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support []byte (more efficient) as well as string in the interfaces.

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change the names; Match is for []byte and MatchString is for string, etc.

R=rsc
DELTA=195  (155 added, 0 deleted, 40 changed)
OCL=32800
CL=32800
This commit is contained in:
Rob Pike 2009-08-05 15:44:45 -07:00
parent 5a4d431dd1
commit 3355cadf3f
7 changed files with 189 additions and 34 deletions
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143
src/pkg/regexp/regexp.go
View file

@ -645,14 +645,20 @@ func addState(s []state, inst instr, match []int) []state {
return s;
}
func (re *Regexp) doExecute(str string, pos int) []int {
// Accepts either string or bytes - the logic is identical either way.
// If bytes == nil, scan str.
func (re *Regexp) doExecute(str string, bytes []byte, pos int) []int {
var s [2][]state; // TODO: use a vector when state values (not ptrs) can be vector elements
s[0] = make([]state, 10)[0:0];
s[1] = make([]state, 10)[0:0];
in, out := 0, 1;
var final state;
found := false;
for pos <= len(str) {
end := len(str);
if bytes != nil {
end = len(bytes)
}
for pos <= end {
if !found {
// prime the pump if we haven't seen a match yet
match := make([]int, 2*(re.nbra+1));
@ -670,8 +676,12 @@ func (re *Regexp) doExecute(str string, pos int) []int {
}
charwidth := 1;
c := endOfFile;
if pos < len(str) {
c, charwidth = utf8.DecodeRuneInString(str[pos:len(str)]);
if pos < end {
if bytes == nil {
c, charwidth = utf8.DecodeRuneInString(str[pos:end]);
} else {
c, charwidth = utf8.DecodeRune(bytes[pos:end]);
}
}
for i := 0; i < len(s[in]); i++ {
st := s[in][i];
@ -681,7 +691,7 @@ func (re *Regexp) doExecute(str string, pos int) []int {
s[in] = addState(s[in], st.inst.next(), st.match)
}
case _EOT:
if pos == len(str) {
if pos == end {
s[in] = addState(s[in], st.inst.next(), st.match)
}
case _CHAR:
@ -720,7 +730,7 @@ func (re *Regexp) doExecute(str string, pos int) []int {
// choose leftmost longest
if !found || // first
st.match[0] < final.match[0] || // leftmost
(st.match[0] == final.match[0] && pos > final.match[1]) { // longest
(st.match[0] == final.match[0] && pos > final.match[1]) { // longest
final = st;
final.match[1] = pos;
}
@ -736,22 +746,41 @@ func (re *Regexp) doExecute(str string, pos int) []int {
}
// Execute matches the Regexp against the string s.
// ExecuteString matches the Regexp against the string s.
// The return value is an array of integers, in pairs, identifying the positions of
// substrings matched by the expression.
// s[a[0]:a[1]] is the substring matched by the entire expression.
// s[a[2*i]:a[2*i+1]] for i > 0 is the substring matched by the ith parenthesized subexpression.
// A negative value means the subexpression did not match any element of the string.
// An empty array means "no match".
func (re *Regexp) Execute(s string) (a []int) {
return re.doExecute(s, 0)
func (re *Regexp) ExecuteString(s string) (a []int) {
return re.doExecute(s, nil, 0)
}
// Match returns whether the Regexp matches the string s.
// Execute matches the Regexp against the byte slice b.
// The return value is an array of integers, in pairs, identifying the positions of
// subslices matched by the expression.
// b[a[0]:a[1]] is the subslice matched by the entire expression.
// b[a[2*i]:a[2*i+1]] for i > 0 is the subslice matched by the ith parenthesized subexpression.
// A negative value means the subexpression did not match any element of the slice.
// An empty array means "no match".
func (re *Regexp) Execute(b []byte) (a []int) {
return re.doExecute("", b, 0)
}
// MatchString returns whether the Regexp matches the string s.
// The return value is a boolean: true for match, false for no match.
func (re *Regexp) Match(s string) bool {
return len(re.doExecute(s, 0)) > 0
func (re *Regexp) MatchString(s string) bool {
return len(re.doExecute(s, nil, 0)) > 0
}
// Match returns whether the Regexp matches the byte slice b.
// The return value is a boolean: true for match, false for no match.
func (re *Regexp) Match(b []byte) bool {
return len(re.doExecute("", b, 0)) > 0
}
@ -761,7 +790,7 @@ func (re *Regexp) Match(s string) bool {
