lubomir@221: /**
lubomir@221:  * Back 2 Browser Bytecode Translator
lubomir@221:  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
lubomir@221:  *
lubomir@221:  * This program is free software: you can redistribute it and/or modify
lubomir@221:  * it under the terms of the GNU General Public License as published by
lubomir@221:  * the Free Software Foundation, version 2 of the License.
lubomir@221:  *
lubomir@221:  * This program is distributed in the hope that it will be useful,
lubomir@221:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
lubomir@221:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
lubomir@221:  * GNU General Public License for more details.
lubomir@221:  *
lubomir@221:  * You should have received a copy of the GNU General Public License
lubomir@221:  * along with this program. Look for COPYING file in the top folder.
lubomir@221:  * If not, see http://opensource.org/licenses/GPL-2.0.
lubomir@221:  */
lubomir@221: package org.apidesign.vm4brwsr;
lubomir@221: 
lubomir@281: import org.apidesign.javap.TypeArray;
lubomir@281: 
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_Bogus;
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_Integer;
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_Float;
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_Double;
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_Long;
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_Null;
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_InitObject;
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_Object;
lubomir@281: import static org.apidesign.javap.RuntimeConstants.ITEM_NewObject;
lubomir@281: 
lubomir@221: public final class StackToVariableMapper {
lubomir@281:     private final TypeArray stackTypeIndexPairs;
lubomir@281:     private int[] typeCounters;
lubomir@281:     private int[] typeMaxCounters;
lubomir@221: 
lubomir@221:     public StackToVariableMapper() {
lubomir@281:         stackTypeIndexPairs = new TypeArray();
lubomir@281:         typeCounters = new int[Variable.LAST_TYPE + 1];
lubomir@281:         typeMaxCounters = new int[Variable.LAST_TYPE + 1];
lubomir@221:     }
lubomir@221: 
lubomir@281:     public void clear() {
lubomir@281:         for (int type = 0; type <= Variable.LAST_TYPE; ++type) {
lubomir@281:             typeCounters[type] = 0;
lubomir@281:         }
lubomir@281:         stackTypeIndexPairs.clear();
lubomir@281:     }
lubomir@281: 
lubomir@281:     public void syncWithFrameStack(final TypeArray frameStack) {
lubomir@281:         clear();
lubomir@281: 
lubomir@281:         final int size = frameStack.getSize();
lubomir@281:         for (int i = 0; i < size; ++i) {
lubomir@281:             final int frameStackValue = frameStack.get(i);
lubomir@281:             switch (frameStackValue & 0xff) {
lubomir@281:                 case ITEM_Integer:
lubomir@281:                     pushTypeImpl(Variable.TYPE_INT);
lubomir@281:                     break;
lubomir@281:                 case ITEM_Float:
lubomir@281:                     pushTypeImpl(Variable.TYPE_FLOAT);
lubomir@281:                     break;
lubomir@281:                 case ITEM_Double:
lubomir@281:                     pushTypeImpl(Variable.TYPE_DOUBLE);
lubomir@281:                     break;
lubomir@281:                 case ITEM_Long:
lubomir@281:                     pushTypeImpl(Variable.TYPE_LONG);
lubomir@281:                     break;
lubomir@281:                 case ITEM_Object:
lubomir@281:                     pushTypeImpl(Variable.TYPE_REF);
lubomir@281:                     break;
lubomir@281: 
lubomir@281:                 case ITEM_Bogus:
lubomir@281:                 case ITEM_Null:
lubomir@281:                 case ITEM_InitObject:
lubomir@281:                 case ITEM_NewObject:
lubomir@281:                     /* unclear how to handle for now */
lubomir@281:                 default:
lubomir@281:                     throw new IllegalStateException(
lubomir@281:                                   "Unhandled frame stack type");
lubomir@281:             }
lubomir@221:         }
lubomir@221:     }
lubomir@221: 
lubomir@281:     public Variable pushI() {
lubomir@281:         return pushT(Variable.TYPE_INT);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable pushL() {
lubomir@281:         return pushT(Variable.TYPE_LONG);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable pushF() {
lubomir@281:         return pushT(Variable.TYPE_FLOAT);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable pushD() {
lubomir@281:         return pushT(Variable.TYPE_DOUBLE);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable pushA() {
lubomir@281:         return pushT(Variable.TYPE_REF);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable pushT(final int type) {
lubomir@281:         return getVariable(pushTypeImpl(type));
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable popI() {
