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Diffstat (limited to 'include/rapidjson/internal/regex.h')
| -rw-r--r-- | include/rapidjson/internal/regex.h | 740 |
1 files changed, 740 insertions, 0 deletions
diff --git a/include/rapidjson/internal/regex.h b/include/rapidjson/internal/regex.h new file mode 100644 index 0000000..16e3559 --- /dev/null +++ b/include/rapidjson/internal/regex.h @@ -0,0 +1,740 @@ +// Tencent is pleased to support the open source community by making RapidJSON available. +// +// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved. +// +// Licensed under the MIT License (the "License"); you may not use this file except +// in compliance with the License. You may obtain a copy of the License at +// +// http://opensource.org/licenses/MIT +// +// Unless required by applicable law or agreed to in writing, software distributed +// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR +// CONDITIONS OF ANY KIND, either express or implied. See the License for the +// specific language governing permissions and limitations under the License. + +#ifndef RAPIDJSON_INTERNAL_REGEX_H_ +#define RAPIDJSON_INTERNAL_REGEX_H_ + +#include "../allocators.h" +#include "../stream.h" +#include "stack.h" + +#ifdef __clang__ +RAPIDJSON_DIAG_PUSH +RAPIDJSON_DIAG_OFF(padded) +RAPIDJSON_DIAG_OFF(switch-enum) +RAPIDJSON_DIAG_OFF(implicit-fallthrough) +#elif defined(_MSC_VER) +RAPIDJSON_DIAG_PUSH +RAPIDJSON_DIAG_OFF(4512) // assignment operator could not be generated +#endif + +#ifdef __GNUC__ +RAPIDJSON_DIAG_PUSH +RAPIDJSON_DIAG_OFF(effc++) +#if __GNUC__ >= 7 +RAPIDJSON_DIAG_OFF(implicit-fallthrough) +#endif +#endif + +#ifndef RAPIDJSON_REGEX_VERBOSE +#define RAPIDJSON_REGEX_VERBOSE 0 +#endif + +RAPIDJSON_NAMESPACE_BEGIN +namespace internal { + +/////////////////////////////////////////////////////////////////////////////// +// DecodedStream + +template <typename SourceStream, typename Encoding> +class DecodedStream { +public: + DecodedStream(SourceStream& ss) : ss_(ss), codepoint_() { Decode(); } + unsigned Peek() { return codepoint_; } + unsigned Take() { + unsigned c = codepoint_; + if (c) // No further decoding when '\0' + Decode(); + return c; + } + +private: + void Decode() { + if (!Encoding::Decode(ss_, &codepoint_)) + codepoint_ = 0; + } + + SourceStream& ss_; + unsigned codepoint_; +}; + +/////////////////////////////////////////////////////////////////////////////// +// GenericRegex + +static const SizeType kRegexInvalidState = ~SizeType(0); //!< Represents an invalid index in GenericRegex::State::out, out1 +static const SizeType kRegexInvalidRange = ~SizeType(0); + +template <typename Encoding, typename Allocator> +class GenericRegexSearch; + +//! Regular expression engine with subset of ECMAscript grammar. +/*! + Supported regular expression syntax: + - \c ab Concatenation + - \c a|b Alternation + - \c a? Zero or one + - \c a* Zero or more + - \c a+ One or more + - \c a{3} Exactly 3 times + - \c a{3,} At least 3 times + - \c a{3,5} 3 to 5 times + - \c (ab) Grouping + - \c ^a At the beginning + - \c a$ At the end + - \c . Any character + - \c [abc] Character classes + - \c [a-c] Character class range + - \c [a-z0-9_] Character class combination + - \c [^abc] Negated character classes + - \c [^a-c] Negated character class range + - \c [\b] Backspace (U+0008) + - \c \\| \\\\ ... Escape characters + - \c \\f Form feed (U+000C) + - \c \\n Line feed (U+000A) + - \c \\r Carriage return (U+000D) + - \c \\t Tab (U+0009) + - \c \\v Vertical