add.c

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         * and going to the rest of the block) -- just do pointers.
         */

        /* just fetch and pass blocks on */
D	nyquist_printf("add[%p,%p] (s%d_nn) %p starting uncopy, togo %d\n", susp->s2, susp->s1,
               2, susp, togo);
        snd_list->block = susp->s2_bptr;
        (susp->s2_bptr->refcnt)++;
D	nyquist_printf("add[%p,%p] (s%d_nn) %p shared block %p zero_block %p\n",susp->s2, susp->s1,
               2, susp, susp->s2_bptr, zero_block);

        susp_took(s2_cnt, togo);
        snd_list->block_len = togo;

        /* if other is terminated and sound_types match, collapse */
        /* NOTE: in order to collapse, we need s1 to be generating
         * blocks and linking them onto a sound list.  This is true
         * when the get_next fn is SND_get_next.  (A counterexample is
         * SND_get_zeros, which returns zero blocks but does not link
         * them onto the sound list.
         */
        if (0) nyquist_printf("s1 %p thissr %g suspsr %g get_next %d lsc %d\n",
                susp->s1, susp->s2->sr, susp->susp.sr,
                susp->s2->get_next == SND_get_next,
                susp->s2->logical_stop_cnt == UNKNOWN);
        if (susp->s1 == NULL && susp->s2->sr == susp->susp.sr &&
            susp->s2->get_next == SND_get_next &&
            susp->s2->logical_stop_cnt == UNKNOWN) {
            snd_list_type addend_list;
D	    nyquist_printf("add[%p,%p]: collapsing! LSC %d\n",
                      susp->s2, susp->s1, (int)susp->s2->logical_stop_cnt);
D	    sound_print_tree(susp->s2);
            /* will "current" values match? */
            /* 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;
            }
            /* free the superfluous sound_type and susp */
            addend_list = susp->s2->list->u.next;
            snd_list_ref(addend_list);
            snd_list_unref(snd_list->u.next);
            snd_list->u.next = addend_list;
            return;
        }
    } else {
        /*
         * we want to copy a partial block
         */

        /* assume the snd_list is the one with a null block */
        /*
         * put a fresh, clean block in the snd_list
         * (get new snd_list later)
         */
        falloc_sample_block(out, "add_s2_nn_fetch");
        snd_list->block = out;
        out_ptr = out->samples;
B       nyquist_printf("add[%p,%p] (s2_nn) %p new block %p\n",
               susp->s2, susp->s1, susp, out);
        n = togo;
        if (n == 0)
            stdputstr("zero block length error in add_s2_nn_fetch\n");
B       nyquist_printf(
        "add[%p,%p] (s2_nn) %p starting copy loop, togo %d\n",
               susp->s2, susp->s1, susp, togo);
        while (n--) { /* the inner sample computation loop */
            /* scale? */
            *out_ptr++ = *(susp->s2_ptr++);
        } /* inner loop */

        susp_took(s2_cnt, togo);
        snd_list->block_len = togo;
    }

    /* add a new snd_list for the susp */
    susp->susp.current += togo;

    if (0) stdputstr("testing...");
    /*
     * test for termination or change of state,
     * note s1_start computed earlier
     */
    if (susp->s1 && susp->susp.current == s1_start &&
        susp->s2->list != zero_snd_list) {
        /* s1 starting and s2 continues */
        /* go to s1+s2 state */
        susp->susp.fetch = add_s1_s2_nn_fetch;
D        stdputstr("add_s_nn_fetch: add_s1_s2_fetch installed\n");
    }
/*    else if (!susp->s1 && susp->s2->list == zero_snd_list) { */
      else if (susp->terminate_bits == 3) {
        /* s1 finished and s2 stops */
        /* go to terminal state */
        susp->s2 = NULL;
D        nyquist_printf("add_s_nn_fetch: go to terminal state.  susp->s1 %p, \
               susp->susp.current %d, s1_start %d, susp->s2->list %p, \
               zero_snd_list %p\n", susp->s1, (int)susp->susp.current,
               s1_start, susp->s2->list, zero_snd_list);
        /* !!! free resources and set up pointers to terminal snd_list */
        /* !!! logically stopped? */
    }

    /* test for logical stop */
    if (susp->logically_stopped) {
D        stdputstr("add_s_nn_fetch: snd_list->logically_stopped\n");
        snd_list->logically_stopped = true;
    } else if (susp->susp.log_stop_cnt == susp->susp.current) {
D        stdputstr("add_s_nn_fetch: susp->logically_stopped\n");
        susp->logically_stopped = true;
    }
    if (0) {
        if (susp->logically_stopped || snd_list->logically_stopped) 
            stdputstr("STOPPED\n");
        else
            nyquist_printf("ok: current %d\n", (int)susp->susp.current);
    }
}



void add_zero_fill_nn_fetch(susp, snd_list)
  register add_susp_type susp;
  snd_list_type snd_list;
{
    int togo, s_start=0;

