/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2000-2009. All Rights Reserved.
*
* The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
* compliance with the License. You should have received a copy of the
* Erlang Public License along with this software. If not, it can be
* retrieved online at http://www.erlang.org/.
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* %CopyrightEnd%
*/
package com.ericsson.otp.erlang;
import java.math.BigInteger;
/**
* Provides a Java representation of Erlang integral types. Erlang does not
* distinguish between different integral types, however this class and its
* subclasses {@link OtpErlangByte}, {@link OtpErlangChar},
* {@link OtpErlangInt}, and {@link OtpErlangShort} attempt to map the Erlang
* types onto the various Java integral types. Two additional classes,
* {@link OtpErlangUInt} and {@link OtpErlangUShort} are provided for Corba
* compatibility. See the documentation for IC for more information.
*/
public class OtpErlangLong extends OtpErlangObject {
// don't change this!
private static final long serialVersionUID = 1610466859236755096L;
private long val;
private BigInteger bigVal = null;
/**
* Create an Erlang integer from the given value.
*
* @param l
* the long value to use.
*/
public OtpErlangLong(final long l) {
val = l;
}
/**
* Create an Erlang integer from the given value.
*
* @param v
* the big integer value to use.
*/
public OtpErlangLong(final BigInteger v) {
if (v == null) {
throw new java.lang.NullPointerException();
}
if (v.bitLength() < 64) {
val = v.longValue();
} else {
bigVal = v;
}
}
/**
* Create an Erlang integer from a stream containing an integer encoded in
* Erlang external format.
*
* @param buf
* the stream containing the encoded value.
*
* @exception OtpErlangDecodeException
* if the buffer does not contain a valid external
* representation of an Erlang integer.
*/
public OtpErlangLong(final OtpInputStream buf)
throws OtpErlangDecodeException {
final byte[] b = buf.read_integer_byte_array();
try {
val = OtpInputStream.byte_array_to_long(b, false);
} catch (final OtpErlangDecodeException e) {
bigVal = new BigInteger(b);
}
}
/**
* Get this number as a BigInteger.
*
* @return the value of this number, as a BigInteger.
*/
public BigInteger bigIntegerValue() {
if (bigVal != null) {
return bigVal;
}
return BigInteger.valueOf(val);
}
/**
* Get this number as a long, or rather truncate all but the least
* significant 64 bits from the 2's complement representation of this number
* and return them as a long.
*
* @return the value of this number, as a long.
*/
public long longValue() {
if (bigVal != null) {
return bigVal.longValue();
}
return val;
}
/**
* Determine if this value can be represented as a long without truncation.
*
* @return true if this value fits in a long, false otherwise.
*/
public boolean isLong() {
// To just chech this.bigVal is a wee bit to simple, since
// there just might have be a mean bignum that arrived on
// a stream, and was a long disguised as more than 8 byte integer.
if (bigVal != null) {
return bigVal.bitLength() < 64;
}
return true;
}
/**
* Determine if this value can be represented as an unsigned long without
* truncation, that is if the value is non-negative and its bit pattern
* completely fits in a long.
*
* @return true if this value is non-negative and fits in a long false
* otherwise.
*/
public boolean isULong() {
// Here we have the same problem as for isLong(), plus
// the whole range 1<<63 .. (1<<64-1) is allowed.
if (bigVal != null) {
return bigVal.signum() >= 0 && bigVal.bitLength() <= 64;
}
return val >= 0;
}
/**
* Returns the number of bits in the minimal two's-complement representation
* of this BigInteger, excluding a sign bit.
*
* @return number of bits in the minimal two's-complement representation of
* this BigInteger, excluding a sign bit.
*/
public int bitLength() {
if (bigVal != null) {
return bigVal.bitLength();
}
if (val == 0 || val == -1) {
return 0;
}
// Binary search for bit length
int i = 32; // mask length
long m = (1L << i) - 1; // AND mask with ones in little end
if (val < 0) {
m = ~m; // OR mask with ones in big end
for (int j = i >> 1; j > 0; j >>= 1) { // mask delta
if ((val | m) == val) { // mask >= enough
i -= j;
m >>= j; // try less bits
} else {
i += j;
m <<= j; // try more bits
}
}
if ((val | m) != val) {
i++; // mask < enough
}
} else {
for (int j = i >> 1; j > 0; j >>= 1) { // mask delta
if ((val & m) == val) { // mask >= enough
i -= j;
m >>= j; // try less bits
} else {
i += j;
m = m << j | m; // try more bits
}
}
if ((val & m) != val) {
i++; // mask < enough
}
}
return i;
}
/**
* Return the signum function of this object.
