#include <stdio.h>#include <stdlib.h>#define NWK 20#define JTRY(j,k,m) ((long)((((double)(k))*((double)(j)))/((double)(m))))typedef struct {	unsigned long *ilob,*iupb,*ncumfq,jdif,nc,minint,nch,ncum,nrad;} arithcode;void arcode(unsigned long *ich, unsigned char **codep, unsigned long *lcode,	unsigned long *lcd, int isign, arithcode *acode){	void arcsum(unsigned long iin[], unsigned long iout[], unsigned long ja,		int nwk, unsigned long nrad, unsigned long nc);	void nrerror(char error_text[]);	int j,k;	unsigned long ihi,ja,jh,jl,m;	if (!isign) {		acode->jdif=acode->nrad-1;		for (j=NWK;j>=1;j--) {			acode->iupb[j]=acode->nrad-1;			acode->ilob[j]=0;			acode->nc=j;			if (acode->jdif > acode->minint) return;			acode->jdif=(acode->jdif+1)*acode->nrad-1;		}		nrerror("NWK too small in arcode.");	} else {		if (isign > 0) {			if (*ich > acode->nch) nrerror("bad ich in arcode.");		}		else {			ja=(*codep)[*lcd]-acode->ilob[acode->nc];			for (j=acode->nc+1;j<=NWK;j++) {				ja *= acode->nrad;				ja += ((*codep)[*lcd+j-acode->nc]-acode->ilob[j]);			}			ihi=acode->nch+1;			*ich=0;			while (ihi-(*ich) > 1) {				m=(*ich+ihi)>>1;				if (ja >= JTRY(acode->jdif,acode->ncumfq[m+1],acode->ncum))					*ich=m;				else ihi=m;			}			if (*ich == acode->nch) return;		}		jh=JTRY(acode->jdif,acode->ncumfq[*ich+2],acode->ncum);		jl=JTRY(acode->jdif,acode->ncumfq[*ich+1],acode->ncum);		acode->jdif=jh-jl;		arcsum(acode->ilob,acode->iupb,jh,NWK,acode->nrad,acode->nc);		arcsum(acode->ilob,acode->ilob,jl,NWK,acode->nrad,acode->nc);		for (j=acode->nc;j<=NWK;j++) {			if (*ich != acode->nch && acode->iupb[j] != acode->ilob[j]) break;			if (*lcd > *lcode) {				fprintf(stderr,"Reached the end of the 'code' array.\n");				fprintf(stderr,"Attempting to expand its size.\n");				*lcode *= 1.5;				if ((*codep=(unsigned char *)realloc(*codep,					(unsigned)(*lcode*sizeof(unsigned char)))) == NULL) {					nrerror("Size expansion failed");				}			}			if (isign > 0) (*codep)[*lcd]=(unsigned char)acode->ilob[j];			++(*lcd);		}		if (j > NWK) return;		acode->nc=j;		for(j=0;acode->jdif<acode->minint;j++)			acode->jdif *= acode->nrad;		if (acode->nc-j < 1) nrerror("NWK too small in arcode.");		if (j) {			for (k=acode->nc;k<=NWK;k++) {				acode->iupb[k-j]=acode->iupb[k];				acode->ilob[k-j]=acode->ilob[k];			}		}		acode->nc -= j;		for (k=NWK-j+1;k<=NWK;k++) acode->iupb[k]=acode->ilob[k]=0;	}	return;}#undef NWK#undef JTRY