cn.nukkit.level.format.anvil.palette.CharPalette Maven / Gradle / Ivy
package cn.nukkit.level.format.anvil.palette;
import io.netty.util.internal.EmptyArrays;
import java.util.Arrays;
/**
* @author https://github.com/boy0001/
*/
public class CharPalette {
private char[] keys = EmptyArrays.EMPTY_CHARS;
private char lastIndex = Character.MAX_VALUE;
public void add(char key) {
keys = insert(key);
lastIndex = Character.MAX_VALUE;
}
protected void set(char[] keys) {
this.keys = keys;
lastIndex = Character.MAX_VALUE;
}
private char[] insert(char val) {
lastIndex = Character.MAX_VALUE;
if (keys.length == 0) {
return new char[] { val };
}
else if (val < keys[0]) {
char[] s = new char[keys.length + 1];
System.arraycopy(keys, 0, s, 1, keys.length);
s[0] = val;
return s;
} else if (val > keys[keys.length - 1]) {
char[] s = Arrays.copyOf(keys, keys.length + 1);
s[keys.length] = val;
return s;
}
char[] s = Arrays.copyOf(keys, keys.length + 1);
for (int i = 0; i < s.length; i++) {
if (keys[i] < val) {
continue;
}
System.arraycopy(keys, i, s, i + 1, s.length - i - 1);
s[i] = val;
break;
}
return s;
}
public char getKey(int index) {
return keys[index];
}
public char getValue(char key) {
char lastTmp = lastIndex;
boolean hasLast = lastTmp != Character.MAX_VALUE;
int index;
if (hasLast) {
char lastKey = keys[lastTmp];
if (lastKey == key) return lastTmp;
if (lastKey > key) {
index = binarySearch0(0, lastTmp, key);
} else {
index = binarySearch0(lastTmp + 1, keys.length, key);
}
} else {
index = binarySearch0(0, keys.length, key);
}
if (index >= keys.length || index < 0) {
return lastIndex = Character.MAX_VALUE;
} else {
return lastIndex = (char) index;
}
}
private int binarySearch0(int fromIndex, int toIndex, char key) {
int low = fromIndex;
int high = toIndex - 1;
while (low <= high) {
int mid = (low + high) >>> 1;
char midVal = keys[mid];
if (midVal < key)
low = mid + 1;
else if (midVal > key)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
}