//
//Copyright (C) 2002-2005  3Dlabs Inc. Ltd.
//Copyright (C) 2012-2013 LunarG, Inc.
//
//All rights reserved.
//
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//modification, are permitted provided that the following conditions
//are met:
//
//    Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//
//    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.
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//    from this software without specific prior written permission.
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//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
//"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 THE
//COPYRIGHT HOLDERS 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.
//

//
// Definition of the in-memory high-level intermediate representation
// of shaders.  This is a tree that parser creates.
//
// Nodes in the tree are defined as a hierarchy of classes derived from 
// TIntermNode. Each is a node in a tree.  There is no preset branching factor;
// each node can have it's own type of list of children.
//

#ifndef __INTERMEDIATE_H
#define __INTERMEDIATE_H

#include "../Include/Common.h"
#include "../Include/Types.h"
#include "../Include/ConstantUnion.h"

namespace glslang {

//
// Operators used by the high-level (parse tree) representation.
//
enum TOperator {
    EOpNull,            // if in a node, should only mean a node is still being built
    EOpSequence,        // denotes a list of statements, or parameters, etc.
    EOpLinkerObjects,   // for aggregate node of objects the linker may need, if not reference by the rest of the AST
    EOpFunctionCall,    
    EOpFunction,        // For function definition
    EOpParameters,      // an aggregate listing the parameters to a function

    //
    // Unary operators
    //
    
    EOpNegative,
    EOpLogicalNot,
    EOpVectorLogicalNot,
    EOpBitwiseNot,

    EOpPostIncrement,
    EOpPostDecrement,
    EOpPreIncrement,
    EOpPreDecrement,

    EOpConvIntToBool,
    EOpConvUintToBool,
    EOpConvFloatToBool,
    EOpConvDoubleToBool,
    EOpConvBoolToFloat,
    EOpConvIntToFloat,
    EOpConvUintToFloat,
    EOpConvDoubleToFloat,
    EOpConvUintToInt,
    EOpConvFloatToInt,
    EOpConvBoolToInt,
    EOpConvDoubleToInt,
    EOpConvIntToUint,
    EOpConvFloatToUint,
    EOpConvBoolToUint,
    EOpConvDoubleToUint,
    EOpConvIntToDouble,
    EOpConvUintToDouble,
    EOpConvFloatToDouble,
    EOpConvBoolToDouble,

    //
    // binary operations
    //

    EOpAdd,
    EOpSub,
    EOpMul,
    EOpDiv,
    EOpMod,
    EOpRightShift,
    EOpLeftShift,
    EOpAnd,
    EOpInclusiveOr,
    EOpExclusiveOr,
    EOpEqual,
    EOpNotEqual,
    EOpVectorEqual,
    EOpVectorNotEqual,
    EOpLessThan,
    EOpGreaterThan,
    EOpLessThanEqual,
    EOpGreaterThanEqual,
    EOpComma,

    EOpVectorTimesScalar,
    EOpVectorTimesMatrix,
    EOpMatrixTimesVector,
    EOpMatrixTimesScalar,

    EOpLogicalOr,
    EOpLogicalXor,
    EOpLogicalAnd,

    EOpIndexDirect,
    EOpIndexIndirect,
    EOpIndexDirectStruct,

    EOpVectorSwizzle,

    EOpMethod,

    //
    // Built-in functions mapped to operators
    //

    EOpRadians,
    EOpDegrees,
    EOpSin,
    EOpCos,
    EOpTan,
    EOpAsin,
    EOpAcos,
    EOpAtan,
    EOpSinh,
    EOpCosh,
    EOpTanh,
    EOpAsinh,
    EOpAcosh,
    EOpAtanh,

    EOpPow,
    EOpExp,
    EOpLog,
    EOpExp2,
    EOpLog2,
    EOpSqrt,
    EOpInverseSqrt,

