/*
 * Copyright 2008 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 java.lang;

/**
 * Wraps a primitive <code>long</code> as an object.
 */
public final class Long extends Number implements Comparable<Long> {

  /**
   * Use nested class to avoid clinit on outer.
   */
  static class BoxedValues {
    // Box values according to JLS - between -128 and 127
    static Long[] boxedValues = new Long[256];
  }

  static class HexLookup {
    /**
     * Super fast char->digit conversion.
     */
    static int[] hexLookup = new int[0];

    static {
      for (char c = '0'; c <= '9'; ++c) {
        hexLookup[c] = c - '0';
      }
      for (char c = 'A'; c <= 'F'; ++c) {
        hexLookup[c] = c - 'A' + 10;
      }
      for (char c = 'a'; c <= 'f'; ++c) {
        hexLookup[c] = c - 'a' + 10;
      }
    }
  }

  public static final long MAX_VALUE = 0x7fffffffffffffffL;
  public static final long MIN_VALUE = 0x8000000000000000L;
  public static final int SIZE = 64;

  public static int bitCount(long i) {
    int high = (int) (i >> 32);
    int low = (int) i;
    return Integer.bitCount(high) + Integer.bitCount(low);
  }

  public static Long decode(String s) throws NumberFormatException {
    __Decode decode = __decodeNumberString(s);
    return new Long(parseLong(decode.payload, decode.radix));
  }

  /**
   * @skip Here for shared implementation with Arrays.hashCode
   */
  public static int hashCode(long l) {
    return (int) l;
  }

  public static long highestOneBit(long i) {
    int high = (int) (i >> 32);
    if (high != 0) {
      return ((long) Integer.highestOneBit(high)) << 32;
    } else {
      return Integer.highestOneBit((int) i);
    }
  }

  public static long lowestOneBit(long i) {
    return i & -i;
  }

  public static int numberOfLeadingZeros(long i) {
    int high = (int) (i >> 32);
    if (high != 0) {
      return Integer.numberOfLeadingZeros(high);
    } else {
      return Integer.numberOfLeadingZeros((int) i) + 32;
    }
  }

  public static int numberOfTrailingZeros(long i) {
    int low = (int) i;
    if (low != 0) {
      return Integer.numberOfTrailingZeros(low);
    } else {
      return Integer.numberOfTrailingZeros((int) (i >> 32)) + 32;
    }
  }

  public static long parseLong(String s) throws NumberFormatException {
    return parseLong(s, 10);
  }
  
  public static long parseLong(String s, int radix) throws NumberFormatException {
    return __parseAndValidateLong(s, radix);
  }
 
  public static long reverse(long i) {
    int high = (int) (i >>> 32);
    int low = (int) i;
    return ((long) Integer.reverse(low) << 32)
        | (Integer.reverse(high) & 0xffffffffL);
  }

  public static long reverseBytes(long i) {
    int high = (int) (i >>> 32);
    int low = (int) i;
    return ((long) Integer.reverseBytes(low) << 32)
        | (Integer.reverseBytes(high) & 0xffffffffL);
  }

  public static long rotateLeft(long i, int distance) {
    while (distance-- > 0) {
      i = i << 1 | ((i < 0) ? 1 : 0);
    }
    return i;
  }

  public static long rotateRight(long i, int distance) {
    long ui = i & MAX_VALUE; // avoid sign extension
    long carry = (i < 0) ? 0x4000000000000000L : 0; // MIN_VALUE rightshifted 1
    while (distance-- > 0) {
      long nextcarry = ui & 1;
      ui = carry | (ui >> 1);
      carry = (nextcarry == 0) ? 0 : 0x4000000000000000L;
    }
    if (carry != 0) {
      ui = ui | MIN_VALUE;
    }
    return ui;
  }

  public static int signum(long i) {
    if (i == 0) {
      return 0;
    } else if (i < 0) {
      return -1;
    } else {
      return 1;
    }
  }

  public static String toBinaryString(long value) {
    return toPowerOfTwoString(value, 1);
  }

