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// Copyright 2009 The RE2 Authors. All Rights Reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "util/test.h"
#include "re2/regexp.h"
#include "re2/walker-inl.h"
namespace re2 {
// Null walker. For benchmarking the walker itself.
class NullWalker : public Regexp::Walker<bool> {
public:
NullWalker() { }
bool PostVisit(Regexp* re, bool parent_arg, bool pre_arg,
bool* child_args, int nchild_args);
bool ShortVisit(Regexp* re, bool a) {
// Should never be called: we use Walk not WalkExponential.
LOG(DFATAL) << "NullWalker::ShortVisit called";
return a;
}
private:
DISALLOW_EVIL_CONSTRUCTORS(NullWalker);
};
// Called after visiting re's children. child_args contains the return
// value from each of the children's PostVisits (i.e., whether each child
// can match an empty string). Returns whether this clause can match an
// empty string.
bool NullWalker::PostVisit(Regexp* re, bool parent_arg, bool pre_arg,
bool* child_args, int nchild_args) {
return false;
}
// Returns whether re can match an empty string.
void Regexp::NullWalk() {
NullWalker w;
w.Walk(this, false);
}
} // namespace re2
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