add numerical recipes library

lib/nr/cpp/recipes/hufmak.cpp

@@ -0,0 +1,58 @@
+#include "nr.h"
+
+void NR::hufmak(Vec_I_ULNG &nfreq, const unsigned long nchin,
+	unsigned long &ilong, unsigned long &nlong, huffcode &hcode)
+{
+	int ibit,j,node;
+	unsigned long k,n,nused;
+	static unsigned long setbit[32]={0x1L,0x2L,0x4L,0x8L,0x10L,0x20L,
+		0x40L,0x80L,0x100L,0x200L,0x400L,0x800L,0x1000L,0x2000L,
+		0x4000L,0x8000L,0x10000L,0x20000L,0x40000L,0x80000L,0x100000L,
+		0x200000L,0x400000L,0x800000L,0x1000000L,0x2000000L,0x4000000L,
+		0x8000000L,0x10000000L,0x20000000L,0x40000000L,0x80000000L};
+
+	hcode.nch=nchin;
+	Vec_ULNG index(2*hcode.nch-1);
+	Vec_ULNG nprob(2*hcode.nch-1);
+	Vec_INT up(2*hcode.nch-1);
+	for (nused=0,j=0;j<hcode.nch;j++) {
+		nprob[j]=nfreq[j];
+		hcode.icod[j]=hcode.ncod[j]=0;
+		if (nfreq[j] != 0) index[nused++]=j;
+	}
+	for (j=nused-1;j>=0;j--)
+		hufapp(index,nprob,nused,j);
+	k=hcode.nch;
+	while (nused > 1) {
+		node=index[0];
+		index[0]=index[(nused--)-1];
+		hufapp(index,nprob,nused,0);
+		nprob[k]=nprob[index[0]]+nprob[node];
+		hcode.left[k]=node;
+		hcode.right[k++]=index[0];
+		up[index[0]] = -int(k);
+		index[0]=k-1;
+		up[node]=k;
+		hufapp(index,nprob,nused,0);
+	}
+	up[(hcode.nodemax=k)-1]=0;
+	for (j=0;j<hcode.nch;j++) {
+		if (nprob[j] != 0) {
+			for (n=0,ibit=0,node=up[j];node;node=up[node-1],ibit++) {
+				if (node < 0) {
+					n |= setbit[ibit];
+					node = -node;
+				}
+			}
+			hcode.icod[j]=n;
+			hcode.ncod[j]=ibit;
+		}
+	}
+	nlong=0;
+	for (j=0;j<hcode.nch;j++) {
+		if (hcode.ncod[j] > nlong) {
+			nlong=hcode.ncod[j];
+			ilong=j;
+		}
+	}
+}