Big-Data-HPC-Platform/ecl/hqlcpp/hqlstmt.cpp

/*##############################################################################

    Copyright (C) 2011 HPCC Systems.

    All rights reserved. This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
############################################################################## */
#include "jliball.hpp"
#include "hql.hpp"

#include "platform.h"
#include "jlib.hpp"
#include "jexcept.hpp"
#include "jmisc.hpp"

#include "hqlexpr.hpp"

#include "hqlstmt.hpp"
#include "hqlstmt.ipp"
#include "hqlfunc.hpp"

#include "hqlcpp.ipp"
#include "hqlcatom.hpp"
#include "hqlcpputil.hpp"
#include "hqlutil.hpp"

#define CLEAR_COPY_THRESHOLD            100

//---------------------------------------------------------------------------

struct HQLCPP_API HqlBoundDefinedValue : public HqlDefinedValue
{
public:
    HqlBoundDefinedValue(IHqlExpression * _original, const CHqlBoundExpr & _bound) : HqlDefinedValue(_original)
    { bound.set(_bound); }

    virtual IHqlExpression * queryExpr() const              { return bound.expr; }
    virtual void getBound(CHqlBoundExpr & result)           { result.set(bound); }

public:
    CHqlBoundExpr       bound;
};


void HqlExprAssociation::getBound(CHqlBoundExpr & result)   
{ 
    result.expr.set(queryExpr()); 
}
    
//---------------------------------------------------------------------------

BuildCtx::BuildCtx(HqlCppInstance & _state, _ATOM section) : state(_state)
{
    init(state.ensureSection(section));
}

BuildCtx::BuildCtx(HqlCppInstance & _state) : state(_state)
{
    init(NULL);
}

BuildCtx::BuildCtx(BuildCtx & _owner) : state(_owner.state)
{
    init(_owner.curStmts);
    ignoreInput = _owner.ignoreInput;
    curPriority = _owner.curPriority;
    nextPriority = _owner.nextPriority;
    ignoreInput = false;
}

BuildCtx::BuildCtx(BuildCtx & _owner, HqlStmts * _root) : state(_owner.state)
{
    init(_root);
}


BuildCtx::~BuildCtx()
{
}

void BuildCtx::set(_ATOM section)
{
    init(state.ensureSection(section));
}

void BuildCtx::set(BuildCtx & _owner)
{
    init(_owner.curStmts);
    ignoreInput = _owner.ignoreInput;
    curPriority = _owner.curPriority;
    nextPriority = _owner.nextPriority;
    ignoreInput = false;
}

IHqlStmt * BuildCtx::addAlias(IHqlStmt * aliased)
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlCompoundStmt(alias_stmt, curStmts);
    HqlStmt * cast = dynamic_cast<HqlStmt *>(aliased);
    assertex(cast);
    next->code.append(*LINK(cast));
    return appendSimple(next);
}


IHqlStmt * BuildCtx::addAssign(IHqlExpression * target, IHqlExpression * value)
{
    if (ignoreInput)
        return NULL;

    HqlStmt * next = new HqlStmt(assign_stmt, curStmts);
    next->addExpr(LINK(target));
    next->addExpr(LINK(value));
    return appendSimple(next);
}


IHqlStmt * BuildCtx::addAssignIncrement(IHqlExpression * target, IHqlExpression * value)
{
    if (ignoreInput)
        return NULL;

    if (value && !matchesConstantValue(value, 1))
    {
        HqlStmt * next = new HqlStmt(assigninc_stmt, curStmts);
        next->addExpr(LINK(target));
        next->addExpr(LINK(value));
        return appendSimple(next);
    }
    else
    {
        OwnedHqlExpr inc = createValue(no_postinc, target->getType(), LINK(target));
        return addExprOwn(inc.getClear());
    }
}


IHqlStmt * BuildCtx::addAssignDecrement(IHqlExpression * target, IHqlExpression * value)
{
    if (ignoreInput)
        return NULL;

    if (value && !matchesConstantValue(value, 1))
    {
        HqlStmt * next = new HqlStmt(assigndec_stmt, curStmts);
        next->addExpr(LINK(target));
        next->addExpr(LINK(value));
        return appendSimple(next);
    }
    else
    {
        OwnedHqlExpr inc = createValue(no_postdec, LINK(target->getType()), LINK(target));
        return addExprOwn(inc.getClear());
    }
}


IHqlStmt * BuildCtx::addBlock()
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlCompoundStmt(block_stmt, curStmts);
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addBreak()
{
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(break_stmt, curStmts);
    return appendSimple(next);
}


IHqlStmt * BuildCtx::addCase(IHqlStmt * _owner, IHqlExpression * source)
{
    if (ignoreInput)
        return NULL;
    assertThrow(_owner->getStmt() == switch_stmt);

    HqlCompoundStmt & owner = (HqlCompoundStmt &)*_owner;
    curStmts = &owner.code;

    HqlCompoundStmt * next = new HqlCompoundStmt(case_stmt, curStmts);
    next->addExpr(LINK(source));
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addContinue()
{
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(continue_stmt, curStmts);
    return appendSimple(next);
}


IHqlStmt * BuildCtx::addDeclare(IHqlExpression * name, IHqlExpression * value)
{
    assertex(name->getOperator() == no_variable);
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(declare_stmt, curStmts);
    next->addExpr(LINK(name));
    if (value)
        next->addExpr(LINK(value));

    appendSimple(next);
    return next;
}


IHqlStmt * BuildCtx::addDeclareExternal(IHqlExpression * name)
{
    assertex(name->getOperator() == no_variable);
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(external_stmt, curStmts);
    next->addExpr(LINK(name));
    appendSimple(next);
    return next;
}


IHqlStmt * BuildCtx::addDeclareAssign(IHqlExpression * name, IHqlExpression * value)
{
    addDeclare(name);
    return addAssign(name, value);
}


IHqlStmt * BuildCtx::addDefault(IHqlStmt * _owner)
{
    if (ignoreInput)
        return NULL;
    assertThrow(_owner->getStmt() == switch_stmt);

    selectCompound(_owner);
    HqlCompoundStmt * next = new HqlCompoundStmt(default_stmt, curStmts);
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addExpr(IHqlExpression * value)
{
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(expr_stmt, curStmts);
    next->addExpr(LINK(value));
    return appendSimple(next);
}

