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C# port of java's StreamTokenizer class. Everything kept same except some renaming for following C# naming convention. And it also implements IEnumerable for foreach support

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StreamTokenizer.cs
C#
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/**
* 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>'&#92;u0000'</code> through <code>'&#92;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>.
*
*/
 
public class StreamTokenizer : IEnumerable<int>
{
 
/* Only one of these will be non-null */
private StreamReader reader = null;
 
private List<char> buf = new List<char>();
 
/**
* 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 const int NEED_CHAR = Int32.MaxValue;
private const int SKIP_LF = Int32.MaxValue - 1;
 
private bool pushedBack;
private bool forceLower;
/** The line number of the last token Read */
 
private bool eolIsSignificantP = false;
private bool slashSlashCommentsP = false;
private bool slashStarCommentsP = false;
 
private byte[] characterType = new byte[256];
private const byte CT_WHITESPACE = 1;
private const byte CT_DIGIT = 2;
private const byte CT_ALPHA = 4;
private const byte CT_QUOTE = 8;
private const byte CT_COMMENT = 16;
 
public int LineNumber { get; private set; }
 
/**
* 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.
*
*/
public int ttype = TT_NOTHING;
 
/**
* A constant indicating that the end of the stream has been Read.
*/
public const int TT_EOF = -1;
 
/**
* A constant indicating that the end of the line has been Read.
*/
public const int TT_EOL = '\n';
 
/**
* A constant indicating that a number token has been Read.
*/
public const int TT_NUMBER = -2;
 
/**
* A constant indicating that a word token has been Read.
*/
public const 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 const 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.
* <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 StringValue { get; private set; }
 
/**
* 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.
*/
public double NumberValue { get; private set; }
 
/** 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();
LineNumber = 1;
}
 
/**
* Create a tokenizer that parses the given character stream.
*
* @param r a Reader object providing the input stream.
*/
public StreamTokenizer(StreamReader r) : this()
{
if (r == null)
{
throw new ArgumentNullException();
}
reader = r;
}
 
/**
* 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.
*/
public void ResetSyntax()
{
Array.Clear(characterType, 0, characterType.Length);
}
 
/**
* Specifies that all characters <i>c</i> in the range
* <code>low&nbsp;&lt;=&nbsp;<i>c</i>&nbsp;&lt;=&nbsp;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 >= characterType.Length)
{
hi = characterType.Length - 1;
}
while (low <= hi)
{
characterType[low++] |= CT_ALPHA;
}
}
 
/**
* Specifies that all characters <i>c</i> in the range
* <code>low&nbsp;&lt;=&nbsp;<i>c</i>&nbsp;&lt;=&nbsp;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 >= characterType.Length)
{
hi = characterType.Length - 1;
}
while (low <= hi)
{
characterType[low++] = CT_WHITESPACE;
}
}
 
/**
* Specifies that all characters <i>c</i> in the range
* <code>low&nbsp;&lt;=&nbsp;<i>c</i>&nbsp;&lt;=&nbsp;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 >= characterType.Length)
{
hi = characterType.Length - 1;
}
while (low <= hi)
{
characterType[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 <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.
*/
public void OrdinaryChar(int ch)
{
if (ch >= 0 && ch < characterType.Length)
characterType[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.
*
* <p>Any other attribute settings for the specified character are cleared.
*
* @param ch the character.
*/
public void CommentChar(int ch)
{
if (ch >= 0 && ch < characterType.Length)
{
characterType[ch] = CT_COMMENT;
}
}
/**
* 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>"&#92;n"</code> and <code>"&#92;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.
*/
public void QuoteChar(int ch) {
if (ch >= 0 && ch < characterType.Length)
characterType[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:
* <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.
*/
public void ParseNumbers()
{
for (int i = '0'; i <= '9'; i++)
{
characterType[i] |= CT_DIGIT;
}
characterType['.'] |= CT_DIGIT;
characterType['-'] |= 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 <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>'&#92;r'</code>) or a newline
* character (<code>'&#92;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.
*/
public void EolIsSignificant(bool flag)
{
eolIsSignificantP = flag;
}
 
/**
* 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>*&#47;</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 bool SlashStarComments
{
get { return slashStarCommentsP; }
set { slashStarCommentsP=value; }
}
 
/**
* 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 bool SlashSlashComments
{
get { return slashSlashCommentsP; }
set { slashSlashCommentsP = value; }
}
 
/**
* 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.
*/
public bool LowerCaseMode
{
set{ forceLower = value; }
}
 
/** Read the next character */
private int Read()
{
if (reader != null)
{
return reader.Read();
}
else
{
throw new InvalidOperationException();
}
}
 
/**
* 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.
*/
public int NextToken()
{
if (pushedBack)
{
pushedBack = false;
return ttype;
}
byte[] ct = characterType;
StringValue = 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') {
LineNumber++;
if (eolIsSignificantP) {
peekc = SKIP_LF;
return ttype = TT_EOL;
}
c = Read();
if (c == '\n')
c = Read();
} else {
if (c == '\n') {
LineNumber++;
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) {
bool 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;
}
NumberValue = neg ? -v : v;
return ttype = TT_NUMBER;
}
 
if ((ctype & CT_ALPHA) != 0) {
int i = 0;
do {
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;
StringValue = new string(buf.ToArray(), 0, i);
if (forceLower)
StringValue = StringValue.ToLower();
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();
}
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;
 
StringValue = new string(buf.ToArray(), 0, i);
return ttype;
}
 
if (c == '/' && (slashSlashCommentsP || slashStarCommentsP)) {
c = Read();
if (c == '*' && slashStarCommentsP) {
int prevc = 0;
while ((c = Read()) != '/' || prevc != '*') {
if (c == '\r') {
LineNumber++;
c = Read();
if (c == '\n') {
c = Read();
}
} else {
if (c == '\n') {
LineNumber++;
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 <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.
*/
public void PushBack()
{
if (ttype != TT_NOTHING) /* No-op if nextToken() not called */
{
pushedBack = true;
}
}
 
/**
* 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
*/
public override string ToString()
{
string ret;
switch (ttype) {
case TT_EOF:
ret = "EOF";
break;
case TT_EOL:
ret = "EOL";
break;
case TT_WORD:
ret = StringValue;
break;
case TT_NUMBER:
ret = "n=" + NumberValue;
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 &&
((characterType[ttype] & CT_QUOTE) != 0)) {
ret = StringValue;
break;
}
 
char[] s = new char[3];
s[0] = s[2] = '\'';
s[1] = (char) ttype;
ret = new string(s);
break;
}
}
return "Token[" + ret + "], line " + LineNumber;
}
 
 
public IEnumerator<int> GetEnumerator()
{
ResetSyntax();
while(true)
{
int token = NextToken();
if(token == TT_EOF)
{
yield break;
}
yield return token;
}
}
 
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
}

Thank you for this, I'm going to use it tp port java code!

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