hyracks-dataflow-common/src/main/java/edu/uci/ics/hyracks/dataflow/common/data/util/StringUtils.java

/*
 * Copyright 2009-2010 by The Regents of the University of California
 * 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 from
 * 
 *     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 edu.uci.ics.hyracks.dataflow.common.data.util;

import java.io.DataOutput;
import java.io.IOException;

public class StringUtils {
	public static char charAt(byte[] b, int s) {
		int c = b[s] & 0xff;
		switch (c >> 4) {
		case 0:
		case 1:
		case 2:
		case 3:
		case 4:
		case 5:
		case 6:
		case 7:
			return (char) c;

		case 12:
		case 13:
			return (char) (((c & 0x1F) << 6) | ((b[s + 1]) & 0x3F));

		case 14:
			return (char) (((c & 0x0F) << 12) | (((b[s + 1]) & 0x3F) << 6) | (((b[s + 2]) & 0x3F) << 0));

		default:
			throw new IllegalArgumentException();
		}
	}

	public static int charSize(byte[] b, int s) {
		int c = b[s] & 0xff;
		switch (c >> 4) {
		case 0:
		case 1:
		case 2:
		case 3:
		case 4:
		case 5:
		case 6:
		case 7:
			return 1;

		case 12:
		case 13:
			return 2;

		case 14:
			return 3;
		}
		throw new IllegalStateException();
	}

	public static int getModifiedUTF8Len(char c) {
		if (c >= 0x0000 && c <= 0x007F) {
			return 1;
		} else if (c <= 0x07FF) {
			return 2;
		} else {
			return 3;
		}
	}

	public static int getStrLen(byte[] b, int s) {
		int pos = s + 2;
		int end = pos + getUTFLen(b, s);
		int charCount = 0;
		while (pos < end) {
			charCount++;
			pos += charSize(b, pos);
		}
		return charCount;
	}

	public static int getUTFLen(byte[] b, int s) {
		return ((b[s] & 0xff) << 8) + ((b[s + 1] & 0xff) << 0);
	}

	public static char toLowerCase(char c) {
		switch (c) {
		case 'A':
			return 'a';
		case 'B':
			return 'b';
		case 'C':
			return 'c';
		case 'D':
			return 'd';
		case 'E':
			return 'e';
		case 'F':
			return 'f';
		case 'G':
			return 'g';
		case 'H':
			return 'h';
		case 'I':
			return 'i';
		case 'J':
			return 'j';
		case 'K':
			return 'k';
		case 'L':
			return 'l';
		case 'M':
			return 'm';
		case 'N':
			return 'n';
		case 'O':
			return 'o';
		case 'P':
			return 'p';
		case 'Q':
			return 'q';
		case 'R':
			return 'r';
		case 'S':
			return 's';
		case 'T':
			return 't';
		case 'U':
			return 'u';
		case 'V':
			return 'v';
		case 'W':
			return 'w';
		case 'X':
			return 'x';
		case 'Y':
			return 'y';
		case 'Z':
			return 'z';
		case 'Ä':
			return 'ä';
		case 'Ǟ':
			return 'ǟ';
		case 'Ë':
			return 'ë';
		case 'Ḧ':
			return 'ḧ';
		case 'Ï':
			return 'ï';
		case 'Ḯ':
			return 'ḯ';
		case 'Ö':
			return 'ö';
		case 'Ȫ':
			return 'ȫ';
		case 'Ṏ':
			return 'ṏ';
		case 'Ü':
			return 'ü';
		case 'Ǖ':
			return 'ǖ';
		case 'Ǘ':
			return 'ǘ';
		case 'Ǚ':
			return 'ǚ';
		case 'Ǜ':
			return 'ǜ';
		case 'Ṳ':
			return 'ṳ';
		case 'Ṻ':
			return 'ṻ';
		case 'Ẅ':
			return 'ẅ';
		case 'Ẍ':
			return 'ẍ';
		case 'Ÿ':
			return 'ÿ';
		default:
			// since I probably missed some chars above
			// use Java to convert to lower case to be safe
			return Character.toLowerCase(c);
		}
	}

	public static void writeCharAsModifiedUTF8(char c, DataOutput dos)
			throws IOException {

		if (c >= 0x0000 && c <= 0x007F) {
			dos.writeByte(c);
		} else if (c <= 0x07FF) {
			dos.writeByte((byte) (0xC0 | ((c >> 6) & 0x3F)));
			dos.writeByte((byte) (0x80 | (c & 0x3F)));
		} else {
			dos.writeByte((byte) (0xE0 | ((c >> 12) & 0x0F)));
			dos.writeByte((byte) (0x80 | ((c >> 6) & 0x3F)));
			dos.writeByte((byte) (0x80 | (c & 0x3F)));
		}
	}

	public static void writeUTF8Len(int len, DataOutput dos) throws IOException {
		dos.write((len >>> 8) & 0xFF);
		dos.write((len >>> 0) & 0xFF);
	}
}