK_PARAMS;
  	port->params[0] = SPA_PARAM_INFO(SPA_PARAM_EnumFormat, SPA_PARAM_INFO_READ);
  	port->params[1] = SPA_PARAM_INFO(SPA_PARAM_Meta, SPA_PARAM_INFO_READ);
  	port->params[2] = SPA_PARAM_INFO(SPA_PARAM_IO, SPA_PARAM_INFO_READ);
  	port->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
  	port->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
  	port->info.params = port->params;
  	port->info.n_params = 5;
  
  	spa_list_init(&port->queue);
  
  	return 0;
  }
  
  static const struct spa_interface_info impl_interfaces[] = {
  	{SPA_TYPE_INTERFACE_Node,},
  };
  
  static int
  impl_enum_interface_info(const struct spa_handle_factory *factory,
  			 const struct spa_interface_info **info,
  			 uint32_t *index)
  {
  	spa_return_val_if_fail(factory != NULL, -EINVAL);
  	spa_return_val_if_fail(info != NULL, -EINVAL);
  	spa_return_val_if_fail(index != NULL, -EINVAL);
  
  	switch (*index) {
  	case 0:
  		*info = &impl_interfaces[*index];
  		break;
  	default:
  		return 0;
  	}
  	(*index)++;
  	return 1;
  }
  
  const struct spa_handle_factory spa_mixer_dsp_factory = {
  	SPA_VERSION_HANDLE_FACTORY,
  	SPA_NAME_AUDIO_MIXER_DSP,
  	NULL,
  	impl_get_size,
  	impl_init,
  	impl_enum_interface_info,
  };
  