make ToUpper, ToLower etc. handle unicode properly.

Change their names too.

R=rsc
DELTA=206  (123 added, 2 deleted, 81 changed)
OCL=34170
CL=34194

src/pkg/json/struct.go

@@ -188,7 +188,7 @@ func (b *_StructBuilder) Key(k string) Builder {
 		}
 		// Again, case-insensitive.
 		for i := 0; i < t.NumField(); i++ {
-			if strings.LowerASCII(t.Field(i).Name) == k {
+			if strings.ToLower(t.Field(i).Name) == k {
 				return &_StructBuilder{ v.Field(i) }
 			}
 		}

src/pkg/strings/strings.go

@@ -5,7 +5,10 @@
 // A package of simple functions to manipulate strings.
 package strings
 
-import "utf8"
+import (
+	"unicode";
+	"utf8";
+)
 
 // explode splits s into an array of UTF-8 sequences, one per Unicode character (still strings) up to a maximum of n (n <= 0 means no limit).
 // Invalid UTF-8 sequences become correct encodings of U+FFF8.
@@ -145,65 +148,84 @@ func HasSuffix(s, suffix string) bool {
 	return len(s) >= len(suffix) && s[len(s)-len(suffix):len(s)] == suffix
 }
 
-// Upper returns a copy of the string s, with all low ASCII lowercase letters
-// converted to uppercase.
-// TODO: full Unicode support
-func UpperASCII(s string) string {
-	// Note, we can work byte-by-byte because UTF-8 multibyte characters
-	// don't use any low ASCII byte values.
-	b := make([]byte, len(s));
-	for i := 0; i < len(s); i++ {
-		c := s[i];
-		if 'a' <= c && c <= 'z' {
-			c -= 'a' - 'A';
+// Map returns a copy of the string s with all its characters modified
+// according to mapping function.
+func Map(mapping func(rune int) int, s string) string {
+	// In the worst case, the string can grow when mapped, making
+	// things unpleasant.  But it's so rare we barge in assuming it's
+	// fine.  It could also shrink but that falls out naturally.
+	maxbytes := len(s);	// length of b
+	nbytes := 0;	// number of bytes encoded in b
+	b := make([]byte, maxbytes);
+	for i, c := range s {
+		rune := mapping(c);
+		wid := 1;
+		if rune >= utf8.RuneSelf {
+			wid = utf8.RuneLen(rune);
 		}
-		b[i] = c;
+		if nbytes + wid > maxbytes {
+			// Grow the buffer.
+			maxbytes = maxbytes*2 + utf8.UTFMax;
+			nb := make([]byte, maxbytes);
+			for i, c := range b[0:nbytes] {
+				nb[i] = c
+			}
+			b = nb;
+		}
+		nbytes += utf8.EncodeRune(rune, b[nbytes:maxbytes]);
 	}
-	return string(b);
+	return string(b[0:nbytes]);
 }
 
-// Upper returns a copy of the string s, with all low ASCII lowercase letters
-// converted to lowercase.
-// TODO: full Unicode support
-func LowerASCII(s string) string {
-	// Note, we can work byte-by-byte because UTF-8 multibyte characters
-	// don't use any low ASCII byte values.
-	b := make([]byte, len(s));
-	for i := 0; i < len(s); i++ {
-		c := s[i];
-		if 'A' <= c && c <= 'Z' {
-			c += 'a' - 'A';
-		}
-		b[i] = c;
-	}
-	return string(b);
+// ToUpper returns a copy of the string s with all letters mapped to their upper case.
+func ToUpper(s string) string {
+	return Map(unicode.ToUpper, s)
 }
 
-func isWhitespaceASCII(c byte) bool {
-	switch int(c) {
-	case ' ', '\t', '\r', '\n':
-		return true;
-	}
- 	return false;
+// ToUpper returns a copy of the string s with all letters mapped to their lower case.
+func ToLower(s string) string {
+	return Map(unicode.ToLower, s)
 }
 