IHqlStmt * BuildCtx::addExprOwn(IHqlExpression * value)
{
    if (ignoreInput)
    {
        value->Release();
        return NULL;
    }
    HqlStmt * next = new HqlStmt(expr_stmt, curStmts);
    next->addExpr(value);
    return appendSimple(next);
}

IHqlStmt * BuildCtx::addReturn(IHqlExpression * value)
{
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(return_stmt, curStmts);
    if (value)
        next->addExpr( LINK(value));
    return appendSimple(next);
}

IHqlStmt * BuildCtx::addFilter(IHqlExpression * condition)
{
    HqlCompoundStmt * next = new HqlCompoundStmt(filter_stmt, curStmts);
    next->addExpr(LINK(condition));
    appendCompound(next);
    addBlock();
    return next;
}


IHqlStmt * BuildCtx::addFunction(IHqlExpression * funcdef)
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlCompoundStmt(function_stmt, curStmts);
    next->addExpr(LINK(funcdef));
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addIndirection(const BuildCtx & _parent)
{
    HqlCompoundStmt * next = new HqlCompoundStmt(indirect_stmt, _parent.curStmts);
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addLoop(IHqlExpression * cond, IHqlExpression * inc, bool atEnd)
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlCompoundStmt(loop_stmt, curStmts);
    if (cond)
        next->addExpr(LINK(cond));
    if (inc)
        next->addExpr(LINK(inc));
    if (atEnd)
        next->addExpr(createAttribute(endAtom));
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addGoto(const char * labelText)
{
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(goto_stmt, curStmts);
    IHqlExpression * label= createVariable(labelText, makeBoolType());
    next->addExpr(label);
    return appendSimple(next);
}


IHqlStmt * BuildCtx::addGroup()
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlCompoundStmt(group_stmt, curStmts);
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addGroupPass(IHqlExpression * pass)
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlCompoundStmt(pass_stmt, curStmts);
    next->addExpr(LINK(pass));
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addLabel(const char * labelText)
{
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(label_stmt, curStmts);
    IHqlExpression * label= createVariable(labelText, makeBoolType());
    next->addExpr(label);
    return appendSimple(next);
}


IHqlStmt *  BuildCtx::addLine(const char * filename, unsigned lineNum)
{
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlStmt(line_stmt, curStmts);
    if (filename)
    {
        next->addExpr(createConstant(filename));
        next->addExpr(createConstant(createIntValue(lineNum, sizeof(int), true)));
    }
    return appendSimple(next);
}

IHqlStmt * BuildCtx::addQuoted(const char * text)
{
    if (ignoreInput)
        return NULL;
    HqlStmt * next = new HqlQuoteStmt(quote_stmt, curStmts, text);
    return appendSimple(next);
}


IHqlStmt * BuildCtx::addQuotedF(const char * format, ...)
{
    if (ignoreInput)
        return NULL;

    StringBuffer text;
    va_list args;
    va_start(args, format);
    text.valist_appendf(format, args);
    va_end(args);
    HqlStmt * next = new HqlQuoteStmt(quote_stmt, curStmts, text.str());
    return appendSimple(next);
}


IHqlStmt * BuildCtx::addQuotedCompound(const char * text, const char * extra)
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlQuoteStmt(quote_compound_stmt, curStmts, text);
    if (extra)
        next->addExpr(createQuoted(extra, makeVoidType()));
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addQuotedCompoundOpt(const char * text, const char * extra)
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlQuoteStmt(quote_compoundopt_stmt, curStmts, text);
    if (extra)
        next->addExpr(createQuoted(extra, makeVoidType()));
    return appendCompound(next);
}


IHqlStmt * BuildCtx::addSwitch(IHqlExpression * source)
{
    if (ignoreInput)
        return NULL;
    HqlCompoundStmt * next = new HqlCompoundStmt(switch_stmt, curStmts);
    next->addExpr(LINK(source));
    return appendCompound(next);
}


HqlStmt * BuildCtx::appendCompound(HqlCompoundStmt * next)
{
    assertThrow(!ignoreInput);
    appendSimple(next);
    curStmts = &next->code;
    return next;
}

HqlStmt * BuildCtx::appendSimple(HqlStmt * next)                     
{
    assertThrow(!ignoreInput);
    if (nextPriority == OutermostScopePrio)
    {
        appendToOutermostScope(next);
    }
    else
    {
        next->setPriority(nextPriority);
        curStmts->appendStmt(*next);
    }
    nextPriority = curPriority;
    return next; 
}


void BuildCtx::appendToOutermostScope(HqlStmt * next)
{
    HqlStmts * searchStmts = curStmts;
    HqlStmts * insertStmts = NULL;
    HqlStmt * insertBefore = NULL;
    loop
    {
        HqlStmt * owner = searchStmts->owner;
        if (!owner)
            break;

        HqlStmts * ownerStmts = owner->queryContainer();
        switch (owner->getStmt())
        {
        case quote_compound_stmt:
        case quote_compoundopt_stmt:
        case indirect_stmt:
            goto found;
        case group_stmt:
            break;
        default:
            insertBefore = owner;
            insertStmts = ownerStmts;
            break;
        }

        searchStmts = ownerStmts;
    }

found:
    if (insertBefore)
    {
        next->setPriority(insertBefore->queryPriority());
        insertStmts->add(*next, insertStmts->find(*insertBefore));
    }
    else
    {
        next->setPriority(curPriority);
        curStmts->appendStmt(*next); 
    }
}


void BuildCtx::associate(HqlExprAssociation & next)
{
    assertex(next.represents->queryBody() == next.represents);
    if (!ignoreInput)
    {
        curStmts->appendOwn(OLINK(next));
    }
}


void BuildCtx::associateOwn(HqlExprAssociation & next)
{
    assertex(next.represents->queryBody() == next.represents);
    if (!ignoreInput)
    {
        curStmts->appendOwn(next);
    }
    else
        next.Release();             // can cause serious problems....
}


HqlExprAssociation *BuildCtx::associateExpr(IHqlExpression * represents, IHqlExpression * expr)
{
    if (!ignoreInput)
    {
        HqlExprAssociation * assoc = new HqlSimpleDefinedValue(represents->queryBody(), expr);
        curStmts->appendOwn(*assoc);
        return assoc;
    }
    return NULL;
}