lubomir@281:         return popT(Variable.TYPE_INT);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable popL() {
lubomir@281:         return popT(Variable.TYPE_LONG);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable popF() {
lubomir@281:         return popT(Variable.TYPE_FLOAT);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable popD() {
lubomir@281:         return popT(Variable.TYPE_DOUBLE);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable popA() {
lubomir@281:         return popT(Variable.TYPE_REF);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable popT(final int type) {
lubomir@281:         final Variable variable = getT(0, type);
lubomir@281:         popImpl(1);
lubomir@281:         return variable;
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable pop() {
lubomir@281:         final Variable variable = get(0);
lubomir@281:         popImpl(1);
lubomir@281:         return variable;
lubomir@281:     }
lubomir@281: 
lubomir@281:     public void pop(final int count) {
lubomir@281:         final int stackSize = stackTypeIndexPairs.getSize();
lubomir@281:         if (count > stackSize) {
lubomir@281:             throw new IllegalStateException("Stack underflow");
lubomir@281:         }
lubomir@281:         popImpl(count);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable getI(final int indexFromTop) {
lubomir@281:         return getT(indexFromTop, Variable.TYPE_INT);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable getL(final int indexFromTop) {
lubomir@281:         return getT(indexFromTop, Variable.TYPE_LONG);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable getF(final int indexFromTop) {
lubomir@281:         return getT(indexFromTop, Variable.TYPE_FLOAT);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable getD(final int indexFromTop) {
lubomir@281:         return getT(indexFromTop, Variable.TYPE_DOUBLE);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable getA(final int indexFromTop) {
lubomir@281:         return getT(indexFromTop, Variable.TYPE_REF);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable getT(final int indexFromTop, final int type) {
lubomir@281:         final int stackSize = stackTypeIndexPairs.getSize();
lubomir@281:         if (indexFromTop >= stackSize) {
lubomir@281:             throw new IllegalStateException("Stack underflow");
lubomir@281:         }
lubomir@281:         final int stackValue =
lubomir@281:                 stackTypeIndexPairs.get(stackSize - indexFromTop - 1);
lubomir@281:         if ((stackValue & 0xff) != type) {
lubomir@281:             throw new IllegalStateException("Type mismatch");
lubomir@281:         }
lubomir@281: 
lubomir@281:         return getVariable(stackValue);
lubomir@281:     }
lubomir@281: 
lubomir@281:     public Variable get(final int indexFromTop) {
lubomir@281:         final int stackSize = stackTypeIndexPairs.getSize();
lubomir@281:         if (indexFromTop >= stackSize) {
lubomir@281:             throw new IllegalStateException("Stack underflow");
lubomir@281:         }
lubomir@281:         final int stackValue =
lubomir@281:                 stackTypeIndexPairs.get(stackSize - indexFromTop - 1);
lubomir@281: 
lubomir@281:         return getVariable(stackValue);
lubomir@281:     }
lubomir@281: 
lubomir@281:     private int pushTypeImpl(final int type) {
lubomir@281:         final int count = typeCounters[type];
lubomir@281:         final int value = (count << 8) | (type & 0xff);
lubomir@281:         incCounter(type);
lubomir@281:         stackTypeIndexPairs.add(value);
lubomir@281: 
lubomir@281:         return value;
lubomir@281:     }
lubomir@281: 
lubomir@281:     private void popImpl(final int count) {
lubomir@281:         final int stackSize = stackTypeIndexPairs.getSize();
lubomir@281:         for (int i = stackSize - count; i < stackSize; ++i) {
lubomir@281:             final int value = stackTypeIndexPairs.get(i);
lubomir@281:             decCounter(value & 0xff);
lubomir@281:         }
lubomir@281: 
lubomir@281:         stackTypeIndexPairs.setSize(stackSize - count);
lubomir@281:     }
lubomir@281: 
lubomir@281:     private void incCounter(final int type) {
lubomir@281:         final int newValue = ++typeCounters[type];
lubomir@281:         if (typeMaxCounters[type] < newValue) {
lubomir@281:             typeMaxCounters[type] = newValue;
lubomir@221:         }
lubomir@221:     }
lubomir@221: 
lubomir@281:     private void decCounter(final int type) {
lubomir@281:         --typeCounters[type];
lubomir@221:     }
lubomir@221: 
lubomir@281:     public Variable getVariable(final int typeAndIndex) {
lubomir@281:         final int type = typeAndIndex & 0xff;
lubomir@281:         final int index = typeAndIndex >> 8;
lubomir@221: 
lubomir@281:         return Variable.getStackVariable(type, index);
lubomir@221:     }
lubomir@221: }