mirror of
https://github.com/cookiengineer/audacity
synced 2025-05-05 14:18:53 +02:00
140 lines
3.7 KiB
C
140 lines
3.7 KiB
C
#include "stdio.h"
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#ifndef mips
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#include "stdlib.h"
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#endif
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#include "xlisp.h"
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#include "sound.h"
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#include "falloc.h"
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#include "cext.h"
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#include "fmfb.h"
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void fmfb_free();
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typedef struct fmfb_susp_struct {
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snd_susp_node susp;
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long terminate_cnt;
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double yy;
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double sin_y;
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double xx;
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double x_incr;
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double index;
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} fmfb_susp_node, *fmfb_susp_type;
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void fmfb__fetch(register fmfb_susp_type susp, snd_list_type snd_list)
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{
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int cnt = 0; /* how many samples computed */
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int togo;
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int n;
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sample_block_type out;
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register sample_block_values_type out_ptr;
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register sample_block_values_type out_ptr_reg;
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register double yy_reg;
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register double sin_y_reg;
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register double xx_reg;
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register double x_incr_reg;
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register double index_reg;
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falloc_sample_block(out, "fmfb__fetch");
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out_ptr = out->samples;
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snd_list->block = out;
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while (cnt < max_sample_block_len) { /* outer loop */
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/* first compute how many samples to generate in inner loop: */
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/* don't overflow the output sample block: */
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togo = max_sample_block_len - cnt;
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/* don't run past terminate time */
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if (susp->terminate_cnt != UNKNOWN &&
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susp->terminate_cnt <= susp->susp.current + cnt + togo) {
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togo = susp->terminate_cnt - (susp->susp.current + cnt);
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if (togo == 0) break;
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}
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n = togo;
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yy_reg = susp->yy;
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sin_y_reg = susp->sin_y;
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xx_reg = susp->xx;
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x_incr_reg = susp->x_incr;
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index_reg = susp->index;
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out_ptr_reg = out_ptr;
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if (n) do { /* the inner sample computation loop */
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xx_reg += x_incr_reg;
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if (xx_reg > SINE_TABLE_LEN) xx_reg -= SINE_TABLE_LEN;
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/* xx_reg incremented and index_reg scaled to table index_reg, and
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sin_y_reg is a signal (-1 to +1) */
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yy_reg = xx_reg + index_reg * sin_y_reg;
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/* so yy_reg is a table index_reg */
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while (yy_reg > SINE_TABLE_LEN) yy_reg -= SINE_TABLE_LEN;
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while (yy_reg < 0) yy_reg += SINE_TABLE_LEN;
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sin_y_reg = sine_table[(int) yy_reg]; /* truncation gets valid index_reg */
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/* sin_y_reg is now a signal not ready for table lookup */
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*out_ptr_reg++ = sin_y_reg;;
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} while (--n); /* inner loop */
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susp->yy = yy_reg;
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susp->sin_y = sin_y_reg;
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susp->xx = xx_reg;
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susp->index = index_reg;
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out_ptr += togo;
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cnt += togo;
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} /* outer loop */
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/* test for termination */
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if (togo == 0 && cnt == 0) {
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snd_list_terminate(snd_list);
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} else {
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snd_list->block_len = cnt;
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susp->susp.current += cnt;
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}
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} /* fmfb__fetch */
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void fmfb_free(fmfb_susp_type susp)
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{
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ffree_generic(susp, sizeof(fmfb_susp_node), "fmfb_free");
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}
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void fmfb_print_tree(fmfb_susp_type susp, int n)
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{
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}
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sound_type snd_make_fmfb(time_type t0, double hz, rate_type sr, double index, time_type d)
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{
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register fmfb_susp_type susp;
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/* sr specified as input parameter */
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/* t0 specified as input parameter */
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sample_type scale_factor = 1.0F;
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falloc_generic(susp, fmfb_susp_node, "snd_make_fmfb");
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susp->yy = 0.0;
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susp->sin_y = 0.0;
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susp->xx = 0.0;
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susp->x_incr = hz * SINE_TABLE_LEN / sr;
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susp->index = index * SINE_TABLE_LEN / PI2;
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susp->susp.fetch = fmfb__fetch;
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susp->terminate_cnt = round((d) * sr);
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/* initialize susp state */
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susp->susp.free = fmfb_free;
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susp->susp.sr = sr;
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susp->susp.t0 = t0;
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susp->susp.mark = NULL;
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susp->susp.print_tree = fmfb_print_tree;
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susp->susp.name = "fmfb";
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susp->susp.log_stop_cnt = UNKNOWN;
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susp->susp.current = 0;
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return sound_create((snd_susp_type)susp, t0, sr, scale_factor);
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}
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sound_type snd_fmfb(time_type t0, double hz, rate_type sr, double index, time_type d)
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{
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return snd_make_fmfb(t0, hz, sr, index, d);
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}
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