add numerical recipes library

lib/nr/ansi/recipes/hufenc.c

@@ -0,0 +1,38 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct {
+	unsigned long *icod,*ncod,*left,*right,nch,nodemax;
+} huffcode;
+
+void hufenc(unsigned long ich, unsigned char **codep, unsigned long *lcode,
+	unsigned long *nb, huffcode *hcode)
+{
+	void nrerror(char error_text[]);
+	int l,n;
+	unsigned long k,nc;
+	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};
+
+	k=ich+1;
+	if (k > hcode->nch || k < 1) nrerror("ich out of range in hufenc.");
+	for (n=hcode->ncod[k]-1;n>=0;n--,++(*nb)) {
+		nc=(*nb >> 3);
+		if (++nc >= *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.");
+			}
+		}
+		l=(*nb) & 7;
+		if (!l) (*codep)[nc]=0;
+		if (hcode->icod[k] & setbit[n]) (*codep)[nc] |= setbit[l];
+	}
+}