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Diffstat (limited to 'src/3rdparty/masm/yarr/YarrPattern.cpp')
| -rw-r--r-- | src/3rdparty/masm/yarr/YarrPattern.cpp | 880 |
1 files changed, 880 insertions, 0 deletions
diff --git a/src/3rdparty/masm/yarr/YarrPattern.cpp b/src/3rdparty/masm/yarr/YarrPattern.cpp new file mode 100644 index 0000000000..3ce0216e5f --- /dev/null +++ b/src/3rdparty/masm/yarr/YarrPattern.cpp @@ -0,0 +1,880 @@ +/* + * Copyright (C) 2009, 2013 Apple Inc. All rights reserved. + * Copyright (C) 2010 Peter Varga (pvarga@inf.u-szeged.hu), University of Szeged + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "config.h" +#include "YarrPattern.h" + +#include "Yarr.h" +#include "YarrCanonicalizeUCS2.h" +#include "YarrParser.h" +#include <wtf/Vector.h> + +using namespace WTF; + +namespace JSC { namespace Yarr { + +#include "RegExpJitTables.h" + +class CharacterClassConstructor { +public: + CharacterClassConstructor(bool isCaseInsensitive = false) + : m_isCaseInsensitive(isCaseInsensitive) + { + } + + void reset() + { + m_matches.clear(); + m_ranges.clear(); + m_matchesUnicode.clear(); + m_rangesUnicode.clear(); + } + + void append(const CharacterClass* other) + { + for (size_t i = 0; i < other->m_matches.size(); ++i) + addSorted(m_matches, other->m_matches[i]); + for (size_t i = 0; i < other->m_ranges.size(); ++i) + addSortedRange(m_ranges, other->m_ranges[i].begin, other->m_ranges[i].end); + for (size_t i = 0; i < other->m_matchesUnicode.size(); ++i) + addSorted(m_matchesUnicode, other->m_matchesUnicode[i]); + for (size_t i = 0; i < other->m_rangesUnicode.size(); ++i) + addSortedRange(m_rangesUnicode, other->m_rangesUnicode[i].begin, other->m_rangesUnicode[i].end); + } + + void putChar(UChar ch) + { + // Handle ascii cases. + if (ch <= 0x7f) { + if (m_isCaseInsensitive && isASCIIAlpha(ch)) { + addSorted(m_matches, toASCIIUpper(ch)); + addSorted(m_matches, toASCIILower(ch)); + } else + addSorted(m_matches, ch); + return; + } + + // Simple case, not a case-insensitive match. + if (!m_isCaseInsensitive) { + addSorted(m_matchesUnicode, ch); + return; + } + + // Add multiple matches, if necessary. + UCS2CanonicalizationRange* info = rangeInfoFor(ch); + if (info->type == CanonicalizeUnique) + addSorted(m_matchesUnicode, ch); + else + putUnicodeIgnoreCase(ch, info); + } + + void putUnicodeIgnoreCase(UChar ch, UCS2CanonicalizationRange* info) + { + ASSERT(m_isCaseInsensitive); + ASSERT(ch > 0x7f); + ASSERT(ch >= info->begin && ch <= info->end); + ASSERT(info->type != CanonicalizeUnique); + if (info->type == CanonicalizeSet) { + for (uint16_t* set = characterSetInfo[info->value]; (ch = *set); ++set) + addSorted(m_matchesUnicode, ch); + } else { + addSorted(m_matchesUnicode, ch); + addSorted(m_matchesUnicode, getCanonicalPair(info, ch)); + } + } + + void putRange(UChar lo, UChar hi) + { + if (lo <= 0x7f) { + char asciiLo = lo; + char asciiHi = std::min(hi, (UChar)0x7f); + addSortedRange(m_ranges, lo, asciiHi); + + if (m_isCaseInsensitive) { + if ((asciiLo <= 'Z') && (asciiHi >= 'A')) + addSortedRange(m_ranges, std::max(asciiLo, 'A')+('a'-'A'), std::min(asciiHi, 'Z')+('a'-'A')); + if ((asciiLo <= 'z') && (asciiHi >= 'a')) + addSortedRange(m_ranges, std::max(asciiLo, 'a')+('A'-'a'), std::min(asciiHi, 'z')+('A'-'a')); + } + } + if (hi <= 0x7f) + return; + + lo = std::max(lo, (UChar)0x80); + addSortedRange(m_rangesUnicode, lo, hi); + + if (!m_isCaseInsensitive) + return; + + UCS2CanonicalizationRange* info = rangeInfoFor(lo); + while (true) { + // Handle the range [lo .. end] + UChar end = std::min<UChar>(info->end, hi); + + switch (info->type) { + case CanonicalizeUnique: + // Nothing to do - no canonical equivalents. + break; + case CanonicalizeSet: { + UChar ch; + for (uint16_t* set = characterSetInfo[info->value]; (ch = *set); ++set) + addSorted(m_matchesUnicode, ch); + break; + } + case CanonicalizeRangeLo: + addSortedRange(m_rangesUnicode, lo + info->value, end + info->value); + break; + case CanonicalizeRangeHi: + addSortedRange(m_rangesUnicode, lo - info->value, end - info->value); + break; + case CanonicalizeAlternatingAligned: + // Use addSortedRange since there is likely an abutting range to combine with. + if (lo & 1) + addSortedRange(m_rangesUnicode, lo - 1, lo - 1); + if (!