strings: define byteBitmap.isSet

LGTM=dave
R=golang-codereviews, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/109090048

diff --git a/src/pkg/strings/replace.go b/src/pkg/strings/replace.go
index c66126561339ce8fd19756744ca5019d390686aa..03fb6b249d649ce19ade31429decf03a182c8f0d 100644 (file)
--- a/src/pkg/strings/replace.go
+++ b/src/pkg/strings/replace.go
@@ -26,6 +26,10 @@ func (m *byteBitmap) set(b byte) {
        m[b>>5] |= uint32(1 << (b & 31))
 }
 
+func (m *byteBitmap) isSet(b byte) bool {
+       return m[b>>5]&uint32(1<<(b&31)) != 0
+}
+
 // NewReplacer returns a new Replacer from a list of old, new string pairs.
 // Replacements are performed in order, without overlapping matches.
 func NewReplacer(oldnew ...string) *Replacer {
@@ -51,7 +55,7 @@ func NewReplacer(oldnew ...string) *Replacer {
                bb := &byteReplacer{}
                for i := 0; i < len(oldnew); i += 2 {
                        o, n := oldnew[i][0], oldnew[i+1][0]
-                       if bb.old[o>>5]&uint32(1<<(o&31)) != 0 {
+                       if bb.old.isSet(o) {
                                // Later old->new maps do not override previous ones with the same old string.
                                continue
                        }
@@ -64,7 +68,7 @@ func NewReplacer(oldnew ...string) *Replacer {
        bs := &byteStringReplacer{}
        for i := 0; i < len(oldnew); i += 2 {
                o, new := oldnew[i][0], oldnew[i+1]
-               if bs.old[o>>5]&uint32(1<<(o&31)) != 0 {
+               if bs.old.isSet(o) {
                        // Later old->new maps do not override previous ones with the same old string.
                        continue
                }
@@ -431,7 +435,7 @@ func (r *byteReplacer) Replace(s string) string {
        var buf []byte // lazily allocated
        for i := 0; i < len(s); i++ {
                b := s[i]
-               if r.old[b>>5]&uint32(1<<(b&31)) != 0 {
+               if r.old.isSet(b) {
                        if buf == nil {
                                buf = []byte(s)
                        }
@@ -456,7 +460,7 @@ func (r *byteReplacer) WriteString(w io.Writer, s string) (n int, err error) {
                ncopy := copy(buf, s[:])
                s = s[ncopy:]
                for i, b := range buf[:ncopy] {
-                       if r.old[b>>5]&uint32(1<<(b&31)) != 0 {
+                       if r.old.isSet(b) {
                                buf[i] = r.new[b]
                        }
                }
@@ -486,7 +490,7 @@ func (r *byteStringReplacer) Replace(s string) string {
        anyChanges := false
        for i := 0; i < len(s); i++ {
                b := s[i]
-               if r.old[b>>5]&uint32(1<<(b&31)) != 0 {
+               if r.old.isSet(b) {
                        anyChanges = true
                        newSize += len(r.new[b])
                } else {
@@ -500,7 +504,7 @@ func (r *byteStringReplacer) Replace(s string) string {
        bi := buf
        for i := 0; i < len(s); i++ {
                b := s[i]
-               if r.old[b>>5]&uint32(1<<(b&31)) != 0 {
+               if r.old.isSet(b) {
                        n := copy(bi, r.new[b])
                        bi = bi[n:]
                } else {
@@ -516,7 +520,7 @@ func (r *byteStringReplacer) WriteString(w io.Writer, s string) (n int, err erro
        last := 0
        for i := 0; i < len(s); i++ {
                b := s[i]
-               if r.old[b>>5]&uint32(1<<(b&31)) == 0 {
+               if !r.old.isSet(b) {
                        continue
                }
                if last != i {