From 613a5c8bc6f766269a1073511b88f3e517e8aa4d Mon Sep 17 00:00:00 2001
From: Rob Pike <r@golang.org>
Date: Fri, 31 Oct 2008 15:26:14 -0700
Subject: [PATCH] \x00 for NUL in type string.

R=rsc
DELTA=14  (9 added, 0 deleted, 5 changed)
OCL=18281
CL=18281
---
 src/lib/reflect/test.go     |  2 +-
 src/lib/reflect/tostring.go |  2 +-
 src/lib/reflect/type.go     | 15 ++++++++++++---
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/lib/reflect/test.go b/src/lib/reflect/test.go
index 0ed53a3ac4e..9ec22d1ac44 100644
--- a/src/lib/reflect/test.go
+++ b/src/lib/reflect/test.go
@@ -119,7 +119,7 @@ func main() {
 	typedump("struct {a int8; b int8; c int8; d int8; b int32}", "struct{a int8; b int8; c int8; d int8; b int32}");
 	typedump("struct {a int8; b int8; c int8; d int8; e int8; b int32}", "struct{a int8; b int8; c int8; d int8; e int8; b int32}");
 	typedump("struct {a int8 \"hi there\"; }", "struct{a int8 \"hi there\"}");
-	typedump("struct {a int8 \"hi \\0there\\t\\n\\\"\\\\\"; }", "struct{a int8 \"hi \\0there\\t\\n\\\"\\\\\"}");
+	typedump("struct {a int8 \"hi \\x00there\\t\\n\\\"\\\\\"; }", "struct{a int8 \"hi \\x00there\\t\\n\\\"\\\\\"}");
 
 	valuedump("int8", "8");
 	valuedump("int16", "16");
diff --git a/src/lib/reflect/tostring.go b/src/lib/reflect/tostring.go
index c57e1995f57..963ab0fbb3e 100644
--- a/src/lib/reflect/tostring.go
+++ b/src/lib/reflect/tostring.go
@@ -25,7 +25,7 @@ func DoubleQuote(s string) string {
 		case '\t':
 			out += `\t`;
 		case '\x00':
-			out += `\0`;
+			out += `\x00`;
 		case '"':
 			out += `\"`;
 		case '\\':
diff --git a/src/lib/reflect/type.go b/src/lib/reflect/type.go
index 0d73944bb1f..3e5179190cd 100644
--- a/src/lib/reflect/type.go
+++ b/src/lib/reflect/type.go
@@ -453,7 +453,7 @@ func init() {
 	typename =
 		name '.' name
 	doublequotedstring = 
-		string in " ";  escapes are \0 (NUL) \n \t \" \\
+		string in " ";  escapes are \x00 (NUL) \n \t \" \\
 	fieldlist =
 		[ field { [ ',' | ';' ] field } ]
 	field =
@@ -492,6 +492,10 @@ func special(c uint8) bool {
 	return false;
 }
 
+func hex00(s string, i int) bool {
+	return i + 2 < len(s) && s[i] == '0' && s[i+1] == '0'
+}
+
 // Process backslashes.  String known to be well-formed.
 // Initial double-quote is left in, as an indication this token is a string.
 func unescape(s string, backslash bool) string {
@@ -509,8 +513,13 @@ func unescape(s string, backslash bool) string {
 				c = '\n';
 			case 't':
 				c = '\t';
-			case '0':	// it's not a legal go string but \0 means NUL
-				c = '\x00';
+			case 'x':
+				if hex00(s, i+1) {
+					i += 2;
+					c = 0;
+					break;
+				}
+			// otherwise just put an 'x'; erroneous but safe.
 			// default is correct already; \\ is \; \" is "
 			}
 		}