(end & 1)) + addSortedRange(m_rangesUnicode, end + 1, end + 1); + break; + case CanonicalizeAlternatingUnaligned: + // Use addSortedRange since there is likely an abutting range to combine with. + if (!(lo & 1)) + addSortedRange(m_rangesUnicode, lo - 1, lo - 1); + if (end & 1) + addSortedRange(m_rangesUnicode, end + 1, end + 1); + break; + } + + if (hi == end) + return; + + ++info; + lo = info->begin; + }; + + } + + PassOwnPtr<CharacterClass> charClass() + { + OwnPtr<CharacterClass> characterClass = adoptPtr(new CharacterClass); + + characterClass->m_matches.swap(m_matches); + characterClass->m_ranges.swap(m_ranges); + characterClass->m_matchesUnicode.swap(m_matchesUnicode); + characterClass->m_rangesUnicode.swap(m_rangesUnicode); + + return characterClass.release(); + } + +private: + void addSorted(Vector<UChar>& matches, UChar ch) + { + unsigned pos = 0; + unsigned range = matches.size(); + + // binary chop, find position to insert char. + while (range) { + unsigned index = range >> 1; + + int val = matches[pos+index] - ch; + if (!val) + return; + else if (val > 0) + range = index; + else { + pos += (index+1); + range -= (index+1); + } + } + + if (pos == matches.size()) + matches.append(ch); + else + matches.insert(pos, ch); + } + + void addSortedRange(Vector<CharacterRange>& ranges, UChar lo, UChar hi) + { + unsigned end = ranges.size(); + + // Simple linear scan - I doubt there are that many ranges anyway... + // feel free to fix this with something faster (eg binary chop). + for (unsigned i = 0; i < end; ++i) { + // does the new range fall before the current position in the array + if (hi < ranges[i].begin) { + // optional optimization: concatenate appending ranges? - may not be worthwhile. + if (hi == (ranges[i].begin - 1)) { + ranges[i].begin = lo; + return; + } + ranges.insert(i, CharacterRange(lo, hi)); + return; + } + // Okay, since we didn't hit the last case, the end of the new range is definitely at or after the begining + // If the new range start at or before the end of the last range, then the overlap (if it starts one after the + // end of the last range they concatenate, which is just as good. + if (lo <= (ranges[i].end + 1)) { + // found an intersect! we'll replace this entry in the array. + ranges[i].begin = std::min(ranges[i].begin, lo); + ranges[i].end = std::max(ranges[i].end, hi); + + // now check if the new range can subsume any subsequent ranges. + unsigned next = i+1; + // each iteration of the loop we will either remove something from the list, or break the loop. + while (next < ranges.size()) { + if (ranges[next].begin <= (ranges[i].end + 1)) { + // the next entry now overlaps / concatenates this one. + ranges[i].end = std::max(ranges[i].end, ranges[next].end); + ranges.remove(next); + } else + break; + } + + return; + } + } + + // CharacterRange comes after all existing ranges. + ranges.append(CharacterRange(lo, hi)); + } + + bool m_isCaseInsensitive; + + Vector<UChar> m_matches; + Vector<CharacterRange> m_ranges; + Vector<UChar> m_matchesUnicode; + Vector<CharacterRange> m_rangesUnicode; +}; + +class YarrPatternConstructor { +public: + YarrPatternConstructor(YarrPattern& pattern) + : m_pattern(pattern) + , m_characterClassConstructor(pattern.m_ignoreCase) + , m_invertParentheticalAssertion(false) + { + OwnPtr<PatternDisjunction> body = adoptPtr(new PatternDisjunction); + m_pattern.m_body = body.get(); + m_alternative = body->addNewAlternative(); + m_pattern.m_disjunctions.append(body.release()); + } + + ~YarrPatternConstructor() + { + } + + void reset() + { + m_pattern.reset(); + m_characterClassConstructor.reset(); + + OwnPtr<PatternDisjunction> body = adoptPtr(new PatternDisjunction); + m_pattern.m_body = body.get(); + m_alternative = body->addNewAlternative(); + m_pattern.m_disjunctions.append(body.release()); + } + + void assertionBOL() + { + if (!m_alternative->m_terms.size() & !m_invertParentheticalAssertion) { + m_alternative->m_startsWithBOL = true; + m_alternative->m_containsBOL = true; + m_pattern.m_containsBOL = true; + } + m_alternative->m_terms.append(PatternTerm::BOL()); + } + void assertionEOL() + { + m_alternative->m_terms.append(PatternTerm::EOL()); + } + void assertionWordBoundary(bool invert) + { + m_alternative->m_terms.append(PatternTerm::WordBoundary(invert)); + } + + void atomPatternCharacter(UChar ch) + { + // We handle case-insensitive checking of unicode characters which do have both + // cases by handling them as if they were defined using a CharacterClass. + if (!m_pattern.m_ignoreCase || isASCII(ch)) { + m_alternative->m_terms.append(PatternTerm(ch)); + return; + } + + UCS2CanonicalizationRange* info = rangeInfoFor(ch); + if (info->type == CanonicalizeUnique) { + m_alternative->m_terms.append(PatternTerm(ch)); + return; + } + + m_characterClassConstructor.putUnicodeIgnoreCase(ch, info); + OwnPtr<CharacterClass> newCharacterClass = m_characterClassConstructor.charClass(); + m_alternative->m_terms.append(PatternTerm(newCharacterClass.get(), false)); + m_pattern.m_userCharacterClasses.append(newCharacterClass.release()); + } + + void atomBuiltInCharacterClass(BuiltInCharacterClassID classID, bool invert) + { + switch (classID) { + case DigitClassID: + m_alternative->m_terms.append(PatternTerm(m_pattern.digitsCharacterClass(), invert)); + break; + case SpaceClassID: + m_alternative->m_terms.append(PatternTerm(m_pattern.spacesCharacterClass(), invert)); + break; + case WordClassID: + m_alternative->m_terms.append(PatternTerm(m_pattern.wordcharCharacterClass(), invert)); + break; + case NewlineClassID: + m_alternative->m_terms.append(PatternTerm(m_pattern.newlineCharacterClass(), invert)); + break; + } + } + + void atomCharacterClassBegin(bool invert = false) + { + m_invertCharacterClass = invert; + } + + void atomCharacterClassAtom(UChar ch) + { + m_characterClassConstructor.putChar(ch); + } + + void atomCharacterClassRange(UChar begin, UChar end) + { + m_characterClassConstructor.putRange(begin, end); + } + + void atomCharacterClassBuiltIn(BuiltInCharacterClassID classID, bool invert) + { + ASSERT(classID != NewlineClassID); + + switch (classID) { + case DigitClassID: + m_characterClassConstructor.append(invert ? m_pattern.nondigitsCharacterClass() : m_pattern.digitsCharacterClass()); + break; + + case SpaceClassID: + m_characterClassConstructor.append(invert ? m_pattern.nonspacesCharacterClass() : m_pattern.spacesCharacterClass()); + break; + + case WordClassID: + m_characterClassConstructor.append(invert ? m_pattern.nonwordcharCharacterClass() : m_pattern.wordcharCharacterClass()); + break; + + default: + RELEASE_ASSERT_NOT_REACHED(); + } + } + + void atomCharacterClassEnd() + { + OwnPtr<CharacterClass> newCharacterClass = m_characterClassConstructor.charClass(); + m_alternative->m_terms.append(PatternTerm(newCharacterClass.get(), m_invertCharacterClass)); + m_pattern.m_userCharacterClasses.append(newCharacterClass.release()); + } + + void atomParenthesesSubpatternBegin(bool capture = true) + { + unsigned subpatternId = m_pattern.m_numSubpatterns + 1; + if (capture) + m_pattern.m_numSubpatterns++; + + OwnPtr<PatternDisjunction> parenthesesDisjunction = adoptPtr(new PatternDisjunction(m_alternative)); + m_alternative->m_terms.append(PatternTerm(PatternTerm::TypeParenthesesSubpattern, subpatternId, parenthesesDisjunction.get(), capture, false)); + m_alternative = parenthesesDisjunction->addNewAlternative(); + m_pattern.m_disjunctions.append(parenthesesDisjunction.release()); + } + + void atomParentheticalAssertionBegin(bool invert = false) + { + OwnPtr<PatternDisjunction> parenthesesDisjunction = adoptPtr(new PatternDisjunction(m_alternative)); + m_alternative->m_terms.append(PatternTerm(PatternTerm::TypeParentheticalAssertion, m_pattern.m_numSubpatterns + 1, parenthesesDisjunction.get(), false, invert)); + m_alternative = parenthesesDisjunction->addNewAlternative(); + m_invertParentheticalAssertion = invert; + m_pattern.m_disjunctions.append(parenthesesDisjunction.release()); + } + + void atomParenthesesEnd() + { + ASSERT(m_alternative->m_parent); + ASSERT(m_alternative->m_parent->m_parent); + + PatternDisjunction* parenthesesDisjunction = m_alternative->m_parent; + m_alternative = m_alternative->m_parent->m_parent; + + PatternTerm& lastTerm = m_alternative->lastTerm(); + + unsigned numParenAlternatives = parenthesesDisjunction->m_alternatives.size(); + unsigned numBOLAnchoredAlts = 0; + + for (unsigned i = 0; i < numParenAlternatives; i++) { + // Bubble up BOL flags + if (parenthesesDisjunction->m_alternatives[i]->m_startsWithBOL) + numBOLAnchoredAlts++; + } + + if (numBOLAnchoredAlts) { + m_alternative->m_containsBOL = true; + // If all the alternatives in parens start with BOL, then so does this one + if (numBOLAnchoredAlts == numParenAlternatives) + m_alternative->m_startsWithBOL = true; + } + + lastTerm.parentheses.lastSubpatternId = m_pattern.m_numSubpatterns; + m_invertParentheticalAssertion = false; + } + + void atomBackReference(unsigned subpatternId) + { + ASSERT(subpatternId); + m_pattern.m_containsBackreferences = true; + m_pattern.m_maxBackReference = std::max(m_pattern.m_maxBackReference, subpatternId); + + if (subpatternId > m_pattern.m_numSubpatterns) { + m_alternative->m_terms.append(PatternTerm::ForwardReference()); + return; + } + + PatternAlternative* currentAlternative = m_alternative; + ASSERT(currentAlternative); + + // Note to self: if we waited until the AST was baked, we could also remove forwards refs + while ((currentAlternative = currentAlternative->m_parent->m_parent)) { + PatternTerm& term = currentAlternative->lastTerm(); + ASSERT((term.type == PatternTerm::TypeParenthesesSubpattern) || (term.type == PatternTerm::TypeParentheticalAssertion)); + + if ((term.type == PatternTerm::TypeParenthesesSubpattern) && term.capture() && (subpatternId == term.parentheses.subpatternId)) { + m_alternative->m_terms.append(PatternTerm::ForwardReference()); + return; + } + } + + m_alternative->m_terms.append(PatternTerm(subpatternId)); + } + + // deep copy the argument disjunction. If filterStartsWithBOL is true, + // skip alternatives with m_startsWithBOL set true. + PatternDisjunction* copyDisjunction(PatternDisjunction* disjunction, bool filterStartsWithBOL = false) + { + OwnPtr<PatternDisjunction> newDisjunction; + for (unsigned alt = 0; alt < disjunction->m_alternatives.size(); ++alt) { + PatternAlternative* alternative = disjunction->m_alternatives[alt].get(); + if (!filterStartsWithBOL || !alternative->m_startsWithBOL) { + if (!newDisjunction) { + newDisjunction = adoptPtr(new PatternDisjunction()); + newDisjunction->m_parent = disjunction->m_parent; + } + PatternAlternative* newAlternative = newDisjunction->addNewAlternative(); + newAlternative->m_terms.reserveInitialCapacity(alternative->m_terms.size()); + for (unsigned i = 0; i < alternative->m_terms.size(); ++i) + newAlternative->m_terms.append(copyTerm(alternative->m_terms[i], filterStartsWithBOL)); + } + } + + if (!newDisjunction) + return 0; + + PatternDisjunction* copiedDisjunction = newDisjunction.get(); + m_pattern.m_disjunctions.append(newDisjunction.release()); + return copiedDisjunction; + } + + PatternTerm copyTerm(PatternTerm& term, bool filterStartsWithBOL = false) + { + if ((term.type != PatternTerm::TypeParenthesesSubpattern) && (term.type != PatternTerm::TypeParentheticalAssertion)) + return PatternTerm(term); + + PatternTerm termCopy = term; + termCopy.parentheses.disjunction = copyDisjunction(termCopy.parentheses.disjunction, filterStartsWithBOL); + return termCopy; + } + + void quantifyAtom(unsigned min, unsigned max, bool greedy) + { + ASSERT(min <= max); + ASSERT(m_alternative->m_terms.size()); + + if (!max) { + m_alternative->removeLastTerm(); + return; + } + + PatternTerm& term = m_alternative->lastTerm(); + ASSERT(term.type > PatternTerm::TypeAssertionWordBoundary); + ASSERT((term.quantityCount == 1) && (term.quantityType == QuantifierFixedCount)); + + if (term.type == PatternTerm::TypeParentheticalAssertion) { + // If an assertion is quantified with a minimum count of zero, it can simply be removed. + // This arises from the RepeatMatcher behaviour in the spec. Matching an assertion never + // results in any input being consumed, however the continuation passed to the assertion + // (called in steps, 8c and 9 of the RepeatMatcher definition, ES5.1 15.10.2.5) will + // reject all zero length matches (see step 2.1). A match from the continuation of the + // expression will still be accepted regardless (via steps 8a and 11) - the upshot of all + // this is that matches from the assertion are not required, and won't be accepted anyway, + // so no need to ever run it. + if (!min) + m_alternative->removeLastTerm(); + // We never need to run an assertion more than once. Subsequent interations will be run + // with the same start index (since assertions are non-capturing) and the same captures + // (per step 4 of RepeatMatcher in ES5.1 15.10.2.5), and as such will always produce the + // same result and captures. If the first match succeeds then the subsequent (min - 1) + // matches will too. Any additional optional matches will fail (on the same basis as the + // minimum zero quantified assertions, above), but this will still result in a match. + return; + } + + if (min == 0) + term.quantify(max, greedy ? QuantifierGreedy : QuantifierNonGreedy); + else if (min == max) + term.quantify(min, QuantifierFixedCount); + else { + term.quantify(min, QuantifierFixedCount); + m_alternative->m_terms.append(copyTerm(term)); + // NOTE: this term is interesting from an analysis perspective, in that it can be ignored..... + m_alternative->lastTerm().quantify((max == quantifyInfinite) ? max : max - min, greedy ? QuantifierGreedy : QuantifierNonGreedy); + if (m_alternative->lastTerm().type == PatternTerm::TypeParenthesesSubpattern) + m_alternative->lastTerm().parentheses.isCopy = true; + } + } + + void disjunction() + { + m_alternative = m_alternative->m_parent->addNewAlternative(); + } + + unsigned setupAlternativeOffsets(PatternAlternative* alternative, unsigned currentCallFrameSize, unsigned initialInputPosition) + { + alternative->m_hasFixedSize = true; + Checked<unsigned> currentInputPosition = initialInputPosition; + + for (unsigned i = 0; i < alternative->m_terms.size(); ++i) { + PatternTerm& term = alternative->m_terms[i]; + + switch (term.type) { + case PatternTerm::TypeAssertionBOL: + case PatternTerm::TypeAssertionEOL: + case PatternTerm::TypeAssertionWordBoundary: + term.inputPosition = currentInputPosition.unsafeGet(); + break; + + case PatternTerm::TypeBackReference: + term.inputPosition = currentInputPosition.unsafeGet(); + term.frameLocation = currentCallFrameSize; + currentCallFrameSize += YarrStackSpaceForBackTrackInfoBackReference; + alternative->m_hasFixedSize = false; + break; + + case PatternTerm::TypeForwardReference: + break; + + case PatternTerm::TypePatternCharacter: + term.inputPosition = currentInputPosition.unsafeGet(); + if (term.quantityType != QuantifierFixedCount) { + term.frameLocation = currentCallFrameSize; + currentCallFrameSize += YarrStackSpaceForBackTrackInfoPatternCharacter; + alternative->m_hasFixedSize = false; + } else + currentInputPosition += term.quantityCount; + break; + + case PatternTerm::TypeCharacterClass: + term.inputPosition = currentInputPosition.unsafeGet(); + if (term.quantityType != QuantifierFixedCount) { + term.frameLocation = currentCallFrameSize; + currentCallFrameSize += YarrStackSpaceForBackTrackInfoCharacterClass; + alternative->m_hasFixedSize = false; + } else + currentInputPosition += term.quantityCount; + break; + + case PatternTerm::TypeParenthesesSubpattern: + // Note: for fixed once parentheses we will ensure at least the minimum is available; others are on their own. + term.frameLocation = currentCallFrameSize; + if (term.quantityCount == 1 && !term.parentheses.isCopy) { + if (term.quantityType != QuantifierFixedCount) + currentCallFrameSize += YarrStackSpaceForBackTrackInfoParenthesesOnce; + currentCallFrameSize = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize, currentInputPosition.unsafeGet()); + // If quantity is fixed, then pre-check its minimum size. + if (term.quantityType == QuantifierFixedCount) + currentInputPosition += term.parentheses.disjunction->m_minimumSize; + term.inputPosition = currentInputPosition.unsafeGet(); + } else if (term.parentheses.isTerminal) { + currentCallFrameSize += YarrStackSpaceForBackTrackInfoParenthesesTerminal; + currentCallFrameSize = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize, currentInputPosition.unsafeGet()); + term.inputPosition = currentInputPosition.unsafeGet(); + } else { + term.inputPosition = currentInputPosition.unsafeGet(); + setupDisjunctionOffsets(term.parentheses.disjunction, 0, currentInputPosition.unsafeGet()); + currentCallFrameSize += YarrStackSpaceForBackTrackInfoParentheses; + } + // Fixed count of 1 could be accepted, if they have a fixed size *AND* if all alternatives are of the same length. + alternative->m_hasFixedSize = false; + break; + + case PatternTerm::TypeParentheticalAssertion: + term.inputPosition = currentInputPosition.unsafeGet(); + term.frameLocation = currentCallFrameSize; + currentCallFrameSize = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize + YarrStackSpaceForBackTrackInfoParentheticalAssertion, currentInputPosition.unsafeGet()); + break; + + case PatternTerm::TypeDotStarEnclosure: + alternative->m_hasFixedSize = false; + term.inputPosition = initialInputPosition; + break; + } + } + + alternative->m_minimumSize = (currentInputPosition - initialInputPosition).unsafeGet(); + return currentCallFrameSize; + } + + unsigned setupDisjunctionOffsets(PatternDisjunction* disjunction, unsigned initialCallFrameSize, unsigned initialInputPosition) + { + if ((disjunction != m_pattern.m_body) && (disjunction->m_alternatives.size() > 1)) + initialCallFrameSize += YarrStackSpaceForBackTrackInfoAlternative; + + unsigned minimumInputSize = UINT_MAX; + unsigned maximumCallFrameSize = 0; + bool hasFixedSize = true; + + for (unsigned alt = 0; alt < disjunction->m_alternatives.size(); ++alt) { + PatternAlternative* alternative = disjunction->m_alternatives[alt].get(); + unsigned currentAlternativeCallFrameSize = setupAlternativeOffsets(alternative, initialCallFrameSize, initialInputPosition); + minimumInputSize = std::min(minimumInputSize, alternative->m_minimumSize); + maximumCallFrameSize = std::max(maximumCallFrameSize, currentAlternativeCallFrameSize); + hasFixedSize &= alternative->m_hasFixedSize; + } + + ASSERT(minimumInputSize != UINT_MAX); + ASSERT(maximumCallFrameSize >= initialCallFrameSize); + + disjunction->m_hasFixedSize = hasFixedSize; + disjunction->m_minimumSize = minimumInputSize; + disjunction->m_callFrameSize = maximumCallFrameSize; + return maximumCallFrameSize; + } + + void setupOffsets() + { + setupDisjunctionOffsets(m_pattern.m_body, 0, 0); + } + + // This optimization identifies sets of parentheses that we will never need to backtrack. + // In these cases we do not need to store state from prior iterations. + // We can presently avoid backtracking for: + // * where the parens are at the end of the regular expression (last term in any of the + // alternatives of the main body disjunction). + // * where the parens are non-capturing, and quantified unbounded greedy (*). + // * where the parens do not contain any capturing subpatterns. + void checkForTerminalParentheses() + { + // This check is much too crude; should be just checking whether the candidate + // node contains nested capturing subpatterns, not the whole expression! + if (m_pattern.m_numSubpatterns) + return; + + Vector<OwnPtr<PatternAlternative> >& alternatives = m_pattern.m_body->m_alternatives; + for (size_t i = 0; i < alternatives.size(); ++i) { + Vector<PatternTerm>& terms = alternatives[i]->m_terms; + if (terms.size()) { + PatternTerm& term = terms.last(); + if (term.type == PatternTerm::TypeParenthesesSubpattern + && term.quantityType == QuantifierGreedy + && term.quantityCount == quantifyInfinite + && !term.capture()) + term.parentheses.isTerminal = true; + } + } + } + + void optimizeBOL() + { + // Look for expressions containing beginning of line (^) anchoring and unroll them. + // e.g. /^a|^b|c/ becomes /^a|^b|c/ which is executed once followed by /c/ which loops + // This code relies on the parsing code tagging alternatives with m_containsBOL and + // m_startsWithBOL and rolling those up to containing alternatives. + // At this point, this is only valid for non-multiline expressions. + PatternDisjunction* disjunction = m_pattern.m_body; + + if (!m_pattern.m_containsBOL || m_pattern.m_multiline) + return; + + PatternDisjunction* loopDisjunction = copyDisjunction(disjunction, true); + + // Set alternatives in disjunction to "onceThrough" + for (unsigned alt = 0; alt < disjunction->m_alternatives.size(); ++alt) + disjunction->m_alternatives[alt]->setOnceThrough(); + + if (loopDisjunction) { + // Move alternatives from loopDisjunction to disjunction + for (unsigned alt = 0; alt < loopDisjunction->m_alternatives.size(); ++alt) + disjunction->m_alternatives.append(loopDisjunction->m_alternatives[alt].release()); + + loopDisjunction->m_alternatives.clear(); + } + } + + bool containsCapturingTerms(PatternAlternative* alternative, size_t firstTermIndex, size_t lastTermIndex) + { + Vector<PatternTerm>& terms = alternative->m_terms; + + for (size_t termIndex = firstTermIndex; termIndex <= lastTermIndex; ++termIndex) { + PatternTerm& term = terms[termIndex]; + + if (term.m_capture) + return true; + + if (term.type == PatternTerm::TypeParenthesesSubpattern) { + PatternDisjunction* nestedDisjunction = term.parentheses.disjunction; + for (unsigned alt = 0; alt < nestedDisjunction->m_alternatives.size(); ++alt) { + if (containsCapturingTerms(nestedDisjunction->m_alternatives[alt].get(), 0, nestedDisjunction->m_alternatives[alt]->m_terms.size() - 1)) + return true; + } + } + } + + return false; + } + + // This optimization identifies alternatives in the form of + // [^].