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Implementation

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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:
 *
 * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
 *
 * 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.
 */

#ifndef yarr_YarrInterpreter_h
#define yarr_YarrInterpreter_h

#include "yarr/YarrPattern.h"

namespace WTF {
class BumpPointerAllocator;
}
using WTF::BumpPointerAllocator;

namespace JSC { namespace Yarr {

class ByteDisjunction;

struct ByteTerm {
    enum Type {
        TypeBodyAlternativeBegin,
        TypeBodyAlternativeDisjunction,
        TypeBodyAlternativeEnd,
        TypeAlternativeBegin,
        TypeAlternativeDisjunction,
        TypeAlternativeEnd,
        TypeSubpatternBegin,
        TypeSubpatternEnd,
        TypeAssertionBOL,
        TypeAssertionEOL,
        TypeAssertionWordBoundary,
        TypePatternCharacterOnce,
        TypePatternCharacterFixed,
        TypePatternCharacterGreedy,
        TypePatternCharacterNonGreedy,
        TypePatternCasedCharacterOnce,
        TypePatternCasedCharacterFixed,
        TypePatternCasedCharacterGreedy,
        TypePatternCasedCharacterNonGreedy,
        TypeCharacterClass,
        TypeBackReference,
        TypeParenthesesSubpattern,
        TypeParenthesesSubpatternOnceBegin,
        TypeParenthesesSubpatternOnceEnd,
        TypeParenthesesSubpatternTerminalBegin,
        TypeParenthesesSubpatternTerminalEnd,
        TypeParentheticalAssertionBegin,
        TypeParentheticalAssertionEnd,
        TypeCheckInput,
        TypeUncheckInput,
        TypeDotStarEnclosure
    } type;
    union {
        struct {
            union {
                UChar patternCharacter;
                struct {
                    UChar lo;
                    UChar hi;
                } casedCharacter;
                CharacterClass* characterClass;
                unsigned subpatternId;
            };
            union {
                ByteDisjunction* parenthesesDisjunction;
                unsigned parenthesesWidth;
            };
            QuantifierType quantityType;
            unsigned quantityCount;
        } atom;
        struct {
            int next;
            int end;
            bool onceThrough;
        } alternative;
        struct {
            bool m_bol : 1;
            bool m_eol : 1;
        } anchors;
        unsigned checkInputCount;
    };
    unsigned frameLocation;
    bool m_capture : 1;
    bool m_invert : 1;
    unsigned inputPosition;

    ByteTerm(UChar ch, int inputPos, unsigned frameLocation, Checked<unsigned> quantityCount, QuantifierType quantityType)
        : frameLocation(frameLocation)
        , m_capture(false)
        , m_invert(false)
    {
        switch (quantityType) {
        case QuantifierFixedCount:
            type = (quantityCount == 1) ? ByteTerm::TypePatternCharacterOnce : ByteTerm::TypePatternCharacterFixed;
            break;
        case QuantifierGreedy:
            type = ByteTerm::TypePatternCharacterGreedy;
            break;
        case QuantifierNonGreedy:
            type = ByteTerm::TypePatternCharacterNonGreedy;
            break;
        }

        atom.patternCharacter = ch;
        atom.quantityType = quantityType;
        atom.quantityCount = quantityCount.unsafeGet();
        inputPosition = inputPos;
    }

    ByteTerm(UChar lo, UChar hi, int inputPos, unsigned frameLocation, Checked<unsigned> quantityCount, QuantifierType quantityType)
        : frameLocation(frameLocation)
        , m_capture(false)
        , m_invert(false)
    {
        switch (quantityType) {
        case QuantifierFixedCount:
            type = (quantityCount == 1) ? ByteTerm::TypePatternCasedCharacterOnce : ByteTerm::TypePatternCasedCharacterFixed;
            break;
        case QuantifierGreedy:
            type = ByteTerm::TypePatternCasedCharacterGreedy;
            break;
        case QuantifierNonGreedy:
            type = ByteTerm::TypePatternCasedCharacterNonGreedy;
            break;
        }

        atom.casedCharacter.lo = lo;
        atom.casedCharacter.hi = hi;
        atom.quantityType = quantityType;
        atom.quantityCount = quantityCount.unsafeGet();
        inputPosition = inputPos;
    }

