/*******************************************************************************
* Copyright (c) 2002 - 2006 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package com.ibm.wala.util.strings;
import java.io.UTFDataFormatException;
import com.ibm.wala.util.debug.Assertions;
/**
* Abstract class that contains conversion routines to/from utf8 and/or pseudo-utf8. It does not support utf8 encodings of more than
* 3 bytes.
*
* The difference between utf8 and pseudo-utf8 is the special treatment of null. In utf8, null is encoded as a single byte directly,
* whereas in pseudo-utf8, it is encoded as a two-byte sequence. See the JVM spec for more information.
*/
public abstract class UTF8Convert {
/**
* Strictly check the format of the utf8/pseudo-utf8 byte array in fromUTF8.
*/
static final boolean STRICTLY_CHECK_FORMAT = false;
/**
* Set fromUTF8 to not throw an exception when given a normal utf8 byte array.
*/
static final boolean ALLOW_NORMAL_UTF8 = false;
/**
* Set fromUTF8 to not throw an exception when given a pseudo utf8 byte array.
*/
static final boolean ALLOW_PSEUDO_UTF8 = true;
/**
* Set toUTF8 to write in pseudo-utf8 (rather than normal utf8).
*/
static final boolean WRITE_PSEUDO_UTF8 = true;
/**
* Convert the given sequence of (pseudo-)utf8 formatted bytes into a String.
*
* The acceptable input formats are controlled by the STRICTLY_CHECK_FORMAT, ALLOW_NORMAL_UTF8, and ALLOW_PSEUDO_UTF8 flags.
*
* @param utf8 (pseudo-)utf8 byte array
* @throws UTFDataFormatException if the (pseudo-)utf8 byte array is not valid (pseudo-)utf8
* @returns unicode string
* @throws IllegalArgumentException if utf8 is null
*/
public static String fromUTF8(byte[] utf8) throws UTFDataFormatException {
if (utf8 == null) {
throw new IllegalArgumentException("utf8 is null");
}
char[] result = new char[utf8.length];
int result_index = 0;
for (int i = 0, n = utf8.length; i < n;) {
byte b = utf8[i++];
if (STRICTLY_CHECK_FORMAT && !ALLOW_NORMAL_UTF8)
if (b == 0)
throw new UTFDataFormatException("0 byte encountered at location " + (i - 1));
if (b >= 0) { // < 0x80 unsigned
// in the range '\001' to '\177'
result[result_index++] = (char) b;
continue;
}
try {
byte nb = utf8[i++];
if (b < -32) { // < 0xe0 unsigned
// '\000' or in the range '\200' to '\u07FF'
char c = result[result_index++] = (char) (((b & 0x1f) << 6) | (nb & 0x3f));
if (STRICTLY_CHECK_FORMAT) {
if (((b & 0xe0) != 0xc0) || ((nb & 0xc0) != 0x80))
throw new UTFDataFormatException("invalid marker bits for double byte char at location " + (i - 2));
if (c < '\200') {
if (!ALLOW_PSEUDO_UTF8 || (c != '\000'))
throw new UTFDataFormatException("encountered double byte char that should have been single byte at location "
+ (i - 2));
} else if (c > '\u07FF')
throw new UTFDataFormatException("encountered double byte char that should have been triple byte at location "
+ (i - 2));
}
} else {
byte nnb = utf8[i++];
// in the range '\u0800' to '\uFFFF'
char c = result[result_index++] = (char) (((b & 0x0f) << 12) | ((nb & 0x3f) << 6) | (nnb & 0x3f));
if (STRICTLY_CHECK_FORMAT) {
if (((b & 0xf0) != 0xe0) || ((nb & 0xc0) != 0x80) || ((nnb & 0xc0) != 0x80))
throw new UTFDataFormatException("invalid marker bits for triple byte char at location " + (i - 3));
if (c < '\u0800')
throw new UTFDataFormatException("encountered triple byte char that should have been fewer bytes at location "
+ (i - 3));
}
}
} catch (ArrayIndexOutOfBoundsException e) {
throw new UTFDataFormatException("unexpected end at location " + i);
}
}
return new String(result, 0, result_index);
}
/**
* Convert the given String into a sequence of (pseudo-)utf8 formatted bytes.
