add numerical recipes library

lib/nr/ansi/recipes/arcmak.c

@@ -0,0 +1,34 @@
+
+#define NRANSI
+#include "nrutil.h"
+#include <limits.h>
+#define MC 512
+#ifdef ULONG_MAX
+#define MAXINT (ULONG_MAX >> 1)
+#else
+#define MAXINT 2147483647
+#endif
+
+typedef struct {
+	unsigned long *ilob,*iupb,*ncumfq,jdif,nc,minint,nch,ncum,nrad;
+} arithcode;
+
+void arcmak(unsigned long nfreq[], unsigned long nchh, unsigned long nradd,
+	arithcode *acode)
+{
+	unsigned long j;
+
+	if (nchh > MC) nrerror("input radix may not exceed MC in arcmak.");
+	if (nradd > 256) nrerror("output radix may not exceed 256 in arcmak.");
+
+	acode->minint=MAXINT/nradd;
+	acode->nch=nchh;
+	acode->nrad=nradd;
+	acode->ncumfq[1]=0;
+	for (j=2;j<=acode->nch+1;j++)
+		acode->ncumfq[j]=acode->ncumfq[j-1]+IMAX(nfreq[j-1],1);
+	acode->ncum=acode->ncumfq[acode->nch+2]=acode->ncumfq[acode->nch+1]+1;
+}
+#undef MC
+#undef MAXINT
+#undef NRANSI