File resamp_core.h¶

#ifndef RESAMP_CORE_H
#define RESAMP_CORE_H

#include "clib_common.h"
#include "dp_state.h"

#ifdef __cplusplus
extern "C"
{
#endif

  typedef struct
  {
    double rate;
    size_t num_phases;
    size_t num_taps;
    unsigned log2_phases;
    int upsample; /* 1 = rate >= 1.0, 0 = rate < 1.0 */

    float *bank; /* num_phases × num_taps, row-major  */

    /* execute state */
    uint32_t phase;
    uint32_t phase_inc;

    /* interpolator / execute_ctrl: dual-buffer delay line */
    float _Complex *delay_buf; /* 2 × delay_cap elements         */
    size_t delay_cap;
    size_t delay_mask;
    size_t delay_head;

    /* decimator transposed-form state (execute, rate < 1) */
    float _Complex *decim_iad; /* integrate-and-dump: num_taps   */
    float _Complex *decim_tfd; /* transposed delay line: num_taps-1 */

    /* execute_ctrl state: double-precision fractional accumulator */
    double ctrl_acc;
  } resamp_state_t;

  /* ------------------------------------------------------------------
   * Lifecycle
   * ------------------------------------------------------------------ */

  resamp_state_t *resamp_create (double rate);

  resamp_state_t *resamp_create_custom (size_t num_phases, size_t num_taps,
                                        const float *bank, double rate);

  void resamp_destroy (resamp_state_t *state);

  void resamp_reset (resamp_state_t *state);

  /* Serializable state (standard bytes interface; see dp_state.h): after the
   * envelope, the polyphase phase, the fractional ctrl accumulator, the
   * delay-line write head, and the three delay buffers (delay_buf, decim_iad,
   * decim_tfd).  Rate, bank, phase increment and sizes are config. */
#define RESAMP_STATE_MAGIC DP_FOURCC ('R', 'S', 'M', 'P')
#define RESAMP_STATE_VERSION 1u

  size_t resamp_state_bytes (const resamp_state_t *state);
  void resamp_get_state (const resamp_state_t *state, void *blob);
  int resamp_set_state (resamp_state_t *state, const void *blob);

  /* ------------------------------------------------------------------
   * Execute
   * ------------------------------------------------------------------ */

  size_t resamp_execute (resamp_state_t *state, const float _Complex *in,
                         size_t num_in, float _Complex *out, size_t max_out);

  size_t resamp_execute_ctrl (resamp_state_t *state, const float _Complex *in,
                              const float _Complex *ctrl, size_t num_in,
                              float _Complex *out, size_t max_out);

  /* ------------------------------------------------------------------
   * Properties
   * ------------------------------------------------------------------ */

  double resamp_get_rate (const resamp_state_t *state);

  void resamp_set_rate (resamp_state_t *state, double rate);

  size_t resamp_get_num_phases (const resamp_state_t *state);
  size_t resamp_get_num_taps (const resamp_state_t *state);

#ifdef __cplusplus
}
#endif

#endif /* RESAMP_CORE_H */