Java example source code file (Scanner.java)
The Scanner.java Java example source code/*
* Copyright (c) 1994, 2004, 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
* questions.
*/
package sun.tools.java;
import java.io.IOException;
import java.io.InputStream;
import java.util.Hashtable;
/**
* A Scanner for Java tokens. Errors are reported
* to the environment object.<p>
*
* The scanner keeps track of the current token,
* the value of the current token (if any), and the start
* position of the current token.<p>
*
* The scan() method advances the scanner to the next
* token in the input.<p>
*
* The match() method is used to quickly match opening
* brackets (ie: '(', '{', or '[') with their closing
* counter part. This is useful during error recovery.<p>
*
* An position consists of: ((linenr << WHEREOFFSETBITS) | offset)
* this means that both the line number and the exact offset into
* the file are encoded in each position value.<p>
*
* The compiler treats either "\n", "\r" or "\r\n" as the
* end of a line.<p>
*
* 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 Scanner implements Constants {
/**
* The increment for each character.
*/
public static final long OFFSETINC = 1;
/**
* The increment for each line.
*/
public static final long LINEINC = 1L << WHEREOFFSETBITS;
/**
* End of input
*/
public static final int EOF = -1;
/**
* Where errors are reported
*/
public Environment env;
/**
* Input reader
*/
protected ScannerInputReader in;
/**
* If true, present all comments as tokens.
* Contents are not saved, but positions are recorded accurately,
* so the comment can be recovered from the text.
* Line terminations are also returned as comment tokens,
* and may be distinguished by their start and end positions,
* which are equal (meaning, these tokens contain no chars).
*/
public boolean scanComments = false;
/**
* Current token
*/
public int token;
/**
* The position of the current token
*/
public long pos;
/**
* The position of the previous token
*/
public long prevPos;
/**
* The current character
*/
protected int ch;
/*
* Token values.
*/
public char charValue;
public int intValue;
public long longValue;
public float floatValue;
public double doubleValue;
public String stringValue;
public Identifier idValue;
public int radix; // Radix, when reading int or long
/*
* A doc comment preceding the most recent token
*/
public String docComment;
/*
* A growable character buffer.
*/
private int count;
private char buffer[] = new char[1024];
private void growBuffer() {
char newBuffer[] = new char[buffer.length * 2];
System.arraycopy(buffer, 0, newBuffer, 0, buffer.length);
buffer = newBuffer;
}
// The following two methods have been hand-inlined in
// scanDocComment. If you make changes here, you should
// check to see if scanDocComment also needs modification.
private void putc(int ch) {
if (count == buffer.length) {
growBuffer();
}
buffer[count++] = (char)ch;
}
private String bufferString() {
return new String(buffer, 0, count);
}
/**
* Create a scanner to scan an input stream.
*/
public Scanner(Environment env, InputStream in) throws IOException {
this.env = env;
useInputStream(in);
}
/**
* Setup input from the given input stream,
* and scan the first token from it.
*/
protected void useInputStream(InputStream in) throws IOException {
try {
this.in = new ScannerInputReader(env, in);
} catch (Exception e) {
env.setCharacterEncoding(null);
this.in = new ScannerInputReader(env, in);
}
ch = this.in.read();
prevPos = this.in.pos;
scan();
}
/**
* Create a scanner to scan an input stream.
*/
protected Scanner(Environment env) {
this.env = env;
// Expect the subclass to call useInputStream at the right time.
}
/**
* Define a keyword.
