$NetBSD: patch-printf_c,v 1.1 2012/12/28 03:03:09 dholland Exp $

- use standard headers
  (this is supposed to substitute for libc's printf, so it *must*
  match stdio.h)
- use own headers
- declare local functions static
- avoid implicit int
- return values from non-void functions
- use const for string constants
- remove/replace code that intentionally uses signed overflow

--- printf.c.orig	2012-12-27 21:57:52.000000000 +0000
+++ printf.c
@@ -82,6 +82,8 @@ static char sccsid[] = "@(#)printf.c	1.1
 /* The pwb version this is based on */
 /* from printf.c:2.2 6/5/79 */
 
+#include <stdio.h>
+
 #ifndef	__STDC__
 #include "varargs.h"
 #else
@@ -95,6 +97,8 @@ extern	nl_catd	catd;
 #define	catgets(a, b, c, d)	(d)
 #endif
 
+#include "ex.h"
+#include "ex_proto.h"
 #include "config.h"
 
 /*
@@ -115,15 +119,13 @@ extern	nl_catd	catd;
 
 static int width, sign, fill;
 
-extern int putchar __P((int));
-
-char *p_dconv __P((long, char *));
-int p_emit __P((char *, char *));
+static void p_emit __P((const char *, const char *));
 
 #ifdef	__STDC__
 int vprintf(const char *fmt, va_list ap);
 #endif
 
+int
 #ifndef	__STDC__
 printf(va_alist)
 	va_dcl
@@ -155,14 +157,17 @@ printf(const char *fmt, ...)
 	return ret;
 }
 
+int
 vprintf(const char *fmt, va_list ap)
 {
 	char fcode;
 	int prec;
 	int length,mask1,nbits,n;
 	long int mask2, num;
-	register char *bptr;
-	char *ptr;
+	unsigned long unum;
+	register const char *bptr;
+	register char *vbptr;
+	const char *ptr;
 	char buf[134];
 #endif	/* __STDC__ */
 
@@ -171,7 +176,7 @@ vprintf(const char *fmt, va_list ap)
 		while ((fcode = *fmt++)!='%') {
 			/* ordinary (non-%) character */
 			if (fcode=='\0')
-				return;
+				return 0;
 			putchar(fcode);
 		}
 		/* length modifier: -1 for h, 1 for l, 0 for none */
@@ -288,18 +293,18 @@ vprintf(const char *fmt, va_list ap)
 					nbits = 4;
 				}
 				n = (num!=0);
-				bptr = buf + MAXOCT + 3;
+				vbptr = buf + MAXOCT + 3;
 				/* shift and mask for speed */
 				do
 				    if (((int) num & mask1) < 10)
-					*--bptr = ((int) num & mask1) + 060;
+					*--vbptr = ((int) num & mask1) + 060;
 				    else
-					*--bptr = ((int) num & mask1) + 0127;
-				while (num = (num >> nbits) & mask2);
+					*--vbptr = ((int) num & mask1) + 0127;
+				while ((num = (num >> nbits) & mask2) != 0);
 				
 				if (fcode=='o') {
 					if (n)
-						*--bptr = '0';
+						*--vbptr = '0';
 				}
 				else
 					if (!sign && fill <= 0) {
@@ -308,9 +313,10 @@ vprintf(const char *fmt, va_list ap)
 						width -= 2;
 					}
 					else {
-						*--bptr = fcode;
-						*--bptr = '0';
+						*--vbptr = fcode;
+						*--vbptr = '0';
 					}
+				bptr = vbptr;
 				ptr = buf + MAXOCT + 3;
 				break;
 			case 'D':
@@ -331,14 +337,20 @@ vprintf(const char *fmt, va_list ap)
 					else
 						num = (long) n;
 				}
-				if (n = (fcode != 'u' && num < 0))
-					num = -num;
+				if ((n = (fcode != 'u' && num < 0)) != 0) {
+					/* avoid overflow on -LONG_MAX */
+					unum = ((unsigned long)-(num + 1)) + 1;
+				}
+				else {
+					unum = (unsigned long) num;
+				}
 				/* now convert to digits */
-				bptr = p_dconv(num, buf);
+				vbptr = p_dconv(unum, buf);
 				if (n)
-					*--bptr = '-';
+					*--vbptr = '-';
 				if (fill == 0)
 					fill = -1;
+				bptr = vbptr;
 				ptr = buf + MAXDIGS + 1;
 				break;
 			default:
@@ -369,13 +381,15 @@ vprintf(const char *fmt, va_list ap)
  */
 char *
 p_dconv(value, buffer)
-	long value;
+	unsigned long value;
 	char *buffer;
 {
 	register char *bp;
-	register int svalue;
+	register unsigned int svalue;
+#if 0
 	int n;
 	long lval;
+#endif
 	
 	bp = buffer;
 	
@@ -386,6 +400,7 @@ p_dconv(value, buffer)
 		return(bp);
 	}
 	
+#if 0 /* original code, undefined behavior */
 	/* develop the leading digit of the value in "n" */
 	n = 0;
 	while (value < 0) {
@@ -399,6 +414,7 @@ p_dconv(value, buffer)
 	
 	/* stash it in buffer[1] to allow for a sign */
 	bp[1] = n + '0';
+#endif
 	/*
 	 * Now develop the rest of the digits. Since speed counts here,
 	 * we do it in two loops. The first gets "value" down until it
@@ -417,13 +433,15 @@ p_dconv(value, buffer)
 		*--bp = (svalue % 10) + '0';
 		svalue /= 10;
 	}
-	
+
+#if 0	
 	/* fill in intermediate zeroes if needed */
 	if (buffer[1] != '0') {
 		while (bp > buffer + 2)
 			*--bp = '0';
 		--bp;
 	}
+#endif
 	return(bp);
 }
 
@@ -439,9 +457,10 @@ p_dconv(value, buffer)
  * any padding in right-justification (to avoid printing "-3" as
  * "000-3" where "-0003" was intended).
  */
+static void
 p_emit(s, send)
-	register char *s;
-	char *send;
+	register const char *s;
+	const char *send;
 {
 	char cfill;
 	register int alen;