CharUtil

package com.opslab.util;

import java.io.UnsupportedEncodingException;

/**
* Various character and character sequence utilities, including <code>char[]</code> - <code>byte[]</code> conversions.
*/
public final class CharUtil {

/**
* Converts (signed) byte to (unsigned) char.
*/
public static char toChar(byte b) {
return (char) (b & 0xFF);
}

/**
* Converts char array into byte array by stripping the high byte of each character.
*/
public final static byte[] toSimpleByteArray(char[] carr) {
byte[] barr = new byte[carr.length];
for (int i = 0; i < carr.length; i++) {
barr[i] = (byte) carr[i];
}
return barr;
}

/**
* Converts char sequence into byte array.
*
* @see #toSimpleByteArray(char[])
*/
public final static byte[] toSimpleByteArray(CharSequence charSequence) {
byte[] barr = new byte[charSequence.length()];
for (int i = 0; i < barr.length; i++) {
barr[i] = (byte) charSequence.charAt(i);
}
return barr;
}

// ---------------------------------------------------------------- ascii

/**
* Converts byte array to char array by simply extending bytes to chars.
*/
public final static char[] toSimpleCharArray(byte[] barr) {
char[] carr = new char[barr.length];
for (int i = 0; i < barr.length; i++) {
carr[i] = (char) (barr[i] & 0xFF);
}
return carr;
}

/**
* Returns ASCII value of a char. In case of overload, 0x3F is returned.
*/
public final static int toAscii(char c) {
if (c <= 0xFF) {
return c;
} else {
return 0x3F;
}
}

/**
* Converts char array into {@link #toAscii(char) ASCII} array.
*/
public final static byte[] toAsciiByteArray(char[] carr) {
byte[] barr = new byte[carr.length];
for (int i = 0; i < carr.length; i++) {
barr[i] = (byte) ((int) (carr[i] <= 0xFF ? carr[i] : 0x3F));
}
return barr;
}

// ---------------------------------------------------------------- raw arrays

/**
* Converts char sequence into ASCII byte array.
*/
public final static byte[] toAsciiByteArray(CharSequence charSequence) {
byte[] barr = new byte[charSequence.length()];
for (int i = 0; i < barr.length; i++) {
char c = charSequence.charAt(i);
barr[i] = (byte) ((int) (c <= 0xFF ? c : 0x3F));
}
return barr;
}

/**
* Converts char array into byte array by replacing each character with two bytes.
*/
public final static byte[] toRawByteArray(char[] carr) {
byte[] barr = new byte[carr.length << 1];
for (int i = 0, bpos = 0; i < carr.length; i++) {
char c = carr[i];
barr[bpos++] = (byte) ((c & 0xFF00) >> 8);
barr[bpos++] = (byte) (c & 0x00FF);
}
return barr;
}

// ---------------------------------------------------------------- encoding

public final static char[] toRawCharArray(byte[] barr) {
int carrLen = barr.length >> 1;
if (carrLen << 1 < barr.length) {
carrLen++;
}
char[] carr = new char[carrLen];
int i = 0, j = 0;
while (i < barr.length) {
char c = (char) (barr[i] << 8);
i++;

if (i != barr.length) {
c += barr[i] & 0xFF;
i++;
}
carr[j++] = c;
}
return carr;
}

/**
* Converts char array to byte array using default Jodd encoding.
*/
public final static byte[] toByteArray(char[] carr) throws UnsupportedEncodingException {
return new String(carr).getBytes(CharsetUtil.UTF_8);
}

/**
* Converts char array to byte array using provided encoding.
*/
public final static byte[] toByteArray(char[] carr, String charset) throws UnsupportedEncodingException {
return new String(carr).getBytes(charset);
}

/**
* Converts byte array of default Jodd encoding to char array.
*/
public final static char[] toCharArray(byte[] barr) throws UnsupportedEncodingException {
return new String(barr, CharsetUtil.UTF_8).toCharArray();
}

// ---------------------------------------------------------------- find

/**
* Converts byte array of specific encoding to char array.
*/
public final static char[] toCharArray(byte[] barr, String charset) throws UnsupportedEncodingException {
return new String(barr, charset).toCharArray();
}

/**
* Match if one character equals to any of the given character.
*
* @return <code>true</code> if characters match any character from given array,
* otherwise <code>false</code>
*/
public final static boolean equalsOne(char c, char[] match) {
for (char aMatch : match) {
if (c == aMatch) {
return true;
}
}
return false;
}

