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package java.io;
import java.util.Arrays;
The StreamTokenizer
class takes an input stream and
parses it into "tokens", allowing the tokens to be
read one at a time. The parsing process is controlled by a table
and a number of flags that can be set to various states. The
stream tokenizer can recognize identifiers, numbers, quoted
strings, and various comment styles.
Each byte read from the input stream is regarded as a character
in the range '\u0000'
through '\u00FF'
.
The character value is used to look up five possible attributes of
the character: white space, alphabetic,
numeric, string quote, and comment character.
Each character can have zero or more of these attributes.
In addition, an instance has four flags. These flags indicate:
- Whether line terminators are to be returned as tokens or treated
as white space that merely separates tokens.
- Whether C-style comments are to be recognized and skipped.
- Whether C++-style comments are to be recognized and skipped.
- Whether the characters of identifiers are converted to lowercase.
A typical application first constructs an instance of this class,
sets up the syntax tables, and then repeatedly loops calling the
nextToken
method in each iteration of the loop until
it returns the value TT_EOF
.
Author: James Gosling See Also: Since: JDK1.0
/**
* The <code>StreamTokenizer</code> class takes an input stream and
* parses it into "tokens", allowing the tokens to be
* read one at a time. The parsing process is controlled by a table
* and a number of flags that can be set to various states. The
* stream tokenizer can recognize identifiers, numbers, quoted
* strings, and various comment styles.
* <p>
* Each byte read from the input stream is regarded as a character
* in the range <code>'\u0000'</code> through <code>'\u00FF'</code>.
* The character value is used to look up five possible attributes of
* the character: <i>white space</i>, <i>alphabetic</i>,
* <i>numeric</i>, <i>string quote</i>, and <i>comment character</i>.
* Each character can have zero or more of these attributes.
* <p>
* In addition, an instance has four flags. These flags indicate:
* <ul>
* <li>Whether line terminators are to be returned as tokens or treated
* as white space that merely separates tokens.
* <li>Whether C-style comments are to be recognized and skipped.
* <li>Whether C++-style comments are to be recognized and skipped.
* <li>Whether the characters of identifiers are converted to lowercase.
* </ul>
* <p>
* A typical application first constructs an instance of this class,
* sets up the syntax tables, and then repeatedly loops calling the
* <code>nextToken</code> method in each iteration of the loop until
* it returns the value <code>TT_EOF</code>.
*
* @author James Gosling
* @see java.io.StreamTokenizer#nextToken()
* @see java.io.StreamTokenizer#TT_EOF
* @since JDK1.0
*/
public class StreamTokenizer {
/* Only one of these will be non-null */
private Reader reader = null;
private InputStream input = null;
private char buf[] = new char[20];
The next character to be considered by the nextToken method. May also
be NEED_CHAR to indicate that a new character should be read, or SKIP_LF
to indicate that a new character should be read and, if it is a '\n'
character, it should be discarded and a second new character should be
read.
/**
* The next character to be considered by the nextToken method. May also
* be NEED_CHAR to indicate that a new character should be read, or SKIP_LF
* to indicate that a new character should be read and, if it is a '\n'
* character, it should be discarded and a second new character should be
* read.
*/
private int peekc = NEED_CHAR;
private static final int NEED_CHAR = Integer.MAX_VALUE;
private static final int SKIP_LF = Integer.MAX_VALUE - 1;
private boolean pushedBack;
private boolean forceLower;
The line number of the last token read /** The line number of the last token read */
private int LINENO = 1;
private boolean eolIsSignificantP = false;
private boolean slashSlashCommentsP = false;
private boolean slashStarCommentsP = false;
private byte ctype[] = new byte[256];
private static final byte CT_WHITESPACE = 1;
private static final byte CT_DIGIT = 2;
private static final byte CT_ALPHA = 4;
private static final byte CT_QUOTE = 8;
private static final byte CT_COMMENT = 16;
After a call to the nextToken
method, this field
contains the type of the token just read. For a single character
token, its value is the single character, converted to an integer.
