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

#include "falloc.h"
#include "cext.h"
#include "biquadfilt.h"

void biquadfilt_free(snd_susp_type a_susp);


typedef struct biquadfilt_susp_struct {
    snd_susp_node susp;
    long terminate_cnt;
    boolean logically_stopped;
    sound_type s;
    long s_cnt;
    sample_block_values_type s_ptr;

    double z1;
    double z2;
    double b0;
    double b1;
    double b2;
    double a1;
    double a2;
} biquadfilt_susp_node, *biquadfilt_susp_type;


void biquadfilt_n_fetch(snd_susp_type a_susp, snd_list_type snd_list)
{
    biquadfilt_susp_type susp = (biquadfilt_susp_type) a_susp;
    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 z1_reg;
    register double z2_reg;
    register double b0_reg;
    register double b1_reg;
    register double b2_reg;
    register double a1_reg;
    register double a2_reg;
    register sample_block_values_type s_ptr_reg;
    falloc_sample_block(out, "biquadfilt_n_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 input sample block: */
	susp_check_term_log_samples(s, s_ptr, s_cnt);
	togo = min(togo, susp->s_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) togo = 0;  /* avoids rounding errros */
	    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 < 0) to_stop = 0; /* avoids rounding errors */
	    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;
	z1_reg = susp->z1;
	z2_reg = susp->z2;
	b0_reg = susp->b0;
	b1_reg = susp->b1;
	b2_reg = susp->b2;
	a1_reg = susp->a1;
	a2_reg = susp->a2;
	s_ptr_reg = susp->s_ptr;
	out_ptr_reg = out_ptr;
	if (n) do { /* the inner sample computation loop */
            double z0;            z0 = *s_ptr_reg++ + a1_reg*z1_reg + a2_reg*z2_reg;
            *out_ptr_reg++ = (sample_type) (z0*b0_reg + z1_reg*b1_reg + z2_reg*b2_reg);
            z2_reg = z1_reg; z1_reg = z0;
	} while (--n); /* inner loop */

	susp->z1 = z1_reg;
	susp->z2 = z2_reg;
	/* using s_ptr_reg is a bad idea on RS/6000: */
	susp->s_ptr += togo;
	out_ptr += togo;
	susp_took(s_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;
    }
} /* biquadfilt_n_fetch */


void biquadfilt_toss_fetch(snd_susp_type a_susp, snd_list_type snd_list)
    {
    biquadfilt_susp_type susp = (biquadfilt_susp_type) a_susp;
    time_type final_time = susp->susp.t0;
    long n;

    /* fetch samples from s up to final_time for this block of zeros */
    while ((round((final_time - susp->s->t0) * susp->s->sr)) >=
	   susp->s->current)
	susp_get_samples(s, s_ptr, s_cnt);
    /* convert to normal processing when we hit final_count */
    /* we want each signal positioned at final_time */
    n = round((final_time - susp->s->t0) * susp->s->sr -
         (susp->s->current - susp->s_cnt));
    susp->s_ptr += n;
    susp_took(s_cnt, n);
    susp->susp.fetch = susp->susp.keep_fetch;
    (*(susp->susp.fetch))(a_susp, snd_list);
}


void biquadfilt_mark(snd_susp_type a_susp)
{
    biquadfilt_susp_type susp = (biquadfilt_susp_type) a_susp;
    sound_xlmark(susp->s);
}


void biquadfilt_free(snd_susp_type a_susp)
{
    biquadfilt_susp_type susp = (biquadfilt_susp_type) a_susp;
    sound_unref(susp->s);
    ffree_generic(susp, sizeof(biquadfilt_susp_node), "biquadfilt_free");
}


void biquadfilt_print_tree(snd_susp_type a_susp, int n)
{
    biquadfilt_susp_type susp = (biquadfilt_susp_type) a_susp;
    indent(n);
    stdputstr("s:");
    sound_print_tree_1(susp->s, n);
}


sound_type snd_make_biquadfilt(sound_type s, double b0, double b1, double b2, double a1, double a2, double z1init, double z2init)
{
    register biquadfilt_susp_type susp;
    rate_type sr = s->sr;
    time_type t0 = s->t0;
    sample_type scale_factor = 1.0F;
    time_type t0_min = t0;
    /* combine scale factors of linear inputs (S) */
    scale_factor *= s->scale;
    s->scale = 1.0F;

    /* try to push scale_factor back to a low sr input */
    if (s->sr < sr) { s->scale = scale_factor; scale_factor = 1.0F; }

    falloc_generic(susp, biquadfilt_susp_node, "snd_make_biquadfilt");
    susp->z1 = z1init;
    susp->z2 = z2init;
    susp->b0 = b0;
    susp->b1 = b1;
    susp->b2 = b2;
    susp->a1 = a1;
    susp->a2 = a2;
    susp->susp.fetch = biquadfilt_n_fetch;
    susp->terminate_cnt = UNKNOWN;
    /* handle unequal start times, if any */
    if (t0 < s->t0) sound_prepend_zeros(s, t0);
    /* minimum start time over all inputs: */
    t0_min = min(s->t0, t0);
    /* how many samples to toss before t0: */
    susp->susp.toss_cnt = (long) ((t0 - t0_min) * sr + 0.5);
    if (susp->susp.toss_cnt > 0) {
        susp->susp.keep_fetch = susp->susp.fetch;
        susp->susp.fetch = biquadfilt_toss_fetch;
    }

    /* initialize susp state */
    susp->susp.free = biquadfilt_free;
    susp->susp.sr = sr;
    susp->susp.t0 = t0;
    susp->susp.mark = biquadfilt_mark;
    susp->susp.print_tree = biquadfilt_print_tree;
    susp->susp.name = "biquadfilt";
    susp->logically_stopped = false;
    susp->susp.log_stop_cnt = logical_stop_cnt_cvt(s);
    susp->susp.current = 0;
    susp->s = s;
    susp->s_cnt = 0;
    return sound_create((snd_susp_type)susp, t0, sr, scale_factor);
}


sound_type snd_biquadfilt(sound_type s, double b0, double b1, double b2, double a1, double a2, double z1init, double z2init)
{
    sound_type s_copy = sound_copy(s);
    return snd_make_biquadfilt(s_copy, b0, b1, b2, a1, a2, z1init, z2init);
}
