change utf8.FullRuneInString and utf8.DecodeRuneInString

to use single string argument instead of string, index.

R=r
DELTA=136  (9 added, 7 deleted, 120 changed)
OCL=28642
CL=28644

src/lib/fmt/print.go

@@ -469,7 +469,7 @@ func (p *pp) doprintf(format string, v reflect.StructValue) {
 	end := len(format) - 1;
 	fieldnum := 0;	// we process one field per non-trivial format
 	for i := 0; i <= end;  {
-		c, w := utf8.DecodeRuneInString(format, i);
+		c, w := utf8.DecodeRuneInString(format[i:len(format)]);
 		if c != '%' || i == end {
 			p.add(c);
 			i += w;
@@ -500,7 +500,7 @@ func (p *pp) doprintf(format string, v reflect.StructValue) {
 		if i < end && format[i] == '.' {
 			p.fmt.prec, p.fmt.prec_present, i = parsenum(format, i+1, end);
 		}
-		c, w = utf8.DecodeRuneInString(format, i);
+		c, w = utf8.DecodeRuneInString(format[i:len(format)]);
 		i += w;
 		// percent is special - absorbs no operand
 		if c == '%' {

src/lib/go/ast/ast.go

@@ -426,7 +426,7 @@ func (x *ChanType) Visit(v ExprVisitor) { v.DoChanType(x); }
 // IsExported returns whether name is an exported Go symbol
 // (i.e., whether it begins with an uppercase letter).
 func IsExported(name string) bool {
-	ch, len := utf8.DecodeRuneInString(name, 0);
+	ch, len := utf8.DecodeRuneInString(name);
 	return unicode.IsUpper(ch);
 }
 

src/lib/json/parse.go

@@ -114,7 +114,7 @@ func Unquote(s string) (t string, ok bool) {
 			w++;
 		// Coerce to well-formed UTF-8.
 		default:
-			rune, size := utf8.DecodeRuneInString(s, r);
+			rune, size := utf8.DecodeRuneInString(s[r:len(s)]);
 			r += size;
 			w += utf8.EncodeRune(rune, b[w:len(b)]);
 		}

src/lib/reflect/type.go

@@ -698,7 +698,7 @@ func (p *typeParser) Next() {
 		return;
 	}
 	start := p.index;
-	c, w := utf8.DecodeRuneInString(p.str, p.index);
+	c, w := utf8.DecodeRuneInString(p.str[p.index:len(p.str)]);
 	p.index += w;
 	switch {
 	case c == '<':

src/lib/regexp/regexp.go

@@ -263,7 +263,7 @@ func (p *parser) nextc() int {
 	if p.pos >= len(p.re.expr) {
 		p.ch = endOfFile
 	} else {
-		c, w := utf8.DecodeRuneInString(p.re.expr, p.pos);
+		c, w := utf8.DecodeRuneInString(p.re.expr[p.pos:len(p.re.expr)]);
 		p.ch = c;
 		p.pos += w;
 	}
@@ -653,7 +653,7 @@ func (re *Regexp) doExecute(str string, pos int) []int {
 		charwidth := 1;
 		c := endOfFile;
 		if pos < len(str) {
-			c, charwidth = utf8.DecodeRuneInString(str, pos);
+			c, charwidth = utf8.DecodeRuneInString(str[pos:len(str)]);
 		}
 		for i := 0; i < len(s[in]); i++ {
 			st := s[in][i];

