/*
* )
*
* 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.j2me;
import java.io.*;
import com.sun.cldc.i18n.*;
/**
* Generic interface for stream conversion reading of
* specific character encoded input streams.
*/
public class Gen_Reader extends StreamReader {
/** Saved encoding string from construction. */
private String enc;
/** Native handle for conversion routines. */
private int id;
/** Local buffer to read converted characters. */
private byte[] buf;
/** Maximum length of characters in local buffer. */
private int maxByteLen;
/**
* Constructor for generic reader.
* @param inp_enc character encoding to use for byte to character
* conversion.
* @exception ClassNotFoundException is thrown if the conversion
* class is not available
*/
Gen_Reader(String inp_enc) throws ClassNotFoundException {
id = Conv.getHandler(inp_enc);
if (id == -1) {
// this lets Helper throw UnsupportedEncodingException
throw new ClassNotFoundException();
}
enc = inp_enc;
maxByteLen = Conv.getMaxByteLength(id);
pos = maxByteLen;
tmp = new byte[pos];
buf = new byte[pos];
}
/**
* Generic routine to open an InputStream with a specific
* character encoding.
*
* @param in the input stream to process
* @param open_enc the character encoding of the input stream
* @return Reader instance for converted characters
* @throws UnsupportedEncodingException if encoding is not supported
*/
public Reader open(InputStream in, String open_enc)
throws UnsupportedEncodingException {
if (!open_enc.equals(enc)) {
throw new UnsupportedEncodingException();
}
init();
return super.open(in, open_enc);
}
/**
* Read a single converted character.
*
* @return a single converted character
* @exception IOException is thrown if the input stream
* could not be read for the raw unconverted character
*/
synchronized public int read() throws IOException {
int c = get();
if (c == -1) {
return -1;
}
char[] cb = {(char)0xFFFD};
int bufLen = 0;
buf[bufLen++] = (byte) c;
boolean eof = false;
for (int i = 1; i < maxByteLen; i++) {
c = get();
if (c == -1) {
eof = true;
break;
}
buf[bufLen++] = (byte) c;
}
int bytelen = Conv.getByteLength(id, buf, 0, bufLen);
/* the byte indicates that there are tailing bytes */
if (bytelen == -1) {
/* if the stream is in the end, throw IOException */
if (eof) {
throw new IOException(/* "incomplete byte" */);
}
/* put the read ahead bytes back to the stream */
for (int i = bufLen; i > 1; i--) {
put(buf[--bufLen]);
}
/* return the leading byte as an unknown character */
return cb[0];
}
/* the byte is invalid */
if (bytelen == 0) {
for (int i = bufLen; i > 1; i--) {
put(buf[--bufLen]);
}
return cb[0];
}
/* put the read ahead bytes back to the stream */
if (bytelen < bufLen) {
for (int i = bufLen; i > bytelen; i--) {
put(buf[--bufLen]);
}
}
int convLen = Conv.byteToChar(id, buf, 0, bufLen, cb, 0, 1);
if (convLen != 1) {
throw new IOException(/* "Converter error" */);
}
return cb[0];
}
/**
* Read a block of converted characters.
*
* @param cbuf output buffer for converted characters read
* @param off initial offset into the provided buffer
* @param len length of characters in the buffer
* @return the number of converted characters, or -1
* if an error occurred in the input arguments
* @exception IOException is thrown if the input stream
* could not be read for the raw unconverted character
*/
synchronized public int read(char cbuf[], int off, int len)
throws IOException {
/* first, check that the stream has been reached to eof */
int c = get();
if (c == -1) {
return -1;
}
put(c); /* put it back */
int maxlen = len * maxByteLen;
if (buf.length < maxlen) {
buf = new byte[maxlen];
}
int bufLen = readNumOfChars(buf, len);
int ret = 0;
if (bufLen > 0) {
ret = Conv.byteToChar(id, buf, 0, bufLen, cbuf, off, len);
}
if (buf.length > maxByteLen) {
buf = new byte[maxByteLen];
}
return ret;
}
/**
* Skip over a number of bytes in the input stream.
*
* @param n number of bytes to bypass from the input stream.
* @return the number of characters skipped
* @throws IOException if an I/O error occurs
*/
public long skip(long n) throws IOException {
if (n < 0L) {
throw new IllegalArgumentException("skip value is negative");
}
/* see the stream has been reached to eof */
int c = get();
if (c == -1) {
return 0;
}
put(c);
return readNumOfChars(null, (int) n);
}
/**
* Get the size of the converted bytes as a Unicode
* byte array.
*
* @param c array of bytes to compute size
* @param offset offset in the provided buffer
* @param length length of bytes to process
* @return length of converted characters.
*/
public int sizeOf(byte[] c, int offset, int length) {
return Conv.sizeOfByteInUnicode(id, c, offset, length);
}
/**
* Reset the stream.
*
* @exception IOException If an I/O error occurs
*/
public void reset() throws IOException {
init();
}
/**
* Read a specific number of characters from the
* input stream.
*
* @param b array of bytes to read
* @param num count of bytes to read
* @return number of characters read
* @exception IOException is thrown, if an error occurred
* reading the raw input stream
*/
private int readNumOfChars(byte[] b, int num) throws IOException {
int charsRead = 0;
int bbLen = 0;
byte bb[];
if (b == null) {
bb = new byte[num * maxByteLen];
} else {
bb = b;
}
boolean eof = false;
while (charsRead < num) {
int c = get();
if (c == -1) {
break;
}
int offset = bbLen;
bb[bbLen++] = (byte) c;
for (int i = 1; i < maxByteLen; i++) {
c = get();
if (c == -1) {
eof = true;
break;
}
bb[bbLen++] = (byte) c;
}
int readNum = bbLen - offset;
int bytelen = Conv.getByteLength(id, bb, offset, readNum);
/* the byte indicates that there are tailing bytes */
if (bytelen == -1) {
/* save the leading byte for the next read */
if (eof) {
for (int i = readNum; i > 0; i--) {
put(bb[--bbLen]);
}
break;
}
/* put the rest of bytes back into the stream */
for (int i = readNum; i > 1; i--) {
put(bb[--bbLen]);
}
/* the byte is invalid */
} else if (bytelen == 0) {
for (int i = readNum; i > 1; i--) {
put(bb[--bbLen]);
}
} else if (bytelen < readNum) {
for (int i = readNum; i > bytelen; i--) {
put(bb[--bbLen]);
}
}
charsRead++;
}
if (b != null) {
return bbLen;
} else {
return charsRead;
}
}
/** Local buffer for conversion routines. */
private byte[] tmp;
/** Current position in the temporary buffer. */
private int pos;
/**
* Get a byte from the temporary buffer or from the
* input stream.
* @return the next byte from the input stream or local buffer
* @exception IOException is thrown, if an error occurred
* reading the raw input stream
*/
private int get() throws IOException {
if (pos < tmp.length) {
return tmp[pos++] & 0xff;
}
return in.read();
}
/**
* Put a byte back into the temporary buffer.
* @param b the character to put back in the temporary buffer
* @exception IOException is thrown, if putting a character back
* past the beginning of the local temporary buffer
*/
private void put(int b) throws IOException {
if (pos == 0) {
throw new IOException();
}
tmp[--pos] = (byte) b;
}
/** reset the state */
private void init() {
pos = maxByteLen;
}
}
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