    EOpAbs,
    EOpSign,
    EOpFloor,
    EOpTrunc,
    EOpRound,
    EOpRoundEven,
    EOpCeil,
    EOpFract,
    EOpModf,
    EOpMin,
    EOpMax,
    EOpClamp,
    EOpMix,
    EOpStep,
    EOpSmoothStep,

    EOpIsNan,
    EOpIsInf,

    EOpFma,

    EFrexp,
    ELdexp,

    EOpFloatBitsToInt,
    EOpFloatBitsToUint,
    EOpIntBitsToFloat,
    EOpUintBitsToFloat,
    EOpPackSnorm2x16,
    EOpUnpackSnorm2x16,
    EOpPackUnorm2x16,
    EOpUnpackUnorm2x16,
    EOpPackSnorm4x8,
    EOpUnpackSnorm4x8,
    EOpPackUnorm4x8,
    EOpUnpackUnorm4x8,
    EOpPackHalf2x16,
    EOpUnpackHalf2x16,
    EOpPackDouble2x32,
    EOpUnpackDouble2x32,

    EOpLength,
    EOpDistance,
    EOpDot,
    EOpCross,
    EOpNormalize,
    EOpFaceForward,
    EOpReflect,
    EOpRefract,

    EOpDPdx,            // Fragment only
    EOpDPdy,            // Fragment only
    EOpFwidth,          // Fragment only
    EOpDPdxFine,        // Fragment only
    EOpDPdyFine,        // Fragment only
    EOpFwidthFine,      // Fragment only
    EOpDPdxCoarse,      // Fragment only
    EOpDPdyCoarse,      // Fragment only
    EOpFwidthCoarse,    // Fragment only

    EOpMatrixTimesMatrix,
    EOpOuterProduct,
    EOpDeterminant,
    EOpMatrixInverse,
    EOpTranspose,

    EOpFtransform,

    EOpEmitVertex,           // geometry only
    EOpEndPrimitive,         // geometry only
    EOpEmitStreamVertex,     // geometry only
    EOpEndStreamPrimitive,   // geometry only

    EOpBarrier,
    EOpMemoryBarrier,
    EOpMemoryBarrierAtomicCounter,
    EOpMemoryBarrierBuffer,
    EOpMemoryBarrierImage,
    EOpMemoryBarrierShared,  // compute only
    EOpGroupMemoryBarrier,   // compute only

    EOpAtomicAdd,
    EOpAtomicMin,
    EOpAtomicMax,
    EOpAtomicAnd,
    EOpAtomicOr,
    EOpAtomicXor,
    EOpAtomicExchange,
    EOpAtomicCompSwap,

    EOpAtomicCounterIncrement,
    EOpAtomicCounterDecrement,
    EOpAtomicCounter,

    EOpAny,
    EOpAll,

    //
    // Branch
    //

    EOpKill,            // Fragment only
    EOpReturn,
    EOpBreak,
    EOpContinue,
    EOpCase,
    EOpDefault,

    //
    // Constructors
    //

    EOpConstructGuardStart,
    EOpConstructInt,          // these first scalar forms also identify what implicit conversion is needed
    EOpConstructUint,
    EOpConstructBool,
    EOpConstructFloat,
    EOpConstructDouble,
    EOpConstructVec2,
    EOpConstructVec3,
    EOpConstructVec4,
    EOpConstructDVec2,
    EOpConstructDVec3,
    EOpConstructDVec4,
    EOpConstructBVec2,
    EOpConstructBVec3,
    EOpConstructBVec4,
    EOpConstructIVec2,
    EOpConstructIVec3,
    EOpConstructIVec4,
    EOpConstructUVec2,
    EOpConstructUVec3,
    EOpConstructUVec4,
    EOpConstructMat2x2,
    EOpConstructMat2x3,
    EOpConstructMat2x4,
    EOpConstructMat3x2,
    EOpConstructMat3x3,
    EOpConstructMat3x4,
    EOpConstructMat4x2,
    EOpConstructMat4x3,
    EOpConstructMat4x4,
    EOpConstructDMat2x2,
    EOpConstructDMat2x3,
    EOpConstructDMat2x4,
    EOpConstructDMat3x2,
    EOpConstructDMat3x3,
    EOpConstructDMat3x4,
    EOpConstructDMat4x2,
    EOpConstructDMat4x3,
    EOpConstructDMat4x4,
    EOpConstructStruct,
    EOpConstructGuardEnd,