For a quoted string token, its value is the quote character.
Otherwise, its value is one of the following:
TT_WORD
indicates that the token is a word.
TT_NUMBER
indicates that the token is a number.
TT_EOL
indicates that the end of line has been read.
The field can only have this value if the
eolIsSignificant
method has been called with the
argument true
.
TT_EOF
indicates that the end of the input stream
has been reached.
The initial value of this field is -4.
See Also: - eolIsSignificant.eolIsSignificant(boolean)
- nextToken()
- quoteChar(int)
- TT_EOF
- TT_EOL
- TT_NUMBER
- TT_WORD
/**
* After a call to the <code>nextToken</code> method, this field
* contains the type of the token just read. For a single character
* token, its value is the single character, converted to an integer.
* For a quoted string token, its value is the quote character.
* Otherwise, its value is one of the following:
* <ul>
* <li><code>TT_WORD</code> indicates that the token is a word.
* <li><code>TT_NUMBER</code> indicates that the token is a number.
* <li><code>TT_EOL</code> indicates that the end of line has been read.
* The field can only have this value if the
* <code>eolIsSignificant</code> method has been called with the
* argument <code>true</code>.
* <li><code>TT_EOF</code> indicates that the end of the input stream
* has been reached.
* </ul>
* <p>
* The initial value of this field is -4.
*
* @see java.io.StreamTokenizer#eolIsSignificant(boolean)
* @see java.io.StreamTokenizer#nextToken()
* @see java.io.StreamTokenizer#quoteChar(int)
* @see java.io.StreamTokenizer#TT_EOF
* @see java.io.StreamTokenizer#TT_EOL
* @see java.io.StreamTokenizer#TT_NUMBER
* @see java.io.StreamTokenizer#TT_WORD
*/
public int ttype = TT_NOTHING;
A constant indicating that the end of the stream has been read.
/**
* A constant indicating that the end of the stream has been read.
*/
public static final int TT_EOF = -1;
A constant indicating that the end of the line has been read.
/**
* A constant indicating that the end of the line has been read.
*/
public static final int TT_EOL = '\n';
A constant indicating that a number token has been read.
/**
* A constant indicating that a number token has been read.
*/
public static final int TT_NUMBER = -2;
A constant indicating that a word token has been read.
/**
* A constant indicating that a word token has been read.
*/
public static final int TT_WORD = -3;
/* A constant indicating that no token has been read, used for
* initializing ttype. FIXME This could be made public and
* made available as the part of the API in a future release.
*/
private static final int TT_NOTHING = -4;
If the current token is a word token, this field contains a
string giving the characters of the word token. When the current
token is a quoted string token, this field contains the body of
the string.
The current token is a word when the value of the
ttype
field is TT_WORD
. The current token is
a quoted string token when the value of the ttype
field is
a quote character.
The initial value of this field is null.
See Also:
/**
* If the current token is a word token, this field contains a
* string giving the characters of the word token. When the current
* token is a quoted string token, this field contains the body of
* the string.
* <p>
* The current token is a word when the value of the
* <code>ttype</code> field is <code>TT_WORD</code>. The current token is
* a quoted string token when the value of the <code>ttype</code> field is
* a quote character.
* <p>
* The initial value of this field is null.
*
* @see java.io.StreamTokenizer#quoteChar(int)
* @see java.io.StreamTokenizer#TT_WORD
* @see java.io.StreamTokenizer#ttype
*/
public String sval;
If the current token is a number, this field contains the value
of that number. The current token is a number when the value of
the ttype
field is TT_NUMBER
.
The initial value of this field is 0.0.
See Also: - TT_NUMBER.TT_NUMBER
- ttype
/**
* If the current token is a number, this field contains the value
* of that number. The current token is a number when the value of
* the <code>ttype</code> field is <code>TT_NUMBER</code>.
* <p>
* The initial value of this field is 0.0.