tab (U+000B) + + \note This is a Thompson NFA engine, implemented with reference to + Cox, Russ. "Regular Expression Matching Can Be Simple And Fast (but is slow in Java, Perl, PHP, Python, Ruby,...).", + https://swtch.com/~rsc/regexp/regexp1.html +*/ +template <typename Encoding, typename Allocator = CrtAllocator> +class GenericRegex { +public: + typedef Encoding EncodingType; + typedef typename Encoding::Ch Ch; + template <typename, typename> friend class GenericRegexSearch; + + GenericRegex(const Ch* source, Allocator* allocator = 0) : + ownAllocator_(allocator ? 0 : RAPIDJSON_NEW(Allocator)()), allocator_(allocator ? allocator : ownAllocator_), + states_(allocator_, 256), ranges_(allocator_, 256), root_(kRegexInvalidState), stateCount_(), rangeCount_(), + anchorBegin_(), anchorEnd_() + { + GenericStringStream<Encoding> ss(source); + DecodedStream<GenericStringStream<Encoding>, Encoding> ds(ss); + Parse(ds); + } + + ~GenericRegex() + { + RAPIDJSON_DELETE(ownAllocator_); + } + + bool IsValid() const { + return root_ != kRegexInvalidState; + } + +private: + enum Operator { + kZeroOrOne, + kZeroOrMore, + kOneOrMore, + kConcatenation, + kAlternation, + kLeftParenthesis + }; + + static const unsigned kAnyCharacterClass = 0xFFFFFFFF; //!< For '.' + static const unsigned kRangeCharacterClass = 0xFFFFFFFE; + static const unsigned kRangeNegationFlag = 0x80000000; + + struct Range { + unsigned start; // + unsigned end; + SizeType next; + }; + + struct State { + SizeType out; //!< Equals to kInvalid for matching state + SizeType out1; //!< Equals to non-kInvalid for split + SizeType rangeStart; + unsigned codepoint; + }; + + struct Frag { + Frag(SizeType s, SizeType o, SizeType m) : start(s), out(o), minIndex(m) {} + SizeType start; + SizeType out; //!< link-list of all output states + SizeType minIndex; + }; + + State& GetState(SizeType index) { + RAPIDJSON_ASSERT(index < stateCount_); + return states_.template Bottom<State>()[index]; + } + + const State& GetState(SizeType index) const { + RAPIDJSON_ASSERT(index < stateCount_); + return states_.template Bottom<State>()[index]; + } + + Range& GetRange(SizeType index) { + RAPIDJSON_ASSERT(index < rangeCount_); + return ranges_.template Bottom<Range>()[index]; + } + + const Range& GetRange(SizeType index) const { + RAPIDJSON_ASSERT(index < rangeCount_); + return ranges_.template Bottom<Range>()[index]; + } + + template <typename InputStream> + void Parse(DecodedStream<InputStream, Encoding>& ds) { + Stack<Allocator> operandStack(allocator_, 256); // Frag + Stack<Allocator> operatorStack(allocator_, 256); // Operator + Stack<Allocator> atomCountStack(allocator_, 256); // unsigned (Atom per parenthesis) + + *atomCountStack.template Push<unsigned>() = 0; + + unsigned codepoint; + while (ds.Peek() != 0) { + switch (codepoint = ds.Take()) { + case '^': + anchorBegin_ = true; + break; + + case '$': + anchorEnd_ = true; + break; + + case '|': + while (!operatorStack.Empty() && *operatorStack.template Top<Operator>() < kAlternation) + if (!Eval(operandStack, *operatorStack.template Pop<Operator>(1))) + return; + *operatorStack.template Push<Operator>() = kAlternation; + *atomCountStack.template Top<unsigned>() = 0; + break; + + case '(': + *operatorStack.template Push<Operator>() = kLeftParenthesis; + *atomCountStack.template Push<unsigned>() = 0; + break; + + case ')': + while (!operatorStack.Empty() && *operatorStack.template Top<Operator>() != kLeftParenthesis) + if (!Eval(operandStack, *operatorStack.template