HqlExprAssociation * BuildCtx::associateExpr(IHqlExpression * represents, const CHqlBoundExpr & bound)
{ 
    if (!ignoreInput)
    {
        HqlExprAssociation * assoc = new HqlBoundDefinedValue(represents->queryBody(), bound);
        curStmts->appendOwn(*assoc);
        return assoc;
    }
    return NULL;
}

IHqlExpression * BuildCtx::getTempDeclare(ITypeInfo * type, IHqlExpression * value)
{
    IHqlExpression * temp = createVariable(LINK(type));
    addDeclare(temp, value);
    return temp;
}

bool BuildCtx::hasAssociation(HqlExprAssociation & search, bool unconditional)
{
    HqlStmts * searchStmts = curStmts;
    loop
    {
        if (searchStmts->defs.contains(search))
            return true;
        HqlStmt * limitStmt = searchStmts->queryStmt();
        if (!limitStmt)
            return false;
        if (!unconditional)
        {
            switch (limitStmt->getStmt())
            {
            case filter_stmt:
                if (!matchesBoolean(limitStmt->queryExpr(0), true))
                    return false;
                break;
            case quote_compound_stmt:
            case quote_compoundopt_stmt:
            case switch_stmt:
            case case_stmt:
            case default_stmt:
            case loop_stmt:
                return false;
            }
        }
        searchStmts = limitStmt->queryContainer();
    }
}


void BuildCtx::walkAssociations(IAssociationVisitor & visitor)
{
    HqlStmts * searchStmts = curStmts;

    // walk all associations in the tree before this one
    loop
    {
        CIArrayOf<HqlExprAssociation> & defs = searchStmts->defs;
        ForEachItemInRev(idx, defs)
        {
            HqlExprAssociation & cur = defs.item(idx);
            if (visitor.visit(cur))
                return;
        }

        HqlStmt * limitStmt = searchStmts->queryStmt();
        if (!limitStmt)
            break;
        searchStmts = limitStmt->queryContainer();
    }
}


HqlExprAssociation * BuildCtx::queryAssociation(IHqlExpression * search, AssocKind kind, HqlExprCopyArray * selectors)
{
    HqlStmts * searchStmts = curStmts;

    if (!search)
        return NULL;
    search = search->queryBody();

    // search all statements in the tree before this one, to see
    // if an expression already exists...  If so return the target
    // of the assignment.
    loop
    {
        const CIArrayOf<HqlExprAssociation> & defs = searchStmts->defs;
#ifdef CACHE_DEFINITION_HASHES
        if (!selectors)
        {
            unsigned searchHash = getSearchHash(search);
            const DefinitionHashArray & hashes = searchStmts->exprHashes;
            ForEachItemInRev(idx, hashes)
            {
                if (hashes.item(idx) == searchHash)
                {
                    HqlExprAssociation & cur = defs.item(idx);
                    if (cur.represents == search)
                    {
                        if ((kind == AssocAny) || (cur.getKind() == kind))
                            return &cur;
                    }
                }
            }
        }
        else
#endif
        {
            ForEachItemInRev(idx, defs)
            {
                HqlExprAssociation & cur = defs.item(idx);
                IHqlExpression * represents = cur.represents.get();
                if (selectors && (cur.getKind() == AssocCursor))
                {
                    if (selectors->contains(*represents))
                        return NULL;
                }
                if (represents == search)
                    if ((kind == AssocAny) || (cur.getKind() == kind))
                        return &cur;
            }
        }

        HqlStmt * limitStmt = searchStmts->queryStmt();
        if (!limitStmt)
            break;
        searchStmts = limitStmt->queryContainer();
    }
    return NULL;
}


void BuildCtx::removeAssociation(HqlExprAssociation * search)
{
    if (!search)
        return;
    HqlStmts * searchStmts = curStmts;
    loop
    {
        bool matched = searchStmts->zap(*search);
        if (matched)
            return;
        HqlStmt * limitStmt = searchStmts->queryStmt();
        if (!limitStmt)
            break;
        searchStmts = limitStmt->queryContainer();
    }
        
    assertex(!"Association not found");
}


HqlExprAssociation * BuildCtx::queryFirstAssociation(AssocKind searchKind)
{
    HqlStmts * searchStmts = curStmts;

    // search all statements in the tree before this one, to see
    // if an expression already exists...  If so return the target
    // of the assignment.
    loop
    {
        CIArray & defs = searchStmts->defs;
        ForEachItemInRev(idx, defs)
        {
            HqlExprAssociation & cur = (HqlExprAssociation &)defs.item(idx);
            if (cur.getKind() == searchKind)
                return &cur;
        }

        HqlStmt * limitStmt = searchStmts->queryStmt();
        if (!limitStmt)
            break;
        searchStmts = limitStmt->queryContainer();
    }
    return NULL;
}


//Search for an association, but don't allow it to be conditional, or be hidden by the definition of a cursor.
HqlExprAssociation * BuildCtx::queryFirstCommonAssociation(AssocKind searchKind)
{
    HqlStmts * searchStmts = curStmts;

    // search all statements in the tree before this one, to see
    // if an expression already exists...  If so return the target
    // of the assignment.
    loop
    {
        CIArray & defs = searchStmts->defs;
        ForEachItemInRev(idx, defs)
        {
            HqlExprAssociation & cur = (HqlExprAssociation &)defs.item(idx);
            AssocKind kind = cur.getKind();
            if (kind == searchKind)
                return &cur;
            if (kind == AssocCursor)
                return NULL;
        }

        HqlStmt * limitStmt = searchStmts->queryStmt();
        if (!limitStmt)
            break;
        switch (limitStmt->getStmt())
        {
        //case quote_compound_stmt:
        //case quote_compoundopt_stmt,
        case filter_stmt:
        case label_stmt:
        case switch_stmt:
        case case_stmt:
        case default_stmt:
        case break_stmt:
        case continue_stmt:
            return NULL;
        }

        searchStmts = limitStmt->queryContainer();
    }
    return NULL;
}


HqlExprAssociation * BuildCtx::queryMatchExpr(IHqlExpression * search)
{
    HqlExprCopyArray selectors;
    search->gatherTablesUsed(NULL, &selectors);
    return queryAssociation(search, AssocExpr, selectors.ordinality() ? &selectors : NULL);
}


bool BuildCtx::getMatchExpr(IHqlExpression * expr, CHqlBoundExpr & tgt)
{
    HqlExprAssociation * match = queryMatchExpr(expr);

    if (match)
    {
        match->getBound(tgt);
        return true;
    }
    return false;
}