#ifdef GC_DEBUG
    snd_list_report(snd_list, "add_zero_fill_nn_fetch");
#endif
    togo = max_sample_block_len;

    if (0) fprintf(stderr, "add_zero_fill_nn_fetch, susp.current %d\n",
                   (int)susp->susp.current);
    /* don't run past start time ... */
    if (susp->s1) {
        s_start = ROUND((susp->s1->t0 - susp->susp.t0) * susp->s1->sr);
        if (s_start < susp->susp.current + togo) {
            togo = s_start - susp->susp.current;
        }
    } else if (susp->s2) {
        s_start = ROUND((susp->s2->t0 - susp->susp.t0) * susp->s2->sr);
        if (s_start < susp->susp.current + togo) {
            togo = s_start - susp->susp.current;
        }
    }

    snd_list->block_len = togo;
    susp->susp.current += togo;
    /*
     * test for change of state,
     * note s_start computed earlier
     */
    if (susp->s1 && susp->susp.current == s_start) {
        /* s1 starting, go to s1 state */
        susp->susp.fetch = add_s1_nn_fetch;
D        stdputstr("add_zero_fill_nn_fetch: add_s1_nn_fetch installed\n");
    } else if (susp->s2 && susp->susp.current == s_start) {
        /* s2 starting, go to s2 state */
        susp->susp.fetch = add_s2_nn_fetch;
D       stdputstr("add_zero_fill_nn_fetch: add_s2_nn_fetch installed\n");
    }
} /* add_zero_fill_nn_fetch */


void add_free(add_susp_type susp)
{
    sound_unref(susp->s1);
    sound_unref(susp->s2);
    ffree_generic(susp, sizeof(add_susp_node), "add_free");
}


void add_mark(add_susp_type susp)
{
/*    nyquist_printf("add_mark(%p)\n", susp);*/
/*    nyquist_printf("marking s1@%p in add@%p\n", susp->s1, susp);*/
    sound_xlmark(susp->s1);
/*    nyquist_printf("marking s2@%p in add@%p\n", susp->s2, susp);*/
    sound_xlmark(susp->s2);

}


void add_print_tree(add_susp_type susp, int n)
{
    indent(n);
    nyquist_printf("logically_stopped %d logical_stop_bits %d terminate_bits %d\n", 
           susp->logically_stopped, susp->logical_stop_bits, susp->terminate_bits);
    indent(n);
    stdputstr("s1:");
    if (susp->s1) sound_print_tree_1(susp->s1, n);
    else stdputstr(" NULL\n");

    indent(n);
    stdputstr("s2:");
    if (susp->s2) sound_print_tree_1(susp->s2, n);
    else stdputstr(" NULL\n");
}


sound_type snd_make_add(s1, s2)
  sound_type s1;
  sound_type s2;
{
    register add_susp_type susp;
    rate_type sr = MAX(s1->sr, s2->sr);
    time_type t0 = MIN(s1->t0, s2->t0);
    int interp_desc = 0;
    double sample_offset;

    /* sort commutative signals: (S1 S2) */
    snd_sort_2(&s1, &s2, sr);

    falloc_generic(susp, add_susp_node, "snd_make_add");

    /* select a susp fn based on sample rates */
    interp_desc = (interp_style(s1, sr) << 2) + interp_style(s2, sr);
    switch (interp_desc) {
      case INTERP_nn:
      case INTERP_ns:
      case INTERP_ss:
        /* eliminate scale factor on s1 if any */
        if (((interp_desc >> INTERP_SHIFT) & INTERP_MASK) == INTERP_s) {
            /* stdputstr("add: prescaling s1\n");*/
            s1 = snd_make_normalize(s1);
        }
        /* eliminate scale factor on s2 if any */
        if ((interp_desc & INTERP_MASK) == INTERP_s) {
            /* stdputstr("add: prescaling s2\n"); */
            s2 = snd_make_normalize(s2);
        }
        sample_offset = (s2->t0 - s1->t0) * sr;
        if (sample_offset >= 0.5) { /* s1 starts first */
            susp->susp.fetch = add_s1_nn_fetch;
D            stdputstr("snd_make_add: add_s1_nn_fetch installed\n");
        } else if (sample_offset < -0.5) { /* s2 starts first */
            susp->susp.fetch = add_s2_nn_fetch;
D            stdputstr("snd_make_add: add_s2_nn_fetch installed\n");
        } else {	/* equal start times */
            susp->susp.fetch = add_s1_s2_nn_fetch;
D            stdputstr("snd_make_add: add_s1_s2_nn_fetch installed\n");
        }
        break;
      case INTERP_ni:
      case INTERP_nr:
        errputstr("add: can't interpolate!\n");
        EXIT(1);
      default:
        errputstr("add: can't add these operands!\n");
        EXIT(1);
    }

    susp->terminate_cnt = UNKNOWN;
    susp->terminate_bits = 0;   /* bits for s1 and s2 termination */
    susp->logical_stop_bits = 0;    /* bits for s1 and s2 logical stop */

    /* initialize susp state */
    susp->susp.free = add_free;
    susp->susp.sr = sr;
    susp->susp.t0 = t0;
    susp->susp.mark = add_mark;
    susp->susp.print_tree = add_print_tree;
    susp->susp.name = "add";
    susp->logically_stopped = false;
    susp->susp.log_stop_cnt = UNKNOWN;
    susp->started = false;
    susp->susp.current = 0;
    susp->s1 = s1;
    susp->s1_cnt = 0;
    susp->s2 = s2;
    susp->s2_cnt = 0;
#ifdef UPSAMPLECODE
    susp->susp.s2_phase = 0.0;
    susp->susp.s2_phase_incr = s2->sr / sr;
    susp->susp.output_per_s2 = sr / s2->sr;
#endif
    return sound_create((snd_susp_type)susp, t0, sr, 1.0);
}


sound_type snd_add(s1, s2, t0)
  sound_type s1;
  sound_type s2;
  time_type t0;
{
    sound_type s1_copy = sound_copy(s1);
    sound_type s2_copy = sound_copy(s2);
/*    nyquist_printf("snd_add %p %p copied to %p %p\n", s1, s2, s1_copy,  s2_copy); */
    return snd_make_add(s1_copy, s2_copy, t0);
}