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/**
* Copyright (C) 2006-2014 phloc systems
* http://www.phloc.com
* office[at]phloc[dot]com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.phloc.css.parser;
import java.util.regex.Matcher;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.RegEx;
import javax.annotation.concurrent.Immutable;
import com.phloc.commons.annotations.PresentForCodeCoverage;
import com.phloc.commons.regex.RegExHelper;
import com.phloc.commons.string.StringHelper;
import com.phloc.css.propertyvalue.CCSSValue;
/**
* This class is used by the generated parsers to do some common stuff.
*
* @author Philip Helger
*/
@Immutable
public final class ParseUtils
{
/** The character used to quote elements in CSS URLs */
public static final char URL_ESCAPE_CHAR = '\\';
// Order of the rules in brackets is important!
@RegEx
private static final String SPLIT_NUMBER_REGEX = "^([0-9]*\\.[0-9]+|[0-9]+).*$";
@PresentForCodeCoverage
@SuppressWarnings ("unused")
private static final ParseUtils s_aInstance = new ParseUtils ();
private ParseUtils ()
{}
@Nonnull
private static String _trimBy (@Nonnull final CharSequence s, final int nLeftSkip, final int nRightSkip)
{
return s.toString ().substring (nLeftSkip, s.length () - nRightSkip);
}
/**
* Remove surrounding quotes (single or double) of a string (if present). If
* the start and the end quote are not equal, nothing happens.
*
* @param sStr
* The string where the quotes should be removed
* @return The string without quotes.
*/
@Nullable
public static String extractStringValue (@Nullable final String sStr)
{
if (StringHelper.hasNoText (sStr) || sStr.length () < 2)
return sStr;
final char cFirst = sStr.charAt (0);
if ((cFirst == '"' || cFirst == '\'') && StringHelper.getLastChar (sStr) == cFirst)
{
// Remove quotes around the string
return _trimBy (sStr, 1, 1);
}
return sStr;
}
/**
* Unescape all escaped characters in a CSS URL. All characters masked with a
* '\\' character replaced.
*
* @param sEscapedURL
* The escaped URL. May not be null!
* @return The unescaped URL or the original string, if not a single escape
* sequence is found.
*/
@Nonnull
public static String unescapeURL (@Nonnull final String sEscapedURL)
{
int nIndex = sEscapedURL.indexOf (URL_ESCAPE_CHAR);
if (nIndex < 0)
{
// No escape sequence found
return sEscapedURL;
}
final StringBuilder aSB = new StringBuilder (sEscapedURL.length ());
int nPrevIndex = 0;
do
{
// Append everything before the first quote char
aSB.append (sEscapedURL, nPrevIndex, nIndex);
// Append the quoted char itself
aSB.append (sEscapedURL, nIndex + 1, nIndex + 2);
// The new position to start searching
nPrevIndex = nIndex + 2;
// Search the next escaped char
nIndex = sEscapedURL.indexOf (URL_ESCAPE_CHAR, nPrevIndex);
} while (nIndex >= 0);
// Append the rest
aSB.append (sEscapedURL.substring (nPrevIndex));
return aSB.toString ();
}
/**
* Remove the leading "url(" and the trailing ")" from an URL CSS value. No
* check is performed for the existence of a leading "url("! This method
* should only be called from within the parser.
*
* @param s
* The value to remove the string from.
* @return The trimmed value. Never null.
*/
@Nonnull
public static String trimUrl (@Nonnull final CharSequence s)
{
// Extract from "url(...)"
final String sTrimmed = _trimBy (s, CCSSValue.PREFIX_URL_OPEN.length (), CCSSValue.SUFFIX_URL_CLOSE.length ()).trim ();
// Remove the trailing quotes (if any)
final String sUnquoted = extractStringValue (sTrimmed);
// Unescape all escaped chars
return unescapeURL (sUnquoted);
}
@Nonnull
public static String splitNumber (@Nonnull final StringBuilder aPattern)
{
// Find the longest matching number within the pattern
final Matcher m = RegExHelper.getMatcher (SPLIT_NUMBER_REGEX, aPattern.toString ());
if (m.matches ())
return m.group (1);
return "";
}
/**
* In CSS, identifiers (including element names, classes, and IDs in
* selectors) can contain only the characters [a-zA-Z0-9] and ISO 10646
* characters U+00A0 and higher, plus the hyphen (-) and the underscore (_);
* they cannot start with a digit, two hyphens, or a hyphen followed by a
* digit. Identifiers can also contain escaped characters and any ISO 10646
* character as a numeric code (see next item). For instance, the identifier
* "B&W?" may be written as "B\&W\?" or "B\26 W\3F".
*
* @param aPattern
* pattern to check
* @return The input string
*/
@Nonnull
public static String validateIdentifier (@Nonnull final StringBuilder aPattern)
{
final int nLength = aPattern.length ();
final char c1 = aPattern.charAt (0);
final char c2 = nLength <= 1 ? 0 : aPattern.charAt (1);
// Starts with a hack?
if (c1 == '-' || c1 == '$' || c1 == '*')
{
if (nLength > 1 && Character.isDigit (c2))
throw new TokenMgrError ("Identifier may not start with a hyphen and a digit: " + aPattern,
TokenMgrError.LEXICAL_ERROR);
}
else
{
if (Character.isDigit (c1))
throw new TokenMgrError ("Identifier may not start with a digit: " + aPattern, TokenMgrError.LEXICAL_ERROR);
}
if (nLength > 1 && c1 == '-' && c2 == '-')
throw new TokenMgrError ("Identifier may not start with two hyphens: " + aPattern, TokenMgrError.LEXICAL_ERROR);
return aPattern.toString ();
}
/**
* Unescape e.g. \26 or \000026 to
* &.
*
* @param aImage
* Source string
* @return Unmasked string
*/
@Nonnull
public static String unescapeUnicode (final StringBuilder aImage)
{
// FIXME
return aImage.toString ();
}
/**
* Unescape e.g. \x to x.
*
* @param aImage
* Source string
* @return Unmasked string
*/
@Nonnull
public static String unescapeOther (final StringBuilder aImage)
{
// FIXME
return aImage.toString ();
}
}