*
* @see java.io.StreamTokenizer#TT_NUMBER
* @see java.io.StreamTokenizer#ttype
*/
public double nval;
Private constructor that initializes everything except the streams. /** Private constructor that initializes everything except the streams. */
private StreamTokenizer() {
wordChars('a', 'z');
wordChars('A', 'Z');
wordChars(128 + 32, 255);
whitespaceChars(0, ' ');
commentChar('/');
quoteChar('"');
quoteChar('\'');
parseNumbers();
}
Creates a stream tokenizer that parses the specified input
stream. The stream tokenizer is initialized to the following
default state:
- All byte values
'A'
through 'Z'
,
'a'
through 'z'
, and
'\u00A0'
through '\u00FF'
are
considered to be alphabetic.
- All byte values
'\u0000'
through
'\u0020'
are considered to be white space.
'/'
is a comment character.
- Single quote
'\''
and double quote '"'
are string quote characters.
- Numbers are parsed.
- Ends of lines are treated as white space, not as separate tokens.
- C-style and C++-style comments are not recognized.
Params: - is – an input stream.
See Also: Deprecated: As of JDK version 1.1, the preferred way to tokenize an
input stream is to convert it into a character stream, for example:
Reader r = new BufferedReader(new InputStreamReader(is));
StreamTokenizer st = new StreamTokenizer(r);
/**
* Creates a stream tokenizer that parses the specified input
* stream. The stream tokenizer is initialized to the following
* default state:
* <ul>
* <li>All byte values <code>'A'</code> through <code>'Z'</code>,
* <code>'a'</code> through <code>'z'</code>, and
* <code>'\u00A0'</code> through <code>'\u00FF'</code> are
* considered to be alphabetic.
* <li>All byte values <code>'\u0000'</code> through
* <code>'\u0020'</code> are considered to be white space.
* <li><code>'/'</code> is a comment character.
* <li>Single quote <code>'\''</code> and double quote <code>'"'</code>
* are string quote characters.
* <li>Numbers are parsed.
* <li>Ends of lines are treated as white space, not as separate tokens.
* <li>C-style and C++-style comments are not recognized.
* </ul>
*
* @deprecated As of JDK version 1.1, the preferred way to tokenize an
* input stream is to convert it into a character stream, for example:
* <blockquote><pre>
* Reader r = new BufferedReader(new InputStreamReader(is));
* StreamTokenizer st = new StreamTokenizer(r);
* </pre></blockquote>
*
* @param is an input stream.
* @see java.io.BufferedReader
* @see java.io.InputStreamReader
* @see java.io.StreamTokenizer#StreamTokenizer(java.io.Reader)
*/
@Deprecated
public StreamTokenizer(InputStream is) {
this();
if (is == null) {
throw new NullPointerException();
}
input = is;
}
Create a tokenizer that parses the given character stream.
Params: - r – a Reader object providing the input stream.
Since: JDK1.1
/**
* Create a tokenizer that parses the given character stream.
*
* @param r a Reader object providing the input stream.
* @since JDK1.1
*/
public StreamTokenizer(Reader r) {
this();
if (r == null) {
throw new NullPointerException();
}
reader = r;
}
Resets this tokenizer's syntax table so that all characters are
"ordinary." See the ordinaryChar
method
for more information on a character being ordinary.
See Also: - ordinaryChar.ordinaryChar(int)
/**
* Resets this tokenizer's syntax table so that all characters are
* "ordinary." See the <code>ordinaryChar</code> method
* for more information on a character being ordinary.
*
* @see java.io.StreamTokenizer#ordinaryChar(int)
*/
public void resetSyntax() {
for (int i = ctype.length; --i >= 0;)
ctype[i] = 0;
}
Specifies that all characters c in the range
low <= c <= high
are word constituents. A word token consists of a word constituent
followed by zero or more word constituents or number constituents.
Params: - low – the low end of the range.
- hi – the high end of the range.
/**
* Specifies that all characters <i>c</i> in the range
* <code>low <= <i>c</i> <= high</code>
* are word constituents. A word token consists of a word constituent
* followed by zero or more word constituents or number constituents.
*
* @param low the low end of the range.
* @param hi the high end of the range.
