content: /*
   * Copyright (C) 2020 ActiveJ LLC.
   *
   * Licensed 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 io.activej.codegen.expression.impl;
  
  import io.activej.codegen.Context;
  import io.activej.codegen.expression.Expression;
  import io.activej.codegen.expression.Expressions;
  import io.activej.common.annotation.ExposedInternals;
  import io.activej.common.builder.AbstractBuilder;
  import org.objectweb.asm.Label;
  import org.objectweb.asm.Type;
  import org.objectweb.asm.commons.GeneratorAdapter;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import static io.activej.codegen.util.TypeChecks.checkType;
  import static io.activej.codegen.util.TypeChecks.isAssignable;
  import static io.activej.codegen.util.Utils.invokeVirtualOrInterface;
  import static io.activej.codegen.util.Utils.isPrimitiveType;
  import static org.objectweb.asm.Opcodes.*;
  import static org.objectweb.asm.Type.INT_TYPE;
  import static org.objectweb.asm.Type.getType;
  import static org.objectweb.asm.commons.Method.getMethod;
  
  /**
   * Defines methods for hashing some fields
   */
  @ExposedInternals
  public final class HashCode implements Expression {
  	public final List<Expression> arguments;
  
  	public HashCode(List<Expression> arguments) {
  		this.arguments = arguments;
  	}
  
  	public static Builder builder() {
  		return new HashCode(new ArrayList<>()).new Builder();
  	}
  
  	public final class Builder extends AbstractBuilder<Builder, HashCode> {
  		private Builder() {}
  
  		public Builder with(Expression expression) {
  			checkNotBuilt(this);
  			HashCode.this.arguments.add(expression);
  			return this;
  		}
  
  		public Builder withField(String field) {
  			checkNotBuilt(this);
  			return with(Expressions.property(Expressions.self(), field));
  		}
  
  		public Builder withFields(List<String> fields) {
  			checkNotBuilt(this);
  			for (String field : fields) {
  				withField(field);
  			}
  			return this;
  		}
  
  		public Builder withFields(String... fields) {
  			checkNotBuilt(this);
  			return withFields(List.of(fields));
  		}
  
  		@Override
  		protected HashCode doBuild() {
  			return HashCode.this;
  		}
  	}
  
  	@Override
  	public Type load(Context ctx) {
  		GeneratorAdapter g = ctx.getGeneratorAdapter();
  
  		int resultVar = g.newLocal(INT_TYPE);
  
  		boolean firstIteration = true;
  
  		for (Expression argument : arguments) {
  			if (firstIteration) {
  				g.push(0);
  				firstIteration = false;
  			} else {
  				g.push(31);
  				g.loadLocal(resultVar);
  				g.math(IMUL, INT_TYPE);
  			}
  
  			Type fieldType = argument.load(ctx);
  			checkType(fieldType, isAssignable());
  
  			if (isPrimitiveType(fieldType)) {
  				if (fieldType.getSort() == Type.LONG) {
  					g.dup2();
  					g.push(32);
  					g.visitInsn(LUSHR);
  					g.visitInsn(LXOR);
  					g.visitInsn(L2I);
  				}
  				if (fieldType.getSort() == Type.FLOAT) {
  					g.invokeStatic(getType(Float.class), getMethod("int floatToRawIntBits (float)"));
  				}
  				if (fieldType.getSort() == Type.DOUBLE) {
  					g.invokeStatic(getType(Double.class), getMethod("long doubleToRawLongBits (double)"));
  					g.dup2();
  					g.push(32);
  					g.visitInsn(LUSHR);
  					g.visitInsn(LXOR);
  					g.visitInsn(L2I);
  				}
  				g.visitInsn(IADD);
  			} else {
  				int tmpVar = g.newLocal(fieldType);
  				g.storeLocal(tmpVar);
  				g.loadLocal(tmpVar);
  				Label ifNullLabel = g.newLabel();
  				g.ifNull(ifNullLabel);
  				g.loadLocal(tmpVar);
  				invokeVirtualOrInterface(ctx, fieldType, getMethod("int hashCode()"));
  				g.visitInsn(IADD);
  				g.mark(ifNullLabel);
  			}
  
  			g.storeLocal(resultVar);
  		}
  
  		if (firstIteration) {
  			g.push(0);
  		} else {
  			g.loadLocal(resultVar);
  		}
  
  		return INT_TYPE;
  	}
  }
  