    

void BuildCtx::init(HqlStmts * _root)
{
    root = _root;
    curStmts = root;
    curPriority = NormalPrio;
    nextPriority = curPriority;
    ignoreInput = false;
}

bool BuildCtx::isChildOf(HqlStmt * stmt, HqlStmts * stmts)
{
    //MORE: Could improve by using depths
    do
    {
        if (stmts->find(*stmt) != NotFound)
            return true;
        stmt = stmt->queryContainer()->queryStmt();
    } while (stmt);
    return false;
}


void BuildCtx::selectCompound(IHqlStmt * stmt)
{
    HqlCompoundStmt & owner = (HqlCompoundStmt &)*stmt;
    curStmts = &owner.code;
}

void BuildCtx::selectContainer()
{
    HqlStmt * limitStmt = curStmts->queryStmt();
    assertex(limitStmt);
    curStmts = limitStmt->queryContainer();
    assertex(curStmts);
}


void BuildCtx::selectElse(IHqlStmt * stmt)
{
    //Ignoring input does not work, because code expects associations to be kept
    assertex(stmt);
    switch (stmt->getStmt())
    {
    case filter_stmt:
        assertThrow(stmt->numChildren() == 1);
        selectCompound(stmt);
        addBlock();
        break;
    default:
        throwUnexpected();
        break;
    }
}


unsigned BuildCtx::setPriority(unsigned newPrio)
{
    unsigned oldPriority = curPriority;
    if (!ignoreInput)
    {
        curPriority = newPrio;
        nextPriority = curPriority;
    }
    return oldPriority;
}

void BuildCtx::setNextPriority(unsigned newPrio)
{
    if (!ignoreInput)
        nextPriority = newPrio;
}



IHqlStmt * BuildCtx::recursiveGetBestContext(HqlStmts * searchStmts, HqlExprCopyArray & required)
{
    //Is it ok to move the expression before the owner statement?
    //First fail if any of the datasets that this expression is dependent on are defined in this scope.
    if (required.ordinality())
    {
        ForEachItemIn(i, searchStmts->defs)
        {
            HqlExprAssociation & cur = (HqlExprAssociation &)searchStmts->defs.item(i);
            if (required.contains(*cur.represents.get()))
                return NULL;
        }
    }

    HqlStmt * owner = searchStmts->owner;
    //Now check for poor places to hoist
    bool worthHoistingHere = false;
    switch (owner->getStmt())
    {
    case block_stmt:
    case group_stmt:
        break;
    case quote_compound_stmt:
    case quote_compoundopt_stmt:
    case indirect_stmt:
        return NULL;
    case filter_stmt:
    case switch_stmt:
        //MORE: Should make whether something ishoisted dependent on efficiency of the filter condition
        break;
    case loop_stmt:
        //MORE: Should make it dependent on the ordinality of the loop condition.
        worthHoistingHere = true;
        break;
    case case_stmt:
    case default_stmt:
        //Can't hoist here
        break;
    default:
        throwUnexpected();
    }

    HqlStmts * container = owner->queryContainer();
    if (container->owner)// && canHoistInParent)
    {
        IHqlStmt * match = recursiveGetBestContext(container, required);
        if (match)
            return match;
    }

    if (!worthHoistingHere)
        return NULL;

    //We've found somewhere we can insert the expression....
    unsigned existingPos = container->find(*owner);
    assertex(existingPos != NotFound);

    //insert a group just before the current statement
    HqlCompoundStmt * next = new HqlCompoundStmt(group_stmt, container);
    next->setPriority(owner->queryPriority());
    container->add(*next, existingPos);
    curStmts = &next->code;
    return next;
}


IHqlStmt * BuildCtx::replaceExpr(IHqlStmt * stmt, IHqlExpression * expr)
{
    //Highly dangerous - use with utmost care!
    assertex(stmt->getStmt() == expr_stmt);
    HqlStmt * castStmt = static_cast<HqlStmt *>(stmt);
    castStmt->killExprs();
    castStmt->addExpr(LINK(expr));
    return castStmt;
}

IHqlStmt * BuildCtx::selectBestContext(IHqlExpression * expr)
{
    if (containsTranslated(expr) || !curStmts->owner)
        return NULL;

    //MORE: Access to global context, context and other things...
    HqlExprCopyArray inScope;
    expr->gatherTablesUsed(NULL, &inScope);

    return recursiveGetBestContext(curStmts, inScope);
}

//---------------------------------------------------------------------------

HqlStmts::HqlStmts(HqlStmt * _owner)    : owner(_owner) 
{
}

void HqlStmts::appendStmt(HqlStmt & stmt)
{
    unsigned newPrio = stmt.queryPriority();
    unsigned right = ordinality();

    if (right == 0)
    {
        append(stmt);
    }
    else if (newPrio >= item(right-1).queryPriority())
    {
        while (item(right-1).isIncomplete())
        {
            if (newPrio > item(right-1).queryPriority())
                break;
            right--;
            if (right == 0)
                break;
        }
        add(stmt, right);
    }
    else
    {
        unsigned left = 0;
        while (right - left >= 2)
        {
            unsigned mid = (left + right - 1) / 2;
            HqlStmt & cur = item(mid);
            if (newPrio >= cur.queryPriority())
                left = mid+1;
            else
                right = mid+1;
        }

        if (newPrio >= item(left).queryPriority())
            ++left;
        while (left && item(left-1).isIncomplete() && (newPrio == item(left-1).queryPriority()))
            --left;
        add(stmt, left);
    }
}