*/
public void wordChars(int low, int hi) {
if (low < 0)
low = 0;
if (hi >= ctype.length)
hi = ctype.length - 1;
while (low <= hi)
ctype[low++] |= CT_ALPHA;
}
Specifies that all characters c in the range
low <= c <= high
are white space characters. White space characters serve only to
separate tokens in the input stream.
Any other attribute settings for the characters in the specified
range are cleared.
Params: - low – the low end of the range.
- hi – the high end of the range.
/**
* Specifies that all characters <i>c</i> in the range
* <code>low <= <i>c</i> <= high</code>
* are white space characters. White space characters serve only to
* separate tokens in the input stream.
*
* <p>Any other attribute settings for the characters in the specified
* range are cleared.
*
* @param low the low end of the range.
* @param hi the high end of the range.
*/
public void whitespaceChars(int low, int hi) {
if (low < 0)
low = 0;
if (hi >= ctype.length)
hi = ctype.length - 1;
while (low <= hi)
ctype[low++] = CT_WHITESPACE;
}
Specifies that all characters c in the range
low <= c <= high
are "ordinary" in this tokenizer. See the
ordinaryChar
method for more information on a
character being ordinary.
Params: - low – the low end of the range.
- hi – the high end of the range.
See Also:
/**
* Specifies that all characters <i>c</i> in the range
* <code>low <= <i>c</i> <= high</code>
* are "ordinary" in this tokenizer. See the
* <code>ordinaryChar</code> method for more information on a
* character being ordinary.
*
* @param low the low end of the range.
* @param hi the high end of the range.
* @see java.io.StreamTokenizer#ordinaryChar(int)
*/
public void ordinaryChars(int low, int hi) {
if (low < 0)
low = 0;
if (hi >= ctype.length)
hi = ctype.length - 1;
while (low <= hi)
ctype[low++] = 0;
}
Specifies that the character argument is "ordinary"
in this tokenizer. It removes any special significance the
character has as a comment character, word component, string
delimiter, white space, or number character. When such a character
is encountered by the parser, the parser treats it as a
single-character token and sets ttype
field to the
character value.
Making a line terminator character "ordinary" may interfere
with the ability of a StreamTokenizer
to count
lines. The lineno
method may no longer reflect
the presence of such terminator characters in its line count.
Params: - ch – the character.
See Also:
/**
* Specifies that the character argument is "ordinary"
* in this tokenizer. It removes any special significance the
* character has as a comment character, word component, string
* delimiter, white space, or number character. When such a character
* is encountered by the parser, the parser treats it as a
* single-character token and sets <code>ttype</code> field to the
* character value.
*
* <p>Making a line terminator character "ordinary" may interfere
* with the ability of a <code>StreamTokenizer</code> to count
* lines. The <code>lineno</code> method may no longer reflect
* the presence of such terminator characters in its line count.
*
* @param ch the character.
* @see java.io.StreamTokenizer#ttype
*/
public void ordinaryChar(int ch) {
if (ch >= 0 && ch < ctype.length)
ctype[ch] = 0;
}
Specified that the character argument starts a single-line
comment. All characters from the comment character to the end of
the line are ignored by this stream tokenizer.
Any other attribute settings for the specified character are cleared.
Params: - ch – the character.
/**
* Specified that the character argument starts a single-line
* comment. All characters from the comment character to the end of
* the line are ignored by this stream tokenizer.
*
* <p>Any other attribute settings for the specified character are cleared.
*
* @param ch the character.
*/
public void commentChar(int ch) {
if (ch >= 0 && ch < ctype.length)
ctype[ch] = CT_COMMENT;
}
Specifies that matching pairs of this character delimit string
constants in this tokenizer.
When the nextToken
method encounters a string
constant, the ttype
field is set to the string
delimiter and the sval
field is set to the body of
the string.
If a string quote character is encountered, then a string is
recognized, consisting of all characters after (but not including)
the string quote character, up to (but not including) the next
occurrence of that same string quote character, or a line
terminator, or end of file. The usual escape sequences such as
"\n"
and "\t"
are recognized and
converted to single characters as the string is parsed.
