73 lines
1.9 KiB
C++
73 lines
1.9 KiB
C++
#include "nr.h"
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namespace {
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inline unsigned long JTRY(const unsigned long j, const unsigned long k,
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const unsigned long m)
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{
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return (unsigned long) (DP(j)*DP(k)/DP (m));
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}
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}
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void NR::arcode(unsigned long &ich, string &code, unsigned long &lcd,
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const int isign, arithcode &acode)
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{
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int j,k;
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unsigned long ihi,ja,jh,jl,m;
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int NWK=acode.ilob.size();
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if (isign == 0) {
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acode.jdif=acode.nrad-1;
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for (j=NWK-1;j>=0;j--) {
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acode.iupb[j]=acode.nrad-1;
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acode.ilob[j]=0;
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acode.nc=j;
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if (acode.jdif > acode.minint) return;
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acode.jdif=(acode.jdif+1)*acode.nrad-1;
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}
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nrerror("NWK too small in arcode.");
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} else {
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if (isign > 0) {
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if (ich > acode.nch) nrerror("bad ich in arcode.");
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} else {
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ja=(unsigned char) code[lcd]-acode.ilob[acode.nc];
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for (j=acode.nc+1;j<NWK;j++) {
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ja *= acode.nrad;
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ja += ((unsigned char) code[lcd+j-acode.nc]-acode.ilob[j]);
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}
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ihi=acode.nch+1;
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ich=0;
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while (ihi-ich > 1) {
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m=(ich+ihi)>>1;
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if (ja >= JTRY(acode.jdif,acode.ncumfq[m],acode.ncum))
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ich=m;
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else ihi=m;
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}
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if (ich == acode.nch) return;
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}
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jh=JTRY(acode.jdif,acode.ncumfq[ich+1],acode.ncum);
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jl=JTRY(acode.jdif,acode.ncumfq[ich],acode.ncum);
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acode.jdif=jh-jl;
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arcsum(acode.ilob,acode.iupb,jh,NWK,acode.nrad,acode.nc);
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arcsum(acode.ilob,acode.ilob,jl,NWK,acode.nrad,acode.nc);
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for (j=acode.nc;j<NWK;j++) {
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if (ich != acode.nch && acode.iupb[j] != acode.ilob[j]) break;
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if (isign > 0) code += (unsigned char)acode.ilob[j];
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lcd++;
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}
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if (j+1 > NWK) return;
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acode.nc=j;
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for(j=0;acode.jdif<acode.minint;j++)
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acode.jdif *= acode.nrad;
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if (j > acode.nc) nrerror("NWK too small in arcode.");
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if (j != 0) {
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for (k=acode.nc;k<NWK;k++) {
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acode.iupb[k-j]=acode.iupb[k];
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acode.ilob[k-j]=acode.ilob[k];
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}
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}
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acode.nc -= j;
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for (k=NWK-j;k<NWK;k++) acode.iupb[k]=acode.ilob[k]=0;
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}
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return;
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}
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