libgo: Update to October 24 version of master library.

From-SVN: r204466

5 files changed, 33 insertions, 19 deletions

diff --git a/libgo/go/regexp/syntax/doc.go b/libgo/go/regexp/syntax/doc.go
index bcb5d05..e52632e 100644
--- a/libgo/go/regexp/syntax/doc.go
+++ b/libgo/go/regexp/syntax/doc.go
@@ -64,8 +64,8 @@ Empty strings:
   ^              at beginning of text or line (flag m=true)
   $              at end of text (like \z not \Z) or line (flag m=true)
   \A             at beginning of text
-  \b             at word boundary (\w on one side and \W, \A, or \z on the other)
-  \B             not a word boundary
+  \b             at ASCII word boundary (\w on one side and \W, \A, or \z on the other)
+  \B             not an ASCII word boundary
   \z             at end of text
 
 Escape sequences:
@@ -104,8 +104,8 @@ Perl character classes:
   \D             not digits (== [^0-9])
   \s             whitespace (== [\t\n\f\r ])
   \S             not whitespace (== [^\t\n\f\r ])
-  \w             word characters (== [0-9A-Za-z_])
-  \W             not word characters (== [^0-9A-Za-z_])
+  \w             ASCII word characters (== [0-9A-Za-z_])
+  \W             not ASCII word characters (== [^0-9A-Za-z_])
 
 ASCII character classes:
   [:alnum:]      alphanumeric (== [0-9A-Za-z])
diff --git a/libgo/go/regexp/syntax/parse.go b/libgo/go/regexp/syntax/parse.go
index 30e0e8b..42d0bf4 100644
--- a/libgo/go/regexp/syntax/parse.go
+++ b/libgo/go/regexp/syntax/parse.go
@@ -651,7 +651,7 @@ func literalRegexp(s string, flags Flags) *Regexp {
 
 // Parse parses a regular expression string s, controlled by the specified
 // Flags, and returns a regular expression parse tree. The syntax is
-// described in the top-level comment for package regexp.
+// described in the top-level comment.
 func Parse(s string, flags Flags) (*Regexp, error) {
 	if flags&Literal != 0 {
 		// Trivial parser for literal string.
diff --git a/libgo/go/regexp/syntax/parse_test.go b/libgo/go/regexp/syntax/parse_test.go
index 81fd9dc..269d6c3 100644
--- a/libgo/go/regexp/syntax/parse_test.go
+++ b/libgo/go/regexp/syntax/parse_test.go
@@ -542,7 +542,7 @@ func TestToStringEquivalentParse(t *testing.T) {
 			// but "{" is a shorter equivalent in some contexts.
 			nre, err := Parse(s, testFlags)
 			if err != nil {
-				t.Errorf("Parse(%#q.String() = %#q): %v", tt.Regexp, t, err)
+				t.Errorf("Parse(%#q.String() = %#q): %v", tt.Regexp, s, err)
 				continue
 			}
 			nd := dump(nre)
diff --git a/libgo/go/regexp/syntax/prog.go b/libgo/go/regexp/syntax/prog.go
index 902d3b3..a482a82 100644
--- a/libgo/go/regexp/syntax/prog.go
+++ b/libgo/go/regexp/syntax/prog.go
@@ -56,23 +56,26 @@ const (
 // Passing r2 == -1 indicates that the position is
 // at the end of the text.
 func EmptyOpContext(r1, r2 rune) EmptyOp {
-	var op EmptyOp
-	if r1 < 0 {
-		op |= EmptyBeginText | EmptyBeginLine
-	}
-	if r1 == '\n' {
+	var op EmptyOp = EmptyNoWordBoundary
+	var boundary byte
+	switch {
+	case IsWordChar(r1):
+		boundary = 1
+	case r1 == '\n':
 		op |= EmptyBeginLine
+	case r1 < 0:
+		op |= EmptyBeginText | EmptyBeginLine
 	}
-	if r2 < 0 {
-		op |= EmptyEndText | EmptyEndLine
-	}
-	if r2 == '\n' {
+	switch {
+	case IsWordChar(r2):
+		boundary ^= 1
+	case r2 == '\n':
 		op |= EmptyEndLine
+	case r2 < 0:
+		op |= EmptyEndText | EmptyEndLine
 	}
-	if IsWordChar(r1) != IsWordChar(r2) {
-		op |= EmptyWordBoundary
-	} else {
-		op |= EmptyNoWordBoundary
+	if boundary != 0 { // IsWordChar(r1) != IsWordChar(r2)
+		op ^= (EmptyWordBoundary | EmptyNoWordBoundary)
 	}
 	return op
 }
diff --git a/libgo/go/regexp/syntax/prog_test.go b/libgo/go/regexp/syntax/prog_test.go
index 663d5a8..cd71abc 100644
--- a/libgo/go/regexp/syntax/prog_test.go
+++ b/libgo/go/regexp/syntax/prog_test.go
@@ -103,3 +103,14 @@ func TestCompile(t *testing.T) {
 		}
 	}
 }
+
+func BenchmarkEmptyOpContext(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var r1 rune = -1
+		for _, r2 := range "foo, bar, baz\nsome input text.\n" {
+			EmptyOpContext(r1, r2)
+			r1 = r2
+		}
+		EmptyOpContext(r1, -1)
+	}
+}