src/lib/strconv/quote.go

@@ -18,38 +18,38 @@ const lowerhex = "0123456789abcdef"
 func Quote(s string) string {
 	// TODO(rsc): String accumulation could be more efficient.
 	t := `"`;
-	for i := 0; i < len(s); i++ {
-		switch {
-		case s[i] == '"':
+	for ; len(s) > 0; s = s[1:len(s)] {
+		switch c := s[0]; {
+		case c == '"':
 			t += `\"`;
-		case s[i] == '\\':
+		case c == '\\':
 			t += `\\`;
-		case ' ' <= s[i] && s[i] <= '~':
-			t += string(s[i]);
-		case s[i] == '\a':
+		case ' ' <= c && c <= '~':
+			t += string(c);
+		case c == '\a':
 			t += `\a`;
-		case s[i] == '\b':
+		case c == '\b':
 			t += `\b`;
-		case s[i] == '\f':
+		case c == '\f':
 			t += `\f`;
-		case s[i] == '\n':
+		case c == '\n':
 			t += `\n`;
-		case s[i] == '\r':
+		case c == '\r':
 			t += `\r`;
-		case s[i] == '\t':
+		case c == '\t':
 			t += `\t`;
-		case s[i] == '\v':
+		case c == '\v':
 			t += `\v`;
 
-		case s[i] < utf8.RuneSelf:
-			t += `\x` + string(lowerhex[s[i]>>4]) + string(lowerhex[s[i]&0xF]);
+		case c < utf8.RuneSelf:
+			t += `\x` + string(lowerhex[c>>4]) + string(lowerhex[c&0xF]);
 
-		case utf8.FullRuneInString(s, i):
-			r, size := utf8.DecodeRuneInString(s, i);
+		case utf8.FullRuneInString(s):
+			r, size := utf8.DecodeRuneInString(s);
 			if r == utf8.RuneError && size == 1 {
 				goto EscX;
 			}
-			i += size-1;  // i++ on next iteration
+			s = s[size-1:len(s)];	// next iteration will slice off 1 more
 			if r < 0x10000 {
 				t += `\u`;
 				for j:=uint(0); j<4; j++ {
@@ -65,8 +65,8 @@ func Quote(s string) string {
 		default:
 		EscX:
 			t += `\x`;
-			t += string(lowerhex[s[i]>>4]);
-			t += string(lowerhex[s[i]&0xF]);
+			t += string(lowerhex[c>>4]);
+			t += string(lowerhex[c&0xF]);
 		}
 	}
 	t += `"`;
@@ -97,42 +97,42 @@ func unhex(b byte) (v int, ok bool) {
 	return;
 }
 
-func unquoteChar(s string, i int, q byte) (t string, ii int, err os.Error) {
+func unquoteChar(s string, q byte) (t, ns string, err os.Error) {
 	err = os.EINVAL;  // assume error for easy return
 
 	// easy cases
-	switch c := s[i]; {
+	switch c := s[0]; {
 	case c >= utf8.RuneSelf:
-		r, size := utf8.DecodeRuneInString(s, i);
-		return s[i:i+size], i+size, nil;
+		r, size := utf8.DecodeRuneInString(s);
+		return s[0:size], s[size:len(s)], nil;
 	case c == q:
 		return;
 	case c != '\\':
-		return s[i:i+1], i+1, nil;
+		return s[0:1], s[1:len(s)], nil;
 	}
 
 	// hard case: c is backslash
-	if i+1 >= len(s) {
+	if len(s) <= 1 {
 		return;
 	}
-	c := s[i+1];
-	i += 2;
+	c := s[1];
+	s = s[2:len(s)];
 
