dx/src/com/android/jack/dx/io/EncodedValueReader.java

/*
 * 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.jack.dx.io;

import com.android.jack.dx.util.ByteInput;
import com.android.jack.dx.util.Leb128Utils;

/**
 * SAX-style reader for encoded values.
 * TODO(dx team): convert this to a pull-style reader
 */
public class EncodedValueReader {
  public static final int ENCODED_BYTE = 0x00;
  public static final int ENCODED_SHORT = 0x02;
  public static final int ENCODED_CHAR = 0x03;
  public static final int ENCODED_INT = 0x04;
  public static final int ENCODED_LONG = 0x06;
  public static final int ENCODED_FLOAT = 0x10;
  public static final int ENCODED_DOUBLE = 0x11;
  public static final int ENCODED_STRING = 0x17;
  public static final int ENCODED_TYPE = 0x18;
  public static final int ENCODED_FIELD = 0x19;
  public static final int ENCODED_ENUM = 0x1b;
  public static final int ENCODED_METHOD = 0x1a;
  public static final int ENCODED_ARRAY = 0x1c;
  public static final int ENCODED_ANNOTATION = 0x1d;
  public static final int ENCODED_NULL = 0x1e;
  public static final int ENCODED_BOOLEAN = 0x1f;

  protected final ByteInput in;

  public EncodedValueReader(ByteInput in) {
    this.in = in;
  }

  public EncodedValueReader(EncodedValue in) {
    this(in.asByteInput());
  }

  public final void readArray() {
    int size = Leb128Utils.readUnsignedLeb128(in);
    visitArray(size);

    for (int i = 0; i < size; i++) {
      readValue();
    }
  }

  public final void readAnnotation() {
    int typeIndex = Leb128Utils.readUnsignedLeb128(in);
    int size = Leb128Utils.readUnsignedLeb128(in);
    visitAnnotation(typeIndex, size);

    for (int i = 0; i < size; i++) {
      visitAnnotationName(Leb128Utils.readUnsignedLeb128(in));
      readValue();
    }
  }

  public final void readValue() {
    int argAndType = in.readByte() & 0xff;
    int type = argAndType & 0x1f;
    int arg = (argAndType & 0xe0) >> 5;
    int size = arg + 1;

    switch (type) {
      case ENCODED_BYTE:
      case ENCODED_SHORT:
      case ENCODED_CHAR:
      case ENCODED_INT:
      case ENCODED_LONG:
      case ENCODED_FLOAT:
      case ENCODED_DOUBLE:
        visitPrimitive(argAndType, type, arg, size);
        break;
      case ENCODED_STRING:
        visitString(type, readIndex(in, size));
        break;
      case ENCODED_TYPE:
        visitType(type, readIndex(in, size));
        break;
      case ENCODED_FIELD:
      case ENCODED_ENUM:
        visitField(type, readIndex(in, size));
        break;
      case ENCODED_METHOD:
        visitMethod(type, readIndex(in, size));
        break;
      case ENCODED_ARRAY:
        visitArrayValue(argAndType);
        readArray();
        break;
      case ENCODED_ANNOTATION:
        visitAnnotationValue(argAndType);
        readAnnotation();
        break;
      case ENCODED_NULL:
        visitEncodedNull(argAndType);
        break;
      case ENCODED_BOOLEAN:
        visitEncodedBoolean(argAndType);
        break;
    }
  }

  protected void visitArray(int size) {}

  protected void visitAnnotation(int typeIndex, int size) {}

  protected void visitAnnotationName(int nameIndex) {}

  protected void visitPrimitive(int argAndType, int type, int arg, int size) {
    for (int i = 0; i < size; i++) {
      in.readByte();
    }
  }

  protected void visitString(int type, int index) {}

  protected void visitType(int type, int index) {}

  protected void visitField(int type, int index) {}

  protected void visitMethod(int type, int index) {}

  protected void visitArrayValue(int argAndType) {}

  protected void visitAnnotationValue(int argAndType) {}

  protected void visitEncodedBoolean(int argAndType) {}

  protected void visitEncodedNull(int argAndType) {}

  private int readIndex(ByteInput in, int byteCount) {
    int result = 0;
    int shift = 0;
    for (int i = 0; i < byteCount; i++) {
      result += (in.readByte() & 0xff) << shift;
      shift += 8;
    }
    return result;
  }
}