/* oversampling */

#include <stdio.h>	/*stdout*/
#include "defs.h"	/*->inst.h (u8,u15x,...)*/
#include "inst.h"	/*SampleInfo*/
#include "ovs.h"	/*(ovs)*/
#include "mem.h"	/*(memSong)*/

/* LPF fc=fs/4 impulse response * Hamming window (N=19) */
static i15x h2[][8] = /* h(n) = */
{
    /* n = */
    /*-7  -5   -3   -1    1    3   5   7*/
    { -4, 15, -42, 158, 158, -42, 15, -4}
};
/* LPF fc=fs/6 impulse response * Hamming window (N=29) */
static i15x h3[][8] =
{
    /*-10  -7   -4   -1    2    5   8  11*/
    {  -5, 16, -44, 209, 101, -31, 12, -3},
    /*-11  -8   -5   -2    1    4   7  10*/
    {  -3, 12, -31, 101, 209, -44, 16, -5}
};
/* LPF fc=fs/8 impulse response * Hamming window (N=35) */
static i15x h4[][8] =
{
    /*-13  -9   -5   -1    3    7  11  15*/
    {  -4, 13, -38, 229,  72, -22,  7, -2},
    /*-14 -10   -6   -2    2    6  10  14*/
    {  -3, 13, -40, 158, 158, -40, 13, -3},
    /*-15 -11   -7   -3    1    5   9  13*/
    {  -2,  7, -22,  72, 229, -38, 13, -4}
};
static i15x (*hn[])[8] = { h2, h3, h4 };

static SampleInfo sis;

static void
convolute(i15x mag, i7 *dp)
{
    const u8 *sp0;
    i15x i,j;

    for (sp0 = sis.beg; sp0 < sis.end; sp0++) {
	*dp++ = *sp0 ^ sis.xor;
	for (i = 0; i < mag-1; i++,dp++) {
	    i15x *hp = hn[mag-2][i];
	    const u8 *sp = sp0 - 3;
	    i31x sum = 0;
	    for (j = 8; j > 0; j--,sp++,hp++) {
		if (sp < sis.beg) continue;
		if (sp >= sis.end) {
		    if (sis.loopBeg) sp = sis.loopBeg;
		    else break;
		}		
		sum += *hp * (i7)(*sp ^ sis.xor);
	    }
	    sum /= 256;
	    if (sum > 127) sum = 127;
	    else if (sum < -128) sum = -128;
	    *dp = sum;
	}
    }
}

#define ANIM_BACK "%c"
#define ANIM_FORE "."
#if 0
/* by Jeff Epler */
#define ANIM_BACK "\r%c"
#define ANIM_FORE ".oO@Oo. "
/* simple */
#define ANIM_BACK "%c"
#define ANIM_FORE "."
/* bubble */
#define ANIM_BACK "\r%c"
#define ANIM_FORE ".oO* "
/* pac */
#define ANIM_BACK "\r%c"
#define ANIM_FORE "-<(<"
/* baton */
#define ANIM_BACK "\r%c"
#define ANIM_FORE "-\\|/"
/* thinking man */
#define ANIM_BACK "\r(-_-%c)"
#define ANIM_FORE " ';,"
/* twang! */
#define ANIM_BACK "\r%c"
#define ANIM_FORE "TYV~"
#endif

static void
perSampleWork(SampleInfo *sip, u16x c4req)
{
    static SampleInfo sid;
    u8 *dp0;
    u32x len;
    i15x mag;

    mag = c4req / sip->c4spd;
    if (!mag) return; /* no need to oversampling */
    mag++;
    if (mag > 4) mag = 4; /* currently max = 4x */
    sis = *sip;
    len = sis.end - sis.beg;
    if (len <= 2) return; /* too short sample */
    {
	static i15x n;
	printf(ANIM_BACK, ANIM_FORE[n++]);
	fflush(stdout);
	n %= sizeof(ANIM_FORE)-1;
    }
    dp0 = memSong(len * mag);
    sid.beg = dp0;
    sid.end = dp0 + len*mag;
    convolute(mag, dp0);
    sid.loopBeg = sis.loopBeg? (sid.beg + (sis.loopBeg - sis.beg)*mag) : NULL;
    sid.xor = 0;
    sid.c4spd = sis.c4spd;
    sid.vol = sis.vol;
    sid.mag = sis.mag * mag;
    *sip = sid;
}

void
ovs(i15x insNum, SampleInfo *sip, u16x c4req)
{
    printf("Oversampling..\n");
    for (; insNum > 0; insNum--,sip++) perSampleWork(sip, c4req);
    printf("\rdone.%32s\n", "");
}