 	switch c {
 	case 'a':
-		return "\a", i, nil;
+		return "\a", s, nil;
 	case 'b':
-		return "\b", i, nil;
+		return "\b", s, nil;
 	case 'f':
-		return "\f", i, nil;
+		return "\f", s, nil;
 	case 'n':
-		return "\n", i, nil;
+		return "\n", s, nil;
 	case 'r':
-		return "\r", i, nil;
+		return "\r", s, nil;
 	case 't':
-		return "\t", i, nil;
+		return "\t", s, nil;
 	case 'v':
-		return "\v", i, nil;
+		return "\v", s, nil;
 	case 'x', 'u', 'U':
 		n := 0;
 		switch c {
@@ -144,43 +144,45 @@ func unquoteChar(s string, i int, q byte) (t string, ii int, err os.Error) {
 			n = 8;
 		}
 		v := 0;
+		if len(s) < n {
+			return;
+		}
 		for j := 0; j < n; j++ {
-			if i+j >= len(s) {
-				return;
-			}
-			x, ok := unhex(s[i+j]);
+			x, ok := unhex(s[j]);
 			if !ok {
 				return;
 			}
 			v = v<<4 | x;
 		}
+		s = s[n:len(s)];
 		if c == 'x' {
-			return string([]byte{byte(v)}), i+n, nil;
+			// single-byte string, possibly not UTF-8
+			return string([]byte{byte(v)}), s, nil;
 		}
 		if v > utf8.RuneMax {
 			return;
 		}
-		return string(v), i+n, nil;
+		return string(v), s, nil;
 	case '0', '1', '2', '3', '4', '5', '6', '7':
-		v := 0;
-		i--;
-		for j := 0; j < 3; j++ {
-			if i+j >= len(s) {
-				return;
-			}
-			x := int(s[i+j]) - '0';
+		v := int(c) - '0';
+		if len(s) < 2 {
+			return;
+		}
+		for j := 0; j < 2; j++ {	// one digit already; two more
+			x := int(s[j]) - '0';
 			if x < 0 || x > 7 {
 				return;
 			}
 			v = (v<<3) | x;
 		}
+		s = s[2:len(s)];
 		if v > 255 {
 			return;
 		}
-		return string(v), i+3, nil;
-			
+		return string(v), s, nil;
+
 	case '\\', q:
-		return string(c), i, nil;
+		return string(c), s, nil;
 	}
 	return;
 }
@@ -193,37 +195,35 @@ func unquoteChar(s string, i int, q byte) (t string, ii int, err os.Error) {
 func Unquote(s string) (t string, err os.Error) {
 	err = os.EINVAL;  // assume error for easy return
 	n := len(s);
-	if n < 2 || s[0] != s[n-1] {
+	if n < 2 {
 		return;
 	}
+	quote := s[0];
+	if quote != s[n-1] {
+		return;
+	}
+	s = s[1:n-1];
 
-	switch s[0] {
-	case '`':
-		t := s[1:n-1];
-		return t, nil;
-
-	case '"', '\'':
-		// TODO(rsc): String accumulation could be more efficient.
-		t := "";
-		q := s[0];
-		var c string;
-		var err os.Error;
-		for i := 1; i < n-1; {
-			c, i, err = unquoteChar(s, i, q);
-			if err != nil {
-				return "", err;
-			}
-			t += c;
-			if q == '\'' && i != n-1 {
-				// single-quoted must be single character
-				return;
-			}
-			if i > n-1 {
-				// read too far
-				return;
-			}
+	if quote == '`' {
+		return s, nil;
+	}
+	if quote != '"' && quote != '\'' {
+		return;
+	}
+
+	// TODO(rsc): String accumulation could be more efficient.
+	var c, tt string;
+	var err1 os.Error;
+	for len(s) > 0 {
+		if c, s, err1 = unquoteChar(s, quote); err1 != nil {
+			err = err1;
+			return;
+		}
+		tt += c;
+		if quote == '\'' && len(s) != 0 {
+			// single-quoted must be single character
+			return;
 		}
-		return t, nil
 	}
-	return;
+	return tt, nil
 }

src/lib/strings/strings.go

@@ -11,12 +11,13 @@ import "utf8"
 // Invalid UTF-8 sequences become correct encodings of U+FFF8.
 func Explode(s string) []string {
 	a := make([]string, utf8.RuneCountInString(s));
-	j := 0;
 	var size, rune int;
-	for i := 0; i < len(a); i++ {
-		rune, size = utf8.DecodeRuneInString(s, j);
+	i := 0;
+	for len(s) > 0 {
+		rune, size = utf8.DecodeRuneInString(s);
+		s = s[size:len(s)];
 		a[i] = string(rune);
-		j += size;
+		i++;
 	}
 	return a
 }

src/lib/utf8/utf8.go

@@ -108,11 +108,12 @@ func decodeRuneInternal(p []byte) (rune, size int, short bool) {
 	return RuneError, 1, false
 }
 
-func decodeRuneInStringInternal(s string, i int, n int) (rune, size int, short bool) {
+func decodeRuneInStringInternal(s string) (rune, size int, short bool) {
+	n := len(s);
 	if n < 1 {
 		return RuneError, 0, true;
 	}
-	c0 := s[i];
+	c0 := s[0];
 
