/*
*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package com.sun.cldc.i18n;
import java.io.*;
/**
* This class provides general helper functions for the J2ME environment.
* <p>
* <em>No application code should reference this class directly.</em>
*
* @version 2.1M 10/30/01
*/
public class Helper {
/**
* The name of the default character encoding
*/
private static String defaultEncoding;
/**
* Default path to the J2ME classes
*/
private static String defaultMEPath;
/**
* Class initializer
*/
static {
/* Get the default encoding name */
defaultEncoding = System.getProperty("microedition.encoding");
if (defaultEncoding == null) {
defaultEncoding = "ISO8859_1";
}
/* Get the default encoding name */
defaultMEPath = System.getProperty("com.sun.cldc.i18n.Helper.i18npath");
if (defaultMEPath == null) {
defaultMEPath = "com.sun.cldc.i18n.j2me";
}
}
/*------------------------------------------------------------------------------*/
/* Character encoding */
/*------------------------------------------------------------------------------*/
/**
* Get a reader for an InputStream
*
* @param is The input stream the reader is for
* @return A new reader for the stream
*/
public static Reader getStreamReader(InputStream is) {
try {
return getStreamReader(is, defaultEncoding);
} catch(UnsupportedEncodingException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "Missing default encoding "+defaultEncoding
/* #endif */
);
}
}
/**
* Get a reader for an InputStream
*
* @param is The input stream the reader is for
* @param name The name of the decoder
* @return A new reader for the stream
* @exception UnsupportedEncodingException If the encoding is not known
*/
public static Reader getStreamReader(InputStream is, String name) throws UnsupportedEncodingException {
/* Test for null arguments */
if(is == null || name == null) {
throw new NullPointerException();
}
/* Get the reader from the encoding */
StreamReader fr = getStreamReaderPrim(name);
/* Open the connection and return*/
return fr.open(is, name);
}
/**
* Get a reader for an InputStream
*
* @param is The input stream the reader is for
* @param name The name of the decoder
* @return A new reader for the stream
* @exception UnsupportedEncodingException If the encoding is not known
*/
private static StreamReader getStreamReaderPrim(String name) throws UnsupportedEncodingException {
try {
return (StreamReader)getStreamReaderOrWriter(name, "_Reader");
} catch(ClassCastException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "ClassCastException "+x.getMessage()
/* #endif */
);
}
}
private static Object getStreamReaderOrWriter(String name, String suffix)
throws UnsupportedEncodingException {
if (name == null) {
throw new NullPointerException();
}
name = internalNameForEncoding(name);
try {
String className;
/* Get the reader class name */
className = defaultMEPath + '.' + name + suffix;
/* Using the decoder names lookup a class to implement the reader */
Class clazz = Class.forName(className);
/* Return a new instance */
return clazz.newInstance();
} catch(ClassNotFoundException x) {
throw new UnsupportedEncodingException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "Encoding "+name+" not found"
/* #endif */
);
} catch(InstantiationException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "InstantiationException "+x.getMessage()
/* #endif */
);
} catch(IllegalAccessException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "IllegalAccessException "+x.getMessage()
/* #endif */
);
}
}
/**
* Get a writer for an OutputStream
*
* @param os The output stream the reader is for
* @return A new writer for the stream
*/
public static Writer getStreamWriter(OutputStream os) {
try {
return getStreamWriter(os, defaultEncoding);
} catch(UnsupportedEncodingException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "Missing default encoding "+defaultEncoding
/* #endif */
);
}
}
/**
* Get a writer for an OutputStream
*
* @param os The output stream the reader is for
* @param name The name of the decoder
* @return A new writer for the stream
* @exception UnsupportedEncodingException If the encoding is not known
*/
public static Writer getStreamWriter(OutputStream os, String name) throws UnsupportedEncodingException {
/* Test for null arguments */
if(os == null || name == null) {
throw new NullPointerException();
}
/* Get the writer from the encoding */
StreamWriter sw = getStreamWriterPrim(name);
/* Open it on the output stream and return */
return sw.open(os, name);
}
/**
* Get a writer for an OutputStream
*
* @param os The output stream the reader is for
* @param name The name of the decoder
* @return A new writer for the stream
* @exception UnsupportedEncodingException If the encoding is not known
*/
private static StreamWriter getStreamWriterPrim(String name) throws UnsupportedEncodingException {
try {
return (StreamWriter)getStreamReaderOrWriter(name, "_Writer");
} catch(ClassCastException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "ClassCastException "+x.getMessage()
/* #endif */
);
}
}
/**
* Convert a byte array to a char array
*
* @param buffer The byte array buffer
* @param offset The offset
* @param length The length
* @return A new char array
*/
public static char[] byteToCharArray(byte[] buffer, int offset, int length) {
try {
return byteToCharArray(buffer, offset, length, defaultEncoding);
} catch(UnsupportedEncodingException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "Missing default encoding "+defaultEncoding
/* #endif */
);
}
}
/**
* Convert a char array to a byte array
*
* @param buffer The char array buffer
* @param offset The offset
* @param length The length
* @return A new byte array
*/
public static byte[] charToByteArray(char[] buffer, int offset, int length) {
try {
return charToByteArray(buffer, offset, length, defaultEncoding);
} catch(UnsupportedEncodingException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "Missing default encoding "+defaultEncoding
/* #endif */
);
}
}
/*
* Cached variables for byteToCharArray
*/
private static String lastReaderEncoding;
private static StreamReader lastReader;
/**
* Convert a byte array to a char array
*
* @param buffer The byte array buffer
* @param offset The offset
* @param length The length
* @param enc The character encoding
* @return A new char array
* @exception UnsupportedEncodingException If the encoding is not known
*/
public static synchronized char[] byteToCharArray(byte[] buffer, int offset, int length, String enc) throws UnsupportedEncodingException {
if (offset < 0) {
throw new IndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped Integer.toString(offset)
/* #endif */
);
}
if (length < 0) {
throw new IndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped Integer.toString(length)
/* #endif */
);
}
// Note: offset or length might be near -1>>>1.