    //
    // moves
    //
    
    EOpAssign,
    EOpAddAssign,
    EOpSubAssign,
    EOpMulAssign,
    EOpVectorTimesMatrixAssign,
    EOpVectorTimesScalarAssign,
    EOpMatrixTimesScalarAssign,
    EOpMatrixTimesMatrixAssign,
    EOpDivAssign,
    EOpModAssign,
    EOpAndAssign,
    EOpInclusiveOrAssign,
    EOpExclusiveOrAssign,
    EOpLeftShiftAssign,
    EOpRightShiftAssign,

    //
    // Array operators
    //

    EOpArrayLength,      // "Array" distinguishes from length(v) built-in function, but it applies to vectors and matrices as well.

    //
    // Image operations
    //

    // N.B. The following is not being used yet, pending input, as switching
    //      to it from the current text-based approach will break existing consumers.

    EOpImageQuerySize,
    EOpImageQuerySamples,
    EOpImageLoad,
    EOpImageStore,
    EOpImageAtomicAdd,
    EOpImageAtomicMin,
    EOpImageAtomicMax,
    EOpImageAtomicAnd,
    EOpImageAtomicOr,
    EOpImageAtomicXor,
    EOpImageAtomicExchange,
    EOpImageAtomicCompSwap,

    //
    // Texture operations
    //

    EOpTextureGuardBegin,
    EOpTextureQuerySize,
    EOpTextureQueryLod,
    EOpTextureQueryLevels,
    EOpTextureQuerySamples,
    EOpTexture,
    EOpTextureProj,
    EOpTextureLod,
    EOpTextureOffset,
    EOpTextureFetch,
    EOpTextureFetchOffset,
    EOpTextureProjOffset,
    EOpTextureLodOffset,
    EOpTextureProjLod,
    EOpTextureProjLodOffset,
    EOpTextureGrad,
    EOpTextureGradOffset,
    EOpTextureProjGrad,
    EOpTextureProjGradOffset,
    EOpTextureGather,
    EOpTextureGatherOffset,
    EOpTextureGatherOffsets,
    EOpTextureGuardEnd,

    //
    // Integer operations
    //

    EOpAddCarry,
    EOpSubBorrow,
    EOpUMulExtended,
    EOpIMulExtended,
    EOpBitfieldExtract,
    EOpBitfieldInsert,
    EOpBitFieldReverse,
    EOpBitCount,
    EOpFindLSB,
    EOpFindMSB,
};

class TIntermTraverser;
class TIntermOperator;
class TIntermAggregate;
class TIntermUnary;
class TIntermBinary;
class TIntermConstantUnion;
class TIntermSelection;
class TIntermSwitch;
class TIntermBranch;
class TIntermTyped;
class TIntermMethod;
class TIntermSymbol;

} // end namespace glslang

//
// Base class for the tree nodes
//
// (Put outside the glslang namespace, as it's used as part of the external interface.)
//
class TIntermNode {
public:
    POOL_ALLOCATOR_NEW_DELETE(glslang::GetThreadPoolAllocator())

    TIntermNode() { loc.init(); }
    virtual const glslang::TSourceLoc& getLoc() const { return loc; }
    virtual void setLoc(const glslang::TSourceLoc& l) { loc = l; }
    virtual void traverse(glslang::TIntermTraverser*) = 0;
    virtual       glslang::TIntermTyped*         getAsTyped()               { return 0; }
    virtual       glslang::TIntermOperator*      getAsOperator()            { return 0; }
    virtual       glslang::TIntermConstantUnion* getAsConstantUnion()       { return 0; }
    virtual       glslang::TIntermAggregate*     getAsAggregate()           { return 0; }
    virtual       glslang::TIntermUnary*         getAsUnaryNode()           { return 0; }
    virtual       glslang::TIntermBinary*        getAsBinaryNode()          { return 0; }
    virtual       glslang::TIntermSelection*     getAsSelectionNode()       { return 0; }
    virtual       glslang::TIntermSwitch*        getAsSwitchNode()          { return 0; }
    virtual       glslang::TIntermMethod*        getAsMethodNode()          { return 0; }
    virtual       glslang::TIntermSymbol*        getAsSymbolNode()          { return 0; }
    virtual       glslang::TIntermBranch*        getAsBranchNode()          { return 0; }

