/* quantize.c, quantization / inverse quantization                          */

/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */

/*
 * Disclaimer of Warranty
 *
 * These software programs are available to the user without any license fee or
 * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims
 * any and all warranties, whether express, implied, or statuary, including any
 * implied warranties or merchantability or of fitness for a particular
 * purpose.  In no event shall the copyright-holder be liable for any
 * incidental, punitive, or consequential damages of any kind whatsoever
 * arising from the use of these programs.
 *
 * This disclaimer of warranty extends to the user of these programs and user's
 * customers, employees, agents, transferees, successors, and assigns.
 *
 * The MPEG Software Simulation Group does not represent or warrant that the
 * programs furnished hereunder are free of infringement of any third-party
 * patents.
 *
 * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
 * are subject to royalty fees to patent holders.  Many of these patents are
 * general enough such that they are unavoidable regardless of implementation
 * design.
 *
 */

#include <stdio.h>
#include "config.h"
#include "global.h"

static void iquant1_intra _ANSI_ARGS_((short *src, short *dst,
				       int dc_prec,
				       unsigned char *quant_mat,
				       int mquant));
static void iquant1_non_intra
_ANSI_ARGS_(
	    (short *src, short *dst, unsigned char *quant_mat,
	     int mquant));

/* Test Model 5 quantization
 *
 * this quantizer has a bias of 1/8 stepsize towards zero
 * (except for the DC coefficient)
 */
int quant_intra(src, dst, dc_prec, quant_mat, mquant)
short *src, *dst;
int dc_prec;
unsigned char *quant_mat;
int mquant;
{
    int i;
    int x, y, d;

    x = src[0];
    d = 8 >> dc_prec;		/* intra_dc_mult */
    dst[0] = (x >= 0) ? (x + (d >> 1)) / d : -((-x + (d >> 1)) / d);	/* round(x/d) */

    for (i = 1; i < 64; i++) {
	x = src[i];
	d = quant_mat[i];
	y = (32 * (x >= 0 ? x : -x) + (d >> 1)) / d;	/* round(32*x/quant_mat) */
	d = (3 * mquant + 2) >> 2;
	y = (y + d) / (2 * mquant);	/* (y+0.75*mquant) / (2*mquant) */

	/* clip to syntax limits */
	if (y > 255) {
	    if (mpeg1)
		y = 255;
	    else if (y > 2047)
		y = 2047;
	}

	dst[i] = (x >= 0) ? y : -y;

#if 0
	/* this quantizer is virtually identical to the above */
	if (x < 0)
	    x = -x;
	d = mquant * quant_mat[i];
	y = (16 * x + ((3 * d) >> 3)) / d;
	dst[i] = (src[i] < 0) ? -y : y;
#endif
    }

    return 1;
}

int quant_non_intra(src, dst, quant_mat, mquant)
short *src, *dst;
unsigned char *quant_mat;
int mquant;
{
    int i;
    int x, y, d;
    int nzflag;

    nzflag = 0;

    for (i = 0; i < 64; i++) {
	x = src[i];
	d = quant_mat[i];
	y = (32 * (x >= 0 ? x : -x) + (d >> 1)) / d;	/* round(32*x/quant_mat) */
	y /= (2 * mquant);

	/* clip to syntax limits */
	if (y > 255) {
	    if (mpeg1)
		y = 255;
	    else if (y > 2047)
		y = 2047;
	}

	if ((dst[i] = (x >= 0 ? y : -y)) != 0)
	    nzflag = 1;
    }

    return nzflag;
}

/* MPEG-2 inverse quantization */
void iquant_intra(src, dst, dc_prec, quant_mat, mquant)
short *src, *dst;
int dc_prec;
unsigned char *quant_mat;
int mquant;
{
    int i, val, sum;

    if (mpeg1)
	iquant1_intra(src, dst, dc_prec, quant_mat, mquant);
    else {
	sum = dst[0] = src[0] << (3 - dc_prec);
	for (i = 1; i < 64; i++) {
	    val = (int) (src[i] * quant_mat[i] * mquant) / 16;
	    sum += dst[i] =
		(val > 2047) ? 2047 : ((val < -2048) ? -2048 : val);
	}

	/* mismatch control */
	if ((sum & 1) == 0)
	    dst[63] ^= 1;
    }
}

void iquant_non_intra(src, dst, quant_mat, mquant)
short *src, *dst;
unsigned char *quant_mat;
int mquant;
{
    int i, val, sum;

    if (mpeg1)
	iquant1_non_intra(src, dst, quant_mat, mquant);
    else {
	sum = 0;
	for (i = 0; i < 64; i++) {
	    val = src[i];
	    if (val != 0)
		val =
		    (int) ((2 * val + (val > 0 ? 1 : -1)) * quant_mat[i] *
			   mquant) / 32;
	    sum += dst[i] =
		(val > 2047) ? 2047 : ((val < -2048) ? -2048 : val);
	}

	/* mismatch control */
	if ((sum & 1) == 0)
	    dst[63] ^= 1;
    }
}

/* MPEG-1 inverse quantization */
static void iquant1_intra(src, dst, dc_prec, quant_mat, mquant)
short *src, *dst;
int dc_prec;
unsigned char *quant_mat;
int mquant;
{
    int i, val;

    dst[0] = src[0] << (3 - dc_prec);
    for (i = 1; i < 64; i++) {
	val = (int) (src[i] * quant_mat[i] * mquant) / 16;

	/* mismatch control */
	if ((val & 1) == 0 && val != 0)
	    val += (val > 0) ? -1 : 1;

	/* saturation */
	dst[i] = (val > 2047) ? 2047 : ((val < -2048) ? -2048 : val);
    }
}

static void iquant1_non_intra(src, dst, quant_mat, mquant)
short *src, *dst;
unsigned char *quant_mat;
int mquant;
{
    int i, val;

    for (i = 0; i < 64; i++) {
	val = src[i];
	if (val != 0) {
	    val =
		(int) ((2 * val + (val > 0 ? 1 : -1)) * quant_mat[i] *
		       mquant) / 32;

	    /* mismatch control */
	    if ((val & 1) == 0 && val != 0)
		val += (val > 0) ? -1 : 1;
	}

	/* saturation */
	dst[i] = (val > 2047) ? 2047 : ((val < -2048) ? -2048 : val);
    }
}