if (offset > buffer.length - length) {
throw new IndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped Integer.toString(offset + length)
/* #endif */
);
}
//Because most cases use ISO8859_1 encoding, we can optimize this case.
if(enc.compareTo("ISO8859_1") == 0) {
char[] value = new char[length];
for(int i=0; i<length; i++) {
value[i] = (char)(buffer[i+offset] & 0xff);
}
return value;
}
/* If we don't have a cached reader then make one */
if (lastReaderEncoding == null || !lastReaderEncoding.equals(enc)) {
lastReader = getStreamReaderPrim(enc);
lastReaderEncoding = enc;
}
/* Ask the reader for the size the output will be */
int size = lastReader.sizeOf(buffer, offset, length);
/* Allocate a buffer of that size */
char[] outbuf = new char[size];
/* Open the reader on a ByteArrayInputStream */
lastReader.open(new ByteArrayInputStream(buffer, offset, length), enc);
try {
/* Read the input */
int numread = lastReader.read(outbuf, 0, size);
if (numread<size) {
// this may happen only if the last character is truncated
// (say, it should be of 3 bytes, but there are only 2).
lastReader.read(outbuf, numread, size-numread);
}
/* Close the reader */
lastReader.close();
} catch(IOException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "IOException reading reader "+x.getMessage()
/* #endif */
);
}
/* And return the buffer */
return outbuf;
}
/*
* Cached variables for charToByteArray
*/
private static String lastWriterEncoding;
private static StreamWriter lastWriter;
/**
* Convert a char array to a byte array
*
* @param buffer The char array buffer
* @param offset The offset
* @param length The length
* @param enc The character encoding
* @return A new byte array
* @exception UnsupportedEncodingException If the encoding is not known
*/
public static synchronized byte[] charToByteArray(char[] buffer, int offset, int length, String enc) throws UnsupportedEncodingException {
//Because most cases use ISO8859_1 encoding, we can optimize this case.
if(enc.compareTo("ISO8859_1") == 0) {
char c;
byte[] value = new byte[length];
for(int i=0; i<length; i++) {
c = buffer[i+offset];
value[i] = (c <= 255) ? (byte)c : (byte)'?';
}
return value;
}
/* If we don't have a cached writer then make one */
if(lastWriterEncoding == null || !lastWriterEncoding.equals(enc)) {
lastWriter = getStreamWriterPrim(enc);
lastWriterEncoding = enc;
}
/* Ask the writer for the size the output will be */
int size = lastWriter.sizeOf(buffer, offset, length);
/* Get the output stream */
ByteArrayOutputStream os = new ByteArrayOutputStream(size);
/* Open the writer */
lastWriter.open(os, enc);
try {
/* Convert */
lastWriter.write(buffer, offset, length);
/* Close the writer */
lastWriter.close();
} catch(IOException x) {
throw new RuntimeException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "IOException writing writer "+x.getMessage()
/* #endif */
);
}
/* Close the output stream */
try {
os.close();
} catch(IOException x) {};
/* Return the array */
return os.toByteArray();
}
/**
* Get the internal name for an encoding.
*
* @param encodingName encoding name
*
* @return internal name for this encoding
*/
private static String internalNameForEncoding(String encodingName) {
String internalName;
String property;
internalName = normalizeEncodingName(encodingName);
// The preferred MIME name according to the IANA Charset Registry.
if (internalName.equals("US_ASCII")) {
/*
* US-ASCII is subclass of ISO-8859-1 so we do not need a
* separate reader for it.
*/
return "ISO8859_1";
}
// The preferred MIME name according to the IANA Charset Registry.
if (internalName.equals("ISO_8859_1")) {
return "ISO8859_1";
}
/*
* Since IANA character encoding names can start with a digit
* and that some Reader class names that do not match the standard
* name, we have a way to configure alternate names for encodings.
*
* Note: The names must normalized, digits, upper case only with "_"
* and "_" substituted for ":" and "-".
*/
property = System.getProperty(internalName + "_InternalEncodingName");
if (property != null) {
return property;
}
return internalName;
}
/**
* Converts "-" and ":" in a string to "_" and converts the name
* to upper case.
* This is needed because the names of IANA character encodings have
* characters that are not allowed for java class names and
* IANA encoding names are not case sensitive.
*
* @param encodingName encoding name
*
* @return normalized name
*/
private static String normalizeEncodingName(String encodingName) {
StringBuffer normalizedName ;
char currentChar;
normalizedName = new StringBuffer(encodingName);
for (int i = 0; i < normalizedName.length(); i++) {
currentChar = normalizedName.charAt(i);
if (currentChar == '-' || currentChar == ':') {
normalizedName.setCharAt(i, '_');
} else {
normalizedName.setCharAt(i, Character.toUpperCase(currentChar));
}
}
return normalizedName.toString();
}
}
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