strconv: remove dependency on bytes

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5759044

diff --git a/src/pkg/go/build/deps_test.go b/src/pkg/go/build/deps_test.go
index b9f4b127ab4d16a85119eb0947593e0dbcb737cc..9038924058125226c059042e5c5130342f98118e 100644 (file)
--- a/src/pkg/go/build/deps_test.go
+++ b/src/pkg/go/build/deps_test.go
@@ -52,7 +52,7 @@ var pkgDeps = map[string][]string{
        "math/rand":     {"L0", "math"},
        "path":          {"L0", "unicode/utf8", "strings"},
        "sort":          {"math"},
-       "strconv":       {"L0", "bytes", "unicode", "unicode/utf8", "math", "strings"},
+       "strconv":       {"L0", "unicode", "unicode/utf8", "math", "strings"},
        "strings":       {"L0", "unicode", "unicode/utf8"},
        "unicode":       {},
        "unicode/utf16": {},

diff --git a/src/pkg/strconv/quote.go b/src/pkg/strconv/quote.go
index 61dbcae70f4b2892d14492a69e07c26dda0e0687..57cdae1738e79eac3ddca4089e7d433b778cf79b 100644 (file)
--- a/src/pkg/strconv/quote.go
+++ b/src/pkg/strconv/quote.go
@@ -5,7 +5,6 @@
 package strconv
 
 import (
-       "bytes"
        "strings"
        "unicode"
        "unicode/utf8"
@@ -14,8 +13,9 @@ import (
 const lowerhex = "0123456789abcdef"
 
 func quoteWith(s string, quote byte, ASCIIonly bool) string {
-       var buf bytes.Buffer
-       buf.WriteByte(quote)
+       var runeTmp [utf8.UTFMax]byte
+       buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations.
+       buf = append(buf, quote)
        for width := 0; len(s) > 0; s = s[width:] {
                r := rune(s[0])
                width = 1
@@ -23,64 +23,65 @@ func quoteWith(s string, quote byte, ASCIIonly bool) string {
                        r, width = utf8.DecodeRuneInString(s)
                }
                if width == 1 && r == utf8.RuneError {
-                       buf.WriteString(`\x`)
-                       buf.WriteByte(lowerhex[s[0]>>4])
-                       buf.WriteByte(lowerhex[s[0]&0xF])
+                       buf = append(buf, `\x`...)
+                       buf = append(buf, lowerhex[s[0]>>4])
+                       buf = append(buf, lowerhex[s[0]&0xF])
                        continue
                }
                if r == rune(quote) || r == '\\' { // always backslashed
-                       buf.WriteByte('\\')
-                       buf.WriteByte(byte(r))
+                       buf = append(buf, '\\')
+                       buf = append(buf, byte(r))
                        continue
                }
                if ASCIIonly {
                        if r <= unicode.MaxASCII && unicode.IsPrint(r) {
-                               buf.WriteRune(r)
+                               buf = append(buf, byte(r))
                                continue
                        }
                } else if unicode.IsPrint(r) {
-                       buf.WriteRune(r)
+                       n := utf8.EncodeRune(runeTmp[:], r)
+                       buf = append(buf, runeTmp[:n]...)
                        continue
                }
                switch r {
                case '\a':
-                       buf.WriteString(`\a`)
+                       buf = append(buf, `\a`...)
                case '\b':
-                       buf.WriteString(`\b`)
+                       buf = append(buf, `\b`...)
                case '\f':
-                       buf.WriteString(`\f`)
+                       buf = append(buf, `\f`...)
                case '\n':
-                       buf.WriteString(`\n`)
+                       buf = append(buf, `\n`...)
                case '\r':
-                       buf.WriteString(`\r`)
+                       buf = append(buf, `\r`...)
                case '\t':
-                       buf.WriteString(`\t`)
+                       buf = append(buf, `\t`...)
                case '\v':
-                       buf.WriteString(`\v`)
+                       buf = append(buf, `\v`...)
                default:
                        switch {
                        case r < ' ':
-                               buf.WriteString(`\x`)
-                               buf.WriteByte(lowerhex[s[0]>>4])
-                               buf.WriteByte(lowerhex[s[0]&0xF])
+                               buf = append(buf, `\x`...)
+                               buf = append(buf, lowerhex[s[0]>>4])
+                               buf = append(buf, lowerhex[s[0]&0xF])
                        case r > unicode.MaxRune:
                                r = 0xFFFD
                                fallthrough
                        case r < 0x10000:
-                               buf.WriteString(`\u`)
+                               buf = append(buf, `\u`...)
                                for s := 12; s >= 0; s -= 4 {
-                                       buf.WriteByte(lowerhex[r>>uint(s)&0xF])
+                                       buf = append(buf, lowerhex[r>>uint(s)&0xF])
                                }
                        default:
-                               buf.WriteString(`\U`)
+                               buf = append(buf, `\U`...)
                                for s := 28; s >= 0; s -= 4 {
-                                       buf.WriteByte(lowerhex[r>>uint(s)&0xF])
+                                       buf = append(buf, lowerhex[r>>uint(s)&0xF])
                                }
                        }
                }
        }
-       buf.WriteByte(quote)
-       return buf.String()
+       buf = append(buf, quote)
+       return string(buf)
 
 }
 
@@ -329,7 +330,8 @@ func Unquote(s string) (t string, err error) {
                }
        }
 
-       var buf bytes.Buffer
+       var runeTmp [utf8.UTFMax]byte
+       buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations.
        for len(s) > 0 {
                c, multibyte, ss, err := UnquoteChar(s, quote)
                if err != nil {
@@ -337,14 +339,15 @@ func Unquote(s string) (t string, err error) {
                }
                s = ss
                if c < utf8.RuneSelf || !multibyte {
-                       buf.WriteByte(byte(c))
+                       buf = append(buf, byte(c))
                } else {
-                       buf.WriteString(string(c))
+                       n := utf8.EncodeRune(runeTmp[:], c)
+                       buf = append(buf, runeTmp[:n]...)
                }
                if quote == '\'' && len(s) != 0 {
                        // single-quoted must be single character
                        return "", ErrSyntax
                }
        }
-       return buf.String(), nil
+       return string(buf), nil
 }