//---------------------------------------------------------------------------

HqlStmt::HqlStmt(StmtKind _kind, HqlStmts * _container)
{
    kind = _kind;
    container = _container;
    incomplete = false;
    included = true;
}

void HqlStmt::addExpr(IHqlExpression * expr)
{
    exprs.append(*expr);
}

StmtKind HqlStmt::getStmt()
{
    return (StmtKind)kind;
}

StringBuffer & HqlStmt::getTextExtra(StringBuffer & out)
{
    return out;
}

static bool isEmptyGroup(IHqlStmt * stmt)
{
    if (!stmt)
        return true;
    switch (stmt->getStmt())
    {
    case group_stmt:
    case block_stmt:
        return stmt->numChildren() == 0;
    }
    return false;
}

bool HqlStmt::hasChildren() const
{
    if (numChildren() == 0)
        return false;

    unsigned count = numChildren();
    for (unsigned index = 0; index < count; index++)
    {
        IHqlStmt * cur = queryChild(index);
        if (cur->isIncluded())
            return true;
    }
    return false;
}
            
bool HqlStmt::isIncluded() const
{
    if (!included)
        return false;
    switch (kind)
    {
    case quote_compoundopt_stmt:
    case group_stmt:
        return hasChildren();
    case filter_stmt:
        if (isEmptyGroup(queryChild(0)) && isEmptyGroup(queryChild(1)))
            return false;
        break;
    }
    return true;
}

unsigned HqlStmt::numChildren() const
{
    return 0;
}

IHqlStmt * HqlStmt::queryChild(unsigned index) const
{
    return NULL;
}

HqlStmts * HqlStmt::queryContainer()
{
    return container;
}

IHqlExpression * HqlStmt::queryExpr(unsigned index)
{
    if (exprs.isItem(index))
        return &exprs.item(index);
    return NULL;
}


void HqlStmts::inheritDefinitions(HqlStmts & other)
{
    ForEachItemIn(i, other.defs)
    {
        defs.append(OLINK(other.defs.item(i)));
#ifdef CACHE_DEFINITION_HASHES
        exprHashes.append(other.exprHashes.item(i));
#endif
    }

}

//---------------------------------------------------------------------------

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning( disable : 4355 ) // 'this' : used in base member initializer list
#endif
HqlCompoundStmt::HqlCompoundStmt(StmtKind _kind, HqlStmts * _container) : HqlStmt(_kind, _container), code(this)
{
}
#ifdef _MSC_VER
#pragma warning(pop)
#endif


void HqlCompoundStmt::mergeScopeWithContainer()
{
    container->inheritDefinitions(code);
}

unsigned HqlCompoundStmt::numChildren() const
{
    return code.ordinality();
}

IHqlStmt * HqlCompoundStmt::queryChild(unsigned index) const
{
    if (code.isItem(index))
        return &code.item(index);
    return NULL;
}


//---------------------------------------------------------------------------

StringBuffer & HqlQuoteStmt::getTextExtra(StringBuffer & out)
{
    return out.append(text);
}


//---------------------------------------------------------------------------
int queryMemsetChar(IHqlExpression * expr)
{
    if (expr->getOperator() != no_constant)
        return -1;
    unsigned size = expr->queryType()->getSize();
    if (size == 0)
        return -1;
    const byte * data = (const byte *)expr->queryValue()->queryValue();
    byte match = data[0];
    while (--size)
        if (*++data != match)
            return -1;
    return match;
}


static IHqlExpression * extractNonConstant(IHqlExpression * expr, unsigned & delta)
{
    switch (expr->getOperator())
    {
    case no_constant:
        delta += (unsigned)getIntValue(expr);
        return NULL;
    case no_add:
        {
            IHqlExpression * left = expr->queryChild(0);
            OwnedHqlExpr newLeft = extractNonConstant(left, delta);
            IHqlExpression * right = expr->queryChild(1);
            OwnedHqlExpr newRight = extractNonConstant(right, delta);
            if (!newLeft) return newRight.getClear();
            if (!newRight) return newLeft.getClear();
            if ((left == newLeft) && (right == newRight))
                return LINK(expr);
            return createValue(no_add, expr->getType(), newLeft.getClear(), newRight.getClear());
        }
    }
    return LINK(expr);
}

IHqlExpression * peepholeAddExpr(IHqlExpression * left, IHqlExpression * right)
{
    unsigned delta = 0;
    IHqlExpression * simpleLeft = extractNonConstant(left, delta);
    IHqlExpression * simpleRight = extractNonConstant(right, delta);
    IHqlExpression * ret;
    if (simpleLeft)
    {
        if (simpleRight)
            ret = createValue(no_add, left->getType(), simpleLeft, simpleRight);
        else
            ret = simpleLeft;
    }
    else
        ret = simpleRight;

    if (!delta && ret)
        return ret;
    IHqlExpression * value = getSizetConstant(delta);
    if (!ret)
        return value;
    return createValue(no_add, left->getType(), ret, value);
    if ((left->getOperator() == no_constant) && (right->getOperator() == no_constant))
        return getSizetConstant((size32_t)left->queryValue()->getIntValue() + (size32_t)right->queryValue()->getIntValue());
    return createValue(no_add, left->getType(), LINK(left), LINK(right));
}

bool rightFollowsLeft(IHqlExpression * left, IHqlExpression * leftLen, IHqlExpression * right)
{
    OwnedHqlExpr sum = peepholeAddExpr(left, leftLen);
    if (sum == right)
        return true;

    if (left->getOperator() != right->getOperator())
    {
        if (right->getOperator() == no_add)
        {
            if ((left == right->queryChild(0)) && (leftLen == right->queryChild(1)))
                return true;
            if ((left == right->queryChild(1)) && (leftLen == right->queryChild(0)))
                return true;
        }
        return false;
    }

    switch (left->getOperator())
    {
    case no_constant:
        {
            ITypeInfo * leftType = left->queryType();
            ITypeInfo * rightType = right->queryType();
            if (leftType->getTypeCode() != rightType->getTypeCode())
                return false;
            switch (leftType->getTypeCode())
            {
            case type_int:
                if (leftLen->getOperator() != no_constant)
                    return false;
                if (left->queryValue()->getIntValue() + leftLen->queryValue()->getIntValue() == right->queryValue()->getIntValue())
                    return true;
                return false;
            }
            return false;
        }
    case no_add:
        if ((left == right->queryChild(0)) && (leftLen == right->queryChild(1)))
            return true;
        if (left->queryChild(1) == right->queryChild(1))
        {
            if (rightFollowsLeft(left->queryChild(0), leftLen, right->queryChild(0)))
                return true;
        }
        //fall through
    case no_index:
        if (left->queryChild(0) != right->queryChild(0))
            return false;
        return rightFollowsLeft(left->queryChild(1), leftLen, right->queryChild(1));
    }

