/*
* Copyright 2013 Google Inc.
*
* 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 com.google.bitcoin.script;
import com.google.bitcoin.core.Utils;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import static com.google.bitcoin.script.ScriptOpCodes.OP_PUSHDATA1;
import static com.google.bitcoin.script.ScriptOpCodes.OP_PUSHDATA2;
import static com.google.bitcoin.script.ScriptOpCodes.OP_PUSHDATA4;
import static com.google.common.base.Preconditions.checkState;
/**
* An element that is either an opcode or a raw byte array (signature, pubkey, etc).
*/
public class ScriptChunk {
private boolean isOpCode;
public final byte[] data;
private int startLocationInProgram;
public ScriptChunk(boolean isOpCode, byte[] data) {
this(isOpCode, data, -1);
}
public ScriptChunk(boolean isOpCode, byte[] data, int startLocationInProgram) {
this.isOpCode = isOpCode;
this.data = data;
this.startLocationInProgram = startLocationInProgram;
}
public boolean equalsOpCode(int opCode) {
return isOpCode && data.length == 1 && (0xFF & data[0]) == opCode;
}
/**
* If this chunk is a single byte of non-pushdata content (could be OP_RESERVED or some invalid Opcode)
*/
public boolean isOpCode() {
return isOpCode;
}
public int getStartLocationInProgram() {
checkState(startLocationInProgram >= 0);
return startLocationInProgram;
}
public void write(OutputStream stream) throws IOException {
if (isOpCode) {
checkState(data.length == 1);
stream.write(data);
} else {
checkState(data.length <= Script.MAX_SCRIPT_ELEMENT_SIZE);
if (data.length < OP_PUSHDATA1) {
stream.write(data.length);
} else if (data.length <= 0xFF) {
stream.write(OP_PUSHDATA1);
stream.write(data.length);
} else if (data.length <= 0xFFFF) {
stream.write(OP_PUSHDATA2);
stream.write(0xFF & data.length);
stream.write(0xFF & (data.length >> 8));
} else {
stream.write(OP_PUSHDATA4);
Utils.uint32ToByteStreamLE(data.length, stream);
}
stream.write(data);
}
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ScriptChunk chunk = (ScriptChunk) o;
if (isOpCode != chunk.isOpCode) return false;
if (startLocationInProgram != chunk.startLocationInProgram) return false;
if (!Arrays.equals(data, chunk.data)) return false;
return true;
}
@Override
public int hashCode() {
int result = (isOpCode ? 1 : 0);
result = 31 * result + (data != null ? Arrays.hashCode(data) : 0);
result = 31 * result + startLocationInProgram;
return result;
}
}