/*
 * Copyright 2012, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.jf.dexlib2.dexbacked.instruction;

import org.jf.dexlib2.Opcode;
import org.jf.dexlib2.dexbacked.DexBackedDexFile;
import org.jf.dexlib2.dexbacked.DexReader;
import org.jf.dexlib2.iface.instruction.Instruction;
import org.jf.util.ExceptionWithContext;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

public abstract class DexBackedInstruction implements Instruction {
    @Nonnull public final DexBackedDexFile dexFile;
    @Nonnull public final Opcode opcode;
    public final int instructionStart;

    public DexBackedInstruction(@Nonnull DexBackedDexFile dexFile,
                                @Nonnull Opcode opcode,
                                int instructionStart) {
        this.dexFile = dexFile;
        this.opcode = opcode;
        this.instructionStart = instructionStart;
    }

    @Nonnull public Opcode getOpcode() { return opcode; }
    @Override public int getCodeUnits() { return opcode.format.size / 2; }

    @Nonnull
    public static Instruction readFrom(@Nonnull DexReader reader) {
        int opcodeValue = reader.peekUbyte();

        if (opcodeValue == 0) {
            opcodeValue = reader.peekUshort();
        }

        Opcode opcode = reader.dexBuf.getOpcodes().getOpcodeByValue(opcodeValue);

        Instruction instruction = buildInstruction(reader.dexBuf, opcode, reader.getOffset());
        reader.moveRelative(instruction.getCodeUnits()*2);
        return instruction;
    }
    
    private static DexBackedInstruction buildInstruction(@Nonnull DexBackedDexFile dexFile, @Nullable Opcode opcode,
                                                         int instructionStartOffset) {
        if (opcode == null) {
            return new DexBackedUnknownInstruction(dexFile, instructionStartOffset);
        }
        switch (opcode.format) {
            case Format10t:
                return new DexBackedInstruction10t(dexFile, opcode, instructionStartOffset);
            case Format10x:
                return new DexBackedInstruction10x(dexFile, opcode, instructionStartOffset);
            case Format11n:
                return new DexBackedInstruction11n(dexFile, opcode, instructionStartOffset);
            case Format11x:
                return new DexBackedInstruction11x(dexFile, opcode, instructionStartOffset);
            case Format12x:
                return new DexBackedInstruction12x(dexFile, opcode, instructionStartOffset);
            case Format20bc:
                return new DexBackedInstruction20bc(dexFile, opcode, instructionStartOffset);
            case Format20t:
                return new DexBackedInstruction20t(dexFile, opcode, instructionStartOffset);
            case Format21c:
                return new DexBackedInstruction21c(dexFile, opcode, instructionStartOffset);
            case Format21ih:
                return new DexBackedInstruction21ih(dexFile, opcode, instructionStartOffset);
            case Format21lh:
                return new DexBackedInstruction21lh(dexFile, opcode, instructionStartOffset);
            case Format21s:
                return new DexBackedInstruction21s(dexFile, opcode, instructionStartOffset);
            case Format21t:
                return new DexBackedInstruction21t(dexFile, opcode, instructionStartOffset);
            case Format22b:
                return new DexBackedInstruction22b(dexFile, opcode, instructionStartOffset);
            case Format22c:
                return new DexBackedInstruction22c(dexFile, opcode, instructionStartOffset);
            case Format22cs:
                return new DexBackedInstruction22cs(dexFile, opcode, instructionStartOffset);
            case Format22s:
                return new DexBackedInstruction22s(dexFile, opcode, instructionStartOffset);
            case Format22t:
                return new DexBackedInstruction22t(dexFile, opcode, instructionStartOffset);
            case Format22x:
                return new DexBackedInstruction22x(dexFile, opcode, instructionStartOffset);
            case Format23x:
                return new DexBackedInstruction23x(dexFile, opcode, instructionStartOffset);
            case Format25x:
                return new DexBackedInstruction25x(dexFile, opcode, instructionStartOffset);
            case Format30t:
                return new DexBackedInstruction30t(dexFile, opcode, instructionStartOffset);
            case Format31c:
                return new DexBackedInstruction31c(dexFile, opcode, instructionStartOffset);
            case Format31i:
                return new DexBackedInstruction31i(dexFile, opcode, instructionStartOffset);
            case Format31t:
                return new DexBackedInstruction31t(dexFile, opcode, instructionStartOffset);
            case Format32x:
                return new DexBackedInstruction32x(dexFile, opcode, instructionStartOffset);
            case Format35c:
                return new DexBackedInstruction35c(dexFile, opcode, instructionStartOffset);
            case Format35ms:
                return new DexBackedInstruction35ms(dexFile, opcode, instructionStartOffset);
            case Format35mi:
                return new DexBackedInstruction35mi(dexFile, opcode, instructionStartOffset);
            case Format3rc:
                return new DexBackedInstruction3rc(dexFile, opcode, instructionStartOffset);
            case Format3rmi:
                return new DexBackedInstruction3rmi(dexFile, opcode, instructionStartOffset);
            case Format3rms:
                return new DexBackedInstruction3rms(dexFile, opcode, instructionStartOffset);
            case Format51l:
                return new DexBackedInstruction51l(dexFile, opcode, instructionStartOffset);
            case PackedSwitchPayload:
                return new DexBackedPackedSwitchPayload(dexFile, instructionStartOffset);
            case SparseSwitchPayload:
                return new DexBackedSparseSwitchPayload(dexFile, instructionStartOffset);
            case ArrayPayload:
                return new DexBackedArrayPayload(dexFile, instructionStartOffset);
            default:
                throw new ExceptionWithContext("Unexpected opcode format: %s", opcode.format.toString());
        }
    }
}