    unsigned numLeft = left->numChildren();
    if (numLeft == 0 || (numLeft != right->numChildren()))
        return false;
    ForEachChild(idx, left)
    {
        if (!rightFollowsLeft(left->queryChild(idx), leftLen, right->queryChild(idx)))
            return false;
    }
    return true;
}

static IHqlExpression * createDataForMemset(unsigned size, byte value)
{
    if (size < 100)
    {
        void * temp = alloca(size);
        memset(temp, value, size);
        return createConstant(createDataValue((char *)temp, size));
    }
    void * temp = malloc(size);
    memset(temp, value, size);
    IHqlExpression * ret = createConstant(createDataValue((char *)temp, size));
    free(temp);
    return ret;
}


static IHqlExpression * createDataForIntegerZero(unsigned size)
{
    return createDataForMemset(size, 0);
}

class SpecialFunction
{
public:
    SpecialFunction() { wasAssign = false; name = NULL; }

    HqlStmt * createStmt(HqlStmts & curStmts, HqlCppTranslator & translator);

    bool canOptimize() const;
    void expandValue(void * target) const;
    bool extractIsSpecial(IHqlStmt & stmt, bool memsetOnly, unsigned peepholeOptions);
    bool isBigClear() const;
    int queryClearValue() const;
    bool queryCombine(const SpecialFunction & next, bool memsetOnly, size32_t combineStringLimit);

private:
    _ATOM name;
    HqlExprAttr src;
    HqlExprAttr tgt;
    HqlExprAttr srcLen;
    HqlExprAttr tgtLen;
    bool wasAssign;
};

//Always convert rtlWriteInt(rtlReadInt()) the inline memcpy is going to be much better.
//It should probably be converted earlier....
bool isAwkwardIntSize(IHqlExpression * size)
{
    IValue * value = size->queryValue();
    if (value)
    {
        switch (value->getIntValue())
        {
        case 3:
        case 5:
        case 6:
        case 7:
            return true;
        }
    }
    return false;
}


bool SpecialFunction::canOptimize() const
{
    if ((name == memcpyAtom) && (queryMemsetChar(src) >= 0))
    {
        if ((getIntValue(srcLen, 0) > 1) || !wasAssign)
            return true;
    }
    if ((name == memcpyAtom) && isAwkwardIntSize(srcLen))
        return true;

    return false;
}

HqlStmt * SpecialFunction::createStmt(HqlStmts & curStmts, HqlCppTranslator & translator)
{
    HqlExprArray args;

    _ATOM func = name;
    if (name == memsetAtom)
    {
        func = memsetAtom;
        args.append(*LINK(tgt));
        args.append(*LINK(src));
        args.append(*LINK(srcLen));
    }
    else if (name == memcpyAtom)
    {
        int clearByte = queryMemsetChar(src);
        size32_t size = (size32_t)getIntValue(srcLen, 0);
        if (clearByte == 0)
        {
            //if length is 1,2,4 then use an assignment instead.
            switch (size)
            {
            case 1:
            case 2:
            case 4:
            case 8:
                {
                    OwnedITypeInfo type = makeIntType(size, false);
                    OwnedHqlExpr castTgt = createValue(no_cast, makePointerType(LINK(type)), LINK(tgt));
                    OwnedHqlExpr deref = createValue(no_deref, makeReferenceModifier(LINK(type)), LINK(castTgt));
                    OwnedHqlExpr src = createConstant(type->castFrom(true, (__int64)0));
                    HqlStmt * next = new HqlStmt(assign_stmt, &curStmts);
                    next->addExpr(LINK(deref));
                    next->addExpr(LINK(src));
                    return next;
                }
            }
        }
        //MORE: assignment of 1,2,4 bytes possibly better as an assign?
        if (clearByte >= 0)
        {
            func = memsetAtom;
            args.append(*LINK(tgt));
            args.append(*createConstant(createIntValue(clearByte, sizeof(int), true)));
            args.append(*LINK(srcLen));
        }
        else
        {
            args.append(*LINK(tgt));
            args.append(*LINK(src));
            args.append(*LINK(srcLen));
        }
    }
    else if (name == deserializerReadNAtom || name == serializerPutAtom)
    {
        args.append(*LINK(src));
        args.append(*LINK(tgtLen));
        args.append(*LINK(tgt));
    }
    else if ((name == ebcdic2asciiAtom) || (name == ascii2ebcdicAtom))
    {
        args.append(*LINK(tgtLen));
        args.append(*LINK(tgt));
        args.append(*LINK(srcLen));
        args.append(*LINK(src));
    }
    else if (name == deserializerSkipNAtom)
    {
        args.append(*LINK(src));
        args.append(*LINK(srcLen));
    }
    else
        UNIMPLEMENTED;

    HqlStmt * next = new HqlStmt(expr_stmt, &curStmts);
    next->addExpr(translator.bindTranslatedFunctionCall(func, args));
    return next;
}

IHqlExpression * stripTranslatedCasts(IHqlExpression * e)
{
    loop
    {
        switch (e->getOperator())
        {
        case no_cast:
        case no_implicitcast:
        case no_typetransfer:
            {
                IHqlExpression * child = e->queryChild(0);
                if (hasWrapperModifier(child->queryType()))
                    return e;
                e = child;
                break;
            }
        default:
            return e;
        }
    }
}


void SpecialFunction::expandValue(void * target) const
{
    size32_t size = (size32_t)getIntValue(srcLen);
    if (name == memsetAtom)
        memset(target, (int)getIntValue(src), size);
    else
        memcpy(target, src->queryValue()->queryValue(), size);
}


