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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * 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 "js/AllocPolicy.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 final {
+ int32_t start;
+ int32_t limit;
+
+ static constexpr int32_t NoMatch = -1;
+
+ MatchPair() : start(NoMatch), limit(NoMatch) {}
+
+ MatchPair(int32_t start, int32_t limit) : start(start), limit(limit) {}
+
+ size_t length() const {
+ MOZ_ASSERT(!isUndefined());
+ return limit - start;
+ }
+ bool isUndefined() const { return start < 0; }
+
+ inline bool check() const {
+ MOZ_ASSERT(limit >= start);
+ MOZ_ASSERT_IF(start < 0, start == NoMatch);
+ MOZ_ASSERT_IF(limit < 0, limit == NoMatch);
+ return true;
+ }
+
+ // Note: return int32_t instead of size_t to prevent signed => unsigned
+ // conversions in caller functions.
+ static constexpr int32_t offsetOfStart() {
+ return int32_t(offsetof(MatchPair, start));
+ }
+ static constexpr int32_t offsetOfLimit() {
+ return int32_t(offsetof(MatchPair, limit));
+ }
+};
+
+// MachPairs is used as base class for VectorMatchPairs but can also be
+// stack-allocated (without a Vector) in JIT code.
+class MatchPairs {
+ protected:
+ /* Length of pairs_. */
+ uint32_t pairCount_;
+
+ /* Raw pointer into an allocated MatchPair buffer. */
+ MatchPair* pairs_;
+
+ protected:
+ /* Not used directly: use VectorMatchPairs. */
+ MatchPairs() : pairCount_(0), pairs_(nullptr) {}
+
+ protected:
+ /* Functions used by friend classes. */
+ friend class RegExpShared;
+ friend class RegExpStatics;
+
+ void forgetArray() { pairs_ = nullptr; }
+
+ public:
+ 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
+ }
+
+ /* Querying functions in the style of RegExpStatics. */
+ bool empty() const { return pairCount_ == 0; }
+ size_t pairCount() const {
+ MOZ_ASSERT(pairCount_ > 0);
+ return pairCount_;
+ }
+
+ // Note: return int32_t instead of size_t to prevent signed => unsigned
+ // conversions in caller functions.
+ static constexpr int32_t offsetOfPairs() {
+ return int32_t(offsetof(MatchPairs, pairs_));
+ }
+ static constexpr int32_t offsetOfPairCount() {
+ return int32_t(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];
+ }
+};
+
+class VectorMatchPairs : public MatchPairs {
+ Vector<MatchPair, 10, SystemAllocPolicy> vec_;
+
+ protected:
+ friend class RegExpShared;
+ friend class RegExpStatics;
+
+ /* MatchPair buffer allocator: set pairs_ and pairCount_. */
+ bool allocOrExpandArray(size_t pairCount);
+
+ bool initArrayFrom(VectorMatchPairs& copyFrom);
+
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return vec_.sizeOfExcludingThis(mallocSizeOf);
+ }
+};
+
+} /* namespace js */
+
+#endif /* vm_MatchPairs_h */