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/**
*******************************************************************************
* Copyright (C) 1996-2005, International Business Machines Corporation and *
* others. All Rights Reserved. *
*******************************************************************************
*
*
*******************************************************************************
*/
package libcore.icu;
import java.text.CollationKey;
/**
* A concrete implementation of the abstract java.text.CollationKey.
*/
public final class CollationKeyICU extends CollationKey {
/**
* The key.
*/
private final byte[] bytes;
/**
* Cached hash value.
*/
private int hashCode;
CollationKeyICU(String source, byte[] bytes) {
super(source);
this.bytes = bytes;
}
@Override public int compareTo(CollationKey other) {
// Get the bytes from the other collation key.
final byte[] rhsBytes;
if (other instanceof CollationKeyICU) {
rhsBytes = ((CollationKeyICU) other).bytes;
} else {
rhsBytes = other.toByteArray();
}
if (bytes == null || bytes.length == 0) {
if (rhsBytes == null || rhsBytes.length == 0) {
return 0;
}
return -1;
} else {
if (rhsBytes == null || rhsBytes.length == 0) {
return 1;
}
}
int count = Math.min(bytes.length, rhsBytes.length);
for (int i = 0; i < count; ++i) {
int s = bytes[i] & 0xff;
int t = rhsBytes[i] & 0xff;
if (s < t) {
return -1;
}
if (s > t) {
return 1;
}
}
if (bytes.length < rhsBytes.length) {
return -1;
}
if (bytes.length > rhsBytes.length) {
return 1;
}
return 0;
}
@Override public boolean equals(Object object) {
if (object == this) {
return true;
}
if (!(object instanceof CollationKey)) {
return false;
}
return compareTo((CollationKey) object) == 0;
}
/**
* Creates a hash code for this CollationKey.
* Compute the hash by iterating sparsely over about 32 (up to 63) bytes
* spaced evenly through the string. For each byte, multiply the previous
* hash value by a prime number and add the new byte in, like a linear
* congruential random number generator, producing a pseudo-random
* deterministic value well distributed over the output range.
* @return hash value of collation key. Hash value is never 0.
* @stable ICU 2.4
*/
@Override public int hashCode() {
if (hashCode == 0) {
if (bytes != null && bytes.length != 0) {
int len = bytes.length;
int inc = ((len - 32) / 32) + 1;
for (int i = 0; i < len;) {
hashCode = (hashCode * 37) + bytes[i];
i += inc;
}
}
if (hashCode == 0) {
hashCode = 1;
}
}
return hashCode;
}
@Override public byte[] toByteArray() {
if (bytes == null || bytes.length == 0) {
return null;
}
return bytes.clone();
}
}
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