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/* Copyright (c) 2005-2019 Rexx Language Association. All rights reserved.    */
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/*----------------------------------------------------------------------------*/
/******************************************************************************/
/* REXX Translator                                                            */
/*                                                                            */
/* The simple DO UNTIL/WHILE instruction variants                             */
/*                                                                            */
/******************************************************************************/
#include "RexxCore.h"
#include "DoInstruction.hpp"
#include "DoBlock.hpp"
#include "EndInstruction.hpp"


/**
 * Initialize a Do While block
 *
 * @param l      The block label.
 * @param c      A variable name for setting a counter (optional)
 * @param w      The conditional control information.
 */
RexxInstructionDoWhile::RexxInstructionDoWhile(RexxString *l, RexxVariableBase *c, WhileUntilLoop &w)
{
    label = l;
    countVariable = c;
    whileLoop = w;
}


/**
 * Perform garbage collection on a live object.
 *
 * @param liveMark The current live mark.
 */
void RexxInstructionDoWhile::live(size_t liveMark)
{
    // must be first object marked
    memory_mark(nextInstruction);
    memory_mark(end);
    memory_mark(label);
    memory_mark(countVariable);

    // helpers for additional types of loops handle marking here
    whileLoop.live(liveMark);
}


/**
 * Perform generalized live marking on an object.  This is
 * used when mark-and-sweep processing is needed for purposes
 * other than garbage collection.
 *
 * @param reason The reason for the marking call.
 */
void RexxInstructionDoWhile::liveGeneral(MarkReason reason)
{
    // must be first object marked
    memory_mark_general(nextInstruction);
    memory_mark_general(end);
    memory_mark_general(label);
    memory_mark_general(countVariable);

    // helpers for additional types of loops handle marking here
    whileLoop.liveGeneral(reason);
}


/**
 * Flatten a source object.
 *
 * @param envelope The envelope that will hold the flattened object.
 */
void RexxInstructionDoWhile::flatten(Envelope *envelope)
{
    setUpFlatten(RexxInstructionDoWhile)

    flattenRef(nextInstruction);
    flattenRef(end);
    flattenRef(label);
    flattenRef(countVariable);

    // flatten is a bit of a pain with embedded objects because
    // everything depends on having correct pointers to object references in
    // the copied buffer.  We need to directly reference all of the elements here.

    flattenRef(whileLoop.conditional);

    cleanUpFlatten
}


/**
 * Perform a test on whether this loop iteration should
 * be executed or not.
 *
 * @param context The current execution context.
 * @param stack   The current evaluation stack.
 * @param doblock The doblock for this instruction instance.
 * @param first   True if this is the first iteration, false for
 *                reExecute iterations.
 *
 * @return true if we should execute the loop block, false if
 *         we should terminate the loop.
 */
bool RexxInstructionDoWhile::iterate(RexxActivation *context, ExpressionStack *stack, DoBlock *doblock, bool first)
{
    return whileLoop.checkWhile(context, stack);
}


/**
 * Initialize a Do Until block
 *
 * @param l      The block label.
 * @param c      A variable name for setting a counter (optional)
 * @param w      The conditional control information.
 */
RexxInstructionDoUntil::RexxInstructionDoUntil(RexxString *l, RexxVariableBase *c, WhileUntilLoop &w)
{
    label = l;
    countVariable = c;
    whileLoop = w;
}


// NOTE The UNTIL variant does add not any additional fields, so it can
// just use the live() methods inherited from the UNTIL version.


/**
 * Perform a test on whether this loop iteration should
 * be executed or not.
 *
 * @param context The current execution context.
 * @param stack   The current evaluation stack.
 * @param doblock The doblock for this instruction instance.
 * @param first   True if this is the first iteration, false for
 *                reExecute iterations.
 *
 * @return true if we should execute the loop block, false if
 *         we should terminate the loop.
 */
bool RexxInstructionDoUntil::iterate(RexxActivation *context, ExpressionStack *stack, DoBlock *doblock, bool first)
{
    // we don't check the UNTIL condition on the first iteration
    if (!first)
    {
        return !whileLoop.checkUntil(context, stack);
    }
    // always do the first iteration
    return true;
}