org.owasp.html.Strings Maven / Gradle / Ivy
// Copyright (c) 2011, Mike Samuel
// All rights reserved.
//
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// modification, are permitted provided that the following conditions
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//
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// be used to endorse or promote products derived from this software
// without specific prior written permission.
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package org.owasp.html;
import javax.annotation.Nullable;
/**
* Locale independent versions of String case-insensitive operations.
*
* The normal case insensitive operators {@link String#toLowerCase}
* and {@link String#equalsIgnoreCase} depend upon the current locale.
* They will fold the letters "i" and "I" differently if the locale is
* Turkish than if it is English.
*
* These operations ignore all case folding for non-Roman letters, and are
* independent of the current locale.
* Lower-casing is exactly equivalent to {@code tr/A-Z/a-z/}, upper-casing to
* {@code tr/a-z/A-Z/}, and case insensitive comparison is equivalent to
* lower-casing both then comparing by code-unit.
*
* Because of this simpler case folding, it is the case that for all Strings s
*
* Strings.toUpperCase(s).equals(Strings.toUpperCase(Strings.toLowerCase(s)))
* .
*
* @author Mike Samuel ([email protected])
*/
final class Strings {
public static boolean equalsIgnoreCase(
@Nullable String a, @Nullable String b) {
if (a == null) { return b == null; }
if (b == null) { return false; }
int length = a.length();
if (b.length() != length) { return false; }
for (int i = length; --i >= 0;) {
char c = a.charAt(i), d = b.charAt(i);
if (c != d) {
if (c <= 'z' && c >= 'A') {
if (c <= 'Z') { c |= 0x20; }
if (d <= 'Z' && d >= 'A') { d |= 0x20; }
if (c == d) { continue; }
}
return false;
}
}
return true;
}
public static boolean regionMatchesIgnoreCase(
CharSequence a, int aoffset, CharSequence b, int boffset, int n) {
if (aoffset + n > a.length() || boffset + n > b.length()) { return false; }
for (int i = n; --i >= 0;) {
char c = a.charAt(aoffset + i), d = b.charAt(boffset + i);
if (c != d) {
if (c <= 'z' && c >= 'A') {
if (c <= 'Z') { c |= 0x20; }
if (d <= 'Z' && d >= 'A') { d |= 0x20; }
if (c == d) { continue; }
}
return false;
}
}
return true;
}
/** True iff {@code s.equals(String.toLowerCase(s))}. */
public static boolean isLowerCase(CharSequence s) {
for (int i = s.length(); --i >= 0;) {
char c = s.charAt(i);
if (c <= 'Z' && c >= 'A') {
return false;
}
}
return true;
}
private static final char[] LCASE_CHARS = new char['Z' + 1];
private static final char[] UCASE_CHARS = new char['z' + 1];
static {
for (int i = 0; i < 'A'; ++i) { LCASE_CHARS[i] = (char) i; }
for (int i = 'A'; i <= 'Z'; ++i) { LCASE_CHARS[i] = (char) (i | 0x20); }
for (int i = 0; i < 'a'; ++i) { UCASE_CHARS[i] = (char) i; }
for (int i = 'a'; i <= 'z'; ++i) { UCASE_CHARS[i] = (char) (i & ~0x20); }
}
public static String toLowerCase(String s) {
for (int i = s.length(); --i >= 0;) {
char c = s.charAt(i);
if (c <= 'Z' && c >= 'A') {
char[] chars = s.toCharArray();
chars[i] = LCASE_CHARS[c];
while (--i >= 0) {
c = chars[i];
if (c <= 'Z') {
chars[i] = LCASE_CHARS[c];
}
}
return String.valueOf(chars);
}
}
return s;
}
public static String toUpperCase(String s) {
for (int i = s.length(); --i >= 0;) {
char c = s.charAt(i);
if (c <= 'z' && c >= 'a') {
char[] chars = s.toCharArray();
chars[i] = UCASE_CHARS[c];
while (--i >= 0) {
c = chars[i];
if (c <= 'z') {
chars[i] = UCASE_CHARS[c];
}
}
return String.valueOf(chars);
}
}
return s;
}
private Strings() { /* uninstantiable */ }
}