    virtual const glslang::TIntermTyped*         getAsTyped()         const { return 0; }
    virtual const glslang::TIntermOperator*      getAsOperator()      const { return 0; }
    virtual const glslang::TIntermConstantUnion* getAsConstantUnion() const { return 0; }
    virtual const glslang::TIntermAggregate*     getAsAggregate()     const { return 0; }
    virtual const glslang::TIntermUnary*         getAsUnaryNode()     const { return 0; }
    virtual const glslang::TIntermBinary*        getAsBinaryNode()    const { return 0; }
    virtual const glslang::TIntermSelection*     getAsSelectionNode() const { return 0; }
    virtual const glslang::TIntermSwitch*        getAsSwitchNode()    const { return 0; }
    virtual const glslang::TIntermMethod*        getAsMethodNode()    const { return 0; }
    virtual const glslang::TIntermSymbol*        getAsSymbolNode()    const { return 0; }
    virtual const glslang::TIntermBranch*        getAsBranchNode()    const { return 0; }
    virtual ~TIntermNode() { }
protected:
    glslang::TSourceLoc loc;
};

namespace glslang {

//
// This is just to help yacc.
//
struct TIntermNodePair {
    TIntermNode* node1;
    TIntermNode* node2;
};

//
// Intermediate class for nodes that have a type.
//
class TIntermTyped : public TIntermNode {
public:
    TIntermTyped(const TType& t) { type.shallowCopy(t); }
    TIntermTyped(TBasicType basicType) { TType bt(basicType); type.shallowCopy(bt); }
    virtual       TIntermTyped* getAsTyped()       { return this; }
    virtual const TIntermTyped* getAsTyped() const { return this; }
    virtual void setType(const TType& t) { type.shallowCopy(t); }
    virtual const TType& getType() const { return type; }
    virtual TType& getWritableType() { return type; }
    
    virtual TBasicType getBasicType() const { return type.getBasicType(); }
    virtual TQualifier& getQualifier() { return type.getQualifier(); }
    virtual const TQualifier& getQualifier() const { return type.getQualifier(); }
    virtual void propagatePrecision(TPrecisionQualifier);
    virtual int getVectorSize() const { return type.getVectorSize(); }
    virtual int getMatrixCols() const { return type.getMatrixCols(); }
    virtual int getMatrixRows() const { return type.getMatrixRows(); }
    virtual bool isMatrix() const { return type.isMatrix(); }
    virtual bool isArray()  const { return type.isArray(); }
    virtual bool isVector() const { return type.isVector(); }
    virtual bool isScalar() const { return type.isScalar(); }
    virtual bool isStruct() const { return type.isStruct(); }
    TString getCompleteString() const { return type.getCompleteString(); }

protected:
    TType type;
};

//
// Handle for, do-while, and while loops.
//
class TIntermLoop : public TIntermNode {
public:
    TIntermLoop(TIntermNode* aBody, TIntermTyped* aTest, TIntermTyped* aTerminal, bool testFirst) : 
        body(aBody),
        test(aTest),
        terminal(aTerminal),
        first(testFirst) { }
    virtual void traverse(TIntermTraverser*);
    TIntermNode*  getBody() const { return body; }
    TIntermTyped* getTest() const { return test; }
    TIntermTyped* getTerminal() const { return terminal; }
    bool testFirst() const { return first; }
protected:
    TIntermNode* body;       // code to loop over
    TIntermTyped* test;      // exit condition associated with loop, could be 0 for 'for' loops
    TIntermTyped* terminal;  // exists for for-loops
    bool first;              // true for while and for, not for do-while
};