-// Trim returns a slice of the string s, with all leading and trailing whitespace
-// removed.  "Whitespace" for now defined as space, tab, CR, or LF.
-// TODO: full Unicode whitespace support (need a unicode.IsWhitespace method)
-func TrimSpaceASCII(s string) string {
-	// Note, we can work byte-by-byte because UTF-8 multibyte characters
-	// don't use any low ASCII byte values.
+// ToTitle returns a copy of the string s with all letters mapped to their title case.
+func Title(s string) string {
+	return Map(unicode.ToTitle, s)
+}
+
+// Trim returns a slice of the string s, with all leading and trailing white space
+// removed, as defined by Unicode.
+func TrimSpace(s string) string {
 	start, end := 0, len(s);
-	for start < end && isWhitespaceASCII(s[start]) {
-		start++;
+	for wid := 0; start < end; start += wid {
+		wid = 1;
+		rune := int(s[start]);
+		if rune >= utf8.RuneSelf {
+			rune, wid = utf8.DecodeRuneInString(s[start:end])
+		}
+		if !unicode.IsSpace(rune) {
+			break;
+		}
 	}
-	for start < end && isWhitespaceASCII(s[end-1]) {
-		end--;
+	for wid := 0; start < end; end -= wid {
+		wid = 1;
+		rune := int(s[end-1]);
+		if rune >= utf8.RuneSelf {
+			// Back up carefully looking for beginning of rune. Mustn't pass start.
+			for wid = 2; start <= end-wid && !utf8.RuneStart(s[end-wid]); wid++ {
+			}
+			if start > end-wid {	// invalid UTF-8 sequence; stop processing
+				return s[start:end]
+			}
+			rune, wid = utf8.DecodeRuneInString(s[end-wid:end]);
+		}
+		if !unicode.IsSpace(rune) {
+			break;
+		}
 	}
 	return s[start:end];
 }
 
-// Bytes returns an array of the bytes in s.
+// Bytes returns a new slice containing the bytes in s.
 func Bytes(s string) []byte {
 	b := make([]byte, len(s));
 	for i := 0; i < len(s); i++ {
@@ -211,4 +233,3 @@ func Bytes(s string) []byte {
 	}
 	return b;
 }
-

src/pkg/strings/strings_test.go

@@ -7,6 +7,8 @@ package strings_test
 import (
 	. "strings";
 	"testing";
+	"unicode";
+	"utf8";
 )
 
 func eq(a, b []string) bool {
@@ -155,39 +157,131 @@ func runStringTests(t *testing.T, f func(string) string, funcName string, testCa
 	}
 }
 
-var upperASCIITests = []StringTest {
+var upperTests = []StringTest {
 	StringTest{"", ""},
 	StringTest{"abc", "ABC"},
 	StringTest{"AbC123", "ABC123"},
-	StringTest{"azAZ09_", "AZAZ09_"}
+	StringTest{"azAZ09_", "AZAZ09_"},
+	StringTest{"\u0250\u0250\u0250\u0250\u0250", "\u2C6F\u2C6F\u2C6F\u2C6F\u2C6F"},	// grows one byte per char
 }
 
-var lowerASCIITests = []StringTest {
+var lowerTests = []StringTest {
 	StringTest{"", ""},
 	StringTest{"abc", "abc"},
 	StringTest{"AbC123", "abc123"},
-	StringTest{"azAZ09_", "azaz09_"}
+	StringTest{"azAZ09_", "azaz09_"},
+	StringTest{"\u2C6D\u2C6D\u2C6D\u2C6D\u2C6D", "\u0251\u0251\u0251\u0251\u0251"},	// shrinks one byte per char
 }
 
-var trimSpaceASCIITests = []StringTest {
+const space = "\t\v\r\f\n\u0085\u00a0\u2000\u3000"
+
+var trimSpaceTests = []StringTest {
 	StringTest{"", ""},
 	StringTest{"abc", "abc"},
+	StringTest{space + "abc" + space, "abc"},
 	StringTest{" ", ""},
 	StringTest{" \t\r\n \t\t\r\r\n\n ", ""},
 	StringTest{" \t\r\n x\t\t\r\r\n\n ", "x"},
-	StringTest{" \t\r\n x\t\t\r\r\ny\n ", "x\t\t\r\r\ny"},
+	StringTest{" \u2000\t\r\n x\t\t\r\r\ny\n \u3000", "x\t\t\r\r\ny"},
 	StringTest{"1 \t\r\n2", "1 \t\r\n2"},
+	StringTest{" x\x80", "x\x80"},	// invalid UTF-8 on end
+	StringTest{" x\xc0", "x\xc0"},	// invalid UTF-8 on end
+}
+
+func tenRunes(rune int) string {
+	r := make([]int, 10);
+	for i := range r {
+		r[i] = rune
+	}
+	return string(r)
+}
+
+func TestMap(t *testing.T) {
+	// Run a couple of awful growth/shrinkage tests
+	a := tenRunes('a');
+	// 1.  Grow.  This triggers two reallocations in Map.
+	maxRune := func(rune int) int { return unicode.MaxRune };
+	m := Map(maxRune, a);
+	expect := tenRunes(unicode.MaxRune);
+	if m != expect {
+		t.Errorf("growing: expected %q got %q", expect, m);
+	}
+	// 2. Shrink
+	minRune := func(rune int) int { return 'a' };
+	m = Map(minRune, tenRunes(unicode.MaxRune));
+	expect = a;
+	if m != expect {
+		t.Errorf("shrinking: expected %q got %q", expect, m);
+	}
+}
+
+func TestToUpper(t *testing.T) {
+	runStringTests(t, ToUpper, "ToUpper", upperTests);
 }
 