  public static String toHexString(long value) {
    return toPowerOfTwoString(value, 4);
  }

  public static String toOctalString(long value) {
    return toPowerOfTwoString(value, 3);
  }

  public static String toString(long value) {
    return String.valueOf(value);
  }

  public static String toString(long value, int intRadix) {
    if (intRadix == 10 || intRadix < Character.MIN_RADIX
        || intRadix > Character.MAX_RADIX) {
      return String.valueOf(value);
    }

    final int bufSize = 65;
    char[] buf = new char[bufSize];
    char[] digits = __Digits.digits;
    int pos = bufSize - 1;
    // Cache a converted version for performance (pure long ops are faster).
    long radix = intRadix;
    if (value >= 0) {
      while (value >= radix) {
        buf[pos--] = digits[(int) (value % radix)];
        value /= radix;
      }
      buf[pos] = digits[(int) value];
    } else {
      while (value <= -radix) {
        buf[pos--] = digits[(int) -(value % radix)];
        value /= radix;
      }
      buf[pos--] = digits[(int) -value];
      buf[pos] = '-';
    }
    return String.__valueOf(buf, pos, bufSize);
  }

  public static Long valueOf(long i) {
    if (i > -129 && i < 128) {
      int rebase = (int) i + 128;
      Long result = BoxedValues.boxedValues[rebase];
      if (result == null) {
        result = BoxedValues.boxedValues[rebase] = new Long(i);
      }
      return result;
    }
    return new Long(i);
  }

  public static Long valueOf(String s) throws NumberFormatException {
    return new Long(Long.parseLong(s));
  }

  public static Long valueOf(String s, int radix) throws NumberFormatException {
    return new Long(Long.parseLong(s, radix));
  }

  private static native int hexDigit(char c, String s) /*-{
    var val = @java.lang.Long.HexLookup::hexLookup[c];
    if (val == null) {
      throw @java.lang.NumberFormatException::forInputString(Ljava/lang/String;)(s);
    }
    return val;
  }-*/;

  private static long parseHex(String s) {
    // TODO: make faster using int math!
    int len = s.length();
    if (len > 16) {
      throw NumberFormatException.forInputString(s);
    }
    long result = 0;
    for (int i = 0; i < len; ++i) {
      result <<= 4;
      result += hexDigit(s.charAt(i), s);
    }
    return result;
  }

  private static String toPowerOfTwoString(long value, int shift) {
    // TODO: make faster using int math!
    final int bufSize = 64 / shift;
    long bitMask = (1 << shift) - 1;
    char[] buf = new char[bufSize];
    char[] digits = __Digits.digits;
    int pos = bufSize - 1;
    if (value >= 0) {
      while (value > bitMask) {
        buf[pos--] = digits[(int) (value & bitMask)];
        value >>= shift;
      }
    } else {
      while (pos > 0) {
        buf[pos--] = digits[(int) (value & bitMask)];
        value >>= shift;
      }
    }
    buf[pos] = digits[(int) (value & bitMask)];
    return String.__valueOf(buf, pos, bufSize);
  }

  private final transient long value;

  public Long(long value) {
    this.value = value;
  }

  public Long(String s) {
    value = parseLong(s);
  }

  @Override
  public byte byteValue() {
    return (byte) value;
  }

  public int compareTo(Long b) {
    if (value < b.value) {
      return -1;
    } else if (value > b.value) {
      return 1;
    } else {
      return 0;
    }
  }

  @Override
  public double doubleValue() {
    return value;
  }

  @Override
  public boolean equals(Object o) {
    return (o instanceof Long) && (((Long) o).value == value);
  }

  @Override
  public float floatValue() {
    return value;
  }

  @Override
  public int hashCode() {
    return hashCode(value);
  }

  @Override
  public int intValue() {
    return (int) value;
  }

  @Override
  public long longValue() {
    return value;
  }

  @Override
  public short shortValue() {
    return (short) value;
  }

  @Override
  public String toString() {
    return toString(value);
  }
}