Any other attribute settings for the specified character are cleared.
Params: - ch – the character.
See Also:
/**
* Specifies that matching pairs of this character delimit string
* constants in this tokenizer.
* <p>
* When the <code>nextToken</code> method encounters a string
* constant, the <code>ttype</code> field is set to the string
* delimiter and the <code>sval</code> field is set to the body of
* the string.
* <p>
* If a string quote character is encountered, then a string is
* recognized, consisting of all characters after (but not including)
* the string quote character, up to (but not including) the next
* occurrence of that same string quote character, or a line
* terminator, or end of file. The usual escape sequences such as
* <code>"\n"</code> and <code>"\t"</code> are recognized and
* converted to single characters as the string is parsed.
*
* <p>Any other attribute settings for the specified character are cleared.
*
* @param ch the character.
* @see java.io.StreamTokenizer#nextToken()
* @see java.io.StreamTokenizer#sval
* @see java.io.StreamTokenizer#ttype
*/
public void quoteChar(int ch) {
if (ch >= 0 && ch < ctype.length)
ctype[ch] = CT_QUOTE;
}
Specifies that numbers should be parsed by this tokenizer. The
syntax table of this tokenizer is modified so that each of the twelve
characters:
0 1 2 3 4 5 6 7 8 9 . -
has the "numeric" attribute.
When the parser encounters a word token that has the format of a
double precision floating-point number, it treats the token as a
number rather than a word, by setting the ttype
field to the value TT_NUMBER
and putting the numeric
value of the token into the nval
field.
See Also:
/**
* Specifies that numbers should be parsed by this tokenizer. The
* syntax table of this tokenizer is modified so that each of the twelve
* characters:
* <blockquote><pre>
* 0 1 2 3 4 5 6 7 8 9 . -
* </pre></blockquote>
* <p>
* has the "numeric" attribute.
* <p>
* When the parser encounters a word token that has the format of a
* double precision floating-point number, it treats the token as a
* number rather than a word, by setting the <code>ttype</code>
* field to the value <code>TT_NUMBER</code> and putting the numeric
* value of the token into the <code>nval</code> field.
*
* @see java.io.StreamTokenizer#nval
* @see java.io.StreamTokenizer#TT_NUMBER
* @see java.io.StreamTokenizer#ttype
*/
public void parseNumbers() {
for (int i = '0'; i <= '9'; i++)
ctype[i] |= CT_DIGIT;
ctype['.'] |= CT_DIGIT;
ctype['-'] |= CT_DIGIT;
}
Determines whether or not ends of line are treated as tokens.
If the flag argument is true, this tokenizer treats end of lines
as tokens; the nextToken
method returns
TT_EOL
and also sets the ttype
field to
this value when an end of line is read.
A line is a sequence of characters ending with either a
carriage-return character ('\r'
) or a newline
character ('\n'
). In addition, a carriage-return
character followed immediately by a newline character is treated
as a single end-of-line token.
If the flag
is false, end-of-line characters are
treated as white space and serve only to separate tokens.
Params: - flag –
true
indicates that end-of-line characters
are separate tokens; false
indicates that
end-of-line characters are white space.
See Also:
/**
* Determines whether or not ends of line are treated as tokens.
* If the flag argument is true, this tokenizer treats end of lines
* as tokens; the <code>nextToken</code> method returns
* <code>TT_EOL</code> and also sets the <code>ttype</code> field to
* this value when an end of line is read.
* <p>
* A line is a sequence of characters ending with either a
* carriage-return character (<code>'\r'</code>) or a newline
* character (<code>'\n'</code>). In addition, a carriage-return
* character followed immediately by a newline character is treated
* as a single end-of-line token.
* <p>
* If the <code>flag</code> is false, end-of-line characters are
* treated as white space and serve only to separate tokens.
*
* @param flag <code>true</code> indicates that end-of-line characters
* are separate tokens; <code>false</code> indicates that
* end-of-line characters are white space.
