diff --git a/src/core/org/luaj/vm2/lib/BaseLib.java b/src/core/org/luaj/vm2/lib/BaseLib.java
index 5f2e123e..d77ea2d0 100644
--- a/src/core/org/luaj/vm2/lib/BaseLib.java
+++ b/src/core/org/luaj/vm2/lib/BaseLib.java
@@ -230,8 +230,7 @@ public class BaseLib extends OneArgFunction implements ResourceFinder {
 			for ( int i=1, n=args.narg(); i<=n; i++ ) {
 				if ( i>1 ) globals.STDOUT.write( '\t' );
 				LuaString s = tostring.call( args.arg(i) ).strvalue();
-				int z = s.indexOf((byte)0, 0);
-				globals.STDOUT.write( s.m_bytes, s.m_offset, z>=0? z: s.m_length );
+				globals.STDOUT.write( s.m_bytes, s.m_offset, s.m_length );
 			}
 			globals.STDOUT.println();
 			return NONE;
diff --git a/src/core/org/luaj/vm2/lib/StringLib.java b/src/core/org/luaj/vm2/lib/StringLib.java
index 5eb9fb7d..a5a7b324 100644
--- a/src/core/org/luaj/vm2/lib/StringLib.java
+++ b/src/core/org/luaj/vm2/lib/StringLib.java
@@ -303,15 +303,20 @@ public class StringLib extends OneArgFunction {
 				buf.append( (byte)'\\' );
 				buf.append( (byte)c );
 				break;
-			case '\r':
-				buf.append( "\\r" );
-				break;
-			case '\0':
-				buf.append( "\\000" );
-				break;
 			default:
-				buf.append( (byte) c );
-			break;
+				if (c <= 0x1F || c == 0x7F) {
+					buf.append( (byte) '\\' );
+					if (i+1 == n || s.luaByte(i+1) < '0' || s.luaByte(i+1) > '9') {
+						buf.append(Integer.toString(c));
+					} else {
+						buf.append( (byte) '0' );
+						buf.append( (byte) (char) ('0' + c / 10) );
+						buf.append( (byte) (char) ('0' + c % 10) );
+					}
+				} else {
+					buf.append((byte) c);
+				}
+				break;
 			}
 		}
 		buf.append( (byte) '"' );
diff --git a/test/lua/luaj3.0-tests.zip b/test/lua/luaj3.0-tests.zip
index 62b42bc9..740fcbb7 100644
Binary files a/test/lua/luaj3.0-tests.zip and b/test/lua/luaj3.0-tests.zip differ
diff --git a/test/lua/stringlib.lua b/test/lua/stringlib.lua
index ba7834b2..5bf09550 100644
--- a/test/lua/stringlib.lua
+++ b/test/lua/stringlib.lua
@@ -111,18 +111,23 @@ print(string.format("simple%ssimple", " simple "))
 local testformat = function(message,fmt,...)
 	local s,e = pcall( string.format, fmt, ... )
 	if s then
+		if string.find(fmt, 'q') then
+			print(message, e)
+		end
 		print( message, string.byte(e,1,#e) )
 	else
 		print( message, 'error', e )
 	end
 end
 
-specials = "\"specials\": %% \000 \r \n"
 testformat('plain %', "%%")
-testformat("specials (%s)", "---%s---", specials)
-testformat("specials (%q)", "---%q---", specials)
+testformat("specials (%s)", "---%s---", " %% \000 \r \n ")
+testformat("specials (%q)", "---%q---", " %% \000 \r \n ")
+testformat("specials (%q)", "---%q---", "0%%0\0000\r0\n0")
 testformat("controls (%q)", "---%q---", ' \a \b \f \t \v \\ ')
+testformat("controls (%q)", "---%q---", '0\a0\b0\f0\t0\v0\\0')
 testformat("extended (%q)", "---%q---", ' \222 \223 \224 ')
+testformat("extended (%q)", "---%q---", '0\2220\2230\2240')
 testformat("embedded newlines", "%s\r%s\n%s", '===', '===', '===')
 
 -- format long string
@@ -144,7 +149,7 @@ strtests('lower', string.lower, s )
 strtests('upper', string.upper, s )
 strtests('reverse', string.reverse, s )
 strtests('char', string.char, 92, 60, 61, 93 )
-strtests('dump', string.dump, load('print("hello, world")', 'sample') )
+print( 'string.dump test:', load(string.dump(function(x) return 'foo->'..x end),'bar')('bat') )
 
 
 -- floating point formats (not supported yet)