coder_o1.c

好东西呢

/*********

a straightforward order1 coder : code pel conditioned on the log2(parent)

quite competitive

S+P Lena lossless : 4.250 bpp

**********/

#include <stdio.h>
#include <stdlib.h>
#include <crblib/inc.h>
#include <crblib/arithc.h>
#include <crblib/o0coder.h>
#include <crblib/scontext.h>
#include <crblib/intmath.h>

extern int tune_param;

#define ORDER1_TOTMAX		6000
#define ORDER1_INC			20
#define ORDER1_ALPHABET		16
#define ORDER1_ESCAPE		(ORDER1_ALPHABET-1)

#define CONTEXT_MAX			6
#define ORDER1_CONTEXTS		(CONTEXT_MAX+1)
#define CONTEXT(prev)		(min(intlog2(abs(prev)+1),CONTEXT_MAX))

#define ORDER0_TOTMAX		2000
#define ORDER0_ALPHABET		50
#define ORDER0_ESCAPE		(ORDER0_ALPHABET-1)

#include "coder.h"

void coderOone_encodeBand(coder *me,int *band,int w,int h,int fullw,int *parent);
void coderOone_decodeBand(coder *me,int *band,int w,int h,int fullw,int *parent);

typedef struct {
	ozero * o0;
	scontext ** o1;
} myInfo;

void coderOone_init(coder *c)
{
myInfo *d;
int i;

	if ( (d = new(myInfo)) == NULL )
		errexit("ozero init failed");

	c->data = d;

	if ( (d->o0 = ozeroCreateMax(c->arith,ORDER0_ALPHABET,ORDER0_TOTMAX)) == NULL )
		errexit("ozero init failed");

	if ( (d->o1 = newarray(void *,ORDER1_CONTEXTS)) == NULL )
		errexit("Order1_Init failed!");

	for(i=0;i<ORDER1_CONTEXTS;i++) {
		if ( (d->o1[i] = scontextCreate(c->arith,ORDER1_ALPHABET,0,
				ORDER1_TOTMAX,ORDER1_INC,true)) == NULL )
			errexit("context creation failed!");
	}
}

void coderOone_free(coder *c)
{
	if ( c->data ) {
		myInfo *d;
		d = c->data;
		if ( d->o0 ) ozeroFree(d->o0);
		if ( d->o1 ) {
			int i;
			for(i=0;i<ORDER1_CONTEXTS;i++) {
				if ( d->o1[i] ) scontextFree(d->o1[i]);
			}
		}
		free(d);
		c->data = NULL;
	}
}

coder coderOone = {
		"order one",
		coderOone_init,
		coderOone_free,
		coderOone_encodeBand,
		coderOone_decodeBand
	};

void coderOone_encodeBand(coder *me,int *band,int width,int height,int fullw,int *parent)
{
int x,y,val,cntx,sign;
int *dp,*pp;
ozero *o0 = ((myInfo *)me->data)->o0;
scontext **o1 = ((myInfo *)me->data)->o1;
arithInfo *ari = me->arith;

	dp = band;
	pp = parent;
	for(y=0;y<height;y++) {
		if ( coder_timetostop(me) ) { coder_didstop(me,y); return; }
		for(x=0;x<width;x++) {
			cntx = CONTEXT(pp[(x>>1)]);
			val = dp[x]; 
			if ( val == 0 ) {
				scontextEncode(o1[cntx],0);
				continue;
			} else if ( isneg(val) ) { sign = 1; val = -val;
			} else sign = 0;

			if ( val < ORDER1_ESCAPE ) {
				scontextEncode(o1[cntx],val);
			} else {
				scontextEncode(o1[cntx],ORDER1_ESCAPE);
				val -= ORDER1_ESCAPE;

				while( val >= ORDER0_ESCAPE ) {
					ozeroEncode(o0,ORDER0_ESCAPE);
					val -= ORDER0_ESCAPE;
				}
				ozeroEncode(o0,val);
			}
			arithBit(ari,sign);
		}
		if ( y & 1 ) pp += fullw;
		dp += fullw;
	}
}

void coderOone_decodeBand(coder *me,int *band,int width,int height,int fullw,int *parent)
{
int x,y,val,cntx,got;
int *dp,*pp;
ozero *o0 = ((myInfo *)me->data)->o0;
scontext **o1 = ((myInfo *)me->data)->o1;
arithInfo *ari = me->arith;

	dp = band;
	pp = parent;
	for(y=0;y<height;y++) {
		if ( coder_timetostopd(me,y) ) return;
		for(x=0;x<width;x++) {
			cntx = CONTEXT(pp[(x>>1)]);

			got = scontextDecode(o1[cntx]);
			if ( got == 0 ) {
				dp[x] = 0;
				continue;
			} else if ( got < ORDER1_ESCAPE ) {
				val = got;
			} else {
				val = ORDER1_ESCAPE;
				got = ozeroDecode(o0);
				while ( got == ORDER0_ESCAPE ) {
					val += ORDER0_ESCAPE;
					got = ozeroDecode(o0);
				}
				val += got;
			}

			if ( arithGetBit(ari) ) val = -val;
			dp[x] = val;
		}
		if ( y & 1 ) pp += fullw;
		dp += fullw;
	}
}