Pop<Operator>(1))) + return; + if (operatorStack.Empty()) + return; + operatorStack.template Pop<Operator>(1); + atomCountStack.template Pop<unsigned>(1); + ImplicitConcatenation(atomCountStack, operatorStack); + break; + + case '?': + if (!Eval(operandStack, kZeroOrOne)) + return; + break; + + case '*': + if (!Eval(operandStack, kZeroOrMore)) + return; + break; + + case '+': + if (!Eval(operandStack, kOneOrMore)) + return; + break; + + case '{': + { + unsigned n, m; + if (!ParseUnsigned(ds, &n)) + return; + + if (ds.Peek() == ',') { + ds.Take(); + if (ds.Peek() == '}') + m = kInfinityQuantifier; + else if (!ParseUnsigned(ds, &m) || m < n) + return; + } + else + m = n; + + if (!EvalQuantifier(operandStack, n, m) || ds.Peek() != '}') + return; + ds.Take(); + } + break; + + case '.': + PushOperand(operandStack, kAnyCharacterClass); + ImplicitConcatenation(atomCountStack, operatorStack); + break; + + case '[': + { + SizeType range; + if (!ParseRange(ds, &range)) + return; + SizeType s = NewState(kRegexInvalidState, kRegexInvalidState, kRangeCharacterClass); + GetState(s).rangeStart = range; + *operandStack.template Push<Frag>() = Frag(s, s, s); + } + ImplicitConcatenation(atomCountStack, operatorStack); + break; + + case '\\': // Escape character + if (!CharacterEscape(ds, &codepoint)) + return; // Unsupported escape character + // fall through to default + + default: // Pattern character + PushOperand(operandStack, codepoint); + ImplicitConcatenation(atomCountStack, operatorStack); + } + } + + while (!operatorStack.Empty()) + if (!Eval(operandStack, *operatorStack.template Pop<Operator>(1))) + return; + + // Link the operand to matching state. + if (operandStack.GetSize() == sizeof(Frag)) { + Frag* e = operandStack.template Pop<Frag>(1); + Patch(e->out, NewState(kRegexInvalidState, kRegexInvalidState, 0)); + root_ = e->start; + +#if RAPIDJSON_REGEX_VERBOSE + printf("root: %d\n", root_); + for (SizeType i = 0; i < stateCount_ ; i++) { + State& s = GetState(i); + printf("[%2d] out: %2d out1: %2d c: '%c'\n", i, s.out, s.out1, (char)s.codepoint); + } + printf("\n"); +#endif + } + } + + SizeType NewState(SizeType out, SizeType out1, unsigned codepoint) { + State* s = states_.template Push<State>(); + s->out = out; + s->out1 = out1; + s->codepoint = codepoint; + s->rangeStart = kRegexInvalidRange; + return stateCount_++; + } + + void PushOperand(Stack<Allocator>& operandStack, unsigned codepoint) { + SizeType s = NewState(kRegexInvalidState, kRegexInvalidState, codepoint); + *operandStack.template Push<Frag>() = Frag(s, s, s); + } + + void ImplicitConcatenation(Stack<Allocator>& atomCountStack, Stack<Allocator>& operatorStack) { + if (*atomCountStack.template Top<unsigned>()) + *operatorStack.template Push<Operator>() = kConcatenation; + (*atomCountStack.template Top<unsigned>())++; + } + + SizeType Append(SizeType l1, SizeType l2) { + SizeType old = l1; + while (GetState(l1).out != kRegexInvalidState) + l1 = GetState(l1).out; + GetState(l1).out = l2; + return old; + } + + void Patch(SizeType l, SizeType s) { + for (SizeType next; l != kRegexInvalidState; l = next) { + next = GetState(l).out; + GetState(l).out = s; + } + } + + bool Eval(Stack<Allocator>& operandStack, Operator op) { + switch (op) { + case kConcatenation: + RAPIDJSON_ASSERT(operandStack.GetSize() >= sizeof(Frag) * 2); + { + Frag e2 = *operandStack.template Pop<Frag>(1); + Frag e1 = *operandStack.template Pop<Frag>(1); + Patch(e1.out, e2.start); + *operandStack.template