// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
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package org.objectweb.asm;

A dynamically extensible vector of bytes. This class is roughly equivalent to a DataOutputStream
on top of a ByteArrayOutputStream, but is more efficient.
Author:
Eric Bruneton/**
 * A dynamically extensible vector of bytes. This class is roughly equivalent to a DataOutputStream
 * on top of a ByteArrayOutputStream, but is more efficient.
 *
 * @author Eric Bruneton
 */
public class ByteVector {

  
The content of this vector. Only the first length bytes contain real data. /** The content of this vector. Only the first {@link #length} bytes contain real data. */
  byte[] data;

  
The actual number of bytes in this vector. /** The actual number of bytes in this vector. */
  int length;

  
Constructs a new ByteVector with a default initial capacity. /** Constructs a new {@link ByteVector} with a default initial capacity. */
  public ByteVector() {
    data = new byte[64];
  }

  
Constructs a new ByteVector with the given initial capacity. 
Params:
initialCapacity – the initial capacity of the byte vector to be constructed./**
   * Constructs a new {@link ByteVector} with the given initial capacity.
   *
   * @param initialCapacity the initial capacity of the byte vector to be constructed.
   */
  public ByteVector(final int initialCapacity) {
    data = new byte[initialCapacity];
  }

  
Constructs a new ByteVector from the given initial data. 
Params:
data – the initial data of the new byte vector./**
   * Constructs a new {@link ByteVector} from the given initial data.
   *
   * @param data the initial data of the new byte vector.
   */
  ByteVector(final byte[] data) {
    this.data = data;
    this.length = data.length;
  }

  
Puts a byte into this byte vector. The byte vector is automatically enlarged if necessary.
Params:
byteValue – a byte.
Returns:
this byte vector./**
   * Puts a byte into this byte vector. The byte vector is automatically enlarged if necessary.
   *
   * @param byteValue a byte.
   * @return this byte vector.
   */
  public ByteVector putByte(final int byteValue) {
    int currentLength = length;
    if (currentLength + 1 > data.length) {
      enlarge(1);
    }
    data[currentLength++] = (byte) byteValue;
    length = currentLength;
    return this;
  }

  
Puts two bytes into this byte vector. The byte vector is automatically enlarged if necessary.
Params:
byteValue1 – a byte.
byteValue2 – another byte.
Returns:
this byte vector./**
   * Puts two bytes into this byte vector. The byte vector is automatically enlarged if necessary.
   *
   * @param byteValue1 a byte.
   * @param byteValue2 another byte.
   * @return this byte vector.
   */
  final ByteVector put11(final int byteValue1, final int byteValue2) {
    int currentLength = length;
    if (currentLength + 2 > data.length) {
      enlarge(2);
    }
    byte[] currentData = data;
    currentData[currentLength++] = (byte) byteValue1;
    currentData[currentLength++] = (byte) byteValue2;
    length = currentLength;
    return this;
  }

  
Puts a short into this byte vector. The byte vector is automatically enlarged if necessary.
Params:
shortValue – a short.
Returns:
this byte vector./**
   * Puts a short into this byte vector. The byte vector is automatically enlarged if necessary.
   *
   * @param shortValue a short.
   * @return this byte vector.
   */
  public ByteVector putShort(final int shortValue) {
    int currentLength = length;
    if (currentLength + 2 > data.length) {
      enlarge(2);
    }
    byte[] currentData = data;
    currentData[currentLength++] = (byte) (shortValue >>> 8);
    currentData[currentLength++] = (byte) shortValue;
    length = currentLength;
    return this;
  }

  
Puts a byte and a short into this byte vector. The byte vector is automatically enlarged if
necessary.
Params:
byteValue – a byte.
shortValue – a short.
Returns:
this byte vector./**
   * Puts a byte and a short into this byte vector. The byte vector is automatically enlarged if
   * necessary.
   *
   * @param byteValue a byte.
   * @param shortValue a short.
   * @return this byte vector.
   */
  final ByteVector put12(final int byteValue, final int shortValue) {
    int currentLength = length;
    if (currentLength + 3 > data.length) {
      enlarge(3);
    }
    byte[] currentData = data;
    currentData[currentLength++] = (byte) byteValue;
    currentData[currentLength++] = (byte) (shortValue >>> 8);
    currentData[currentLength++] = (byte) shortValue;
    length = currentLength;
    return this;
  }