 	// 1-byte, 7-bit sequence?
 	if c0 < _Tx {
@@ -128,7 +129,7 @@ func decodeRuneInStringInternal(s string, i int, n int) (rune, size int, short b
 	if n < 2 {
 		return RuneError, 1, true
 	}
-	c1 := s[i+1];
+	c1 := s[1];
 	if c1 < _Tx || _T2 <= c1 {
 		return RuneError, 1, false
 	}
@@ -146,7 +147,7 @@ func decodeRuneInStringInternal(s string, i int, n int) (rune, size int, short b
 	if n < 3 {
 		return RuneError, 1, true
 	}
-	c2 := s[i+2];
+	c2 := s[2];
 	if c2 < _Tx || _T2 <= c2 {
 		return RuneError, 1, false
 	}
@@ -164,7 +165,7 @@ func decodeRuneInStringInternal(s string, i int, n int) (rune, size int, short b
 	if n < 4 {
 		return RuneError, 1, true
 	}
-	c3 := s[i+3];
+	c3 := s[3];
 	if c3 < _Tx || _T2 <= c3 {
 		return RuneError, 1, false
 	}
@@ -190,8 +191,8 @@ func FullRune(p []byte) bool {
 }
 
 // FullRuneInString is like FullRune but its input is a string.
-func FullRuneInString(s string, i int) bool {
-	rune, size, short := decodeRuneInStringInternal(s, i, len(s) - i);
+func FullRuneInString(s string) bool {
+	rune, size, short := decodeRuneInStringInternal(s);
 	return !short
 }
 
@@ -203,9 +204,9 @@ func DecodeRune(p []byte) (rune, size int) {
 }
 
 // DecodeRuneInString is like DecodeRune but its input is a string.
-func DecodeRuneInString(s string, i int) (rune, size int) {
+func DecodeRuneInString(s string) (rune, size int) {
 	var short bool;
-	rune, size, short = decodeRuneInStringInternal(s, i, len(s) - i);
+	rune, size, short = decodeRuneInStringInternal(s);
 	return;
 }
 
@@ -281,7 +282,7 @@ func RuneCountInString(s string) int {
 		if s[i] < RuneSelf {
 			i++;
 		} else {
-			rune, size, short := decodeRuneInStringInternal(s, i, ei - i);
+			rune, size, short := decodeRuneInStringInternal(s[i:ei]);
 			i += size;
 		}
 	}

src/lib/utf8/utf8_test.go

@@ -58,17 +58,17 @@ func TestFullRune(t *testing.T) {
 		if !utf8.FullRune(b) {
 			t.Errorf("FullRune(%q) (rune %04x) = false, want true", b, m.rune);
 		}
-		s := "xx"+m.str;
-		if !utf8.FullRuneInString(s, 2) {
-			t.Errorf("FullRuneInString(%q, 2) (rune %04x) = false, want true", s, m.rune);
+		s := m.str;
+		if !utf8.FullRuneInString(s) {
+			t.Errorf("FullRuneInString(%q) (rune %04x) = false, want true", s, m.rune);
 		}
 		b1 := b[0:len(b)-1];
 		if utf8.FullRune(b1) {
 			t.Errorf("FullRune(%q) = true, want false", b1);
 		}
-		s1 := "xxx"+string(b1);
-		if utf8.FullRuneInString(s1, 3) {
-			t.Errorf("FullRune(%q, 3) = true, want false", s1);
+		s1 := string(b1);
+		if utf8.FullRuneInString(s1) {
+			t.Errorf("FullRune(%q) = true, want false", s1);
 		}
 	}
 }
@@ -106,10 +106,10 @@ func TestDecodeRune(t *testing.T) {
 		if rune != m.rune || size != len(b) {
 			t.Errorf("DecodeRune(%q) = 0x%04x, %d want 0x%04x, %d", b, rune, size, m.rune, len(b));
 		}
-		s := "xx"+m.str;
-		rune, size = utf8.DecodeRuneInString(s, 2);
+		s := m.str;
+		rune, size = utf8.DecodeRuneInString(s);
 		if rune != m.rune || size != len(b) {
-			t.Errorf("DecodeRune(%q, 2) = 0x%04x, %d want 0x%04x, %d", s, rune, size, m.rune, len(b));
+			t.Errorf("DecodeRune(%q) = 0x%04x, %d want 0x%04x, %d", s, rune, size, m.rune, len(b));
 		}
 
