59 lines
1.4 KiB
C++
59 lines
1.4 KiB
C++
#include "nr.h"
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void NR::hufmak(Vec_I_ULNG &nfreq, const unsigned long nchin,
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unsigned long &ilong, unsigned long &nlong, huffcode &hcode)
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{
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int ibit,j,node;
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unsigned long k,n,nused;
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static unsigned long setbit[32]={0x1L,0x2L,0x4L,0x8L,0x10L,0x20L,
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0x40L,0x80L,0x100L,0x200L,0x400L,0x800L,0x1000L,0x2000L,
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0x4000L,0x8000L,0x10000L,0x20000L,0x40000L,0x80000L,0x100000L,
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0x200000L,0x400000L,0x800000L,0x1000000L,0x2000000L,0x4000000L,
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0x8000000L,0x10000000L,0x20000000L,0x40000000L,0x80000000L};
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hcode.nch=nchin;
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Vec_ULNG index(2*hcode.nch-1);
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Vec_ULNG nprob(2*hcode.nch-1);
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Vec_INT up(2*hcode.nch-1);
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for (nused=0,j=0;j<hcode.nch;j++) {
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nprob[j]=nfreq[j];
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hcode.icod[j]=hcode.ncod[j]=0;
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if (nfreq[j] != 0) index[nused++]=j;
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}
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for (j=nused-1;j>=0;j--)
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hufapp(index,nprob,nused,j);
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k=hcode.nch;
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while (nused > 1) {
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node=index[0];
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index[0]=index[(nused--)-1];
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hufapp(index,nprob,nused,0);
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nprob[k]=nprob[index[0]]+nprob[node];
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hcode.left[k]=node;
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hcode.right[k++]=index[0];
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up[index[0]] = -int(k);
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index[0]=k-1;
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up[node]=k;
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hufapp(index,nprob,nused,0);
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}
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up[(hcode.nodemax=k)-1]=0;
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for (j=0;j<hcode.nch;j++) {
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if (nprob[j] != 0) {
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for (n=0,ibit=0,node=up[j];node;node=up[node-1],ibit++) {
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if (node < 0) {
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n |= setbit[ibit];
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node = -node;
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}
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}
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hcode.icod[j]=n;
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hcode.ncod[j]=ibit;
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}
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}
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nlong=0;
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for (j=0;j<hcode.nch;j++) {
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if (hcode.ncod[j] > nlong) {
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nlong=hcode.ncod[j];
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ilong=j;
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}
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}
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}
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