  
Puts two bytes and a short into this byte vector. The byte vector is automatically enlarged if
necessary.
Params:
byteValue1 – a byte.
byteValue2 – another byte.
shortValue – a short.
Returns:
this byte vector./**
   * Puts two bytes and a short into this byte vector. The byte vector is automatically enlarged if
   * necessary.
   *
   * @param byteValue1 a byte.
   * @param byteValue2 another byte.
   * @param shortValue a short.
   * @return this byte vector.
   */
  final ByteVector put112(final int byteValue1, final int byteValue2, final int shortValue) {
    int currentLength = length;
    if (currentLength + 4 > data.length) {
      enlarge(4);
    }
    byte[] currentData = data;
    currentData[currentLength++] = (byte) byteValue1;
    currentData[currentLength++] = (byte) byteValue2;
    currentData[currentLength++] = (byte) (shortValue >>> 8);
    currentData[currentLength++] = (byte) shortValue;
    length = currentLength;
    return this;
  }

  
Puts an int into this byte vector. The byte vector is automatically enlarged if necessary.
Params:
intValue – an int.
Returns:
this byte vector./**
   * Puts an int into this byte vector. The byte vector is automatically enlarged if necessary.
   *
   * @param intValue an int.
   * @return this byte vector.
   */
  public ByteVector putInt(final int intValue) {
    int currentLength = length;
    if (currentLength + 4 > data.length) {
      enlarge(4);
    }
    byte[] currentData = data;
    currentData[currentLength++] = (byte) (intValue >>> 24);
    currentData[currentLength++] = (byte) (intValue >>> 16);
    currentData[currentLength++] = (byte) (intValue >>> 8);
    currentData[currentLength++] = (byte) intValue;
    length = currentLength;
    return this;
  }

  
Puts one byte and two shorts into this byte vector. The byte vector is automatically enlarged
if necessary.
Params:
byteValue – a byte.
shortValue1 – a short.
shortValue2 – another short.
Returns:
this byte vector./**
   * Puts one byte and two shorts into this byte vector. The byte vector is automatically enlarged
   * if necessary.
   *
   * @param byteValue a byte.
   * @param shortValue1 a short.
   * @param shortValue2 another short.
   * @return this byte vector.
   */
  final ByteVector put122(final int byteValue, final int shortValue1, final int shortValue2) {
    int currentLength = length;
    if (currentLength + 5 > data.length) {
      enlarge(5);
    }
    byte[] currentData = data;
    currentData[currentLength++] = (byte) byteValue;
    currentData[currentLength++] = (byte) (shortValue1 >>> 8);
    currentData[currentLength++] = (byte) shortValue1;
    currentData[currentLength++] = (byte) (shortValue2 >>> 8);
    currentData[currentLength++] = (byte) shortValue2;
    length = currentLength;
    return this;
  }

  
Puts a long into this byte vector. The byte vector is automatically enlarged if necessary.
Params:
longValue – a long.
Returns:
this byte vector./**
   * Puts a long into this byte vector. The byte vector is automatically enlarged if necessary.
   *
   * @param longValue a long.
   * @return this byte vector.
   */
  public ByteVector putLong(final long longValue) {
    int currentLength = length;
    if (currentLength + 8 > data.length) {
      enlarge(8);
    }
    byte[] currentData = data;
    int intValue = (int) (longValue >>> 32);
    currentData[currentLength++] = (byte) (intValue >>> 24);
    currentData[currentLength++] = (byte) (intValue >>> 16);
    currentData[currentLength++] = (byte) (intValue >>> 8);
    currentData[currentLength++] = (byte) intValue;
    intValue = (int) longValue;
    currentData[currentLength++] = (byte) (intValue >>> 24);
    currentData[currentLength++] = (byte) (intValue >>> 16);
    currentData[currentLength++] = (byte) (intValue >>> 8);
    currentData[currentLength++] = (byte) intValue;
    length = currentLength;
    return this;
  }

  
Puts an UTF8 string into this byte vector. The byte vector is automatically enlarged if
necessary.
Params:
stringValue – a String whose UTF8 encoded length must be less than 65536.
Returns:
this byte vector./**
   * Puts an UTF8 string into this byte vector. The byte vector is automatically enlarged if
   * necessary.
   *
   * @param stringValue a String whose UTF8 encoded length must be less than 65536.
   * @return this byte vector.
   */
  // DontCheck(AbbreviationAsWordInName): can't be renamed (for backward binary compatibility).
  public ByteVector putUTF8(final String stringValue) {
    int charLength = stringValue.length();
    if (charLength > 65535) {
      throw new IllegalArgumentException("UTF8 string too large");
    }
    int currentLength = length;
    if (currentLength + 2 + charLength > data.length) {
      enlarge(2 + charLength);
    }
    byte[] currentData = data;
    // Optimistic algorithm: instead of computing the byte length and then serializing the string
    // (which requires two loops), we assume the byte length is equal to char length (which is the
    // most frequent case), and we start serializing the string right away. During the
    // serialization, if we find that this assumption is wrong, we continue with the general method.
    currentData[currentLength++] = (byte) (charLength >>> 8);
    currentData[currentLength++] = (byte) charLength;
    for (int i = 0; i < charLength; ++i) {
      char charValue = stringValue.charAt(i);
      if (charValue >= '\u0001' && charValue <= '\u007F') {
        currentData[currentLength++] = (byte) charValue;
      } else {
        length = currentLength;
        return encodeUtf8(stringValue, i, 65535);
      }
    }
    length = currentLength;
    return this;
  }