// a[i] for i > 0 is the substring matched by the ith parenthesized subexpression.
// An empty array means ``no match''.
func (re *Regexp) MatchStrings(s string) (a []string) {
r := re.doExecute(s, 0);
r := re.doExecute(s, nil, 0);
if r == nil {
return nil
}
@ -774,26 +803,56 @@ func (re *Regexp) MatchStrings(s string) (a []string) {
return
}
// Match checks whether a textual regular expression
// matches a substring. More complicated queries need
// MatchSlices matches the Regexp against the byte slice b.
// The return value is an array of subslices matched by the expression.
// a[0] is the subslice matched by the entire expression.
// a[i] for i > 0 is the subslice matched by the ith parenthesized subexpression.
// An empty array means ``no match''.
func (re *Regexp) MatchSlices(b []byte) (a [][]byte) {
r := re.doExecute("", b, 0);
if r == nil {
return nil
}
a = make([][]byte, len(r)/2);
for i := 0; i < len(r); i += 2 {
if r[i] != -1 { // -1 means no match for this subexpression
a[i/2] = b[r[i] : r[i+1]]
}
}
return
}
// MatchString checks whether a textual regular expression
// matches a string. More complicated queries need
// to use Compile and the full Regexp interface.
func Match(pattern string, s string) (matched bool, error os.Error) {
func MatchString(pattern string, s string) (matched bool, error os.Error) {
re, err := Compile(pattern);
if err != nil {
return false, err
}
return re.Match(s), nil
return re.MatchString(s), nil
}
// ReplaceAll returns a copy of src in which all matches for the Regexp
// Match checks whether a textual regular expression
// matches a byte slice. More complicated queries need
// to use Compile and the full Regexp interface.
func Match(pattern string, b []byte) (matched bool, error os.Error) {
re, err := Compile(pattern);
if err != nil {
return false, err
}
return re.Match(b), nil
}
// ReplaceAllString returns a copy of src in which all matches for the Regexp
// have been replaced by repl. No support is provided for expressions
// (e.g. \1 or $1) in the replacement string.
func (re *Regexp) ReplaceAll(src, repl string) string {
func (re *Regexp) ReplaceAllString(src, repl string) string {
lastMatchEnd := 0; // end position of the most recent match
searchPos := 0; // position where we next look for a match
buf := new(bytes.Buffer);
for searchPos <= len(src) {
a := re.doExecute(src, searchPos);
a := re.doExecute(src, nil, searchPos);
if len(a) == 0 {
break; // no more matches
}
@ -829,6 +888,50 @@ func (re *Regexp) ReplaceAll(src, repl string) string {
return string(buf.Data());
}
// ReplaceAll returns a copy of src in which all matches for the Regexp
// have been replaced by repl. No support is provided for expressions
// (e.g. \1 or $1) in the replacement text.
func (re *Regexp) ReplaceAll(src, repl []byte) []byte {
lastMatchEnd := 0; // end position of the most recent match
searchPos := 0; // position where we next look for a match
buf := new(bytes.Buffer);
for searchPos <= len(src) {
a := re.doExecute("", src, searchPos);
if len(a) == 0 {
break; // no more matches
}
// Copy the unmatched characters before this match.
buf.Write(src[lastMatchEnd:a[0]]);
// Now insert a copy of the replacement string, but not for a
// match of the empty string immediately after another match.
// (Otherwise, we get double replacement for patterns that
// match both empty and nonempty strings.)
if a[1] > lastMatchEnd || a[0] == 0 {
buf.Write(repl);
}
lastMatchEnd = a[1];
// Advance past this match; always advance at least one character.
rune, width := utf8.DecodeRune(src[searchPos:len(src)]);
if searchPos + width > a[1] {
searchPos += width;
} else if searchPos + 1 > a[1] {
// This clause is only needed at the end of the input
// string. In that case, DecodeRuneInString returns width=0.
searchPos++;
} else {
searchPos = a[1];
}
}
// Copy the unmatched characters after the last match.
buf.Write(src[lastMatchEnd:len(src)]);
return buf.Data();
}
// QuoteMeta returns a string that quotes all regular expression metacharacters
// inside the argument text; the returned string is a regular expression matching
// the literal text. For example, QuoteMeta(`[foo]`) returns `\[foo\]`.