1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/vm/MatchPairs.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,174 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef vm_MatchPairs_h
1.11 +#define vm_MatchPairs_h
1.12 +
1.13 +#include "jsalloc.h"
1.14 +
1.15 +#include "ds/LifoAlloc.h"
1.16 +#include "js/Vector.h"
1.17 +
1.18 +/*
1.19 + * RegExp match results are succinctly represented by pairs of integer
1.20 + * indices delimiting (start, limit] segments of the input string.
1.21 + *
1.22 + * The pair count for a given RegExp match is the capturing parentheses
1.23 + * count plus one for the "0 capturing paren" whole text match.
1.24 + */
1.25 +
1.26 +namespace js {
1.27 +
1.28 +struct MatchPair
1.29 +{
1.30 + int start;
1.31 + int limit;
1.32 +
1.33 + MatchPair()
1.34 + : start(-1), limit(-1)
1.35 + { }
1.36 +
1.37 + MatchPair(int start, int limit)
1.38 + : start(start), limit(limit)
1.39 + { }
1.40 +
1.41 + size_t length() const { JS_ASSERT(!isUndefined()); return limit - start; }
1.42 + bool isEmpty() const { return length() == 0; }
1.43 + bool isUndefined() const { return start < 0; }
1.44 +
1.45 + void displace(size_t amount) {
1.46 + start += (start < 0) ? 0 : amount;
1.47 + limit += (limit < 0) ? 0 : amount;
1.48 + }
1.49 +
1.50 + inline bool check() const {
1.51 + JS_ASSERT(limit >= start);
1.52 + JS_ASSERT_IF(start < 0, start == -1);
1.53 + JS_ASSERT_IF(limit < 0, limit == -1);
1.54 + return true;
1.55 + }
1.56 +};
1.57 +
1.58 +/* Base class for RegExp execution output. */
1.59 +class MatchPairs
1.60 +{
1.61 + protected:
1.62 + size_t pairCount_; /* Length of pairs_. */
1.63 + MatchPair *pairs_; /* Raw pointer into an allocated MatchPair buffer. */
1.64 +
1.65 + protected:
1.66 + /* Not used directly: use ScopedMatchPairs or VectorMatchPairs. */
1.67 + MatchPairs()
1.68 + : pairCount_(0), pairs_(nullptr)
1.69 + { }
1.70 +
1.71 + protected:
1.72 + /* Functions used by friend classes. */
1.73 + friend class RegExpShared;
1.74 + friend class RegExpStatics;
1.75 +
1.76 + /* MatchPair buffer allocator: set pairs_ and pairCount_. */
1.77 + virtual bool allocOrExpandArray(size_t pairCount) = 0;
1.78 +
1.79 + bool initArray(size_t pairCount);
1.80 + bool initArrayFrom(MatchPairs ©From);
1.81 + void forgetArray() { pairs_ = nullptr; }
1.82 +
1.83 + void displace(size_t disp);
1.84 + void checkAgainst(size_t inputLength) {
1.85 +#ifdef DEBUG
1.86 + for (size_t i = 0; i < pairCount_; i++) {
1.87 + const MatchPair &p = pair(i);
1.88 + JS_ASSERT(p.check());
1.89 + if (p.isUndefined())
1.90 + continue;
1.91 + JS_ASSERT(size_t(p.limit) <= inputLength);
1.92 + }
1.93 +#endif
1.94 + }
1.95 +
1.96 + public:
1.97 + /* Querying functions in the style of RegExpStatics. */
1.98 + bool empty() const { return pairCount_ == 0; }
1.99 + size_t pairCount() const { JS_ASSERT(pairCount_ > 0); return pairCount_; }
1.100 + size_t parenCount() const { return pairCount_ - 1; }
1.101 +
1.102 + public:
1.103 + unsigned *rawBuf() const { return reinterpret_cast<unsigned *>(pairs_); }
1.104 + size_t length() const { return pairCount_; }
1.105 +
1.106 + /* Pair accessors. */
1.107 + const MatchPair &pair(size_t i) const {
1.108 + JS_ASSERT(pairCount_ && i < pairCount_);
1.109 + JS_ASSERT(pairs_);
1.110 + return pairs_[i];
1.111 + }
1.112 +
1.113 + const MatchPair &operator[](size_t i) const { return pair(i); }
1.114 +};
1.115 +
1.116 +/* MatchPairs allocated into temporary storage, removed when out of scope. */
1.117 +class ScopedMatchPairs : public MatchPairs
1.118 +{
1.119 + LifoAllocScope lifoScope_;
1.120 +
1.121 + public:
1.122 + /* Constructs an implicit LifoAllocScope. */
1.123 + ScopedMatchPairs(LifoAlloc *lifoAlloc)
1.124 + : lifoScope_(lifoAlloc)
1.125 + { }
1.126 +
1.127 + const MatchPair &operator[](size_t i) const { return pair(i); }
1.128 +
1.129 + protected:
1.130 + bool allocOrExpandArray(size_t pairCount);
1.131 +};
1.132 +
1.133 +/*
1.134 + * MatchPairs allocated into permanent storage, for RegExpStatics.
1.135 + * The Vector of MatchPairs is reusable by Vector expansion.
1.136 + */
1.137 +class VectorMatchPairs : public MatchPairs
1.138 +{
1.139 + Vector<MatchPair, 10, SystemAllocPolicy> vec_;
1.140 +
1.141 + public:
1.142 + VectorMatchPairs() {
1.143 + vec_.clear();
1.144 + }
1.145 +
1.146 + const MatchPair &operator[](size_t i) const { return pair(i); }
1.147 +
1.148 + protected:
1.149 + friend class RegExpStatics;
1.150 + bool allocOrExpandArray(size_t pairCount);
1.151 +};
1.152 +
1.153 +/*
1.154 + * Passes either MatchPair or MatchPairs through ExecuteRegExp()
1.155 + * to avoid duplication of generic code.
1.156 + */
1.157 +struct MatchConduit
1.158 +{
1.159 + union {
1.160 + MatchPair *pair;
1.161 + MatchPairs *pairs;
1.162 + } u;
1.163 + bool isPair;
1.164 +
1.165 + explicit MatchConduit(MatchPair *pair) {
1.166 + isPair = true;
1.167 + u.pair = pair;
1.168 + }
1.169 + explicit MatchConduit(MatchPairs *pairs) {
1.170 + isPair = false;
1.171 + u.pairs = pairs;
1.172 + }
1.173 +};
1.174 +
1.175 +} /* namespace js */
1.176 +
1.177 +#endif /* vm_MatchPairs_h */
