/*- * See the file LICENSE for redistribution information. * * Copyright (c) 2000,2008 Oracle. All rights reserved. * * $Id: UtfOps.java,v 12.6 2008/01/08 20:58:39 bostic Exp $ */ package com.sleepycat.util; /** * UTF operations with more flexibility than is provided by DataInput and * DataOutput. * * @author Mark Hayes */ public class UtfOps { private static byte[] EMPTY_BYTES = {}; private static String EMPTY_STRING = ""; /** * Returns the byte length of a null terminated UTF string, not including * the terminator. * * @param bytes the data containing the UTF string. * * @param offset the beginning of the string the measure. * * @throws IndexOutOfBoundsException if no zero terminator is found. * * @return the number of bytes. */ public static int getZeroTerminatedByteLength(byte[] bytes, int offset) throws IndexOutOfBoundsException { int len = 0; while (bytes[offset++] != 0) { len++; } return len; } /** * Returns the byte length of the UTF string that would be created by * converting the given characters to UTF. * * @param chars the characters that would be converted. * * @return the byte length of the equivalent UTF data. */ public static int getByteLength(char[] chars) { return getByteLength(chars, 0, chars.length); } /** * Returns the byte length of the UTF string that would be created by * converting the given characters to UTF. * * @param chars the characters that would be converted. * * @param offset the first character to be converted. * * @param length the number of characters to be converted. * * @return the byte length of the equivalent UTF data. */ public static int getByteLength(char[] chars, int offset, int length) { int len = 0; length += offset; for (int i = offset; i < length; i++) { int c = chars[i]; if ((c >= 0x0001) && (c <= 0x007F)) { len++; } else if (c > 0x07FF) { len += 3; } else { len += 2; } } return len; } /** * Returns the number of characters represented by the given UTF string. * * @param bytes the UTF string. * * @return the number of characters. * * @throws IndexOutOfBoundsException if a UTF character sequence at the end * of the data is not complete. * * @throws IllegalArgumentException if an illegal UTF sequence is * encountered. */ public static int getCharLength(byte[] bytes) throws IllegalArgumentException, IndexOutOfBoundsException { return getCharLength(bytes, 0, bytes.length); } /** * Returns the number of characters represented by the given UTF string. * * @param bytes the data containing the UTF string. * * @param offset the first byte to be converted. * * @param length the number of byte to be converted. * * @throws IndexOutOfBoundsException if a UTF character sequence at the end * of the data is not complete. * * @throws IllegalArgumentException if an illegal UTF sequence is * encountered. */ public static int getCharLength(byte[] bytes, int offset, int length) throws IllegalArgumentException, IndexOutOfBoundsException { int charCount = 0; length += offset; while (offset < length) { switch ((bytes[offset] & 0xff) >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: offset++; break; case 12: case 13: offset += 2; break; case 14: offset += 3; break; default: throw new IllegalArgumentException(); } charCount++; } return charCount; } /** * Converts byte arrays into character arrays. * * @param bytes the source byte data to convert * * @param byteOffset the offset into the byte array at which * to start the conversion * * @param chars the destination array * * @param charOffset the offset into chars at which to begin the copy * * @param len the amount of information to copy into chars * * @param isByteLen if true then len is a measure of bytes, otherwise * len is a measure of characters * * @throws IndexOutOfBoundsException if a UTF character sequence at the end * of the data is not complete. * * @throws IllegalArgumentException if an illegal UTF sequence is * encountered. */ public static int bytesToChars(byte[] bytes, int byteOffset, char[] chars, int charOffset, int len, boolean isByteLen) throws IllegalArgumentException, IndexOutOfBoundsException { int char1, char2, char3; len += isByteLen ? byteOffset : charOffset; while ((isByteLen ? byteOffset : charOffset) < len) { char1 = bytes[byteOffset++] & 0xff; switch ((char1 & 0xff) >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: chars[charOffset++] = (char) char1; break; case 12: case 13: char2 = bytes[byteOffset++]; if ((char2 & 0xC0) != 0x80) { throw new IllegalArgumentException(); } chars[charOffset++] = (char)(((char1 & 0x1F) << 6) | (char2 & 0x3F)); break; case 14: char2 = bytes[byteOffset++]; char3 = bytes[byteOffset++]; if (((char2 & 0xC0) != 0x80) || ((char3 & 0xC0) != 0x80)) throw new IllegalArgumentException(); chars[charOffset++] = (char)(((char1 & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0)); break; default: throw new IllegalArgumentException(); } } return byteOffset; } /** * Converts character arrays into byte arrays. * * @param chars the source character data to convert * * @param charOffset the offset into the character array at which * to start the conversion * * @param bytes the destination array * * @param byteOffset the offset into bytes at which to begin the copy * * @param charLength the length of characters to copy into bytes */ public static void charsToBytes(char[] chars, int charOffset, byte[] bytes, int byteOffset, int charLength) { charLength += charOffset; for (int i = charOffset; i < charLength; i++) { int c = chars[i]; if ((c >= 0x0001) && (c <= 0x007F)) { bytes[byteOffset++] = (byte) c; } else if (c > 0x07FF) { bytes[byteOffset++] = (byte) (0xE0 | ((c >> 12) & 0x0F)); bytes[byteOffset++] = (byte) (0x80 | ((c >> 6) & 0x3F)); bytes[byteOffset++] = (byte) (0x80 | ((c >> 0) & 0x3F)); } else { bytes[byteOffset++] = (byte) (0xC0 | ((c >> 6) & 0x1F)); bytes[byteOffset++] = (byte) (0x80 | ((c >> 0) & 0x3F)); } } } /** * Converts byte arrays into strings. * * @param bytes the source byte data to convert * * @param offset the offset into the byte array at which * to start the conversion * * @param length the number of bytes to be converted. * * @return the string. * * @throws IndexOutOfBoundsException if a UTF character sequence at the end * of the data is not complete. * * @throws IllegalArgumentException if an illegal UTF sequence is * encountered. */ public static String bytesToString(byte[] bytes, int offset, int length) throws IllegalArgumentException, IndexOutOfBoundsException { if (length == 0) return EMPTY_STRING; int charLen = UtfOps.getCharLength(bytes, offset, length); char[] chars = new char[charLen]; UtfOps.bytesToChars(bytes, offset, chars, 0, length, true); return new String(chars, 0, charLen); } /** * Converts strings to byte arrays. * * @param string the string to convert. * * @return the UTF byte array. */ public static byte[] stringToBytes(String string) { if (string.length() == 0) return EMPTY_BYTES; char[] chars = string.toCharArray(); byte[] bytes = new byte[UtfOps.getByteLength(chars)]; UtfOps.charsToBytes(chars, 0, bytes, 0, chars.length); return bytes; } }