*/
private static void defineKeyword(int val) {
Identifier.lookup(opNames[val]).setType(val);
}
/**
* Initialized keyword and token Hashtables
*/
static {
// Statement keywords
defineKeyword(FOR);
defineKeyword(IF);
defineKeyword(ELSE);
defineKeyword(WHILE);
defineKeyword(DO);
defineKeyword(SWITCH);
defineKeyword(CASE);
defineKeyword(DEFAULT);
defineKeyword(BREAK);
defineKeyword(CONTINUE);
defineKeyword(RETURN);
defineKeyword(TRY);
defineKeyword(CATCH);
defineKeyword(FINALLY);
defineKeyword(THROW);
// Type defineKeywords
defineKeyword(BYTE);
defineKeyword(CHAR);
defineKeyword(SHORT);
defineKeyword(INT);
defineKeyword(LONG);
defineKeyword(FLOAT);
defineKeyword(DOUBLE);
defineKeyword(VOID);
defineKeyword(BOOLEAN);
// Expression keywords
defineKeyword(INSTANCEOF);
defineKeyword(TRUE);
defineKeyword(FALSE);
defineKeyword(NEW);
defineKeyword(THIS);
defineKeyword(SUPER);
defineKeyword(NULL);
// Declaration keywords
defineKeyword(IMPORT);
defineKeyword(CLASS);
defineKeyword(EXTENDS);
defineKeyword(IMPLEMENTS);
defineKeyword(INTERFACE);
defineKeyword(PACKAGE);
defineKeyword(THROWS);
// Modifier keywords
defineKeyword(PRIVATE);
defineKeyword(PUBLIC);
defineKeyword(PROTECTED);
defineKeyword(STATIC);
defineKeyword(TRANSIENT);
defineKeyword(SYNCHRONIZED);
defineKeyword(NATIVE);
defineKeyword(ABSTRACT);
defineKeyword(VOLATILE);
defineKeyword(FINAL);
defineKeyword(STRICTFP);
// reserved keywords
defineKeyword(CONST);
defineKeyword(GOTO);
}
/**
* Scan a comment. This method should be
* called once the initial /, * and the next
* character have been read.
*/
private void skipComment() throws IOException {
while (true) {
switch (ch) {
case EOF:
env.error(pos, "eof.in.comment");
return;
case '*':
if ((ch = in.read()) == '/') {
ch = in.read();
return;
}
break;
default:
ch = in.read();
break;
}
}
}
/**
* Scan a doc comment. This method should be called
* once the initial /, * and * have been read. It gathers
* the content of the comment (witout leading spaces and '*'s)
* in the string buffer.
*/
private String scanDocComment() throws IOException {
// Note: this method has been hand-optimized to yield
// better performance. This was done after it was noted
// that javadoc spent a great deal of its time here.
// This should also help the performance of the compiler
// as well -- it scans the doc comments to find
// @deprecated tags.
//
// The logic of the method has been completely rewritten
// to avoid the use of flags that need to be looked at
// for every character read. Members that are accessed
// more than once have been stored in local variables.
// The methods putc() and bufferString() have been
// inlined by hand. Extra cases have been added to
// switch statements to trick the compiler into generating
// a tableswitch instead of a lookupswitch.
//
// This implementation aims to preserve the previous
// behavior of this method.
int c;
// Put `in' in a local variable.
final ScannerInputReader in = this.in;
// We maintain the buffer locally rather than calling putc().
char[] buffer = this.buffer;
int count = 0;
// We are called pointing at the second star of the doc
// comment:
//
// Input: /** the rest of the comment ... */
// ^
//
// We rely on this in the code below.
// Consume any number of stars.
while ((c = in.read()) == '*')
;
// Is the comment of the form /**/, /***/, /****/, etc.?
if (c == '/') {
// Set ch and return
ch = in.read();
return "";
}
// Skip a newline on the first line of the comment.
if (c == '\n') {
c = in.read();
}
outerLoop:
// The outerLoop processes the doc comment, looping once
// for each line. For each line, it first strips off
// whitespace, then it consumes any stars, then it
// puts the rest of the line into our buffer.
while (true) {
// The wsLoop consumes whitespace from the beginning
// of each line.
wsLoop:
while (true) {
switch (c) {
case ' ':
case '\t':
// We could check for other forms of whitespace
// as well, but this is left as is for minimum
// disturbance of functionality.
//
// Just skip whitespace.
c = in.read();
break;
// We have added extra cases here to trick the
// compiler into using a tableswitch instead of
// a lookupswitch. They can be removed without
// a change in meaning.
case 10: case 11: case 12: case 13: case 14: case 15:
case 16: case 17: case 18: case 19: case 20: case 21:
case 22: case 23: case 24: case 25: case 26: case 27:
case 28: case 29: case 30: case 31:
default:
// We've seen something that isn't whitespace,
// jump out.
break wsLoop;
}
} // end wsLoop.