    ByteTerm(CharacterClass* characterClass, bool invert, int inputPos)
        : type(ByteTerm::TypeCharacterClass)
        , m_capture(false)
        , m_invert(invert)
    {
        atom.characterClass = characterClass;
        atom.quantityType = QuantifierFixedCount;
        atom.quantityCount = 1;
        inputPosition = inputPos;
    }

    ByteTerm(Type type, unsigned subpatternId, ByteDisjunction* parenthesesInfo, bool capture, int inputPos)
        : type(type)
        , m_capture(capture)
        , m_invert(false)
    {
        atom.subpatternId = subpatternId;
        atom.parenthesesDisjunction = parenthesesInfo;
        atom.quantityType = QuantifierFixedCount;
        atom.quantityCount = 1;
        inputPosition = inputPos;
    }
    
    ByteTerm(Type type, bool invert = false)
        : type(type)
        , m_capture(false)
        , m_invert(invert)
    {
        atom.quantityType = QuantifierFixedCount;
        atom.quantityCount = 1;
    }

    ByteTerm(Type type, unsigned subpatternId, bool capture, bool invert, int inputPos)
        : type(type)
        , m_capture(capture)
        , m_invert(invert)
    {
        atom.subpatternId = subpatternId;
        atom.quantityType = QuantifierFixedCount;
        atom.quantityCount = 1;
        inputPosition = inputPos;
    }

    // For js::Vector. Does not create a valid object.
    ByteTerm()
    {
    }

    static ByteTerm BOL(int inputPos)
    {
        ByteTerm term(TypeAssertionBOL);
        term.inputPosition = inputPos;
        return term;
    }

    static ByteTerm CheckInput(Checked<unsigned> count)
    {
        ByteTerm term(TypeCheckInput);
        term.checkInputCount = count.unsafeGet();
        return term;
    }

    static ByteTerm UncheckInput(Checked<unsigned> count)
    {
        ByteTerm term(TypeUncheckInput);
        term.checkInputCount = count.unsafeGet();
        return term;
    }
    
    static ByteTerm EOL(int inputPos)
    {
        ByteTerm term(TypeAssertionEOL);
        term.inputPosition = inputPos;
        return term;
    }

    static ByteTerm WordBoundary(bool invert, int inputPos)
    {
        ByteTerm term(TypeAssertionWordBoundary, invert);
        term.inputPosition = inputPos;
        return term;
    }
    
    static ByteTerm BackReference(unsigned subpatternId, int inputPos)
    {
        return ByteTerm(TypeBackReference, subpatternId, false, false, inputPos);
    }

    static ByteTerm BodyAlternativeBegin(bool onceThrough)
    {
        ByteTerm term(TypeBodyAlternativeBegin);
        term.alternative.next = 0;
        term.alternative.end = 0;
        term.alternative.onceThrough = onceThrough;
        return term;
    }

    static ByteTerm BodyAlternativeDisjunction(bool onceThrough)
    {
        ByteTerm term(TypeBodyAlternativeDisjunction);
        term.alternative.next = 0;
        term.alternative.end = 0;
        term.alternative.onceThrough = onceThrough;
        return term;
    }

    static ByteTerm BodyAlternativeEnd()
    {
        ByteTerm term(TypeBodyAlternativeEnd);
        term.alternative.next = 0;
        term.alternative.end = 0;
        term.alternative.onceThrough = false;
        return term;
    }

    static ByteTerm AlternativeBegin()
    {
        ByteTerm term(TypeAlternativeBegin);
        term.alternative.next = 0;
        term.alternative.end = 0;
        term.alternative.onceThrough = false;
        return term;
    }