Push<Frag>() = Frag(e1.start, e2.out, Min(e1.minIndex, e2.minIndex)); + } + return true; + + case kAlternation: + if (operandStack.GetSize() >= sizeof(Frag) * 2) { + Frag e2 = *operandStack.template Pop<Frag>(1); + Frag e1 = *operandStack.template Pop<Frag>(1); + SizeType s = NewState(e1.start, e2.start, 0); + *operandStack.template Push<Frag>() = Frag(s, Append(e1.out, e2.out), Min(e1.minIndex, e2.minIndex)); + return true; + } + return false; + + case kZeroOrOne: + if (operandStack.GetSize() >= sizeof(Frag)) { + Frag e = *operandStack.template Pop<Frag>(1); + SizeType s = NewState(kRegexInvalidState, e.start, 0); + *operandStack.template Push<Frag>() = Frag(s, Append(e.out, s), e.minIndex); + return true; + } + return false; + + case kZeroOrMore: + if (operandStack.GetSize() >= sizeof(Frag)) { + Frag e = *operandStack.template Pop<Frag>(1); + SizeType s = NewState(kRegexInvalidState, e.start, 0); + Patch(e.out, s); + *operandStack.template Push<Frag>() = Frag(s, s, e.minIndex); + return true; + } + return false; + + case kOneOrMore: + if (operandStack.GetSize() >= sizeof(Frag)) { + Frag e = *operandStack.template Pop<Frag>(1); + SizeType s = NewState(kRegexInvalidState, e.start, 0); + Patch(e.out, s); + *operandStack.template Push<Frag>() = Frag(e.start, s, e.minIndex); + return true; + } + return false; + + default: + // syntax error (e.g. unclosed kLeftParenthesis) + return false; + } + } + + bool EvalQuantifier(Stack<Allocator>& operandStack, unsigned n, unsigned m) { + RAPIDJSON_ASSERT(n <= m); + RAPIDJSON_ASSERT(operandStack.GetSize() >= sizeof(Frag)); + + if (n == 0) { + if (m == 0) // a{0} not support + return false; + else if (m == kInfinityQuantifier) + Eval(operandStack, kZeroOrMore); // a{0,} -> a* + else { + Eval(operandStack, kZeroOrOne); // a{0,5} -> a? + for (unsigned i = 0; i < m - 1; i++) + CloneTopOperand(operandStack); // a{0,5} -> a? a? a? a? a? + for (unsigned i = 0; i < m - 1; i++) + Eval(operandStack, kConcatenation); // a{0,5} -> a?a?a?a?a? + } + return true; + } + + for (unsigned i = 0; i < n - 1; i++) // a{3} -> a a a + CloneTopOperand(operandStack); + + if (m == kInfinityQuantifier) + Eval(operandStack, kOneOrMore); // a{3,} -> a a a+ + else if (m > n) { + CloneTopOperand(operandStack); // a{3,5} -> a a a a + Eval(operandStack, kZeroOrOne); // a{3,5} -> a a a a? + for (unsigned i = n; i < m - 1; i++) + CloneTopOperand(operandStack); // a{3,5} -> a a a a? a? + for (unsigned i = n; i < m; i++) + Eval(operandStack, kConcatenation); // a{3,5} -> a a aa?a? + } + + for (unsigned i = 0; i < n - 1; i++) + Eval(operandStack, kConcatenation); // a{3} -> aaa, a{3,} -> aaa+, a{3.5} -> aaaa?a? + + return true; + } + + static SizeType Min(SizeType a, SizeType b) { return a < b ? a : b; } + + void CloneTopOperand(Stack<Allocator>& operandStack) { + const Frag src = *operandStack.template Top<Frag>(); // Copy constructor to prevent invalidation + SizeType count = stateCount_ - src.minIndex; // Assumes top operand contains states in [src->minIndex, stateCount_) + State* s = states_.template Push<State>(count); + memcpy(s, &GetState(src.minIndex), count * sizeof(State)); + for (SizeType j = 0; j < count; j++) { + if (s[j].out != kRegexInvalidState) + s[j].out += count; + if (s[j].out1 != kRegexInvalidState) + s[j].out1 += count; + } + *operandStack.template Push<Frag>() = Frag(src.start + count, src.out + count, src.minIndex + count); + stateCount_ += count; + } + + template <typename InputStream> + bool ParseUnsigned(DecodedStream<InputStream, Encoding>& ds, unsigned* u) { + unsigned