/*
* Copyright (c) 1995, 2003, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 in the LICENSE file that
* accompanied this code).
*
* 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
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*/
package sun.tools.java;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.FilterReader;
import java.io.UnsupportedEncodingException;
/**
* An input stream for java programs. The stream treats either "\n", "\r"
* or "\r\n" as the end of a line, it always returns \n. It also parses
* UNICODE characters expressed as \uffff. However, if it sees "\\", the
* second slash cannot begin a unicode sequence. It keeps track of the current
* position in the input stream.
*
* WARNING: The contents of this source file are not part of any
* supported API. Code that depends on them does so at its own risk:
* they are subject to change or removal without notice.
*
* @author Arthur van Hoff
*/
public
class ScannerInputReader extends FilterReader implements Constants {
// A note. This class does not really properly subclass FilterReader.
// Since this class only overrides the single character read method,
// and not the multi-character read method, any use of the latter
// will not work properly. Any attempt to use this code outside of
// the compiler should take that into account.
//
// For efficiency, it might be worth moving this code to Scanner and
// getting rid of this class.
Environment env;
long pos;
private long chpos;
private int pushBack = -1;
public ScannerInputReader(Environment env, InputStream in)
throws UnsupportedEncodingException
{
// ScannerInputStream has been modified to no longer use
// BufferedReader. It now does its own buffering for
// performance.
super(env.getCharacterEncoding() != null ?
new InputStreamReader(in, env.getCharacterEncoding()) :
new InputStreamReader(in));
// Start out the buffer empty.
currentIndex = 0;
numChars = 0;
this.env = env;
chpos = Scanner.LINEINC;
}
//------------------------------------------------------------
// Buffering code.
// The size of our buffer.
private static final int BUFFERLEN = 10 * 1024;
// A character buffer.
private final char[] buffer = new char[BUFFERLEN];
// The index of the next character to be "read" from the buffer.
private int currentIndex;
// The number of characters in the buffer. -1 if EOF is reached.
private int numChars;
/**
* Get the next character from our buffer.
* Note: this method has been inlined by hand in the `read' method
* below. Any changes made to this method should be equally applied
* to that code.
*/
private int getNextChar() throws IOException {
// Check to see if we have either run out of characters in our
// buffer or gotten to EOF on a previous call.
if (currentIndex >= numChars) {
numChars = in.read(buffer);
if (numChars == -1) {
// We have reached EOF.
return -1;
}
// No EOF. currentIndex points to first char in buffer.
currentIndex = 0;
}
return buffer[currentIndex++];
}
//------------------------------------------------------------
public int read(char[] buffer, int off, int len) {
throw new CompilerError(
"ScannerInputReader is not a fully implemented reader.");
}
public int read() throws IOException {
pos = chpos;
chpos += Scanner.OFFSETINC;
int c = pushBack;
if (c == -1) {
getchar: try {
// Here the call...
// c = getNextChar();
// has been inlined by hand for performance.
if (currentIndex >= numChars) {
numChars = in.read(buffer);
if (numChars == -1) {
// We have reached EOF.
c = -1;
break getchar;
}
// No EOF. currentIndex points to first char in buffer.
currentIndex = 0;
}
c = buffer[currentIndex++];
} catch (java.io.CharConversionException e) {
env.error(pos, "invalid.encoding.char");
// this is fatal error
return -1;
}
} else {
pushBack = -1;
}
// parse special characters
switch (c) {
case -2:
// -2 is a special code indicating a pushback of a backslash that
// definitely isn't the start of a unicode sequence.
return '\\';
case '\\':
if ((c = getNextChar()) != 'u') {
pushBack = (c == '\\' ? -2 : c);
return '\\';
}
// we have a unicode sequence
chpos += Scanner.OFFSETINC;
while ((c = getNextChar()) == 'u') {
chpos += Scanner.OFFSETINC;
}
// unicode escape sequence
int d = 0;
for (int i = 0 ; i < 4 ; i++, chpos += Scanner.OFFSETINC, c = getNextChar()) {
switch (c) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
d = (d << 4) + c - '0';
break;
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
d = (d << 4) + 10 + c - 'a';
break;
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
d = (d << 4) + 10 + c - 'A';
break;
default:
env.error(pos, "invalid.escape.char");
pushBack = c;
return d;
}
}
pushBack = c;
// To read the following line, switch \ and /...
// Handle /u000a, /u000A, /u000d, /u000D properly as
// line terminators as per JLS 3.4, even though they are encoded
// (this properly respects the order given in JLS 3.2).
switch (d) {
case '\n':
chpos += Scanner.LINEINC;
return '\n';
case '\r':
if ((c = getNextChar()) != '\n') {
pushBack = c;
} else {
chpos += Scanner.OFFSETINC;
}
chpos += Scanner.LINEINC;
return '\n';
default:
return d;
}
case '\n':
chpos += Scanner.LINEINC;
return '\n';
case '\r':
if ((c = getNextChar()) != '\n') {
pushBack = c;
} else {
chpos += Scanner.OFFSETINC;
}
chpos += Scanner.LINEINC;
return '\n';
default:
return c;
}
}
}