//
// Handle case, break, continue, return, and kill.
//
class TIntermBranch : public TIntermNode {
public:
    TIntermBranch(TOperator op, TIntermTyped* e) :
        flowOp(op),
        expression(e) { }
    virtual       TIntermBranch* getAsBranchNode()       { return this; }
    virtual const TIntermBranch* getAsBranchNode() const { return this; }
    virtual void traverse(TIntermTraverser*);
    TOperator getFlowOp() const { return flowOp; }
    TIntermTyped* getExpression() const { return expression; }
protected:
    TOperator flowOp;
    TIntermTyped* expression;
};

//
// Represent method names before seeing their calling signature
// or resolving them to operations.  Just an expression as the base object
// and a textural name.
//
class TIntermMethod : public TIntermTyped {
public:
    TIntermMethod(TIntermTyped* o, const TType& t, const TString& m) : TIntermTyped(t), object(o), method(m) { }
    virtual       TIntermMethod* getAsMethodNode()       { return this; }
    virtual const TIntermMethod* getAsMethodNode() const { return this; }
    virtual const TString& getMethodName() const { return method; }
    virtual TIntermTyped* getObject() const { return object; }
    virtual void traverse(TIntermTraverser*);
protected:
    TIntermTyped* object;
    TString method;
};

//
// Nodes that correspond to symbols or constants in the source code.
//
class TIntermSymbol : public TIntermTyped {
public:
    // if symbol is initialized as symbol(sym), the memory comes from the poolallocator of sym. If sym comes from
    // per process threadPoolAllocator, then it causes increased memory usage per compile
    // it is essential to use "symbol = sym" to assign to symbol
    TIntermSymbol(int i, const TString& n, const TType& t) : 
        TIntermTyped(t), id(i) { name = n;} 
    virtual int getId() const { return id; }
    virtual const TString& getName() const { return name; }
    virtual void traverse(TIntermTraverser*);
    virtual       TIntermSymbol* getAsSymbolNode()       { return this; }
    virtual const TIntermSymbol* getAsSymbolNode() const { return this; }
    void setConstArray(const TConstUnionArray& c) { unionArray = c; }
    const TConstUnionArray& getConstArray() const { return unionArray; }
protected:
    int id;
    TString name;
    TConstUnionArray unionArray;
};

class TIntermConstantUnion : public TIntermTyped {
public:
    TIntermConstantUnion(const TConstUnionArray& ua, const TType& t) : TIntermTyped(t), unionArray(ua), literal(false) { }
    const TConstUnionArray& getConstArray() const { return unionArray; }
    virtual       TIntermConstantUnion* getAsConstantUnion()       { return this; }
    virtual const TIntermConstantUnion* getAsConstantUnion() const { return this; }
    virtual void traverse(TIntermTraverser*);
    virtual TIntermTyped* fold(TOperator, const TIntermTyped*) const;
    virtual TIntermTyped* fold(TOperator, const TType&) const;
    void setLiteral() { literal = true; }
    void setExpression() { literal = false; }
    bool isLiteral() const { return literal; }
protected:
    const TConstUnionArray unionArray;
    bool literal;  // true if node represents a literal in the source code
};

//
// Intermediate class for node types that hold operators.
//
class TIntermOperator : public TIntermTyped {
public:
    virtual       TIntermOperator* getAsOperator()       { return this; }
    virtual const TIntermOperator* getAsOperator() const { return this; }
    TOperator getOp() const { return op; }
    bool modifiesState() const;
    bool isConstructor() const;
    virtual bool promote() { return true; }
protected:
    TIntermOperator(TOperator o) : TIntermTyped(EbtFloat), op(o) {}
    TIntermOperator(TOperator o, TType& t) : TIntermTyped(t), op(o) {}
    TOperator op;
};

