svn commit: r302193 - stable/10/lib/libc/stdlib

[Ed Schouten]

Author: ed
Date: Sat Jun 25 10:08:04 2016
New Revision: 302193
URL: https://svnweb.freebsd.org/changeset/base/302193

Log:
  MFC r300775:
  
    Let l64a() properly null terminate its result.
  
    Though the buffer used by l64a() is initialized with null bytes,
    repetetive calls may end up having trailing garbage of previous
    invocations because we don't end up terminating the string.
  
    Instead of importing NetBSD's fix, use this opportunity to simplify this
    function dramatically, for example by just storing the Base64 character
    set in a string. There is also no need to do the bitmasking, as we can
    just use the proper integer type from <stdint.h>.

Modified:
  stable/10/lib/libc/stdlib/l64a.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/lib/libc/stdlib/l64a.c
==============================================================================
--- stable/10/lib/libc/stdlib/l64a.c	Sat Jun 25 09:32:35 2016	(r302192)
+++ stable/10/lib/libc/stdlib/l64a.c	Sat Jun 25 10:08:04 2016	(r302193)
@@ -12,18 +12,13 @@ __RCSID("$NetBSD: l64a.c,v 1.13 2003/07/
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <stdint.h>
 #include <stdlib.h>
 
-#define	ADOT	46		/* ASCII '.' */
-#define	ASLASH	ADOT + 1	/* ASCII '/' */
-#define	A0	48		/* ASCII '0' */
-#define	AA	65		/* ASCII 'A' */
-#define	Aa	97		/* ASCII 'a' */
-
 char *
 l64a(long value)
 {
-	static char buf[8];
+	static char buf[7];
 
 	(void)l64a_r(value, buf, sizeof(buf));
 	return (buf);
@@ -32,21 +27,18 @@ l64a(long value)
 int
 l64a_r(long value, char *buffer, int buflen)
 {
-	long v;
-	int digit;
-
-	v = value & (long)0xffffffff;
-	for (; v != 0 && buflen > 1; buffer++, buflen--) {
-		digit = v & 0x3f;
-		if (digit < 2)
-			*buffer = digit + ADOT;
-		else if (digit < 12)
-			*buffer = digit + A0 - 2;
-		else if (digit < 38)
-			*buffer = digit + AA - 12;
-		else
-			*buffer = digit + Aa - 38;
+	static const char chars[] =
+	    "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+	uint32_t v;
+
+	v = value;
+	while (buflen-- > 0) {
+		if (v == 0) {
+			*buffer = '\0';
+			return (0);
+		}
+		*buffer++ = chars[v & 0x3f];
 		v >>= 6;
 	}
-	return (v == 0 ? 0 : -1);
+	return (-1);
 }