/* ILEngineer - Crummy .NET Decompiler
 * Copyright (C) 2001-2002  Jay Freeman (saurik)
*/

/*
 *        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.
 * 3. The name of the author may not be used to endorse
 *    or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/

#include "stdafx.h"
#include "ilengineer/Block.h"

#include "ilengineer/Blocks/Do.h"
#include "ilengineer/Blocks/While.h"

#include "ilengineer/Ops/MSIL/Branch.h"
#include "ilengineer/Ops/MSIL/BranchPoint.h"

void ILEngineer::Block::OptimizeDoWhile() {
	for (StatementVector::iterator stI(m_Statements.begin()); stI != m_Statements.end(); stI++)
		if ((*stI)->isBlock())
			dynamic_cast<Block *>(*stI)->OptimizeDoWhile();

	for (size_t i(0); i < m_Statements.size(); i++) {
		Statement *st1 = m_Statements[i];
		if (!st1->isBlock()) {
			Ops::MSIL::BranchPoint *point = dynamic_cast<Ops::MSIL::BranchPoint *>(st1->getOperations()[0]);
			if (point != NULL && point->getTarget() <= point->getOffset()) {
				Statement::Reference wrap;
				Find(point->getTarget(), wrap);

				if (&m_Statements == wrap.stV) {
					Block *block = NULL;
					if (wrap.stI != m_Statements.begin()) {
						Statement *st2 = *(wrap.stI - 1);
						if (!st2->isBlock() && typeid(*st2->getOperations()[0]) == typeid(Ops::MSIL::Branch)) {
							Ops::MSIL::Branch *branch = dynamic_cast<Ops::MSIL::Branch *>(st2->getOperations()[0]);
							if (branch->getTarget() == st1->getOffset()) {
								block = new Blocks::While(m_Method, point, branch->getOffset(), st1->getOffset());
								m_Statements.erase(--wrap.stI);
								delete st2;
								i--;
							}
						}
					}

					if (block == NULL) // This is evil juju.  Beware.
						if ((size_t) (wrap.stI - m_Statements.begin()) < i && typeid(*point) != typeid(Ops::MSIL::Branch))
							block = new Blocks::Do(m_Method, point, (*wrap.stI)->getOffset(), st1->getOffset());
						else
							block = new Blocks::While(m_Method, point, (*wrap.stI)->getOffset(), (*wrap.stI)->getOffset());

					m_Statements[i] = block;
					delete st1;
					for (size_t pos(wrap.stI - m_Statements.begin()); pos < i; i--) {
						block->getStatements().push_back(m_Statements[pos]);
						m_Statements.erase(m_Statements.begin() + pos);
					}

					if (i+1 == m_Statements.size())
						block->setEnd(m_End);
					else
						block->setEnd(m_Statements[i+1]->getOffset());
				}
			}
		}
	}
}