*
* @return -1, 0 or 1 as the value is negative, zero or positive.
*/
public int signum() {
if (bigVal != null) {
return bigVal.signum();
}
return val > 0 ? 1 : val < 0 ? -1 : 0;
}
/**
* Get this number as an int.
*
* @return the value of this number, as an int.
*
* @exception OtpErlangRangeException
* if the value is too large to be represented as an int.
*/
public int intValue() throws OtpErlangRangeException {
final long l = longValue();
final int i = (int) l;
if (i != l) {
throw new OtpErlangRangeException("Value too large for int: " + val);
}
return i;
}
/**
* Get this number as a non-negative int.
*
* @return the value of this number, as an int.
*
* @exception OtpErlangRangeException
* if the value is too large to be represented as an int,
* or if the value is negative.
*/
public int uIntValue() throws OtpErlangRangeException {
final long l = longValue();
final int i = (int) l;
if (i != l) {
throw new OtpErlangRangeException("Value too large for int: " + val);
} else if (i < 0) {
throw new OtpErlangRangeException("Value not positive: " + val);
}
return i;
}
/**
* Get this number as a short.
*
* @return the value of this number, as a short.
*
* @exception OtpErlangRangeException
* if the value is too large to be represented as a
* short.
*/
public short shortValue() throws OtpErlangRangeException {
final long l = longValue();
final short i = (short) l;
if (i != l) {
throw new OtpErlangRangeException("Value too large for short: "
+ val);
}
return i;
}
/**
* Get this number as a non-negative short.
*
* @return the value of this number, as a short.
*
* @exception OtpErlangRangeException
* if the value is too large to be represented as a
* short, or if the value is negative.
*/
public short uShortValue() throws OtpErlangRangeException {
final long l = longValue();
final short i = (short) l;
if (i != l) {
throw new OtpErlangRangeException("Value too large for short: "
+ val);
} else if (i < 0) {
throw new OtpErlangRangeException("Value not positive: " + val);
}
return i;
}
/**
* Get this number as a char.
*
* @return the char value of this number.
*
* @exception OtpErlangRangeException
* if the value is too large to be represented as a char.
*/
public char charValue() throws OtpErlangRangeException {
final long l = longValue();
final char i = (char) l;
if (i != l) {
throw new OtpErlangRangeException("Value too large for char: "
+ val);
}
return i;
}
/**
* Get this number as a byte.
*
* @return the byte value of this number.
*
* @exception OtpErlangRangeException
* if the value is too large to be represented as a byte.
*/
public byte byteValue() throws OtpErlangRangeException {
final long l = longValue();
final byte i = (byte) l;
if (i != l) {
throw new OtpErlangRangeException("Value too large for byte: "
+ val);
}
return i;
}
/**
* Get the string representation of this number.
*
* @return the string representation of this number.
*/
@Override
public String toString() {
if (bigVal != null) {
return "" + bigVal;
}
return "" + val;
}
/**
* Convert this number to the equivalent Erlang external representation.
*
* @param buf
* an output stream to which the encoded number should be
* written.
*/
@Override
public void encode(final OtpOutputStream buf) {
if (bigVal != null) {
buf.write_big_integer(bigVal);
} else {
buf.write_long(val);
}
}
/**
* Determine if two numbers are equal. Numbers are equal if they contain the
* same value.
*
* @param o
* the number to compare to.
*
* @return true if the numbers have the same value.
*/
@Override
public boolean equals(final Object o) {
if (!(o instanceof OtpErlangLong)) {
return false;
}
final OtpErlangLong that = (OtpErlangLong) o;
if (bigVal != null && that.bigVal != null) {
return bigVal.equals(that.bigVal);
} else if (bigVal == null && that.bigVal == null) {
return val == that.val;
}
return false;
}
@Override
protected int doHashCode() {
if (bigVal != null) {
return bigVal.hashCode();
}
return BigInteger.valueOf(val).hashCode();
}
}
