/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package hivemall.smile.vm;
import hivemall.utils.lang.StringUtils;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Stack;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
public final class StackMachine {
public static final String SEP = "; ";
@Nonnull
private final List<Operation> code;
@Nonnull
private final Map<String, Double> valuesMap;
@Nonnull
private final Map<String, Integer> jumpMap;
@Nonnull
private final Stack<Double> programStack;
/**
* Instruction pointer
*/
private int IP;
/**
* Stack pointer
*/
@SuppressWarnings("unused")
private int SP;
private int codeLength;
private boolean[] done;
private Double result;
public StackMachine() {
this.code = new ArrayList<Operation>();
this.valuesMap = new HashMap<String, Double>();
this.jumpMap = new HashMap<String, Integer>();
this.programStack = new Stack<Double>();
this.SP = 0;
this.result = null;
}
public void run(@Nonnull String scripts, @Nonnull double[] features) throws VMRuntimeException {
compile(scripts);
eval(features);
}
public void run(@Nonnull List<String> opslist, @Nonnull double[] features)
throws VMRuntimeException {
compile(opslist);
eval(features);
}
public void compile(@Nonnull String scripts) throws VMRuntimeException {
List<String> opslist = Arrays.asList(scripts.split(SEP));
compile(opslist);
}
public void compile(@Nonnull List<String> opslist) throws VMRuntimeException {
for (String line : opslist) {
String[] ops = line.split(" ", -1);
if (ops.length == 2) {
Operation.OperationEnum o = Operation.OperationEnum.valueOfLowerCase(ops[0]);
code.add(new Operation(o, ops[1]));
} else {
Operation.OperationEnum o = Operation.OperationEnum.valueOfLowerCase(ops[0]);
code.add(new Operation(o));
}
}
int size = opslist.size();
this.codeLength = size - 1;
this.done = new boolean[size];
}
public void eval(final double[] features) throws VMRuntimeException {
init();
bind(features);
execute(0);
}
private void init() {
valuesMap.clear();
jumpMap.clear();
programStack.clear();
this.SP = 0;
this.result = null;
Arrays.fill(done, false);
}
private void bind(final double[] features) {
final StringBuilder buf = new StringBuilder();
for (int i = 0; i < features.length; i++) {
String bindKey = buf.append("x[").append(i).append("]").toString();
valuesMap.put(bindKey, features[i]);
StringUtils.clear(buf);
}
}
private void execute(int entryPoint) throws VMRuntimeException {
valuesMap.put("end", -1.0);
jumpMap.put("last", codeLength);
IP = entryPoint;
while (IP < code.size()) {
if (done[IP]) {
throw new VMRuntimeException("There is a infinite loop in the Machine code.");
}
done[IP] = true;
Operation currentOperation = code.get(IP);
if (!executeOperation(currentOperation)) {
return;
}
}
}
@Nullable
public Double getResult() {
return result;
}
private Double pop() {
SP--;
return programStack.pop();
}
private Double push(Double val) {
programStack.push(val);
SP++;
return val;
}
private boolean executeOperation(Operation currentOperation) throws VMRuntimeException {
if (IP < 0) {
return false;
}
switch (currentOperation.op) {
case GOTO: {
if (StringUtils.isInt(currentOperation.operand)) {
IP = Integer.parseInt(currentOperation.operand);
} else {
IP = jumpMap.get(currentOperation.operand);
}
break;
}
case CALL: {
double candidateIP = valuesMap.get(currentOperation.operand);
if (candidateIP < 0) {
evaluateBuiltinByName(currentOperation.operand);
IP++;
}
break;
}
case IFEQ: {
double a = pop();
double b = pop();
if (a == b) {
IP++;
} else {
if (StringUtils.isInt(currentOperation.operand)) {
IP = Integer.parseInt(currentOperation.operand);
} else {
IP = jumpMap.get(currentOperation.operand);
}
}
break;
}
case IFEQ2: {// follow the rule of smile's Math class.
double a = pop();
double b = pop();
if (smile.math.Math.equals(a, b)) {
IP++;
} else {
if (StringUtils.isInt(currentOperation.operand)) {
IP = Integer.parseInt(currentOperation.operand);
} else {
IP = jumpMap.get(currentOperation.operand);
}
}
break;
}
case IFGE: {
double lower = pop();
double upper = pop();
if (upper >= lower) {
IP++;
} else {
if (StringUtils.isInt(currentOperation.operand)) {
IP = Integer.parseInt(currentOperation.operand);
} else {
IP = jumpMap.get(currentOperation.operand);
}
}
break;
}
case IFGT: {
double lower = pop();
double upper = pop();
if (upper > lower) {
IP++;
} else {
if (StringUtils.isInt(currentOperation.operand)) {
IP = Integer.parseInt(currentOperation.operand);
} else {
IP = jumpMap.get(currentOperation.operand);
}
}
break;
}
case IFLE: {
double lower = pop();
double upper = pop();
if (upper <= lower) {
IP++;
} else {
if (StringUtils.isInt(currentOperation.operand)) {
IP = Integer.parseInt(currentOperation.operand);
} else {
IP = jumpMap.get(currentOperation.operand);
}
}
break;
}
case IFLT: {
double lower = pop();
double upper = pop();
if (upper < lower) {
IP++;
} else {
if (StringUtils.isInt(currentOperation.operand)) {
IP = Integer.parseInt(currentOperation.operand);
} else {
IP = jumpMap.get(currentOperation.operand);
}
}
break;
}
case POP: {
valuesMap.put(currentOperation.operand, pop());
IP++;
break;
}
case PUSH: {
if (StringUtils.isDouble(currentOperation.operand)) {
push(Double.parseDouble(currentOperation.operand));
} else {
Double v = valuesMap.get(currentOperation.operand);
if (v == null) {
throw new VMRuntimeException("value is not binded: "
+ currentOperation.operand);
}
push(v);
}
IP++;
break;
}
default:
throw new VMRuntimeException("Machine code has wrong opcode :"
+ currentOperation.op);
}
return true;
}
private void evaluateBuiltinByName(String name) throws VMRuntimeException {
if (name.equals("end")) {
this.result = pop();
} else {
throw new VMRuntimeException("Machine code has wrong builin function :" + name);
}
}
}