From fcb6a0b280f68a93e9bef45dcf2a897eea663331 Mon Sep 17 00:00:00 2001
From: ed <ed@ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f>
Date: Sat, 25 Jun 2016 10:08:04 +0000
Subject: [PATCH] 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>.


git-svn-id: svn://svn.freebsd.org/base/stable/10@302193 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
---
 lib/libc/stdlib/l64a.c | 36 ++++++++++++++----------------------
 1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/lib/libc/stdlib/l64a.c b/lib/libc/stdlib/l64a.c
index bc105535e..c281d7d82 100644
--- a/lib/libc/stdlib/l64a.c
+++ b/lib/libc/stdlib/l64a.c
@@ -12,18 +12,13 @@ __RCSID("$NetBSD: l64a.c,v 1.13 2003/07/26 19:24:54 salo Exp $");
 #include <sys/cdefs.h>
 __FBSDID("$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);
 }
-- 
2.45.0