* @see java.io.StreamTokenizer#nextToken()
* @see java.io.StreamTokenizer#ttype
* @see java.io.StreamTokenizer#TT_EOL
*/
public void eolIsSignificant(boolean flag) {
eolIsSignificantP = flag;
}
Determines whether or not the tokenizer recognizes C-style comments.
If the flag argument is true
, this stream tokenizer
recognizes C-style comments. All text between successive
occurrences of /*
and */
are discarded.
If the flag argument is false
, then C-style comments
are not treated specially.
Params: - flag –
true
indicates to recognize and ignore
C-style comments.
/**
* Determines whether or not the tokenizer recognizes C-style comments.
* If the flag argument is <code>true</code>, this stream tokenizer
* recognizes C-style comments. All text between successive
* occurrences of <code>/*</code> and <code>*/</code> are discarded.
* <p>
* If the flag argument is <code>false</code>, then C-style comments
* are not treated specially.
*
* @param flag <code>true</code> indicates to recognize and ignore
* C-style comments.
*/
public void slashStarComments(boolean flag) {
slashStarCommentsP = flag;
}
Determines whether or not the tokenizer recognizes C++-style comments.
If the flag argument is true
, this stream tokenizer
recognizes C++-style comments. Any occurrence of two consecutive
slash characters ('/'
) is treated as the beginning of
a comment that extends to the end of the line.
If the flag argument is false
, then C++-style
comments are not treated specially.
Params: - flag –
true
indicates to recognize and ignore
C++-style comments.
/**
* Determines whether or not the tokenizer recognizes C++-style comments.
* If the flag argument is <code>true</code>, this stream tokenizer
* recognizes C++-style comments. Any occurrence of two consecutive
* slash characters (<code>'/'</code>) is treated as the beginning of
* a comment that extends to the end of the line.
* <p>
* If the flag argument is <code>false</code>, then C++-style
* comments are not treated specially.
*
* @param flag <code>true</code> indicates to recognize and ignore
* C++-style comments.
*/
public void slashSlashComments(boolean flag) {
slashSlashCommentsP = flag;
}
Determines whether or not word token are automatically lowercased.
If the flag argument is true
, then the value in the
sval
field is lowercased whenever a word token is
returned (the ttype
field has the
value TT_WORD
by the nextToken
method
of this tokenizer.
If the flag argument is false
, then the
sval
field is not modified.
Params: - fl –
true
indicates that all word tokens should
be lowercased.
See Also:
/**
* Determines whether or not word token are automatically lowercased.
* If the flag argument is <code>true</code>, then the value in the
* <code>sval</code> field is lowercased whenever a word token is
* returned (the <code>ttype</code> field has the
* value <code>TT_WORD</code> by the <code>nextToken</code> method
* of this tokenizer.
* <p>
* If the flag argument is <code>false</code>, then the
* <code>sval</code> field is not modified.
*
* @param fl <code>true</code> indicates that all word tokens should
* be lowercased.
* @see java.io.StreamTokenizer#nextToken()
* @see java.io.StreamTokenizer#ttype
* @see java.io.StreamTokenizer#TT_WORD
*/
public void lowerCaseMode(boolean fl) {
forceLower = fl;
}
Read the next character /** Read the next character */
private int read() throws IOException {
if (reader != null)
return reader.read();
else if (input != null)
return input.read();
else
throw new IllegalStateException();
}
Parses the next token from the input stream of this tokenizer.
The type of the next token is returned in the ttype
field. Additional information about the token may be in the
nval
field or the sval
field of this
tokenizer.
Typical clients of this
class first set up the syntax tables and then sit in a loop
calling nextToken to parse successive tokens until TT_EOF
is returned.
Throws: - IOException – if an I/O error occurs.
See Also: Returns: the value of the ttype
field.
/**
* Parses the next token from the input stream of this tokenizer.
* The type of the next token is returned in the <code>ttype</code>
* field. Additional information about the token may be in the
* <code>nval</code> field or the <code>sval</code> field of this
* tokenizer.
