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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef vm_MatchPairs_h
+#define vm_MatchPairs_h
+
+#include "jsalloc.h"
+
+#include "ds/LifoAlloc.h"
+#include "js/Vector.h"
+
+/*
+ * RegExp match results are succinctly represented by pairs of integer
+ * indices delimiting (start, limit] segments of the input string.
+ *
+ * The pair count for a given RegExp match is the capturing parentheses
+ * count plus one for the "0 capturing paren" whole text match.
+ */
+
+namespace js {
+
+struct MatchPair
+{
+ int32_t start;
+ int32_t limit;
+
+ MatchPair()
+ : start(-1), limit(-1)
+ { }
+
+ MatchPair(int32_t start, int32_t limit)
+ : start(start), limit(limit)
+ { }
+
+ size_t length() const { MOZ_ASSERT(!isUndefined()); return limit - start; }
+ bool isEmpty() const { return length() == 0; }
+ bool isUndefined() const { return start < 0; }
+
+ void displace(size_t amount) {
+ start += (start < 0) ? 0 : amount;
+ limit += (limit < 0) ? 0 : amount;
+ }
+
+ inline bool check() const {
+ MOZ_ASSERT(limit >= start);
+ MOZ_ASSERT_IF(start < 0, start == -1);
+ MOZ_ASSERT_IF(limit < 0, limit == -1);
+ return true;
+ }
+};
+
+/* Base class for RegExp execution output. */
+class MatchPairs
+{
+ protected:
+ /* Length of pairs_. */
+ uint32_t pairCount_;
+
+ /* Raw pointer into an allocated MatchPair buffer. */
+ MatchPair* pairs_;
+
+ protected:
+ /* Not used directly: use ScopedMatchPairs or VectorMatchPairs. */
+ MatchPairs()
+ : pairCount_(0), pairs_(nullptr)
+ { }
+
+ protected:
+ /* Functions used by friend classes. */
+ friend class RegExpShared;
+ friend class RegExpStatics;
+
+ /* MatchPair buffer allocator: set pairs_ and pairCount_. */
+ virtual bool allocOrExpandArray(size_t pairCount) = 0;
+
+ bool initArrayFrom(MatchPairs& copyFrom);
+ void forgetArray() { pairs_ = nullptr; }
+
+ void checkAgainst(size_t inputLength) {
+#ifdef DEBUG
+ for (size_t i = 0; i < pairCount_; i++) {
+ const MatchPair& p = (*this)[i];
+ MOZ_ASSERT(p.check());
+ if (p.isUndefined())
+ continue;
+ MOZ_ASSERT(size_t(p.limit) <= inputLength);
+ }
+#endif
+ }
+
+ public:
+ /* Querying functions in the style of RegExpStatics. */
+ bool empty() const { return pairCount_ == 0; }
+ size_t pairCount() const { MOZ_ASSERT(pairCount_ > 0); return pairCount_; }
+ size_t parenCount() const { return pairCount_ - 1; }
+
+ static size_t offsetOfPairs() { return offsetof(MatchPairs, pairs_); }
+ static size_t offsetOfPairCount() { return offsetof(MatchPairs, pairCount_); }
+
+ int32_t* pairsRaw() { return reinterpret_cast<int32_t*>(pairs_); }
+
+ public:
+ size_t length() const { return pairCount_; }
+
+ const MatchPair& operator[](size_t i) const {
+ MOZ_ASSERT(i < pairCount_);
+ return pairs_[i];
+ }
+ MatchPair& operator[](size_t i) {
+ MOZ_ASSERT(i < pairCount_);
+ return pairs_[i];
+ }
+};
+
+/* MatchPairs allocated into temporary storage, removed when out of scope. */
+class ScopedMatchPairs : public MatchPairs
+{
+ LifoAllocScope lifoScope_;
+
+ public:
+ /* Constructs an implicit LifoAllocScope. */
+ explicit ScopedMatchPairs(LifoAlloc* lifoAlloc)
+ : lifoScope_(lifoAlloc)
+ { }
+
+ protected:
+ bool allocOrExpandArray(size_t pairCount);
+};
+
+/*
+ * MatchPairs allocated into permanent storage, for RegExpStatics.
+ * The Vector of MatchPairs is reusable by Vector expansion.
+ */
+class VectorMatchPairs : public MatchPairs
+{
+ Vector<MatchPair, 10, SystemAllocPolicy> vec_;
+
+ public:
+ VectorMatchPairs() {
+ vec_.clear();
+ }
+
+ protected:
+ friend class RegExpStatics;
+ bool allocOrExpandArray(size_t pairCount);
+};
+
+} /* namespace js */
+
+#endif /* vm_MatchPairs_h */