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/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * 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.android.dx.io.instructions;

import com.android.dex.DexException;
import com.android.dx.io.IndexType;
import com.android.dx.io.OpcodeInfo;
import com.android.dx.io.Opcodes;
import com.android.dx.util.Hex;
import java.io.EOFException;

/**
 * A decoded Dalvik instruction. This consists of a format codec, a
 * numeric opcode, an optional index type, and any additional
 * arguments of the instruction. The additional arguments (if any) are
 * represented as uninterpreted data.
 *
 * 

Note: The names of the arguments are not meant to * match the names given in the Dalvik instruction format * specification, specification which just names fields (somewhat) * arbitrarily alphabetically from A. In this class, non-register * fields are given descriptive names and register fields are * consistently named alphabetically.

*/ public abstract class DecodedInstruction { /** non-null; instruction format / codec */ private final InstructionCodec format; /** opcode number */ private final int opcode; /** constant index argument */ private final int index; /** null-ok; index type */ private final IndexType indexType; /** * target address argument. This is an absolute address, not just * a signed offset. Note: The address is unsigned, even * though it is stored in an {@code int}. */ private final int target; /** * literal value argument; also used for special verification error * constants (format 20bc) as well as should-be-zero values * (formats 10x, 20t, 30t, and 32x) */ private final long literal; /** * Decodes an instruction from the given input source. */ public static DecodedInstruction decode(CodeInput in) throws EOFException { int opcodeUnit = in.read(); int opcode = Opcodes.extractOpcodeFromUnit(opcodeUnit); InstructionCodec format = OpcodeInfo.getFormat(opcode); return format.decode(opcodeUnit, in); } /** * Decodes an array of instructions. The result has non-null * elements at each offset that represents the start of an * instruction. */ public static DecodedInstruction[] decodeAll(short[] encodedInstructions) { int size = encodedInstructions.length; DecodedInstruction[] decoded = new DecodedInstruction[size]; ShortArrayCodeInput in = new ShortArrayCodeInput(encodedInstructions); try { while (in.hasMore()) { decoded[in.cursor()] = DecodedInstruction.decode(in); } } catch (EOFException ex) { throw new DexException(ex); } return decoded; } /** * Constructs an instance. */ public DecodedInstruction(InstructionCodec format, int opcode, int index, IndexType indexType, int target, long literal) { if (format == null) { throw new NullPointerException("format == null"); } if (!Opcodes.isValidShape(opcode)) { throw new IllegalArgumentException("invalid opcode"); } this.format = format; this.opcode = opcode; this.index = index; this.indexType = indexType; this.target = target; this.literal = literal; } public final InstructionCodec getFormat() { return format; } public final int getOpcode() { return opcode; } /** * Gets the opcode, as a code unit. */ public final short getOpcodeUnit() { return (short) opcode; } public final int getIndex() { return index; } /** * Gets the index, as a code unit. */ public final short getIndexUnit() { return (short) index; } public final IndexType getIndexType() { return indexType; } /** * Gets the raw target. */ public final int getTarget() { return target; } /** * Gets the target as a relative offset from the given address. */ public final int getTarget(int baseAddress) { return target - baseAddress; } /** * Gets the target as a relative offset from the given base * address, as a code unit. This will throw if the value is out of * the range of a signed code unit. */ public final short getTargetUnit(int baseAddress) { int relativeTarget = getTarget(baseAddress); if (relativeTarget != (short) relativeTarget) { throw new DexException("Target out of range: " + Hex.s4(relativeTarget)); } return (short) relativeTarget; } /** * Gets the target as a relative offset from the given base * address, masked to be a byte in size. This will throw if the * value is out of the range of a signed byte. */ public final int getTargetByte(int baseAddress) { int relativeTarget = getTarget(baseAddress); if (relativeTarget != (byte) relativeTarget) { throw new DexException("Target out of range: " + Hex.s4(relativeTarget)); } return relativeTarget & 0xff; } public final long getLiteral() { return literal; } /** * Gets the literal value, masked to be an int in size. This will * throw if the value is out of the range of a signed int. */ public final int getLiteralInt() { if (literal != (int) literal) { throw new DexException("Literal out of range: " + Hex.u8(literal)); } return (int) literal; } /** * Gets the literal value, as a code unit. This will throw if the * value is out of the range of a signed code unit. */ public final short getLiteralUnit() { if (literal != (short) literal) { throw new DexException("Literal out of range: " + Hex.u8(literal)); } return (short) literal; } /** * Gets the literal value, masked to be a byte