/*
* Portions Copyright 2000-2007 Sun Microsystems, Inc. All Rights
* Reserved. Use is subject to license terms.
* 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 gov.nist.core;
import java.util.*;
/**
* Base string token splitter.
*
* @version JAIN-SIP-1.1
*
*
* <a href="{@docRoot}/uncopyright.html">This code is in the public domain.</a>
*
*/
public class StringTokenizer {
/** Current buffer to be parsed. */
protected String buffer;
/** Current offset int input buffer. */
protected int ptr;
/** Saved pointer for peek operations. */
protected int savedPtr;
/** Current token delimiter. */
char delimiter;
/**
* Default constructor.
* Resets the buffer offset to 0 and the default
* newline delimiter.
*/
public StringTokenizer() {
this.delimiter = '\n';
this.ptr = 0;
}
/**
* Constructs a string tokenizer for input buffer.
* @param buffer the text to be parsed
*/
public StringTokenizer(String buffer) {
this.buffer = buffer;
this.ptr = 0;
this.delimiter = '\n';
}
/**
* Constructs a string tokenizer for input buffer
* and specified field separator.
* @param buffer the text to be parsed
* @param delimiter the field separator character
*/
public StringTokenizer(String buffer, char delimiter) {
this.buffer = buffer;
this.delimiter = delimiter;
this.ptr = 0;
}
/**
* Gets the next token.
* @return the next token, not including the field separator
*/
public String nextToken() {
StringBuffer retval = new StringBuffer();
while (ptr < buffer.length()) {
if (buffer.charAt(ptr) == delimiter) {
retval.append(buffer.charAt(ptr));
ptr++;
break;
} else {
retval.append(buffer.charAt(ptr));
ptr++;
}
}
return retval.toString();
}
/**
* Checks if more characters are available.
* @return true if more characters can be processed
*/
public boolean hasMoreChars() {
return ptr < buffer.length();
}
/**
* Checks if character is part of a hexadecimal number.
* @param ch character to be checked
* @return true if the character is a hex digit
*/
public static boolean isHexDigit(char ch) {
if (isDigit(ch))
return true;
else {
char ch1 = Character.toUpperCase(ch);
return ch1 == 'A' || ch1 == 'B' || ch1 == 'C' ||
ch1 == 'D' || ch1 == 'E' || ch1 == 'F';
}
}
/**
* Checks if the character is an alphabetic character.
* @param ch the character to be checked.
* @return true if the character is alphabetic
*/
public static boolean isAlpha(char ch) {
boolean retval = Character.isUpperCase(ch) ||
Character.isLowerCase(ch);
// Debug.println("isAlpha is returning " + retval + " for " + ch);
return retval;
}
/**
* Checks if the character is a numeric character.
* @param ch the character to be checked.
* @return true if the character is a deciomal digit
*/
public static boolean isDigit(char ch) {
boolean retval = Character.isDigit(ch);
// Debug.println("isDigit is returning " + retval + " for " + ch);
return retval;
}
/**
* Checks if the string contains numeric characters only.
* @param str the string to be checked.
* @return true if the string contains numeric characters only
*/
public static boolean isDigitString(String str) {
int len = str.length();
if (len == 0) { // empty string - return false
return false;
} else {
boolean retval = true;
for (int i = 0; i < str.length(); i++) {
if (!Character.isDigit(str.charAt(i))) {
retval = false;
break;
}
}
return retval;
}
}
/**
* Checks if the given character is allowed in method/header/parameter name.
* The character is valid if it is: (1) a digit or (2) a letter, or
* (3) is one of the characters on the next list: -.!%*_+`'~
* @param ch the character to check
* @return true if the character is valid, false otherwise
*/
public static boolean isValidChar(char ch) {
String validChars = "-.!%*_+`'~";
if (!((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'Z') ||
(ch >= 'a' && ch <= 'z')) && (validChars.indexOf(ch) == -1)) {
// ("Invalid character '" + ch + "' in the name.");
return false;
}
return true;
}
/**
* Checks if the given symbol belongs to the escaped group.
* The character is escaped if it is satisfies the next ABNF
* (see RFC3261 p.220): <br>
* escaped = "%" HEXDIG HEXDIG
* <br>
* @param name the string to be parsed for escaped value
* @param index shift inside parsed string
* @return true if string contains escaped value, false otherwise
*/
public static boolean isEscaped(String name, int index) {
// RFC3261 p.220
// escaped = "%" HEXDIG HEXDIG
//
if (name.charAt(index) != '%' ||
(name.length() - index - 2) < 0 ||
!isHexDigit(name.charAt(index + 1)) ||
!isHexDigit(name.charAt(index + 2))) {
return false;
}
return true;
}
/**
* Checks if the given sequence is quoted pair.
*
* @param name the string to be parsed for quoted pair
* @param offset inside parsed string
* @return true if quoted pair is placed at <code>name</code>
* [<code>offset</code>], false otherwise
*/
public static boolean isQuotedPair(String name, int offset) {
// RFC3261 p.222
// quoted-pair = "\" (%x00-09 / %x0B-0C
// / %x0E-7F)
//
if (name.charAt(offset) != '\\' ||
(name.length() - offset - 1) <= 0) {
return false;
}
char ch = name.charAt(offset + 1);
if (ch == 0xA ||
ch == 0xD ||
ch > 0x7F) {
return false;
}
return true;
}
/**
* Gets the next line of text.