// Are there stars here? If so, consume them all
// and check for the end of comment.
if (c == '*') {
// Skip all of the stars...
do {
c = in.read();
} while (c == '*');
// ...then check for the closing slash.
if (c == '/') {
// We're done with the doc comment.
// Set ch and break out.
ch = in.read();
break outerLoop;
}
}
// The textLoop processes the rest of the characters
// on the line, adding them to our buffer.
textLoop:
while (true) {
switch (c) {
case EOF:
// We've seen a premature EOF. Break out
// of the loop.
env.error(pos, "eof.in.comment");
ch = EOF;
break outerLoop;
case '*':
// Is this just a star? Or is this the
// end of a comment?
c = in.read();
if (c == '/') {
// This is the end of the comment,
// set ch and return our buffer.
ch = in.read();
break outerLoop;
}
// This is just an ordinary star. Add it to
// the buffer.
if (count == buffer.length) {
growBuffer();
buffer = this.buffer;
}
buffer[count++] = '*';
break;
case '\n':
// We've seen a newline. Add it to our
// buffer and break out of this loop,
// starting fresh on a new line.
if (count == buffer.length) {
growBuffer();
buffer = this.buffer;
}
buffer[count++] = '\n';
c = in.read();
break textLoop;
// Again, the extra cases here are a trick
// to get the compiler to generate a tableswitch.
case 0: case 1: case 2: case 3: case 4: case 5:
case 6: case 7: case 8: case 11: case 12: case 13:
case 14: case 15: case 16: case 17: case 18: case 19:
case 20: case 21: case 22: case 23: case 24: case 25:
case 26: case 27: case 28: case 29: case 30: case 31:
case 32: case 33: case 34: case 35: case 36: case 37:
case 38: case 39: case 40:
default:
// Add the character to our buffer.
if (count == buffer.length) {
growBuffer();
buffer = this.buffer;
}
buffer[count++] = (char)c;
c = in.read();
break;
}
} // end textLoop
} // end outerLoop
// We have scanned our doc comment. It is stored in
// buffer. The previous implementation of scanDocComment
// stripped off all trailing spaces and stars from the comment.
// We will do this as well, so as to cause a minimum of
// disturbance. Is this what we want?
if (count > 0) {
int i = count - 1;
trailLoop:
while (i > -1) {
switch (buffer[i]) {
case ' ':
case '\t':
case '*':
i--;
break;
// And again, the extra cases here are a trick
// to get the compiler to generate a tableswitch.
case 0: case 1: case 2: case 3: case 4: case 5:
case 6: case 7: case 8: case 10: case 11: case 12:
case 13: case 14: case 15: case 16: case 17: case 18:
case 19: case 20: case 21: case 22: case 23: case 24:
case 25: case 26: case 27: case 28: case 29: case 30:
case 31: case 33: case 34: case 35: case 36: case 37:
case 38: case 39: case 40:
default:
break trailLoop;
}
}
count = i + 1;
// Return the text of the doc comment.
return new String(buffer, 0, count);
} else {
return "";
}
}
/**
* Scan a number. The first digit of the number should be the current
* character. We may be scanning hex, decimal, or octal at this point
*/
private void scanNumber() throws IOException {
boolean seenNonOctal = false;
boolean overflow = false;
boolean seenDigit = false; // used to detect invalid hex number 0xL
radix = (ch == '0' ? 8 : 10);
long value = ch - '0';
count = 0;
putc(ch); // save character in buffer
numberLoop:
for (;;) {
switch (ch = in.read()) {
case '.':
if (radix == 16)
break numberLoop; // an illegal character
scanReal();
return;
case '8': case '9':
// We can't yet throw an error if reading an octal. We might
// discover we're really reading a real.