in size. This will * throw if the value is out of the range of a signed byte. */ public final int getLiteralByte() { if (literal != (byte) literal) { throw new DexException("Literal out of range: " + Hex.u8(literal)); } return (int) literal & 0xff; } /** * Gets the literal value, masked to be a nibble in size. This * will throw if the value is out of the range of a signed nibble. */ public final int getLiteralNibble() { if ((literal < -8) || (literal > 7)) { throw new DexException("Literal out of range: " + Hex.u8(literal)); } return (int) literal & 0xf; } public abstract int getRegisterCount(); public int getA() { return 0; } public int getB() { return 0; } public int getC() { return 0; } public int getD() { return 0; } public int getE() { return 0; } /** * Gets the register count, as a code unit. This will throw if the * value is out of the range of an unsigned code unit. */ public final short getRegisterCountUnit() { int registerCount = getRegisterCount(); if ((registerCount & ~0xffff) != 0) { throw new DexException("Register count out of range: " + Hex.u8(registerCount)); } return (short) registerCount; } /** * Gets the A register number, as a code unit. This will throw if the * value is out of the range of an unsigned code unit. */ public final short getAUnit() { int a = getA(); if ((a & ~0xffff) != 0) { throw new DexException("Register A out of range: " + Hex.u8(a)); } return (short) a; } /** * Gets the A register number, as a byte. This will throw if the * value is out of the range of an unsigned byte. */ public final short getAByte() { int a = getA(); if ((a & ~0xff) != 0) { throw new DexException("Register A out of range: " + Hex.u8(a)); } return (short) a; } /** * Gets the A register number, as a nibble. This will throw if the * value is out of the range of an unsigned nibble. */ public final short getANibble() { int a = getA(); if ((a & ~0xf) != 0) { throw new DexException("Register A out of range: " + Hex.u8(a)); } return (short) a; } /** * Gets the B register number, as a code unit. This will throw if the * value is out of the range of an unsigned code unit. */ public final short getBUnit() { int b = getB(); if ((b & ~0xffff) != 0) { throw new DexException("Register B out of range: " + Hex.u8(b)); } return (short) b; } /** * Gets the B register number, as a byte. This will throw if the * value is out of the range of an unsigned byte. */ public final short getBByte() { int b = getB(); if ((b & ~0xff) != 0) { throw new DexException("Register B out of range: " + Hex.u8(b)); } return (short) b; } /** * Gets the B register number, as a nibble. This will throw if the * value is out of the range of an unsigned nibble. */ public final short getBNibble() { int b = getB(); if ((b & ~0xf) != 0) { throw new DexException("Register B out of range: " + Hex.u8(b)); } return (short) b; } /** * Gets the C register number, as a code unit. This will throw if the * value is out of the range of an unsigned code unit. */ public final short getCUnit() { int c = getC(); if ((c & ~0xffff) != 0) { throw new DexException("Register C out of range: " + Hex.u8(c)); } return (short) c; } /** * Gets the C register number, as a byte. This will throw if the * value is out of the range of an unsigned byte. */ public final short getCByte() { int c = getC(); if ((c & ~0xff) != 0) { throw new DexException("Register C out of range: " + Hex.u8(c)); } return (short) c; } /** * Gets the C register number, as a nibble. This will throw if the * value is out of the range of an unsigned nibble. */ public final short getCNibble() { int c = getC(); if ((c & ~0xf) != 0) { throw new DexException("Register C out of range: " + Hex.u8(c)); } return (short) c; } /** * Gets the D register number, as a code unit. This will throw if the * value is out of the range of an unsigned code unit. */ public final short getDUnit() { int d = getD(); if ((d & ~0xffff) != 0) { throw new DexException("Register D out of range: " + Hex.u8(d)); } return (short) d; } /** * Gets the D register number, as a byte. This will throw if the * value is out of the range of an unsigned byte. */ public final short getDByte() { int d = getD(); if ((d & ~0xff) != 0) { throw new DexException("Register D out of range: " + Hex.u8(d)); } return (short) d; } /** * Gets the D register number, as a nibble. This will throw if the * value is out of the range of an unsigned nibble. */ public final short getDNibble() { int d = getD(); if ((d & ~0xf) != 0) { throw new DexException("Register D out of range: " + Hex.u8(d)); } return (short) d; } /** * Gets the E register number, as a nibble. This will throw if the * value is out of the range of an unsigned nibble. */ public final short getENibble() { int e = getE(); if ((e & ~0xf) != 0) { throw new DexException("Register E out of range: " + Hex.u8(e)); } return (short) e; } /** * Encodes this instance to the given output. */ public final void encode(CodeOutput out) { format.encode(this, out); } /** * Returns an instance just like this one, except with the index replaced * with the given one. */ public abstract DecodedInstruction withIndex(int newIndex); }




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