* <p>
* Typical clients of this
* class first set up the syntax tables and then sit in a loop
* calling nextToken to parse successive tokens until TT_EOF
* is returned.
*
* @return the value of the <code>ttype</code> field.
* @exception IOException if an I/O error occurs.
* @see java.io.StreamTokenizer#nval
* @see java.io.StreamTokenizer#sval
* @see java.io.StreamTokenizer#ttype
*/
public int nextToken() throws IOException {
if (pushedBack) {
pushedBack = false;
return ttype;
}
byte ct[] = ctype;
sval = null;
int c = peekc;
if (c < 0)
c = NEED_CHAR;
if (c == SKIP_LF) {
c = read();
if (c < 0)
return ttype = TT_EOF;
if (c == '\n')
c = NEED_CHAR;
}
if (c == NEED_CHAR) {
c = read();
if (c < 0)
return ttype = TT_EOF;
}
ttype = c; /* Just to be safe */
/* Set peekc so that the next invocation of nextToken will read
* another character unless peekc is reset in this invocation
*/
peekc = NEED_CHAR;
int ctype = c < 256 ? ct[c] : CT_ALPHA;
while ((ctype & CT_WHITESPACE) != 0) {
if (c == '\r') {
LINENO++;
if (eolIsSignificantP) {
peekc = SKIP_LF;
return ttype = TT_EOL;
}
c = read();
if (c == '\n')
c = read();
} else {
if (c == '\n') {
LINENO++;
if (eolIsSignificantP) {
return ttype = TT_EOL;
}
}
c = read();
}
if (c < 0)
return ttype = TT_EOF;
ctype = c < 256 ? ct[c] : CT_ALPHA;
}
if ((ctype & CT_DIGIT) != 0) {
boolean neg = false;
if (c == '-') {
c = read();
if (c != '.' && (c < '0' || c > '9')) {
peekc = c;
return ttype = '-';
}
neg = true;
}
double v = 0;
int decexp = 0;
int seendot = 0;
while (true) {
if (c == '.' && seendot == 0)
seendot = 1;
else if ('0' <= c && c <= '9') {
v = v * 10 + (c - '0');
decexp += seendot;
} else
break;
c = read();
}
peekc = c;
if (decexp != 0) {
double denom = 10;
decexp--;
while (decexp > 0) {
denom *= 10;
decexp--;
}
/* Do one division of a likely-to-be-more-accurate number */
v = v / denom;
}
nval = neg ? -v : v;
return ttype = TT_NUMBER;
}
if ((ctype & CT_ALPHA) != 0) {
int i = 0;
do {
if (i >= buf.length) {
buf = Arrays.copyOf(buf, buf.length * 2);
}
buf[i++] = (char) c;
c = read();
ctype = c < 0 ? CT_WHITESPACE : c < 256 ? ct[c] : CT_ALPHA;
} while ((ctype & (CT_ALPHA | CT_DIGIT)) != 0);
peekc = c;
sval = String.copyValueOf(buf, 0, i);
if (forceLower)
sval = sval.toLowerCase();
return ttype = TT_WORD;
}
if ((ctype & CT_QUOTE) != 0) {
ttype = c;
int i = 0;
/* Invariants (because \Octal needs a lookahead):
* (i) c contains char value
* (ii) d contains the lookahead
*/
int d = read();
while (d >= 0 && d != ttype && d != '\n' && d != '\r') {
if (d == '\\') {
c = read();
int first = c; /* To allow \377, but not \477 */
if (c >= '0' && c <= '7') {
c = c - '0';
int c2 = read();
if ('0' <= c2 && c2 <= '7') {
c = (c << 3) + (c2 - '0');
c2 = read();
if ('0' <= c2 && c2 <= '7' && first <= '3') {
c = (c << 3) + (c2 - '0');
d = read();
} else
d = c2;
} else
d = c2;
} else {
switch (c) {
case 'a':
c = 0x7;
break;
case 'b':
c = '\b';
break;
case 'f':
c = 0xC;
break;
case 'n':
c = '\n';
break;
case 'r':
c = '\r';
break;
case 't':
c = '\t';
break;
case 'v':
c = 0xB;
break;
}
d = read();
}
} else {
c = d;
d = read();
}
if (i >= buf.length) {
buf = Arrays.copyOf(buf, buf.length * 2);
}
buf[i++] = (char)c;
}
/* If we broke out of the loop because we found a matching quote
* character then arrange to read a new character next time
* around; otherwise, save the character.