* @return characters up to the next newline
*/
public String getLine() {
StringBuffer retval = new StringBuffer();
while (ptr < buffer.length() && buffer.charAt(ptr) != '\n') {
retval.append(buffer.charAt(ptr));
ptr++;
}
if (ptr < buffer.length() && buffer.charAt(ptr) == '\n') {
retval.append('\n');
ptr++;
}
return retval.toString();
}
/**
* Peeks at the next line without consuming the
* characters.
* @return the next line of text
*/
public String peekLine() {
int curPos = ptr;
String retval = this.getLine();
ptr = curPos;
return retval;
}
/**
* Looks ahead one character in the input buffer
* without consuming the character.
* @return the next character in the input buffer
* @exception ParseException if a parsing error occurs
*/
public char lookAhead() throws ParseException {
return lookAhead(0);
}
/**
* Looks ahead a specified number of characters in the input buffer
* without consuming the character.
* @param k the number of characters to advance the
* current buffer offset
* @return the requested character in the input buffer
* @exception ParseException if a parsing error occurs
*/
public char lookAhead(int k) throws ParseException {
// Debug.out.println("ptr = " + ptr);
if (ptr+k < buffer.length())
return buffer.charAt(ptr + k);
else return '\0';
}
/**
* Gets one character in the input buffer
* and consumes the character.
* @return the next character in the input buffer
* @exception ParseException if a parsing error occurs
*/
public char getNextChar() throws ParseException {
if (ptr >= buffer.length())
throw new ParseException
(buffer + " getNextChar: End of buffer", ptr);
else return buffer.charAt(ptr++);
}
/**
* Advances the current pointer to the saved peek pointer
* to consume the characters that were pending parsing
* completion.
*/
public void consume() {
ptr = savedPtr;
}
/**
* Consume the specified number of characters from the input
* buffer.
* @param k the number of characters to advance the
* current buffer offset
*/
public void consume(int k) {
ptr += k;
}
/**
* Gets a Vector of the buffer tokenized by lines.
* @return vector of tokens
*/
public Vector getLines() {
Vector result = new Vector();
while (hasMoreChars()) {
String line = getLine();
result.addElement(line);
}
return result;
}
/**
* Gets the next token from the buffer.
* @param delim the field separator
* @return the next textual token
* @exception ParseException if a parsing error occurs
*/
public String getNextToken(char delim) throws ParseException {
StringBuffer retval = new StringBuffer();
while (true) {
char la = lookAhead(0);
// System.out.println("la = " + la);
if (la == delim) break;
else if (la == '\0')
throw new ParseException("EOL reached", 0);
retval.append(buffer.charAt(ptr));
consume(1);
}
return retval.toString();
}
/**
* Gets the SDP field name of the line.
* @param line the input buffer to be parsed
* @return the SDP field name
*/
public static String getSDPFieldName(String line) {
if (line == null)
return null;
String fieldName = null;
try {
int begin = line.indexOf("=");
fieldName = line.substring(0, begin);
} catch (IndexOutOfBoundsException e) {
return null;
}
return fieldName;
}
/**
* According to the RFC 3261, section 7.3.1:
*
* Header fields can be extended over multiple lines by preceding each
* extra line with at least one SP or horizontal tab (HT). The line
* break and the whitespace at the beginning of the next line are
* treated as a single SP character.
*
* This function converts all pairs of newline+space/tab in the
* string 's' into signle spaces.
*
* @param s string to handle.
* @return processed string.
*/
public static String convertNewLines(String s) {
int i;
char chCurr;
String result = "";
// new Exception("convertNewLines").printStackTrace();
if (s.length() == 0) {
return result;
}
// Eat leading spaces and carriage returns (necessary??).
i = 0;
i = skipWhiteSpace(s, i);
while (i < s.length()) {
chCurr = s.charAt(i);
// Actually, the spec requires "<CRLF> <Space|Tab>" for multiline
// header values, but we support also LFCR, LF and CR.
if (chCurr == '\n' || chCurr == '\r') {
if (i < s.length() - 1 &&
(s.charAt(i+1) == '\t' || s.charAt(i+1) == ' ')) {
// Check if the last saved symbol is CR or LF.
// This will be needed if we decide not to skip CRLF bellow.
result += ' ';
i++;
} else {
/*
* RFC 3261, p. 221:
* A CRLF is allowed in the definition of TEXT-UTF8-TRIM
* only as part of a header field continuation. It is
* expected that the folding LWS will be replaced with
* a single SP before interpretation of the TEXT-UTF8-TRIM
* value.
*
* But it's not clearly defined what to do if CRLF or CR, or
* LF without following LWS is occured, so we just skip it.
*/
}
} else {
result += chCurr;
}
i++;
} // end while()
// System.out.println("@@@\nconverted from:\n<<"+s+">> " +
// "into:\n<<"+result+">>");
return result;
}
/**
* Skip whitespace that starts at offset i in the string s
* @param s string containing some text
* @param i offset where the whitespace begins
* @return offset of the text following the whitespace
*/
private static int skipWhiteSpace(String s, int i) {
int len = s.length();
if (i >= len) {
return i;
}
char chCurr;
chCurr = s.charAt(i);
while (chCurr == '\n' || chCurr == '\r' ||
chCurr == '\t' || chCurr == ' ') {
i++;
if (i >= len) break;
chCurr = s.charAt(i);
}
return i;
}
}
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