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// * This file is part of the COLOBOT source code
// * Copyright (C) 2001-2008, Daniel ROUX & EPSITEC SA, www.epsitec.ch
// *
// * This program is free software: you can redistribute it and/or modify
// * it under the terms of the GNU 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 General Public License for more details.
// *
// * You should have received a copy of the GNU General Public License
// * along with this program. If not, see http://www.gnu.org/licenses/.
///////////////////////////////////////////////////////////////////////
// instruction if (condition) operation1 else operation2;
#include "CBot.h"
// various constructors / destructors
CBotIf::CBotIf()
{
m_Condition =
m_Block =
m_BlockElse = NULL; // NULL so that delete is not possible further
name = "CBotIf"; // debug
}
CBotIf::~CBotIf()
{
delete m_Condition; // frees the condition
delete m_Block; // frees the block of instruction1
delete m_BlockElse; // frees the block of instruction2
}
// compilation (static routine)
// called when the token "if" has been found
CBotInstr* CBotIf::Compile(CBotToken* &p, CBotCStack* pStack)
{
CBotToken* pp = p; // preserves at the ^ token (starting instruction)
if (!IsOfType(p, ID_IF)) return NULL; // should never happen
CBotCStack* pStk = pStack->TokenStack(pp); // un petit bout de pile svp
CBotIf* inst = new CBotIf(); // create the object
inst->SetToken( pp );
if ( NULL != (inst->m_Condition = CBotCondition::Compile( p, pStk )) )
{
// the condition does exist
inst->m_Block = CBotBlock::CompileBlkOrInst( p, pStk, true );
if ( pStk->IsOk() )
{
// the statement block is ok (can be empty)
// see if the next instruction is the token "else"
if (IsOfType(p, ID_ELSE))
{
// if so, compiles the following statement block
inst->m_BlockElse = CBotBlock::CompileBlkOrInst( p, pStk, true );
if (!pStk->IsOk())
{
// there is no correct block after the else
// frees the object, and transmits the error that is on the stack
delete inst;
return pStack->Return(NULL, pStk);
}
}
// return the corrent object to the application
return pStack->Return(inst, pStk);
}
}
// error, frees the object
delete inst;
// and transmits the error that is on the stack.
return pStack->Return(NULL, pStk);
}
// execution of the instruction
bool CBotIf :: Execute(CBotStack* &pj)
{
CBotStack* pile = pj->AddStack(this); // adds an item to the stack
// or found in case of recovery
// if ( pile == EOX ) return true;
if ( pile->IfStep() ) return false;
// according to recovery, it may be in one of two states
if( pile->GivState() == 0 )
{
// evaluates the condition
if ( !m_Condition->Execute(pile) ) return false; // interrupted here?
// terminates if there is an error
if ( !pile->IsOk() )
{
return pj->Return(pile); // returns the results and releases the stack
}
// passes into the second state
if (!pile->SetState(1)) return false; // ready for further
}
// second state, evaluates the associated instructions
// the result of the condition is on the stack
if ( pile->GivVal() == true ) // condition was true?
{
if ( m_Block != NULL && // block may be absent
!m_Block->Execute(pile) ) return false; // interrupted here?
}
else
{
if ( m_BlockElse != NULL && // if there is an alternate block
!m_BlockElse->Execute(pile) ) return false; // interrupted here
}
// sends the results and releases the stack
return pj->Return(pile);
}
void CBotIf :: RestoreState(CBotStack* &pj, bool bMain)
{
if ( !bMain ) return;
CBotStack* pile = pj->RestoreStack(this); // adds an item to the stack
if ( pile == NULL ) return;
// according to recovery, it may be in one of two states
if( pile->GivState() == 0 )
{
// evaluates the condition
m_Condition->RestoreState(pile, bMain); // interrupted here!
return;
}
// second state, evaluates the associated instructions
// the result of the condition is on the stack
if ( pile->GivVal() == true ) // condition was true?
{
if ( m_Block != NULL ) // block may be absent
m_Block->RestoreState(pile, bMain); // interrupted here!
}
else
{
if ( m_BlockElse != NULL ) // if there is an alternate block
m_BlockElse->RestoreState(pile, bMain); // interrupted here!
}
}
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