*[?]<expression>.*[$] for expressions that don't have any + // capturing terms. The alternative is changed to <expression> + // followed by processing of the dot stars to find and adjust the + // beginning and the end of the match. + void optimizeDotStarWrappedExpressions() + { + Vector<OwnPtr<PatternAlternative> >& alternatives = m_pattern.m_body->m_alternatives; + if (alternatives.size() != 1) + return; + + PatternAlternative* alternative = alternatives[0].get(); + Vector<PatternTerm>& terms = alternative->m_terms; + if (terms.size() >= 3) { + bool startsWithBOL = false; + bool endsWithEOL = false; + size_t termIndex, firstExpressionTerm, lastExpressionTerm; + + termIndex = 0; + if (terms[termIndex].type == PatternTerm::TypeAssertionBOL) { + startsWithBOL = true; + ++termIndex; + } + + PatternTerm& firstNonAnchorTerm = terms[termIndex]; + if ((firstNonAnchorTerm.type != PatternTerm::TypeCharacterClass) || (firstNonAnchorTerm.characterClass != m_pattern.newlineCharacterClass()) || !((firstNonAnchorTerm.quantityType == QuantifierGreedy) || (firstNonAnchorTerm.quantityType == QuantifierNonGreedy))) + return; + + firstExpressionTerm = termIndex + 1; + + termIndex = terms.size() - 1; + if (terms[termIndex].type == PatternTerm::TypeAssertionEOL) { + endsWithEOL = true; + --termIndex; + } + + PatternTerm& lastNonAnchorTerm = terms[termIndex]; + if ((lastNonAnchorTerm.type != PatternTerm::TypeCharacterClass) || (lastNonAnchorTerm.characterClass != m_pattern.newlineCharacterClass()) || (lastNonAnchorTerm.quantityType != QuantifierGreedy)) + return; + + lastExpressionTerm = termIndex - 1; + + if (firstExpressionTerm > lastExpressionTerm) + return; + + if (!containsCapturingTerms(alternative, firstExpressionTerm, lastExpressionTerm)) { + for (termIndex = terms.size() - 1; termIndex > lastExpressionTerm; --termIndex) + terms.remove(termIndex); + + for (termIndex = firstExpressionTerm; termIndex > 0; --termIndex) + terms.remove(termIndex - 1); + + terms.append(PatternTerm(startsWithBOL, endsWithEOL)); + + m_pattern.m_containsBOL = false; + } + } + } + +private: + YarrPattern& m_pattern; + PatternAlternative* m_alternative; + CharacterClassConstructor m_characterClassConstructor; + bool m_invertCharacterClass; + bool m_invertParentheticalAssertion; +}; + +const char* YarrPattern::compile(const String& patternString) +{ + YarrPatternConstructor constructor(*this); + + if (const char* error = parse(constructor, patternString)) + return error; + + // If the pattern contains illegal backreferences reset & reparse. + // Quoting Netscape's "What's new in JavaScript 1.2", + // "Note: if the number of left parentheses is less than the number specified + // in \#, the \# is taken as an octal escape as described in the next row." + if (containsIllegalBackReference()) { + unsigned numSubpatterns = m_numSubpatterns; + + constructor.reset(); +#if !ASSERT_DISABLED + const char* error = +#endif + parse(constructor, patternString, numSubpatterns); + + ASSERT(!error); + ASSERT(numSubpatterns == m_numSubpatterns); + } + + constructor.checkForTerminalParentheses(); + constructor.optimizeDotStarWrappedExpressions(); + constructor.optimizeBOL(); + + constructor.setupOffsets(); + + return 0; +} + +YarrPattern::YarrPattern(const String& pattern, bool ignoreCase, bool multiline, const char** error) + : m_ignoreCase(ignoreCase) + , m_multiline(multiline) + , m_containsBackreferences(false) + , m_containsBOL(false) + , m_numSubpatterns(0) + , m_maxBackReference(0) + , newlineCached(0) + , digitsCached(0) + , spacesCached(0) + , wordcharCached(0) + , nondigitsCached(0) + , nonspacesCached(0) + , nonwordcharCached(0) +{ + *error = compile(pattern); +} + +} } |