  
Puts an UTF8 string into this byte vector. The byte vector is automatically enlarged if
necessary. The string length is encoded in two bytes before the encoded characters, if there is
space for that (i.e. if this.length - offset - 2 >= 0).
Params:
stringValue – the String to encode.
offset – the index of the first character to encode. The previous characters are supposed
    to have already been encoded, using only one byte per character.
maxByteLength – the maximum byte length of the encoded string, including the already
    encoded characters.
Returns:
this byte vector./**
   * Puts an UTF8 string into this byte vector. The byte vector is automatically enlarged if
   * necessary. The string length is encoded in two bytes before the encoded characters, if there is
   * space for that (i.e. if this.length - offset - 2 &gt;= 0).
   *
   * @param stringValue the String to encode.
   * @param offset the index of the first character to encode. The previous characters are supposed
   *     to have already been encoded, using only one byte per character.
   * @param maxByteLength the maximum byte length of the encoded string, including the already
   *     encoded characters.
   * @return this byte vector.
   */
  final ByteVector encodeUtf8(final String stringValue, final int offset, final int maxByteLength) {
    int charLength = stringValue.length();
    int byteLength = offset;
    for (int i = offset; i < charLength; ++i) {
      char charValue = stringValue.charAt(i);
      if (charValue >= 0x0001 && charValue <= 0x007F) {
        byteLength++;
      } else if (charValue <= 0x07FF) {
        byteLength += 2;
      } else {
        byteLength += 3;
      }
    }
    if (byteLength > maxByteLength) {
      throw new IllegalArgumentException("UTF8 string too large");
    }
    // Compute where 'byteLength' must be stored in 'data', and store it at this location.
    int byteLengthOffset = length - offset - 2;
    if (byteLengthOffset >= 0) {
      data[byteLengthOffset] = (byte) (byteLength >>> 8);
      data[byteLengthOffset + 1] = (byte) byteLength;
    }
    if (length + byteLength - offset > data.length) {
      enlarge(byteLength - offset);
    }
    int currentLength = length;
    for (int i = offset; i < charLength; ++i) {
      char charValue = stringValue.charAt(i);
      if (charValue >= 0x0001 && charValue <= 0x007F) {
        data[currentLength++] = (byte) charValue;
      } else if (charValue <= 0x07FF) {
        data[currentLength++] = (byte) (0xC0 | charValue >> 6 & 0x1F);
        data[currentLength++] = (byte) (0x80 | charValue & 0x3F);
      } else {
        data[currentLength++] = (byte) (0xE0 | charValue >> 12 & 0xF);
        data[currentLength++] = (byte) (0x80 | charValue >> 6 & 0x3F);
        data[currentLength++] = (byte) (0x80 | charValue & 0x3F);
      }
    }
    length = currentLength;
    return this;
  }

  
Puts an array of bytes into this byte vector. The byte vector is automatically enlarged if
necessary.
Params:
byteArrayValue – an array of bytes. May be null to put byteLength null bytes into this byte vector.
byteOffset – index of the first byte of byteArrayValue that must be copied.
byteLength – number of bytes of byteArrayValue that must be copied.
Returns:
this byte vector./**
   * Puts an array of bytes into this byte vector. The byte vector is automatically enlarged if
   * necessary.
   *
   * @param byteArrayValue an array of bytes. May be {@literal null} to put {@code byteLength} null
   *     bytes into this byte vector.
   * @param byteOffset index of the first byte of byteArrayValue that must be copied.
   * @param byteLength number of bytes of byteArrayValue that must be copied.
   * @return this byte vector.
   */
  public ByteVector putByteArray(
      final byte[] byteArrayValue, final int byteOffset, final int byteLength) {
    if (length + byteLength > data.length) {
      enlarge(byteLength);
    }
    if (byteArrayValue != null) {
      System.arraycopy(byteArrayValue, byteOffset, data, length, byteLength);
    }
    length += byteLength;
    return this;
  }

  
Enlarges this byte vector so that it can receive 'size' more bytes.
Params:
size – number of additional bytes that this byte vector should be able to receive./**
   * Enlarges this byte vector so that it can receive 'size' more bytes.
   *
   * @param size number of additional bytes that this byte vector should be able to receive.
   */
  private void enlarge(final int size) {
    int doubleCapacity = 2 * data.length;
    int minimalCapacity = length + size;
    byte[] newData = new byte[doubleCapacity > minimalCapacity ? doubleCapacity : minimalCapacity];
    System.arraycopy(data, 0, newData, 0, length);
    data = newData;
  }
}