buzz.c

Audacity是一款用於錄音和編輯聲音的、免費的開放源碼軟體。它可以執行於Mac OS X、Microsoft Windows、GNU/Linux和其它作業系統

#include "stdio.h"
#ifndef mips
#include "stdlib.h"
#endif
#include "xlisp.h"
#include "sound.h"

#include "falloc.h"
#include "cext.h"
#include "buzz.h"

void buzz_free();


typedef struct buzz_susp_struct {
    snd_susp_node susp;
    boolean started;
    long terminate_cnt;
    boolean logically_stopped;
    sound_type s_fm;
    long s_fm_cnt;
    sample_block_values_type s_fm_ptr;

    /* support for interpolation of s_fm */
    sample_type s_fm_x1_sample;
    double s_fm_pHaSe;
    double s_fm_pHaSe_iNcR;

    /* support for ramp between samples of s_fm */
    double output_per_s_fm;
    long s_fm_n;

    double ph_incr;
    float n_2_r;
    float n_2_p1;
    double phase;
} buzz_susp_node, *buzz_susp_type;


#include "sine.h"


void buzz_s_fetch(register buzz_susp_type susp, snd_list_type snd_list)
{
    int cnt = 0; /* how many samples computed */
    int togo;
    int n;
    sample_block_type out;
    register sample_block_values_type out_ptr;

    register sample_block_values_type out_ptr_reg;

    register double ph_incr_reg;
    register float n_2_r_reg;
    register float n_2_p1_reg;
    register double phase_reg;
    register sample_type s_fm_scale_reg = susp->s_fm->scale;
    register sample_block_values_type s_fm_ptr_reg;
    falloc_sample_block(out, "buzz_s_fetch");
    out_ptr = out->samples;
    snd_list->block = out;

    while (cnt < max_sample_block_len) { /* outer loop */
	/* first compute how many samples to generate in inner loop: */
	/* don't overflow the output sample block: */
	togo = max_sample_block_len - cnt;

	/* don't run past the s_fm input sample block: */
	susp_check_term_log_samples(s_fm, s_fm_ptr, s_fm_cnt);
	togo = MIN(togo, susp->s_fm_cnt);

	/* don't run past terminate time */
	if (susp->terminate_cnt != UNKNOWN &&
	    susp->terminate_cnt <= susp->susp.current + cnt + togo) {
	    togo = susp->terminate_cnt - (susp->susp.current + cnt);
	    if (togo == 0) break;
	}


	/* don't run past logical stop time */
	if (!susp->logically_stopped && susp->susp.log_stop_cnt != UNKNOWN) {
	    int to_stop = susp->susp.log_stop_cnt - (susp->susp.current + cnt);
	    /* break if to_stop == 0 (we're at the logical stop)
	     * AND cnt > 0 (we're not at the beginning of the
	     * output block).
	     */
	    if (to_stop < togo) {
		if (to_stop == 0) {
		    if (cnt) {
			togo = 0;
			break;
		    } else /* keep togo as is: since cnt == 0, we
		            * can set the logical stop flag on this
		            * output block
		            */
			susp->logically_stopped = true;
		} else /* limit togo so we can start a new
		        * block at the LST
		        */
		    togo = to_stop;
	    }
	}

	n = togo;
	ph_incr_reg = susp->ph_incr;
	n_2_r_reg = susp->n_2_r;
	n_2_p1_reg = susp->n_2_p1;
	phase_reg = susp->phase;
	s_fm_ptr_reg = susp->s_fm_ptr;
	out_ptr_reg = out_ptr;
	if (n) do { /* the inner sample computation loop */
	    long table_index;
            double x1;
            sample_type num, denom, samp;

            table_index = (long) phase_reg;
            x1 = sine_table[table_index];
            denom = (sample_type) (x1 + (phase_reg - table_index) * 
                          (sine_table[table_index + 1] - x1));
            if (denom < 0.001 && denom > -0.005) {
                samp = 1.0F;
            } else {
                double phn2p1 = phase_reg * n_2_p1_reg * (1.0/SINE_TABLE_LEN);
                phn2p1 = (phn2p1 - (long) phn2p1) * SINE_TABLE_LEN;
                table_index = (long) phn2p1;
                x1 = sine_table[table_index];
                num = (sample_type) (x1 + (phn2p1 - table_index) *
                        (sine_table[table_index + 1] - x1));
                samp = ((num / denom) - 1.0F) * n_2_r_reg;
            }
            *out_ptr_reg++ = samp;
            phase_reg += ph_incr_reg + (s_fm_scale_reg * *s_fm_ptr_reg++);
            while (phase_reg > SINE_TABLE_LEN) phase_reg -= SINE_TABLE_LEN;
            /* watch out for negative frequencies! */
            while (phase_reg < 0) phase_reg += SINE_TABLE_LEN;
	} while (--n); /* inner loop */

	susp->phase = phase_reg;
	/* using s_fm_ptr_reg is a bad idea on RS/6000: */
	susp->s_fm_ptr += togo;
	out_ptr += togo;
	susp_took(s_fm_cnt, togo);
	cnt += togo;
    } /* outer loop */