 		// there's an extra byte that bytes left behind - make sure trailing byte works
@@ -117,10 +117,10 @@ func TestDecodeRune(t *testing.T) {
 		if rune != m.rune || size != len(b) {
 			t.Errorf("DecodeRune(%q) = 0x%04x, %d want 0x%04x, %d", b, rune, size, m.rune, len(b));
 		}
-		s = "x"+m.str+"\x00";
-		rune, size = utf8.DecodeRuneInString(s, 1);
+		s = m.str+"\x00";
+		rune, size = utf8.DecodeRuneInString(s);
 		if rune != m.rune || size != len(b) {
-			t.Errorf("DecodeRuneInString(%q, 1) = 0x%04x, %d want 0x%04x, %d", s, rune, size, m.rune, len(b));
+			t.Errorf("DecodeRuneInString(%q) = 0x%04x, %d want 0x%04x, %d", s, rune, size, m.rune, len(b));
 		}
 
 		// make sure missing bytes fail
@@ -132,10 +132,10 @@ func TestDecodeRune(t *testing.T) {
 		if rune != RuneError || size != wantsize {
 			t.Errorf("DecodeRune(%q) = 0x%04x, %d want 0x%04x, %d", b[0:len(b)-1], rune, size, RuneError, wantsize);
 		}
-		s = "xxx"+m.str[0:len(m.str)-1];
-		rune, size = utf8.DecodeRuneInString(s, 3);
+		s = m.str[0:len(m.str)-1];
+		rune, size = utf8.DecodeRuneInString(s);
 		if rune != RuneError || size != wantsize {
-			t.Errorf("DecodeRuneInString(%q, 3) = 0x%04x, %d want 0x%04x, %d", s, rune, size, RuneError, wantsize);
+			t.Errorf("DecodeRuneInString(%q) = 0x%04x, %d want 0x%04x, %d", s, rune, size, RuneError, wantsize);
 		}
 
 		// make sure bad sequences fail
@@ -148,10 +148,10 @@ func TestDecodeRune(t *testing.T) {
 		if rune != RuneError || size != 1 {
 			t.Errorf("DecodeRune(%q) = 0x%04x, %d want 0x%04x, %d", b, rune, size, RuneError, 1);
 		}
-		s = "xxxx"+string(b);
+		s = string(b);
 		rune, size = utf8.DecodeRune(b);
 		if rune != RuneError || size != 1 {
-			t.Errorf("DecodeRuneInString(%q, 4) = 0x%04x, %d want 0x%04x, %d", s, rune, size, RuneError, 1);
+			t.Errorf("DecodeRuneInString(%q) = 0x%04x, %d want 0x%04x, %d", s, rune, size, RuneError, 1);
 		}
 	}
 }

test/stringrange.go

@@ -21,7 +21,7 @@ func main() {
 	ok := true;
 	cnum := 0;
 	for i, c = range s {
-		rune, size := utf8.DecodeRuneInString(s, i);  // check it another way
+		rune, size := utf8.DecodeRuneInString(s[i:len(s)]);  // check it another way
 		if i != offset {
 			fmt.Printf("unexpected offset %d not %d\n", i, offset);
 			ok = false;

test/utf.go

@@ -23,7 +23,7 @@ func main() {
 	var l = len(s);
 	for w, i, j := 0,0,0; i < l; i += w {
 		var r int;
-		r, w = utf8.DecodeRuneInString(s, i);
+		r, w = utf8.DecodeRuneInString(s[i:len(s)]);
 		if w == 0 { panic("zero width in string") }
 		if r != chars[j] { panic("wrong value from string") }
 		j++;