text: /* Spa ALSA Sink
   *
   * 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.
   */
  
  #ifndef SPA_ALSA_UTILS_H
  #define SPA_ALSA_UTILS_H
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #include <stddef.h>
  #include <math.h>
  
  #include <alsa/asoundlib.h>
  
  #include <spa/support/plugin.h>
  #include <spa/support/loop.h>
  #include <spa/support/log.h>
  #include <spa/utils/list.h>
  
  #include <spa/node/node.h>
  #include <spa/node/utils.h>
  #include <spa/node/io.h>
  #include <spa/param/param.h>
  #include <spa/param/audio/format-utils.h>
  
  #define MIN_LATENCY	16
  #define MAX_LATENCY	8192
  
  #define DEFAULT_RATE		48000u
  #define DEFAULT_CHANNELS	2u
  
  struct props {
  	char device[64];
  	char device_name[128];
  	char card_name[128];
  	uint32_t min_latency;
  	uint32_t max_latency;
  };
  
  #define MAX_BUFFERS 32
  
  struct buffer {
  	uint32_t id;
  #define BUFFER_FLAG_OUT	(1<<0)
  	uint32_t flags;
  	struct spa_buffer *buf;
  	struct spa_meta_header *h;
  	struct spa_list link;
  };
  
  #define BW_MAX		0.128
  #define BW_MED		0.064
  #define BW_MIN		0.016
  #define BW_PERIOD	(3 * SPA_NSEC_PER_SEC)
  
  struct state {
  	struct spa_handle handle;
  	struct spa_node node;
  
  	struct spa_log *log;
  	struct spa_system *data_system;
  	struct spa_loop *data_loop;
  
  	snd_pcm_stream_t stream;
  	snd_output_t *output;
  
  	struct spa_hook_list hooks;
  	struct spa_callbacks callbacks;
  
  	uint64_t info_all;
  	struct spa_node_info info;
  	struct spa_param_info params[8];
  	struct props props;
  
  	bool opened;
  	snd_pcm_t *hndl;
  	int card;
  
  	bool have_format;
  	struct spa_audio_info current_format;
  
  	snd_pcm_uframes_t buffer_frames;
  	snd_pcm_uframes_t period_frames;
  	snd_pcm_format_t format;
  	int rate;
  	int channels;
  	size_t frame_size;
  	int rate_denom;
  	uint32_t delay;
  	uint32_t read_size;
  
  	uint64_t port_info_all;
  	struct spa_port_info port_info;
  	struct spa_param_info port_params[8];
  	struct spa_io_buffers *io;
  	struct spa_io_clock *clock;
  	struct spa_io_position *position;
  	struct spa_io_rate_match *rate_match;
  
  	struct buffer buffers[MAX_BUFFERS];
  	unsigned int n_buffers;
  
  	struct spa_list free;
  	struct spa_list ready;
  
  	size_t ready_offset;
  
  	bool started;
  	struct spa_source source;
  	int timerfd;
  	uint32_t threshold;
  	uint32_t last_threshold;
  
  	uint32_t duration;
  	uint32_t last_duration;
  	uint64_t last_position;
  	unsigned int alsa_started:1;
  	unsigned int alsa_sync:1;
  	unsigned int alsa_recovering:1;
  	unsigned int slaved:1;
  	unsigned int matching:1;
  
  	int64_t sample_count;
  
  	int64_t sample_time;
  	uint64_t current_time;
  	uint64_t next_time;
  	uint64_t base_time;
  
  	uint64_t underrun;
  	double safety;
  
  	double bw;
  	double z1, z2, z3;
  	double w0, w1, w2;
  };
  
  int
  spa_alsa_enum_format(struct state *state, int seq,
  		     uint32_t start, uint32_t num,
  		     const struct spa_pod *filter);
  
  int spa_alsa_set_format(struct state *state, struct spa_audio_info *info, uint32_t flags);
  
  int spa_alsa_start(struct state *state);
  int spa_alsa_reslave(struct state *state);
  int spa_alsa_pause(struct state *state);
  int spa_alsa_close(struct state *state);
  
  int spa_alsa_write(struct state *state, snd_pcm_uframes_t silence);
  int spa_alsa_read(struct state *state, snd_pcm_uframes_t silence);
  
  #ifdef __cplusplus
  } /* extern "C" */
  #endif
  
  #endif /* SPA_ALSA_UTILS_H */
  