seenNonOctal = true;
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
seenDigit = true;
putc(ch);
if (radix == 10) {
overflow = overflow || (value * 10)/10 != value;
value = (value * 10) + (ch - '0');
overflow = overflow || (value - 1 < -1);
} else if (radix == 8) {
overflow = overflow || (value >>> 61) != 0;
value = (value << 3) + (ch - '0');
} else {
overflow = overflow || (value >>> 60) != 0;
value = (value << 4) + (ch - '0');
}
break;
case 'd': case 'D': case 'e': case 'E': case 'f': case 'F':
if (radix != 16) {
scanReal();
return;
}
// fall through
case 'a': case 'A': case 'b': case 'B': case 'c': case 'C':
seenDigit = true;
putc(ch);
if (radix != 16)
break numberLoop; // an illegal character
overflow = overflow || (value >>> 60) != 0;
value = (value << 4) + 10 +
Character.toLowerCase((char)ch) - 'a';
break;
case 'l': case 'L':
ch = in.read(); // skip over 'l'
longValue = value;
token = LONGVAL;
break numberLoop;
case 'x': case 'X':
// if the first character is a '0' and this is the second
// letter, then read in a hexadecimal number. Otherwise, error.
if (count == 1 && radix == 8) {
radix = 16;
seenDigit = false;
break;
} else {
// we'll get an illegal character error
break numberLoop;
}
default:
intValue = (int)value;
token = INTVAL;
break numberLoop;
}
} // while true
// We have just finished reading the number. The next thing better
// not be a letter or digit.
// Note: There will be deprecation warnings against these uses
// of Character.isJavaLetterOrDigit and Character.isJavaLetter.
// Do not fix them yet; allow the compiler to run on pre-JDK1.1 VMs.
if (Character.isJavaLetterOrDigit((char)ch) || ch == '.') {
env.error(in.pos, "invalid.number");
do { ch = in.read(); }
while (Character.isJavaLetterOrDigit((char)ch) || ch == '.');
intValue = 0;
token = INTVAL;
} else if (radix == 8 && seenNonOctal) {
// A bogus octal literal.
intValue = 0;
token = INTVAL;
env.error(pos, "invalid.octal.number");
} else if (radix == 16 && seenDigit == false) {
// A hex literal with no digits, 0xL, for example.
intValue = 0;
token = INTVAL;
env.error(pos, "invalid.hex.number");
} else {
if (token == INTVAL) {
// Check for overflow. Note that base 10 literals
// have different rules than base 8 and 16.
overflow = overflow ||
(value & 0xFFFFFFFF00000000L) != 0 ||
(radix == 10 && value > 2147483648L);
if (overflow) {
intValue = 0;
// Give a specific error message which tells
// the user the range.
switch (radix) {
case 8:
env.error(pos, "overflow.int.oct");
break;
case 10:
env.error(pos, "overflow.int.dec");
break;
case 16:
env.error(pos, "overflow.int.hex");
break;
default:
throw new CompilerError("invalid radix");
}
}
} else {
if (overflow) {
longValue = 0;
// Give a specific error message which tells
// the user the range.
switch (radix) {
case 8:
env.error(pos, "overflow.long.oct");
break;
case 10:
env.error(pos, "overflow.long.dec");
break;
case 16:
env.error(pos, "overflow.long.hex");
break;
default:
throw new CompilerError("invalid radix");
}
}
}
}
}
/**
* Scan a float. We are either looking at the decimal, or we have already
* seen it and put it into the buffer. We haven't seen an exponent.
* Scan a float. Should be called with the current character is either
* the 'e', 'E' or '.'
*/
private void scanReal() throws IOException {
boolean seenExponent = false;
boolean isSingleFloat = false;
char lastChar;
if (ch == '.') {
putc(ch);
ch = in.read();
}
numberLoop:
for ( ; ; ch = in.read()) {
switch (ch) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
putc(ch);
break;
case 'e': case 'E':
if (seenExponent)
break numberLoop; // we'll get a format error
putc(ch);
seenExponent = true;
break;
case '+': case '-':
lastChar = buffer[count - 1];
if (lastChar != 'e' && lastChar != 'E')
break numberLoop; // this isn't an error, though!