*/
peekc = (d == ttype) ? NEED_CHAR : d;
sval = String.copyValueOf(buf, 0, i);
return ttype;
}
if (c == '/' && (slashSlashCommentsP || slashStarCommentsP)) {
c = read();
if (c == '*' && slashStarCommentsP) {
int prevc = 0;
while ((c = read()) != '/' || prevc != '*') {
if (c == '\r') {
LINENO++;
c = read();
if (c == '\n') {
c = read();
}
} else {
if (c == '\n') {
LINENO++;
c = read();
}
}
if (c < 0)
return ttype = TT_EOF;
prevc = c;
}
return nextToken();
} else if (c == '/' && slashSlashCommentsP) {
while ((c = read()) != '\n' && c != '\r' && c >= 0);
peekc = c;
return nextToken();
} else {
/* Now see if it is still a single line comment */
if ((ct['/'] & CT_COMMENT) != 0) {
while ((c = read()) != '\n' && c != '\r' && c >= 0);
peekc = c;
return nextToken();
} else {
peekc = c;
return ttype = '/';
}
}
}
if ((ctype & CT_COMMENT) != 0) {
while ((c = read()) != '\n' && c != '\r' && c >= 0);
peekc = c;
return nextToken();
}
return ttype = c;
}
Causes the next call to the nextToken
method of this
tokenizer to return the current value in the ttype
field, and not to modify the value in the nval
or
sval
field.
See Also:
/**
* Causes the next call to the <code>nextToken</code> method of this
* tokenizer to return the current value in the <code>ttype</code>
* field, and not to modify the value in the <code>nval</code> or
* <code>sval</code> field.
*
* @see java.io.StreamTokenizer#nextToken()
* @see java.io.StreamTokenizer#nval
* @see java.io.StreamTokenizer#sval
* @see java.io.StreamTokenizer#ttype
*/
public void pushBack() {
if (ttype != TT_NOTHING) /* No-op if nextToken() not called */
pushedBack = true;
}
Return the current line number.
Returns: the current line number of this stream tokenizer.
/**
* Return the current line number.
*
* @return the current line number of this stream tokenizer.
*/
public int lineno() {
return LINENO;
}
Returns the string representation of the current stream token and
the line number it occurs on.
The precise string returned is unspecified, although the following
example can be considered typical:
Token['a'], line 10
See Also: Returns: a string representation of the token
/**
* Returns the string representation of the current stream token and
* the line number it occurs on.
*
* <p>The precise string returned is unspecified, although the following
* example can be considered typical:
*
* <blockquote><pre>Token['a'], line 10</pre></blockquote>
*
* @return a string representation of the token
* @see java.io.StreamTokenizer#nval
* @see java.io.StreamTokenizer#sval
* @see java.io.StreamTokenizer#ttype
*/
public String toString() {
String ret;
switch (ttype) {
case TT_EOF:
ret = "EOF";
break;
case TT_EOL:
ret = "EOL";
break;
case TT_WORD:
ret = sval;
break;
case TT_NUMBER:
ret = "n=" + nval;
break;
case TT_NOTHING:
ret = "NOTHING";
break;
default: {
/*
* ttype is the first character of either a quoted string or
* is an ordinary character. ttype can definitely not be less
* than 0, since those are reserved values used in the previous
* case statements
*/
if (ttype < 256 &&
((ctype[ttype] & CT_QUOTE) != 0)) {
ret = sval;
break;
}
char s[] = new char[3];
s[0] = s[2] = '\'';
s[1] = (char) ttype;
ret = new String(s);
break;
}
}
return "Token[" + ret + "], line " + LINENO;
}
}