r = 0; + if (ds.Peek() < '0' || ds.Peek() > '9') + return false; + while (ds.Peek() >= '0' && ds.Peek() <= '9') { + if (r >= 429496729 && ds.Peek() > '5') // 2^32 - 1 = 4294967295 + return false; // overflow + r = r * 10 + (ds.Take() - '0'); + } + *u = r; + return true; + } + + template <typename InputStream> + bool ParseRange(DecodedStream<InputStream, Encoding>& ds, SizeType* range) { + bool isBegin = true; + bool negate = false; + int step = 0; + SizeType start = kRegexInvalidRange; + SizeType current = kRegexInvalidRange; + unsigned codepoint; + while ((codepoint = ds.Take()) != 0) { + if (isBegin) { + isBegin = false; + if (codepoint == '^') { + negate = true; + continue; + } + } + + switch (codepoint) { + case ']': + if (start == kRegexInvalidRange) + return false; // Error: nothing inside [] + if (step == 2) { // Add trailing '-' + SizeType r = NewRange('-'); + RAPIDJSON_ASSERT(current != kRegexInvalidRange); + GetRange(current).next = r; + } + if (negate) + GetRange(start).start |= kRangeNegationFlag; + *range = start; + return true; + + case '\\': + if (ds.Peek() == 'b') { + ds.Take(); + codepoint = 0x0008; // Escape backspace character + } + else if (!CharacterEscape(ds, &codepoint)) + return false; + // fall through to default + + default: + switch (step) { + case 1: + if (codepoint == '-') { + step++; + break; + } + // fall through to step 0 for other characters + + case 0: + { + SizeType r = NewRange(codepoint); + if (current != kRegexInvalidRange) + GetRange(current).next = r; + if (start == kRegexInvalidRange) + start = r; + current = r; + } + step = 1; + break; + + default: + RAPIDJSON_ASSERT(step == 2); + GetRange(current).end = codepoint; + step = 0; + } + } + } + return false; + } + + SizeType NewRange(unsigned codepoint) { + Range* r = ranges_.template Push<Range>(); + r->start = r->end = codepoint; + r->next = kRegexInvalidRange; + return rangeCount_++; + } + + template <typename InputStream> + bool CharacterEscape(DecodedStream<InputStream, Encoding>& ds, unsigned* escapedCodepoint) { + unsigned codepoint; + switch (codepoint = ds.Take()) { + case '^': + case '$': + case '|': + case '(': + case ')': + case '?': + case '*': + case '+': + case '.': + case '[': + case ']': + case '{': + case '}': + case '\\': + *escapedCodepoint = codepoint; return true; + case 'f': *escapedCodepoint = 0x000C; return true; + case 'n': *escapedCodepoint = 0x000A; return true; + case 'r': *escapedCodepoint = 0x000D; return true; + case 't': *escapedCodepoint = 0x0009; return true; + case 'v': *escapedCodepoint = 0x000B; return true; + default: + return false; // Unsupported escape character + } + } + + Allocator* ownAllocator_; + Allocator* allocator_; + Stack<Allocator> states_; + Stack<Allocator> ranges_; + SizeType root_; + SizeType stateCount_; + SizeType rangeCount_; + + static const unsigned kInfinityQuantifier = ~0u; + + // For SearchWithAnchoring() + bool anchorBegin_; + bool anchorEnd_; +}; + +template <typename RegexType, typename Allocator = CrtAllocator> +class GenericRegexSearch { +public: + typedef typename RegexType::EncodingType Encoding; + typedef typename Encoding::Ch Ch; + + GenericRegexSearch(const RegexType& regex, Allocator* allocator = 0) : + regex_(regex), allocator_(allocator), ownAllocator_(0), + state0_(allocator, 0), state1_(allocator, 0), stateSet_() + { + RAPIDJSON_ASSERT(regex_.IsValid()); + if (!allocator_) + ownAllocator_ = allocator_ = RAPIDJSON_NEW(Allocator)(); + stateSet_ = static_cast<unsigned*>(allocator_->Malloc(GetStateSetSize())); + state0_.template Reserve<SizeType>(regex_.stateCount_); + state1_.template Reserve<SizeType>(regex_.stateCount_); + } + + ~GenericRegexSearch() { + Allocator::Free(stateSet_); + RAPIDJSON_DELETE(ownAllocator_); + } + + template <typename InputStream> + bool Match(InputStream& is) { + return SearchWithAnchoring(is, true, true); + } + + bool Match(const Ch* s) { + GenericStringStream<Encoding> is(s); + return Match(is); + } + + template <typename InputStream> + bool Search(InputStream& is) { + return SearchWithAnchoring(is, regex_.anchorBegin_, regex_.anchorEnd_); + } + + bool Search(const Ch* s) { + GenericStringStream<Encoding> is(s); + return Search(is); + } + +private: + typedef typename RegexType::State State; + typedef typename RegexType::Range Range; + + template <typename InputStream> + bool SearchWithAnchoring(InputStream& is, bool anchorBegin, bool anchorEnd) { + DecodedStream<InputStream, Encoding> ds(is); + + state0_.Clear(); + Stack<Allocator> *current = &state0_, *next = &state1_; + const size_t stateSetSize = GetStateSetSize(); + std::memset(stateSet_, 0, stateSetSize); + + bool matched = AddState(*current, regex_.root_); + unsigned codepoint; + while (!current->Empty() && (codepoint = ds.Take()) != 0) { + std::memset(stateSet_, 0, stateSetSize); + next->Clear(); + matched = false; + for (const SizeType* s = current->template Bottom<SizeType>(); s != current->template End<SizeType>(); ++s) { + const State& sr = regex_.GetState(*s); + if (sr.codepoint == codepoint || + sr.codepoint == RegexType::kAnyCharacterClass || + (sr.codepoint == RegexType::kRangeCharacterClass && MatchRange(sr.rangeStart, codepoint))) + { + matched = AddState(*next, sr.out) || matched; + if (!anchorEnd && matched) + return true; + } + if (!anchorBegin) + AddState(*next, regex_.root_); + } + internal::Swap(current, next); + } + + return matched; + } + + size_t GetStateSetSize() const { + return (regex_.stateCount_ + 31) / 32 * 4; + } + + // Return whether the added states is a match state + bool AddState(Stack<Allocator>& l, SizeType index) { + RAPIDJSON_ASSERT(index != kRegexInvalidState); + + const State& s = regex_.GetState(index); + if (s.out1 != kRegexInvalidState) { // Split + bool matched = AddState(l, s.out); + return AddState(l, s.out1) || matched; + } + else if (!(stateSet_[index >> 5] & (1u << (index & 31)))) { + stateSet_[index >> 5] |= (1u << (index & 31)); + *l.template PushUnsafe<SizeType>() = index; + } + return s.out == kRegexInvalidState; // by using PushUnsafe() above, we can ensure s is not validated due to reallocation. + } + + bool MatchRange(SizeType rangeIndex, unsigned codepoint) const { + bool yes = (regex_.GetRange(rangeIndex).start & RegexType::kRangeNegationFlag) == 0; + while (rangeIndex != kRegexInvalidRange) { + const Range& r = regex_.GetRange(rangeIndex); + if (codepoint >= (r.start & ~RegexType::kRangeNegationFlag) && codepoint <= r.end) + return yes; + rangeIndex = r.next; + } + return !yes; + } + + const RegexType& regex_; + Allocator* allocator_; + Allocator* ownAllocator_; + Stack<Allocator> state0_; + Stack<Allocator> state1_; + uint32_t* stateSet_; +}; + +typedef GenericRegex<UTF8<> > Regex; +typedef GenericRegexSearch<Regex> RegexSearch; + +} // namespace internal +RAPIDJSON_NAMESPACE_END + +#ifdef __GNUC__ +RAPIDJSON_DIAG_POP +#endif + +#if defined(__clang__) || defined(_MSC_VER) +RAPIDJSON_DIAG_POP +#endif + +#endif // RAPIDJSON_INTERNAL_REGEX_H_ |