putc(ch);
break;
case 'f': case 'F':
ch = in.read(); // skip over 'f'
isSingleFloat = true;
break numberLoop;
case 'd': case 'D':
ch = in.read(); // skip over 'd'
// fall through
default:
break numberLoop;
} // sswitch
} // loop
// we have just finished reading the number. The next thing better
// not be a letter or digit.
if (Character.isJavaLetterOrDigit((char)ch) || ch == '.') {
env.error(in.pos, "invalid.number");
do { ch = in.read(); }
while (Character.isJavaLetterOrDigit((char)ch) || ch == '.');
doubleValue = 0;
token = DOUBLEVAL;
} else {
token = isSingleFloat ? FLOATVAL : DOUBLEVAL;
try {
lastChar = buffer[count - 1];
if (lastChar == 'e' || lastChar == 'E'
|| lastChar == '+' || lastChar == '-') {
env.error(in.pos -1, "float.format");
} else if (isSingleFloat) {
String string = bufferString();
floatValue = Float.valueOf(string).floatValue();
if (Float.isInfinite(floatValue)) {
env.error(pos, "overflow.float");
} else if (floatValue == 0 && !looksLikeZero(string)) {
env.error(pos, "underflow.float");
}
} else {
String string = bufferString();
doubleValue = Double.valueOf(string).doubleValue();
if (Double.isInfinite(doubleValue)) {
env.error(pos, "overflow.double");
} else if (doubleValue == 0 && !looksLikeZero(string)) {
env.error(pos, "underflow.double");
}
}
} catch (NumberFormatException ee) {
env.error(pos, "float.format");
doubleValue = 0;
floatValue = 0;
}
}
return;
}
// We have a token that parses as a number. Is this token possibly zero?
// i.e. does it have a non-zero value in the mantissa?
private static boolean looksLikeZero(String token) {
int length = token.length();
for (int i = 0; i < length; i++) {
switch (token.charAt(i)) {
case 0: case '.':
continue;
case '1': case '2': case '3': case '4': case '5':
case '6': case '7': case '8': case '9':
return false;
case 'e': case 'E': case 'f': case 'F':
return true;
}
}
return true;
}
/**
* Scan an escape character.
* @return the character or -1 if it escaped an
* end-of-line.
*/
private int scanEscapeChar() throws IOException {
long p = in.pos;
switch (ch = in.read()) {
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7': {
int n = ch - '0';
for (int i = 2 ; i > 0 ; i--) {
switch (ch = in.read()) {
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
n = (n << 3) + ch - '0';
break;
default:
if (n > 0xFF) {
env.error(p, "invalid.escape.char");
}
return n;
}
}
ch = in.read();
if (n > 0xFF) {
env.error(p, "invalid.escape.char");
}
return n;
}
case 'r': ch = in.read(); return '\r';
case 'n': ch = in.read(); return '\n';
case 'f': ch = in.read(); return '\f';
case 'b': ch = in.read(); return '\b';
case 't': ch = in.read(); return '\t';
case '\\': ch = in.read(); return '\\';
case '\"': ch = in.read(); return '\"';
case '\'': ch = in.read(); return '\'';
}
env.error(p, "invalid.escape.char");
ch = in.read();
return -1;
}
/**
* Scan a string. The current character
* should be the opening " of the string.
*/
private void scanString() throws IOException {
token = STRINGVAL;
count = 0;
ch = in.read();
// Scan a String
while (true) {
switch (ch) {
case EOF:
env.error(pos, "eof.in.string");
stringValue = bufferString();
return;
case '\r':
case '\n':
ch = in.read();
env.error(pos, "newline.in.string");
stringValue = bufferString();
return;
case '"':
ch = in.read();
stringValue = bufferString();
return;
case '\\': {
int c = scanEscapeChar();
if (c >= 0) {
putc((char)c);
}
break;
}
default:
putc(ch);
ch = in.read();
break;
}
}
}
/**
* Scan a character. The current character should be
* the opening ' of the character constant.