    static ByteTerm AlternativeDisjunction()
    {
        ByteTerm term(TypeAlternativeDisjunction);
        term.alternative.next = 0;
        term.alternative.end = 0;
        term.alternative.onceThrough = false;
        return term;
    }

    static ByteTerm AlternativeEnd()
    {
        ByteTerm term(TypeAlternativeEnd);
        term.alternative.next = 0;
        term.alternative.end = 0;
        term.alternative.onceThrough = false;
        return term;
    }

    static ByteTerm SubpatternBegin()
    {
        return ByteTerm(TypeSubpatternBegin);
    }

    static ByteTerm SubpatternEnd()
    {
        return ByteTerm(TypeSubpatternEnd);
    }
    
    static ByteTerm DotStarEnclosure(bool bolAnchor, bool eolAnchor)
    {
        ByteTerm term(TypeDotStarEnclosure);
        term.anchors.m_bol = bolAnchor;
        term.anchors.m_eol = eolAnchor;
        return term;
    }

    bool invert()
    {
        return m_invert;
    }

    bool capture()
    {
        return m_capture;
    }
};

class ByteDisjunction {
    WTF_MAKE_FAST_ALLOCATED;
public:
    ByteDisjunction(unsigned numSubpatterns, unsigned frameSize)
        : m_numSubpatterns(numSubpatterns)
        , m_frameSize(frameSize)
    {
    }

    Vector<ByteTerm> terms;
    unsigned m_numSubpatterns;
    unsigned m_frameSize;
};

struct BytecodePattern {
    WTF_MAKE_FAST_ALLOCATED;
public:
    BytecodePattern(PassOwnPtr<ByteDisjunction> body, Vector<ByteDisjunction*>& allParenthesesInfo, YarrPattern& pattern, BumpPointerAllocator* allocator)
        : m_body(body)
        , m_ignoreCase(pattern.m_ignoreCase)
        , m_multiline(pattern.m_multiline)
        , m_allocator(allocator)
    {
        newlineCharacterClass = pattern.newlineCharacterClass();
        wordcharCharacterClass = pattern.wordcharCharacterClass();

        // Trick: 'Steal' the YarrPattern's ParenthesesInfo!
        // The input vector isn't used afterwards anymore,
        // that way we don't have to copy the input.
        JS_ASSERT(m_allParenthesesInfo.size() == 0);
        m_allParenthesesInfo.swap(allParenthesesInfo);

        // Trick: 'Steal' the YarrPattern's CharacterClasses!
        // The input vector isn't used afterwards anymore,
        // that way we don't have to copy the input.
        JS_ASSERT(m_userCharacterClasses.size() == 0);
        m_userCharacterClasses.swap(pattern.m_userCharacterClasses);
    }

    ~BytecodePattern()
    {
        deleteAllValues(m_allParenthesesInfo);
        deleteAllValues(m_userCharacterClasses);
    }

    OwnPtr<ByteDisjunction> m_body;
    bool m_ignoreCase;
    bool m_multiline;
    // Each BytecodePattern is associated with a RegExp, each RegExp is associated
    // with a JSGlobalData.  Cache a pointer to out JSGlobalData's m_regExpAllocator.
    BumpPointerAllocator* m_allocator;

    CharacterClass* newlineCharacterClass;
    CharacterClass* wordcharCharacterClass;

private:
    Vector<ByteDisjunction*> m_allParenthesesInfo;
    Vector<CharacterClass*> m_userCharacterClasses;
};

JS_EXPORT_PRIVATE PassOwnPtr<BytecodePattern> byteCompile(YarrPattern&, BumpPointerAllocator*);
JS_EXPORT_PRIVATE unsigned interpret(JSContext* cx, BytecodePattern*, const String& input, unsigned start, unsigned* output);
unsigned interpret(JSContext* cx, BytecodePattern*, const LChar* input, unsigned length, unsigned start, unsigned* output);
unsigned interpret(JSContext* cx, BytecodePattern*, const UChar* input, unsigned length, unsigned start, unsigned* output);

} } // namespace JSC::Yarr

#endif /* yarr_YarrInterpreter_h */