bool SpecialFunction::extractIsSpecial(IHqlStmt & stmt, bool memsetOnly, unsigned peepholeOptions)
{
    if (stmt.getStmt() == expr_stmt)
    {
        IHqlExpression * expr = stmt.queryExpr(0);
        if (expr->getOperator() != no_externalcall)
            return false;
        name = expr->queryName();
        if (name == memcpyAtom)
        {
            src.set(stripTranslatedCasts(expr->queryChild(1)));
            if (memsetOnly && (queryMemsetChar(src) == -1))
                return false;
            tgt.set(stripTranslatedCasts(expr->queryChild(0)));
            srcLen.set(expr->queryChild(2));
            tgtLen.set(srcLen);
            return true;
        }
        if (name == deserializerReadNAtom || name == serializerPutAtom)
        {
            if (memsetOnly)
                return false;
            src.set(expr->queryChild(0));
            tgt.set(stripTranslatedCasts(expr->queryChild(2)));
            tgtLen.set(expr->queryChild(1));
            return true;
        }
        if ((name == ebcdic2asciiAtom) || (name == ascii2ebcdicAtom))
        {
            if (memsetOnly)
                return false;
            src.set(expr->queryChild(3));
            tgt.set(expr->queryChild(1));
            srcLen.set(expr->queryChild(2));
            tgtLen.set(expr->queryChild(0));
            return srcLen == tgtLen;
        }
        if (name == memsetAtom)
        {
            IHqlExpression * value = expr->queryChild(1);
            IHqlExpression * len = expr->queryChild(2);
            if (len->queryValue() && value->queryValue())
            {
                tgt.set(stripTranslatedCasts(expr->queryChild(0)));
                src.set(value);
                srcLen.set(len);
                tgtLen.set(srcLen);
            }
            return true;
        }
        if (name == deserializerSkipNAtom)
        {
            src.set(expr->queryChild(0));
            srcLen.set(expr->queryChild(1));
            return true;
        }
        unsigned size = 0;
        if (name == writeIntAtom[3])
            size = 3;
        else if (name == writeIntAtom[5])
            size = 5;
        else if (name == writeIntAtom[6])
            size = 6;
        else if (name == writeIntAtom[7])
            size = 7;
        if (size)
        {
            IHqlExpression * value = expr->queryChild(1);
            if (isZero(value))
            {
                name = memcpyAtom;
                src.setown(createDataForIntegerZero(size));
                tgt.set(stripTranslatedCasts(expr->queryChild(0)));
                srcLen.setown(getSizetConstant(size));
                tgtLen.set(srcLen);
                return true;
            }
            if (memsetOnly)
                return false;

            while (value->getOperator() == no_typetransfer)
                value = value->queryChild(0);
            if (value->getOperator() == no_externalcall)
            {
                if ((value->queryName() == readIntAtom[size][true]) ||
                    (value->queryName() == readIntAtom[size][false]))
                {
                    name = memcpyAtom;
                    src.set(stripTranslatedCasts(value->queryChild(0)));
                    tgt.set(stripTranslatedCasts(expr->queryChild(0)));
                    srcLen.setown(getSizetConstant(size));
                    tgtLen.set(srcLen);
                    return true;
                }
            }
        }
        return false;
    }
    else if (stmt.getStmt() == assign_stmt)
    {
        wasAssign = true;
        tgt.set(stmt.queryExpr(0));
        src.set(stmt.queryExpr(1));
        ITypeInfo * tgtType = tgt->queryType();
        ITypeInfo * srcType = src->queryType();
        if (!isSameBasicType(srcType, tgtType))
        {
            if (!isSameFullyUnqualifiedType(srcType, tgtType))
                return false;
        }
        while (tgt->getOperator() == no_typetransfer)
            tgt.set(tgt->queryChild(0));
        if (tgt->getOperator() != no_deref)
            return false;
        while (src->getOperator() == no_typetransfer)
            src.set(src->queryChild(0));

        size32_t targetSize = tgtType->getSize();
        if (src->getOperator() != no_deref)
        {
            type_t tc = tgtType->getTypeCode();

            OwnedHqlExpr newSrcExpr;
            switch (tc)
            {
            case type_pointer:
            case type_table:
            //case type_row:
                if (src->getOperator() == no_nullptr)
                {
                    void * ptr = NULL;
                    targetSize = sizeof(void *);
                    newSrcExpr.setown(createConstant(createDataValue((const char *)&ptr, targetSize)));
                }
                break;
            }
            
            if (!memsetOnly)
            {
                switch (tc)
                {
                case type_int:
                case type_swapint:
                case type_boolean:
                    if (src->getOperator() == no_constant)
                    {
                        OwnedHqlExpr cast = ensureExprType(src, tgtType);
                        IValue * castValue = cast->queryValue();
                        if (castValue)
                        {
                            void * temp = alloca(targetSize);
                            castValue->toMem(temp);
                            newSrcExpr.setown(createConstant(createDataValue((const char *)temp, targetSize)));
                        }
                    }
                    break;
                case type_real:
                    if ((peepholeOptions & PHOconvertReal) && (src->getOperator() == no_constant))
                    {
                        OwnedHqlExpr cast = ensureExprType(src, tgtType);
                        IValue * castValue = cast->queryValue();
                        if (castValue)
                        {
                            void * temp = alloca(targetSize);
                            castValue->toMem(temp);
                            newSrcExpr.setown(createConstant(createDataValue((const char *)temp, targetSize)));
                        }
                    }
                    break;
                }
            }

            if (!newSrcExpr && isZero(src))
                newSrcExpr.setown(createDataForIntegerZero(targetSize));

            if (!newSrcExpr)
                return false;
            src.set(newSrcExpr);
        }
        else
        {
            if (memsetOnly)
                return false;
            src.set(src->queryChild(0));
        }
        srcLen.setown(getSizetConstant(targetSize));
        tgtLen.set(srcLen);
        tgt.set(stripTranslatedCasts(tgt->queryChild(0)));
        src.set(stripTranslatedCasts(src));
        name = memcpyAtom;
        return true;
    }
    return false;
}

bool SpecialFunction::isBigClear() const
{
    if ((name == memsetAtom) || (name == memcpyAtom))
        return getIntValue(srcLen, 0) > CLEAR_COPY_THRESHOLD;
    return false;
}

int SpecialFunction::queryClearValue() const
{
    if (name == memcpyAtom) 
        return queryMemsetChar(src);
    if (name == memsetAtom)
        return (int)getIntValue(src, -1);
    return -1;
}

