ecu.h

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#pragma once
 
#include <stdint.h>
#include <stdbool.h>
 
#include <osmocom/core/defs.h>
#include <osmocom/codec/codec.h>
 
/* ECU state for GSM-FR - deprecated version only! */
struct osmo_ecu_fr_state {
        bool subsequent_lost_frame;
        uint8_t frame_backup[GSM_FR_BYTES];
};
 
void osmo_ecu_fr_reset(struct osmo_ecu_fr_state *state, const uint8_t *frame)
        OSMO_DEPRECATED_OUTSIDE("Use generic ECU abstraction layer instead");
int osmo_ecu_fr_conceal(struct osmo_ecu_fr_state *state, uint8_t *frame)
        OSMO_DEPRECATED_OUTSIDE("Use generic ECU abstraction layer instead");
 
enum osmo_ecu_codec {
        OSMO_ECU_CODEC_HR,
        OSMO_ECU_CODEC_FR,
        OSMO_ECU_CODEC_EFR,
        OSMO_ECU_CODEC_AMR,
        _NUM_OSMO_ECU_CODECS
};
 
/***********************************************************************
 * Generic ECU abstraction layer below
 ***********************************************************************/
 
/* As the developer and copyright holder of the related code, I hereby
 * state that any ECU implementation using 'struct osmo_ecu_ops' and
 * registering with the 'osmo_ecu_register()' function shall not be
 * considered as a derivative work under any applicable copyright law;
 * the copyleft terms of GPLv2 shall hence not apply to any such ECU
 * implementation.
 *
 * The intent of the above exception is to allow anyone to combine third
 * party Error Concealment Unit implementations with libosmocodec.
 * including but not limited to such published by ETSI.
 *
 *   -- Harald Welte <laforge@gnumonks.org> on August 1, 2019.
 */
 
/* Codec independent ECU state */
struct osmo_ecu_state {
        enum osmo_ecu_codec codec;
        uint8_t data[0];
};
 
/* initialize an ECU instance */
struct osmo_ecu_state *osmo_ecu_init(void *ctx, enum osmo_ecu_codec codec);
 
/* destroy an ECU instance */
void osmo_ecu_destroy(struct osmo_ecu_state *st);
 
/* process a received frame a substitute/erroneous frame */
int osmo_ecu_frame_in(struct osmo_ecu_state *st, bool bfi,
                      const uint8_t *frame, unsigned int frame_bytes);
 
/* generate output data for a substitute/erroneous frame */
int osmo_ecu_frame_out(struct osmo_ecu_state *st, uint8_t *frame_out);
 
/* is the stream handled by this ECU currently in a DTX pause? */
bool osmo_ecu_is_dtx_pause(struct osmo_ecu_state *st);
 
struct osmo_ecu_ops {
        struct osmo_ecu_state * (*init)(void *ctx, enum osmo_ecu_codec codec);
        void (*destroy)(struct osmo_ecu_state *);
        int (*frame_in)(struct osmo_ecu_state *st, bool bfi,
                        const uint8_t *frame, unsigned int frame_bytes);
        int (*frame_out)(struct osmo_ecu_state *st, uint8_t *frame_out);
        bool (*is_dtx_pause)(struct osmo_ecu_state *st);
};
 
int osmo_ecu_register(const struct osmo_ecu_ops *ops, enum osmo_ecu_codec codec);