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package org.glassfish.jersey.message.internal;
/**
* Class containing static utility methods to work with HTTP headers.
*
* @author Paul Sandoz
* @author Martin Matula
*/
final class GrammarUtil {
/**
* Represents token type in the TYPE_TABLE.
*/
public static final int TOKEN = 0;
/**
* Represents quotes type in the TYPE_TABLE.
*/
public static final int QUOTED_STRING = 1;
/**
* Represents comment type in the TYPE_TABLE.
*/
public static final int COMMENT = 2;
/**
* Represents separator type in the TYPE_TABLE.
*/
public static final int SEPARATOR = 3;
/**
* Represents control type in the TYPE_TABLE.
*/
public static final int CONTROL = 4;
/**
* Array of chars representing white spaces.
*/
private static final char[] WHITE_SPACE = {'\t', '\r', '\n', ' '};
/**
* Array of chars representing separators.
*/
private static final char[] SEPARATORS =
{'(', ')', '<', '>', '@', ',', ';', ':', '\\', '"', '/', '[', ']', '?', '=', '{', '}', ' ', '\t'};
/**
* Mapping of chars to types.
*/
private static final int[] TYPE_TABLE = createEventTable();
/**
* Convenience table mapping chars to true if they are white space chars.
*/
private static final boolean[] IS_WHITE_SPACE = createWhiteSpaceTable();
/**
* convenience table mapping chars to true if they are tokens.
*/
private static final boolean[] IS_TOKEN = createTokenTable();
private static int[] createEventTable() {
int[] table = new int[Byte.MAX_VALUE + 1];
// Control
final int control_char_bound = 32;
for (int i = 0; i < control_char_bound; i++) {
table[i] = CONTROL;
}
table[Byte.MAX_VALUE] = CONTROL;
// Token
for (int i = control_char_bound; i < Byte.MAX_VALUE; i++) {
table[i] = TOKEN;
}
// Separator
for (char c : SEPARATORS) {
table[c] = SEPARATOR;
}
// Comment
table['('] = COMMENT;
// QuotedString
table['"'] = QUOTED_STRING;
// White space
for (char c : WHITE_SPACE) {
table[c] = -1;
}
return table;
}
private static boolean[] createWhiteSpaceTable() {
boolean[] table = new boolean[Byte.MAX_VALUE + 1];
for (char c : WHITE_SPACE) {
table[c] = true;
}
return table;
}
private static boolean[] createTokenTable() {
boolean[] table = new boolean[Byte.MAX_VALUE + 1];
for (int i = 0; i <= Byte.MAX_VALUE; i++) {
table[i] = (TYPE_TABLE[i] == TOKEN);
}
return table;
}
/**
* Returns {@code true} if the provided char is a white space.
*
* @param c char to check.
* @return {@code true} if c is a white space.
*/
public static boolean isWhiteSpace(final char c) {
return (c <= Byte.MAX_VALUE && IS_WHITE_SPACE[c]);
}
/**
* Returns {@code true} if the provided char is a token.
*
* @param c char to check.
* @return {@code true} if c is a token.
*/
public static boolean isToken(final char c) {
return (c <= Byte.MAX_VALUE && IS_TOKEN[c]);
}
/**
* Get the character type.
*
* @param c char to check.
* @return character type identifier.
*
* @throws IllegalArgumentException in case the character value is greater than 127.
*/
public static int getType(final char c) {
if (c > Byte.MAX_VALUE) {
throw new IllegalArgumentException("Unsupported character - ordinal value too high: " + c);
}
return TYPE_TABLE[c];
}
/**
* Returns {@code true} if the provided char is a separator.
*
* @param c char to check.
* @return {@code true} if c is a token.
*/
public static boolean isSeparator(final char c) {
return (c <= Byte.MAX_VALUE && TYPE_TABLE[c] == SEPARATOR);
}
/**
* Returns {@code true} if all chars in string s are tokens.
*
* @param s string to check for tokens.
* @return {@code true} if all chars in s are tokens.
*/
public static boolean isTokenString(final String s) {
for (char c : s.toCharArray()) {
if (!isToken(c)) {
return false;
}
}
return true;
}
/**
* Returns {@code true} if string s contains a white space char.
*
* @param s string to check for white spaces.
* @return {@code true} if s contains white spaces.
*/
public static boolean containsWhiteSpace(final String s) {
for (char c : s.toCharArray()) {
if (isWhiteSpace(c)) {
return true;
}
}
return false;
}
/**
* Filter a substring of a string by removing any new-line characters and
* un-escaping escaped characters.
*
* @param s character sequence to use for substring token filtering.
* @param start start filtering position in the string.
* @param end end filtering position in the string.
* @return filtered substring.
*/
public static String filterToken(final CharSequence s, final int start, final int end) {
return filterToken(s, start, end, false);
}
/**
* Filter a substring of a string by removing any new-line characters and
* un-escaping escaped characters (unless preserveBackslash is set to {@code true}).
*
* @param s character sequence to use for substring token filtering.
* @param start start filtering position in the string.
* @param end end filtering position in the string.
* @param preserveBackslash if set to {@code true}, this method does not treat backslash as an escape character
* (treats it as a regular character instead)
* @return filtered substring.
*/
public static String filterToken(final CharSequence s, final int start, final int end, final boolean preserveBackslash) {
StringBuilder sb = new StringBuilder();
char c;
boolean gotEscape = false;
boolean gotCR = false;
for (int i = start; i < end; i++) {
c = s.charAt(i);
if (c == '\n' && gotCR) {
// This LF is part of an unescaped
// CRLF sequence (i.e, LWSP). Skip it.
gotCR = false;
continue;
}
gotCR = false;
if (!gotEscape) {
// Previous character was NOT '\'
if (!preserveBackslash && c == '\\') { // skip this character
gotEscape = true;
} else if (c == '\r') { // skip this character
gotCR = true;
} else { // append this character
sb.append(c);
}
} else {
// Previous character was '\'. So no need to
// bother with any special processing, just
// append this character
sb.append(c);
gotEscape = false;
}
}
return sb.toString();
}
/**
* Prevents instantiation.
*/
private GrammarUtil() {
}
}