bool SpecialFunction::queryCombine(const SpecialFunction & next, bool memsetOnly, size32_t combineStringLimit)
{
    if (name != next.name)
    {
        if (!((name == memsetAtom) && (next.name == memcpyAtom)) && 
            !((name == memcpyAtom) && (next.name == memsetAtom)))
            return false;
    }
    if (name == deserializerSkipNAtom)
    {
        if (src != next.src)
            return false;
        srcLen.setown(peepholeAddExpr(srcLen, next.srcLen));
        return true;
    }
    if (rightFollowsLeft(tgt, tgtLen, next.tgt))
    {
        if ((name != memsetAtom) && (next.name != memsetAtom))
        {
            if (name == deserializerReadNAtom || name == serializerPutAtom)
            {
                tgtLen.setown(peepholeAddExpr(tgtLen, next.tgtLen));
                return true;
            }

            if (rightFollowsLeft(src, srcLen, next.src))
            {
                srcLen.setown(peepholeAddExpr(srcLen, next.srcLen));
                tgtLen.setown(peepholeAddExpr(tgtLen, next.tgtLen));
                return true;
            }
        }
        IValue * srcValue = src->queryValue();
        IValue * nextValue = next.src->queryValue();
        if (srcValue && nextValue)
        {
            //Don't combine things that can be converted to different memsets.
            //This would work better if we first combined items that could be done as memsets and then combined strings
            //processing in order we hit them doesn't work as well.
            int clearValue = queryClearValue();
            int nextClearValue = next.queryClearValue();
            if (memsetOnly)
            {
                assertex((clearValue != -1) && (nextClearValue != -1));
                if (clearValue != nextClearValue)
                    return false;
            }

            if ((isBigClear() && (clearValue != -1)) || (next.isBigClear() && (nextClearValue != -1)))
            {
                if (clearValue != nextClearValue)
                    return false;
            }

            size32_t curSize = (size32_t)getIntValue(srcLen);
            size32_t nextSize = (size32_t)getIntValue(next.srcLen);
            if (curSize + nextSize > combineStringLimit)
                return false;

            byte * temp = (byte *)malloc(curSize + nextSize);
            expandValue(temp);
            next.expandValue(temp+curSize);
            src.setown(createConstant(createDataValue((const char *)temp, curSize + nextSize)));
            free(temp);
            srcLen.setown(getSizetConstant(curSize + nextSize));
            tgtLen.set(srcLen);
            if (name == memsetAtom)
                name = memcpyAtom;
            return true;
        }
    }
    return false;
}

PeepHoleOptimizer::PeepHoleOptimizer(HqlCppTranslator & _translator) : translator(_translator) 
{ 
    combineStringLimit = -1;
    peepholeOptions = 0;
    if (translator.queryOptions().convertRealAssignToMemcpy)
        peepholeOptions |= PHOconvertReal;
    switch (translator.queryOptions().targetCompiler)
    {
    case Vs6CppCompiler:
        combineStringLimit = 32000;
        break;
    }
}

void PeepHoleOptimizer::optimize(HqlStmts & stmts)
{
    unsigned max = stmts.ordinality();      // can change as processing proceeds.
    SpecialFunction prevMatch;
    for (unsigned pass=0; pass < 2; pass++)
    {
        bool memsetOnly = (pass == 0);
        for (unsigned i =0; i < max; i++)
        {
            IHqlStmt & cur = stmts.item(i);
            if (prevMatch.extractIsSpecial(cur, memsetOnly, peepholeOptions))
            {
                unsigned j = i+1;
                unsigned prevMax = max;
                SpecialFunction nextMatch;
                while (j < max)
                {
                    IHqlStmt & next = stmts.item(j);
                    if (!nextMatch.extractIsSpecial(next, memsetOnly, peepholeOptions))
                        break;
                    if (!prevMatch.queryCombine(nextMatch, memsetOnly, combineStringLimit))
                        break;

                    stmts.remove(i);
                    max--;
                }

                if (max != prevMax || prevMatch.canOptimize())
                {
                    stmts.remove(i);
                    stmts.add(*prevMatch.createStmt(stmts, translator), i);
                }
            }
        }
    }

    for (unsigned i2=0; i2 < max; i2++)
    {
        IHqlStmt & cur = stmts.item(i2);
        if (cur.numChildren() != 0)
            optimize(((HqlCompoundStmt&)cur).code);
    }

}



void peepholeOptimize(HqlCppInstance & instance, HqlCppTranslator & translator)
{
    PeepHoleOptimizer optimizer(translator);
    ForEachItemIn(idx, instance.sections)
        optimizer.optimize(((HqlCppSection&)instance.sections.item(idx)).stmts);
}


//---------------------------------------------------------------------------

AssociationIterator::AssociationIterator(BuildCtx & ctx)
{
    rootStmts = ctx.curStmts;
    curStmts = NULL;
    curIdx = 0;
}


bool AssociationIterator::first()
{
    curStmts = rootStmts;
    curIdx = curStmts->defs.ordinality();
    return doNext();
}

bool AssociationIterator::doNext()
{
    loop
    {
        if (curIdx-- != 0)
            return true;

        HqlStmt * limitStmt = curStmts->queryStmt();
        if (!limitStmt)
        {
            curStmts = NULL;
            return false;
        }
        curStmts = limitStmt->queryContainer();
        curIdx = curStmts->defs.ordinality();
    }
}

HqlExprAssociation & AssociationIterator::get()
{
    CIArray & defs = curStmts->defs;
    return (HqlExprAssociation &)defs.item(curIdx);
}


//---------------------------------------------------------------------------

bool FilteredAssociationIterator::doNext()
{
    while (AssociationIterator::doNext())
    {
        HqlExprAssociation & cur = AssociationIterator::get();
        if (cur.getKind() == searchKind)
            return true;
    }

    return false;
}

bool RowAssociationIterator::doNext()
{
    while (AssociationIterator::doNext())
    {
        HqlExprAssociation & cur = AssociationIterator::get();
        if (cur.isRowAssociation())
            return true;
    }

    return false;
};


unsigned calcTotalChildren(IHqlStmt * stmt)
{
    if (!stmt->isIncluded())
        return 0;
    unsigned num = stmt->numChildren();
    unsigned total = 1;
    switch (stmt->getStmt())
    {
        case alias_stmt:
        case group_stmt:
        case pass_stmt:
        case indirect_stmt:
            total = 0;
            break;
    }

    for (unsigned i=0; i < num; i++)
        total += calcTotalChildren(stmt->queryChild(i));
    return total;
}