/**
* Finds index of the first character in given array the matches any from the
* given set of characters.
*
* @return index of matched character or -1
*/
public final static int findFirstEqual(char[] source, int index, char[] match) {
for (int i = index; i < source.length; i++) {
if (equalsOne(source[i], match) == true) {
return i;
}
}
return -1;
}

/**
* Finds index of the first character in given array the matches any from the
* given set of characters.
*
* @return index of matched character or -1
*/
public final static int findFirstEqual(char[] source, int index, char match) {
for (int i = index; i < source.length; i++) {
if (source[i] == match) {
return i;
}
}
return -1;
}

/**
* Finds index of the first character in given array the differs from the
* given set of characters.
*
* @return index of matched character or -1
*/
public final static int findFirstDiff(char[] source, int index, char[] match) {
for (int i = index; i < source.length; i++) {
if (equalsOne(source[i], match) == false) {
return i;
}
}
return -1;
}

/**
* Finds index of the first character in given array the differs from the
* given set of characters.
*
* @return index of matched character or -1
*/
public final static int findFirstDiff(char[] source, int index, char match) {
for (int i = index; i < source.length; i++) {
if (source[i] != match) {
return i;
}
}
return -1;
}

/**
* Returns <code>true</code> if character is a white space ({@code <= ' '}).
* White space definition is taken from String class (see: <code>trim()</code>).
*/
public final static boolean isWhitespace(char c) {
return c <= ' ';
}

/**
* Returns <code>true</code> if specified character is lowercase ASCII.
* If user uses only ASCIIs, it is much much faster.
*/
public final static boolean isLowercaseAlpha(char c) {
return (c >= 'a') && (c <= 'z');
}

/**
* Returns <code>true</code> if specified character is uppercase ASCII.
* If user uses only ASCIIs, it is much much faster.
*/
public final static boolean isUppercaseAlpha(char c) {
return (c >= 'A') && (c <= 'Z');
}

public final static boolean isAlphaOrDigit(char c) {
return isDigit(c) || isAlpha(c);
}

public final static boolean isWordChar(char c) {
return isDigit(c) || isAlpha(c) || (c == '_');
}

public final static boolean isPropertyNameChar(char c) {
return isDigit(c) || isAlpha(c) || (c == '_') || (c == '.') || (c == '[') || (c == ']');
}

/**
* Indicates whether the given character is in the {@code ALPHA} set.
*
* @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
*/
public final static boolean isAlpha(char c) {
return ((c >= 'a') && (c <= 'z')) || ((c >= 'A') && (c <= 'Z'));
}

/**
* Indicates whether the given character is in the {@code DIGIT} set.
*
* @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
*/
public final static boolean isDigit(char c) {
return c >= '0' && c <= '9';
}

/**
* Indicates whether the given character is the hexadecimal digit.
*/
public final static boolean isHexDigit(char c) {
return (c >= '0' && c <= '9') || ((c >= 'a') && (c <= 'f')) || ((c >= 'A') && (c <= 'F'));
}

/**
* Indicates whether the given character is in the <i>gen-delims</i> set.
*
* @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
*/
public final static boolean isGenericDelimiter(int c) {
switch (c) {
case ':':
case '/':
case '?':
case '#':
case '[':
case ']':
case '@':
return true;
default:
return false;
}
}

/**
* Indicates whether the given character is in the <i>sub-delims</i> set.
*
* @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
*/
public final static boolean isSubDelimiter(int c) {
switch (c) {
case '!':
case '$':
case '&':
case '\'':
case '(':
case ')':
case '*':
case '+':
case ',':
case ';':
case '=':
return true;
default:
return false;
}
}

/**
* Indicates whether the given character is in the <i>reserved</i> set.
*
* @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
*/
public final static boolean isReserved(char c) {
return isGenericDelimiter(c) || isSubDelimiter(c);
}

/**
* Indicates whether the given character is in the <i>unreserved</i> set.
*
* @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
*/
public final static boolean isUnreserved(char c) {
return isAlpha(c) || isDigit(c) || c == '-' || c == '.' || c == '_' || c == '~';
}

/**
* Indicates whether the given character is in the <i>pchar</i> set.
*
* @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
*/
public final static boolean isPchar(char c) {
return isUnreserved(c) || isSubDelimiter(c) || c == ':' || c == '@';
}

/**
* Uppers lowercase ASCII char.
*/
public final static char toUpperAscii(char c) {
if (isLowercaseAlpha(c)) {
c -= (char) 0x20;
}
return c;
}

/**
* Lowers uppercase ASCII char.
*/
public final static char toLowerAscii(char c) {
if (isUppercaseAlpha(c)) {
c += (char) 0x20;
}
return c;
}

}