//
// Nodes for all the basic binary math operators.
//
class TIntermBinary : public TIntermOperator {
public:
    TIntermBinary(TOperator o) : TIntermOperator(o) {}
    virtual void traverse(TIntermTraverser*);
    virtual void setLeft(TIntermTyped* n) { left = n; }
    virtual void setRight(TIntermTyped* n) { right = n; }
    virtual TIntermTyped* getLeft() const { return left; }
    virtual TIntermTyped* getRight() const { return right; }
    virtual       TIntermBinary* getAsBinaryNode()       { return this; }
    virtual const TIntermBinary* getAsBinaryNode() const { return this; }
    virtual bool promote();
    virtual void updatePrecision();
protected:
    TIntermTyped* left;
    TIntermTyped* right;
};

//
// Nodes for unary math operators.
//
class TIntermUnary : public TIntermOperator {
public:
    TIntermUnary(TOperator o, TType& t) : TIntermOperator(o, t), operand(0) {}
    TIntermUnary(TOperator o) : TIntermOperator(o), operand(0) {}
    virtual void traverse(TIntermTraverser*);
    virtual void setOperand(TIntermTyped* o) { operand = o; }
    virtual TIntermTyped* getOperand() { return operand; }
    virtual       TIntermUnary* getAsUnaryNode()       { return this; }
    virtual const TIntermUnary* getAsUnaryNode() const { return this; }
    virtual bool promote();
    virtual void updatePrecision();
protected:
    TIntermTyped* operand;
};

typedef TVector<TIntermNode*> TIntermSequence;
typedef TVector<int> TQualifierList;
//
// Nodes that operate on an arbitrary sized set of children.
//
class TIntermAggregate : public TIntermOperator {
public:
    TIntermAggregate() : TIntermOperator(EOpNull), userDefined(false), pragmaTable(0) { }
    TIntermAggregate(TOperator o) : TIntermOperator(o), pragmaTable(0) { }
    ~TIntermAggregate() { delete pragmaTable; }
    virtual       TIntermAggregate* getAsAggregate()       { return this; }
    virtual const TIntermAggregate* getAsAggregate() const { return this; }
    virtual void setOperator(TOperator o) { op = o; }
    virtual       TIntermSequence& getSequence()       { return sequence; }
    virtual const TIntermSequence& getSequence() const { return sequence; }
    virtual void setName(const TString& n) { name = n; }
    virtual const TString& getName() const { return name; }
    virtual void traverse(TIntermTraverser*);
    virtual void setUserDefined() { userDefined = true; }
    virtual bool isUserDefined() { return userDefined; }
    virtual TQualifierList& getQualifierList() { return qualifier; }
    virtual const TQualifierList& getQualifierList() const { return qualifier; }
    void setOptimize(bool o) { optimize = o; }
    void setDebug(bool d) { debug = d; }
    bool getOptimize() const { return optimize; }
    bool getDebug() const { return debug; }
    void addToPragmaTable(const TPragmaTable& pTable);
    const TPragmaTable& getPragmaTable() const { return *pragmaTable; }
protected:
    TIntermAggregate(const TIntermAggregate&); // disallow copy constructor
    TIntermAggregate& operator=(const TIntermAggregate&); // disallow assignment operator
    TIntermSequence sequence;
    TQualifierList qualifier;
    TString name;
    bool userDefined; // used for user defined function names
    bool optimize;
    bool debug;
    TPragmaTable* pragmaTable;
};

//
// For if tests.
//
class TIntermSelection : public TIntermTyped {
public:
    TIntermSelection(TIntermTyped* cond, TIntermNode* trueB, TIntermNode* falseB) :
        TIntermTyped(EbtVoid), condition(cond), trueBlock(trueB), falseBlock(falseB) {}
    TIntermSelection(TIntermTyped* cond, TIntermNode* trueB, TIntermNode* falseB, const TType& type) :
        TIntermTyped(type), condition(cond), trueBlock(trueB), falseBlock(falseB) {}
    virtual void traverse(TIntermTraverser*);
    virtual TIntermTyped* getCondition() const { return condition; }
    virtual TIntermNode* getTrueBlock() const { return trueBlock; }
    virtual TIntermNode* getFalseBlock() const { return falseBlock; }
    virtual       TIntermSelection* getAsSelectionNode()       { return this; }
    virtual const TIntermSelection* getAsSelectionNode() const { return this; }
protected:
    TIntermTyped* condition;
    TIntermNode* trueBlock;
    TIntermNode* falseBlock;
};