*
* The output format is controlled by the WRITE_PSEUDO_UTF8 flag.
*
* @param s String to convert
* @returns array containing sequence of (pseudo-)utf8 formatted bytes
* @throws IllegalArgumentException if s is null
*/
public static byte[] toUTF8(String s) {
if (s == null) {
throw new IllegalArgumentException("s is null");
}
byte[] result = new byte[utfLength(s)];
int result_index = 0;
for (int i = 0, n = s.length(); i < n; ++i) {
char c = s.charAt(i);
// in all shifts below, c is an (unsigned) char,
// so either >>> or >> is ok
if (((!WRITE_PSEUDO_UTF8) || (c >= 0x0001)) && (c <= 0x007F))
result[result_index++] = (byte) c;
else if (c > 0x07FF) {
result[result_index++] = (byte) (0xe0 | (byte) (c >> 12));
result[result_index++] = (byte) (0x80 | ((c & 0xfc0) >> 6));
result[result_index++] = (byte) (0x80 | (c & 0x3f));
} else {
result[result_index++] = (byte) (0xc0 | (byte) (c >> 6));
result[result_index++] = (byte) (0x80 | (c & 0x3f));
}
}
return result;
}
/**
* Returns the length of a string's UTF encoded form.
*
* @throws IllegalArgumentException if s is null
*/
public static int utfLength(String s) {
if (s == null) {
throw new IllegalArgumentException("s is null");
}
int utflen = 0;
for (int i = 0, n = s.length(); i < n; ++i) {
int c = s.charAt(i);
if (((!WRITE_PSEUDO_UTF8) || (c >= 0x0001)) && (c <= 0x007F))
++utflen;
else if (c > 0x07FF)
utflen += 3;
else
utflen += 2;
}
return utflen;
}
/**
* Check whether the given sequence of bytes is valid (pseudo-)utf8.
*
* @param bytes byte array to check
* @returns true iff the given sequence is valid (pseudo-)utf8.
* @throws IllegalArgumentException if bytes is null
*/
public static boolean check(byte[] bytes) {
if (bytes == null) {
throw new IllegalArgumentException("bytes is null");
}
for (int i = 0, n = bytes.length; i < n;) {
byte b = bytes[i++];
if (!ALLOW_NORMAL_UTF8)
if (b == 0)
return false;
if (b >= 0) { // < 0x80 unsigned
// in the range '\001' to '\177'
continue;
}
try {
byte nb = bytes[i++];
if (b < -32) { // < 0xe0 unsigned
// '\000' or in the range '\200' to '\u07FF'
char c = (char) (((b & 0x1f) << 6) | (nb & 0x3f));
if (((b & 0xe0) != 0xc0) || ((nb & 0xc0) != 0x80))
return false;
if (c < '\200') {
if (!ALLOW_PSEUDO_UTF8 || (c != '\000'))
return false;
} else if (c > '\u07FF')
return false;
} else {
byte nnb = bytes[i++];
// in the range '\u0800' to '\uFFFF'
char c = (char) (((b & 0x0f) << 12) | ((nb & 0x3f) << 6) | (nnb & 0x3f));
if (((b & 0xf0) != 0xe0) || ((nb & 0xc0) != 0x80) || ((nnb & 0xc0) != 0x80))
return false;
if (c < '\u0800')
return false;
}
} catch (ArrayIndexOutOfBoundsException e) {
return false;
}
}
return true;
}
public static String fromUTF8(ImmutableByteArray s) {
if (s == null) {
throw new IllegalArgumentException("s is null");
}
try {
return fromUTF8(s.b);
} catch (UTFDataFormatException e) {
e.printStackTrace();
Assertions.UNREACHABLE();
return null;
}
}
}