-func TestUpperASCII(t *testing.T) {
-	runStringTests(t, UpperASCII, "UpperASCII", upperASCIITests);
+func TestToLower(t *testing.T) {
+	runStringTests(t, ToLower, "ToLower", lowerTests);
 }
 
-func TestLowerASCII(t *testing.T) {
-	runStringTests(t, LowerASCII, "LowerASCII", lowerASCIITests);
+func TestTrimSpace(t *testing.T) {
+	runStringTests(t, TrimSpace, "TrimSpace", trimSpaceTests);
 }
 
-func TestTrimSpaceASCII(t *testing.T) {
-	runStringTests(t, TrimSpaceASCII, "TrimSpaceASCII", trimSpaceASCIITests);
+func equal(m string, s1, s2 string, t *testing.T) bool {
+	if s1 == s2 {
+		return true
+	}
+	e1 := Split(s1, "", 0);
+	e2 := Split(s2, "", 0);
+	for i, c1 := range e1 {
+		if i > len(e2) {
+			break
+		}
+		r1, w := utf8.DecodeRuneInString(c1);
+		r2, w := utf8.DecodeRuneInString(e2[i]);
+		if r1 != r2 {
+			t.Errorf("%s diff at %d: U+%04X U+%04X", m, i, r1, r2)
+		}
+	}
+	return false;
 }
 
+func TestCaseConsistency(t *testing.T) {
+	// Make a string of all the runes.
+	a := make([]int, unicode.MaxRune+1);
+	for i := range a {
+		a[i] = i
+	}
+	s := string(a);
+	// convert the cases.
+	upper := ToUpper(s);
+	lower := ToLower(s);
+
+	// Consistency checks
+	if n := utf8.RuneCountInString(upper); n != unicode.MaxRune+1 {
+		t.Error("rune count wrong in upper:", n);
+	}
+	if n := utf8.RuneCountInString(lower); n != unicode.MaxRune+1 {
+		t.Error("rune count wrong in lower:", n);
+	}
+	if !equal("ToUpper(upper)", ToUpper(upper), upper, t) {
+		t.Error("ToUpper(upper) consistency fail");
+	}
+	if !equal("ToLower(lower)", ToLower(lower), lower, t) {
+		t.Error("ToLower(lower) consistency fail");
+	}
+	/*
+	  These fail because of non-one-to-oneness of the data, such as multiple
+	  upper case 'I' mapping to 'i'.  We comment them out but keep them for
+	  interest.
+	  For instance: CAPITAL LETTER I WITH DOT ABOVE:
+		unicode.ToUpper(unicode.ToLower('\u0130')) != '\u0130'
+
+	if !equal("ToUpper(lower)", ToUpper(lower), upper, t) {
+		t.Error("ToUpper(lower) consistency fail");
+	}
+	if !equal("ToLower(upper)", ToLower(upper), lower, t) {
+		t.Error("ToLower(upper) consistency fail");
+	}
+	*/
+}

src/pkg/unicode/maketables.go

@@ -474,7 +474,7 @@ func parseScript(line string, scripts map[string] []Script) {
 	if comment >= 0 {
 		line = line[0:comment]
 	}
-	line = strings.TrimSpaceASCII(line);
+	line = strings.TrimSpace(line);
 	if len(line) == 0 {
 		return
 	}

src/pkg/utf8/utf8.go

@@ -290,3 +290,9 @@ func RuneCountInString(s string) int {
 	return n;
 }
 
+// RuneStart reports whether the byte could be the first byte of
+// an encoded rune.  Second and subsequent bytes always have the top
+// two bits set to 10.
+func RuneStart(b byte) bool {
+	return b & 0xC0 != 0x80
+}