    /* test for termination */
    if (togo == 0 && cnt == 0) {
	snd_list_terminate(snd_list);
    } else {
	snd_list->block_len = cnt;
	susp->susp.current += cnt;
    }
    /* test for logical stop */
    if (susp->logically_stopped) {
	snd_list->logically_stopped = true;
    } else if (susp->susp.log_stop_cnt == susp->susp.current) {
	susp->logically_stopped = true;
    }
} /* buzz_s_fetch */


void buzz_i_fetch(register buzz_susp_type susp, snd_list_type snd_list)
{
    int cnt = 0; /* how many samples computed */
    int togo;
    int n;
    sample_block_type out;
    register sample_block_values_type out_ptr;

    register sample_block_values_type out_ptr_reg;

    register double ph_incr_reg;
    register float n_2_r_reg;
    register float n_2_p1_reg;
    register double phase_reg;
    register double s_fm_pHaSe_iNcR_rEg = susp->s_fm_pHaSe_iNcR;
    register double s_fm_pHaSe_ReG;
    register sample_type s_fm_x1_sample_reg;
    falloc_sample_block(out, "buzz_i_fetch");
    out_ptr = out->samples;
    snd_list->block = out;

    /* make sure sounds are primed with first values */
    if (!susp->started) {
	susp->started = true;
	susp_check_term_log_samples(s_fm, s_fm_ptr, s_fm_cnt);
	susp->s_fm_x1_sample = susp_fetch_sample(s_fm, s_fm_ptr, s_fm_cnt);
    }

    while (cnt < max_sample_block_len) { /* outer loop */
	/* first compute how many samples to generate in inner loop: */
	/* don't overflow the output sample block: */
	togo = max_sample_block_len - cnt;

	/* don't run past terminate time */
	if (susp->terminate_cnt != UNKNOWN &&
	    susp->terminate_cnt <= susp->susp.current + cnt + togo) {
	    togo = susp->terminate_cnt - (susp->susp.current + cnt);
	    if (togo == 0) break;
	}


	/* don't run past logical stop time */
	if (!susp->logically_stopped && susp->susp.log_stop_cnt != UNKNOWN) {
	    int to_stop = susp->susp.log_stop_cnt - (susp->susp.current + cnt);
	    /* break if to_stop == 0 (we're at the logical stop)
	     * AND cnt > 0 (we're not at the beginning of the
	     * output block).
	     */
	    if (to_stop < togo) {
		if (to_stop == 0) {
		    if (cnt) {
			togo = 0;
			break;
		    } else /* keep togo as is: since cnt == 0, we
		            * can set the logical stop flag on this
		            * output block
		            */
			susp->logically_stopped = true;
		} else /* limit togo so we can start a new
		        * block at the LST
		        */
		    togo = to_stop;
	    }
	}

	n = togo;
	ph_incr_reg = susp->ph_incr;
	n_2_r_reg = susp->n_2_r;
	n_2_p1_reg = susp->n_2_p1;
	phase_reg = susp->phase;
	s_fm_pHaSe_ReG = susp->s_fm_pHaSe;
	s_fm_x1_sample_reg = susp->s_fm_x1_sample;
	out_ptr_reg = out_ptr;
	if (n) do { /* the inner sample computation loop */
	    long table_index;
            double x1;
            sample_type num, denom, samp;
	    if (s_fm_pHaSe_ReG >= 1.0) {
/* fixup-depends s_fm */
		/* pick up next sample as s_fm_x1_sample: */
		susp->s_fm_ptr++;
		susp_took(s_fm_cnt, 1);
		s_fm_pHaSe_ReG -= 1.0;
		susp_check_term_log_samples_break(s_fm, s_fm_ptr, s_fm_cnt, s_fm_x1_sample_reg);
		s_fm_x1_sample_reg = susp_current_sample(s_fm, s_fm_ptr);
	    }

            table_index = (long) phase_reg;
            x1 = sine_table[table_index];
            denom = (sample_type) (x1 + (phase_reg - table_index) * 
                          (sine_table[table_index + 1] - x1));
            if (denom < 0.001 && denom > -0.005) {
                samp = 1.0F;
            } else {
                double phn2p1 = phase_reg * n_2_p1_reg * (1.0/SINE_TABLE_LEN);
                phn2p1 = (phn2p1 - (long) phn2p1) * SINE_TABLE_LEN;
                table_index = (long) phn2p1;
                x1 = sine_table[table_index];
                num = (sample_type) (x1 + (phn2p1 - table_index) *
                        (sine_table[table_index + 1] - x1));
                samp = ((num / denom) - 1.0F) * n_2_r_reg;
            }
            *out_ptr_reg++ = samp;
            phase_reg += ph_incr_reg + s_fm_x1_sample_reg;
            while (phase_reg > SINE_TABLE_LEN) phase_reg -= SINE_TABLE_LEN;
            /* watch out for negative frequencies! */
            while (phase_reg < 0) phase_reg += SINE_TABLE_LEN;
	    s_fm_pHaSe_ReG += s_fm_pHaSe_iNcR_rEg;