*/
private void scanCharacter() throws IOException {
token = CHARVAL;
switch (ch = in.read()) {
case '\\':
int c = scanEscapeChar();
charValue = (char)((c >= 0) ? c : 0);
break;
case '\'':
// There are two standard problems this case deals with. One
// is the malformed single quote constant (i.e. the programmer
// uses ''' instead of '\'') and the other is the empty
// character constant (i.e. ''). Just consume any number of
// single quotes and emit an error message.
charValue = 0;
env.error(pos, "invalid.char.constant");
ch = in.read();
while (ch == '\'') {
ch = in.read();
}
return;
case '\r':
case '\n':
charValue = 0;
env.error(pos, "invalid.char.constant");
return;
default:
charValue = (char)ch;
ch = in.read();
break;
}
if (ch == '\'') {
ch = in.read();
} else {
env.error(pos, "invalid.char.constant");
while (true) {
switch (ch) {
case '\'':
ch = in.read();
return;
case ';':
case '\n':
case EOF:
return;
default:
ch = in.read();
}
}
}
}
/**
* Scan an Identifier. The current character should
* be the first character of the identifier.
*/
private void scanIdentifier() throws IOException {
count = 0;
while (true) {
putc(ch);
switch (ch = in.read()) {
case 'a': case 'b': case 'c': case 'd': case 'e':
case 'f': case 'g': case 'h': case 'i': case 'j':
case 'k': case 'l': case 'm': case 'n': case 'o':
case 'p': case 'q': case 'r': case 's': case 't':
case 'u': case 'v': case 'w': case 'x': case 'y':
case 'z':
case 'A': case 'B': case 'C': case 'D': case 'E':
case 'F': case 'G': case 'H': case 'I': case 'J':
case 'K': case 'L': case 'M': case 'N': case 'O':
case 'P': case 'Q': case 'R': case 'S': case 'T':
case 'U': case 'V': case 'W': case 'X': case 'Y':
case 'Z':
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
case '$': case '_':
break;
default:
if (!Character.isJavaLetterOrDigit((char)ch)) {
idValue = Identifier.lookup(bufferString());
token = idValue.getType();
return;
}
}
}
}
/**
* The ending position of the current token
*/
// Note: This should be part of the pos itself.
public long getEndPos() {
return in.pos;
}
/**
* If the current token is IDENT, return the identifier occurrence.
* It will be freshly allocated.
*/
public IdentifierToken getIdToken() {
return (token != IDENT) ? null : new IdentifierToken(pos, idValue);
}
/**
* Scan the next token.
* @return the position of the previous token.
*/
public long scan() throws IOException {
return xscan();
}
protected long xscan() throws IOException {
final ScannerInputReader in = this.in;
long retPos = pos;
prevPos = in.pos;
docComment = null;
while (true) {
pos = in.pos;
switch (ch) {
case EOF:
token = EOF;
return retPos;
case '\n':
if (scanComments) {
ch = ' ';
// Avoid this path the next time around.
// Do not just call in.read; we want to present
// a null token (and also avoid read-ahead).
token = COMMENT;
return retPos;
}
case ' ':
case '\t':
case '\f':
ch = in.read();
break;
case '/':
switch (ch = in.read()) {
case '/':
// Parse a // comment
while (((ch = in.read()) != EOF) && (ch != '\n'));
if (scanComments) {
token = COMMENT;
return retPos;
}
break;
case '*':
ch = in.read();
if (ch == '*') {
docComment = scanDocComment();
} else {
skipComment();
}
if (scanComments) {
return retPos;
}
break;
case '=':
ch = in.read();
token = ASGDIV;
return retPos;
default:
token = DIV;
return retPos;
}
break;
case '"':
scanString();
return retPos;
case '\'':
scanCharacter();
return retPos;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
scanNumber();
return retPos;
case '.':
switch (ch = in.read()) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
count = 0;
putc('.');
scanReal();
break;
default:
token = FIELD;
}
return retPos;
case '{':
ch = in.read();
token = LBRACE;
return retPos;
case '}':
ch = in.read();
token = RBRACE;