//
// For switch statements.  Designed use is that a switch will have sequence of nodes
// that are either case/default nodes or a *single* node that represents all the code
// in between (if any) consecutive case/defaults.  So, a traversal need only deal with
// 0 or 1 nodes per case/default statement.
//
class TIntermSwitch : public TIntermNode {
public:
    TIntermSwitch(TIntermTyped* cond, TIntermAggregate* b) : condition(cond), body(b) { }
    virtual void traverse(TIntermTraverser*);
    virtual TIntermNode* getCondition() const { return condition; }
    virtual TIntermAggregate* getBody() const { return body; }
    virtual       TIntermSwitch* getAsSwitchNode()       { return this; }
    virtual const TIntermSwitch* getAsSwitchNode() const { return this; }
protected:
    TIntermTyped* condition;
    TIntermAggregate* body;
};

enum TVisit
{
    EvPreVisit,
    EvInVisit,
    EvPostVisit
};

//
// For traversing the tree.  User should derive from this, 
// put their traversal specific data in it, and then pass
// it to a Traverse method.
//
// When using this, just fill in the methods for nodes you want visited.
// Return false from a pre-visit to skip visiting that node's subtree.
//
// Explicitly set postVisit to true if you want post visiting, otherwise,
// filled in methods will only be called at pre-visit time (before processing
// the subtree).  Similary for inVisit for in-order visiting of nodes with
// multiple children.
//
// If you only want post-visits, explicitly turn off preVisit (and inVisit) 
// and turn on postVisit.
//
class TIntermTraverser {
public:
    POOL_ALLOCATOR_NEW_DELETE(glslang::GetThreadPoolAllocator())
    TIntermTraverser(bool preVisit = true, bool inVisit = false, bool postVisit = false, bool rightToLeft = false) :
            preVisit(preVisit),
            inVisit(inVisit),
            postVisit(postVisit),
            rightToLeft(rightToLeft),
            depth(0),
            maxDepth(0) { }
    virtual ~TIntermTraverser() { }

    virtual void visitSymbol(TIntermSymbol*)               { }
    virtual void visitConstantUnion(TIntermConstantUnion*) { }
    virtual bool visitBinary(TVisit, TIntermBinary*)       { return true; }
    virtual bool visitUnary(TVisit, TIntermUnary*)         { return true; }
    virtual bool visitSelection(TVisit, TIntermSelection*) { return true; }
    virtual bool visitAggregate(TVisit, TIntermAggregate*) { return true; }
    virtual bool visitLoop(TVisit, TIntermLoop*)           { return true; }
    virtual bool visitBranch(TVisit, TIntermBranch*)       { return true; }
    virtual bool visitSwitch(TVisit, TIntermSwitch*)       { return true; }

    int getMaxDepth() const { return maxDepth; }

    void incrementDepth(TIntermNode *current)
    {
        depth++;
        maxDepth = std::max(maxDepth, depth);
        path.push_back(current);
    }

    void decrementDepth()
    {
        depth--;
        path.pop_back();
    }

    TIntermNode *getParentNode()
    {
        return path.size() == 0 ? NULL : path.back();
    }

    const bool preVisit;
    const bool inVisit;
    const bool postVisit;
    const bool rightToLeft;

protected:
    TIntermTraverser& operator=(TIntermTraverser&);

    int depth;
    int maxDepth;

    // All the nodes from root to the current node's parent during traversing.
    TVector<TIntermNode *> path;
};

} // end namespace glslang

#endif // __INTERMEDIATE_H