return retPos;
case '(':
ch = in.read();
token = LPAREN;
return retPos;
case ')':
ch = in.read();
token = RPAREN;
return retPos;
case '[':
ch = in.read();
token = LSQBRACKET;
return retPos;
case ']':
ch = in.read();
token = RSQBRACKET;
return retPos;
case ',':
ch = in.read();
token = COMMA;
return retPos;
case ';':
ch = in.read();
token = SEMICOLON;
return retPos;
case '?':
ch = in.read();
token = QUESTIONMARK;
return retPos;
case '~':
ch = in.read();
token = BITNOT;
return retPos;
case ':':
ch = in.read();
token = COLON;
return retPos;
case '-':
switch (ch = in.read()) {
case '-':
ch = in.read();
token = DEC;
return retPos;
case '=':
ch = in.read();
token = ASGSUB;
return retPos;
}
token = SUB;
return retPos;
case '+':
switch (ch = in.read()) {
case '+':
ch = in.read();
token = INC;
return retPos;
case '=':
ch = in.read();
token = ASGADD;
return retPos;
}
token = ADD;
return retPos;
case '<':
switch (ch = in.read()) {
case '<':
if ((ch = in.read()) == '=') {
ch = in.read();
token = ASGLSHIFT;
return retPos;
}
token = LSHIFT;
return retPos;
case '=':
ch = in.read();
token = LE;
return retPos;
}
token = LT;
return retPos;
case '>':
switch (ch = in.read()) {
case '>':
switch (ch = in.read()) {
case '=':
ch = in.read();
token = ASGRSHIFT;
return retPos;
case '>':
if ((ch = in.read()) == '=') {
ch = in.read();
token = ASGURSHIFT;
return retPos;
}
token = URSHIFT;
return retPos;
}
token = RSHIFT;
return retPos;
case '=':
ch = in.read();
token = GE;
return retPos;
}
token = GT;
return retPos;
case '|':
switch (ch = in.read()) {
case '|':
ch = in.read();
token = OR;
return retPos;
case '=':
ch = in.read();
token = ASGBITOR;
return retPos;
}
token = BITOR;
return retPos;
case '&':
switch (ch = in.read()) {
case '&':
ch = in.read();
token = AND;
return retPos;
case '=':
ch = in.read();
token = ASGBITAND;
return retPos;
}
token = BITAND;
return retPos;
case '=':
if ((ch = in.read()) == '=') {
ch = in.read();
token = EQ;
return retPos;
}
token = ASSIGN;
return retPos;
case '%':
if ((ch = in.read()) == '=') {
ch = in.read();
token = ASGREM;
return retPos;
}
token = REM;
return retPos;
case '^':
if ((ch = in.read()) == '=') {
ch = in.read();
token = ASGBITXOR;
return retPos;
}
token = BITXOR;
return retPos;
case '!':
if ((ch = in.read()) == '=') {
ch = in.read();
token = NE;
return retPos;
}
token = NOT;
return retPos;
case '*':
if ((ch = in.read()) == '=') {
ch = in.read();
token = ASGMUL;
return retPos;
}
token = MUL;
return retPos;
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
case 'g': case 'h': case 'i': case 'j': case 'k': case 'l':
case 'm': case 'n': case 'o': case 'p': case 'q': case 'r':
case 's': case 't': case 'u': case 'v': case 'w': case 'x':
case 'y': case 'z':
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
case 'G': case 'H': case 'I': case 'J': case 'K': case 'L':
case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R':
case 'S': case 'T': case 'U': case 'V': case 'W': case 'X':
case 'Y': case 'Z':
case '$': case '_':
scanIdentifier();
return retPos;
case '\u001a':
// Our one concession to DOS.
if ((ch = in.read()) == EOF) {
token = EOF;
return retPos;
}
env.error(pos, "funny.char");
ch = in.read();
break;
default:
if (Character.isJavaLetter((char)ch)) {
scanIdentifier();
return retPos;
}
env.error(pos, "funny.char");
ch = in.read();
break;
}
}
}
/**
* Scan to a matching '}', ']' or ')'. The current token must be
* a '{', '[' or '(';
*/
public void match(int open, int close) throws IOException {
int depth = 1;
while (true) {
scan();
if (token == open) {
depth++;
} else if (token == close) {
if (--depth == 0) {
return;
}
} else if (token == EOF) {
env.error(pos, "unbalanced.paren");
return;
}
}
}
}
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