Java tutorial
package org.bouncycastle.util; import java.security.AccessController; import java.security.PrivilegedAction; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.OutputStream; import java.util.ArrayList; import java.util.List; import java.util.Vector; import java.util.Iterator; public final class Strings { private static String LINE_SEPARATOR; static { try { LINE_SEPARATOR = (String) AccessController.doPrivileged(new PrivilegedAction() { public Object run() { // the easy way return System.getProperty("line.separator"); } }); } catch (Exception e) { LINE_SEPARATOR = "\n"; // we're desperate use this... } } public static String fromUTF8ByteArray(byte[] bytes) { int i = 0; int length = 0; while (i < bytes.length) { length++; if ((bytes[i] & 0xf0) == 0xf0) { // surrogate pair length++; i += 4; } else if ((bytes[i] & 0xe0) == 0xe0) { i += 3; } else if ((bytes[i] & 0xc0) == 0xc0) { i += 2; } else { i += 1; } } char[] cs = new char[length]; i = 0; length = 0; while (i < bytes.length) { char ch; if ((bytes[i] & 0xf0) == 0xf0) { int codePoint = ((bytes[i] & 0x03) << 18) | ((bytes[i + 1] & 0x3F) << 12) | ((bytes[i + 2] & 0x3F) << 6) | (bytes[i + 3] & 0x3F); int U = codePoint - 0x10000; char W1 = (char) (0xD800 | (U >> 10)); char W2 = (char) (0xDC00 | (U & 0x3FF)); cs[length++] = W1; ch = W2; i += 4; } else if ((bytes[i] & 0xe0) == 0xe0) { ch = (char) (((bytes[i] & 0x0f) << 12) | ((bytes[i + 1] & 0x3f) << 6) | (bytes[i + 2] & 0x3f)); i += 3; } else if ((bytes[i] & 0xd0) == 0xd0) { ch = (char) (((bytes[i] & 0x1f) << 6) | (bytes[i + 1] & 0x3f)); i += 2; } else if ((bytes[i] & 0xc0) == 0xc0) { ch = (char) (((bytes[i] & 0x1f) << 6) | (bytes[i + 1] & 0x3f)); i += 2; } else { ch = (char) (bytes[i] & 0xff); i += 1; } cs[length++] = ch; } return new String(cs); } public static byte[] toUTF8ByteArray(String string) { return toUTF8ByteArray(string.toCharArray()); } public static byte[] toUTF8ByteArray(char[] string) { ByteArrayOutputStream bOut = new ByteArrayOutputStream(); try { toUTF8ByteArray(string, bOut); } catch (IOException e) { throw new IllegalStateException("cannot encode string to byte array!"); } return bOut.toByteArray(); } public static void toUTF8ByteArray(char[] string, OutputStream sOut) throws IOException { char[] c = string; int i = 0; while (i < c.length) { char ch = c[i]; if (ch < 0x0080) { sOut.write(ch); } else if (ch < 0x0800) { sOut.write(0xc0 | (ch >> 6)); sOut.write(0x80 | (ch & 0x3f)); } // surrogate pair else if (ch >= 0xD800 && ch <= 0xDFFF) { // in error - can only happen, if the Java String class has a // bug. if (i + 1 >= c.length) { throw new IllegalStateException("invalid UTF-16 codepoint"); } char W1 = ch; ch = c[++i]; char W2 = ch; // in error - can only happen, if the Java String class has a // bug. if (W1 > 0xDBFF) { throw new IllegalStateException("invalid UTF-16 codepoint"); } int codePoint = (((W1 & 0x03FF) << 10) | (W2 & 0x03FF)) + 0x10000; sOut.write(0xf0 | (codePoint >> 18)); sOut.write(0x80 | ((codePoint >> 12) & 0x3F)); sOut.write(0x80 | ((codePoint >> 6) & 0x3F)); sOut.write(0x80 | (codePoint & 0x3F)); } else { sOut.write(0xe0 | (ch >> 12)); sOut.write(0x80 | ((ch >> 6) & 0x3F)); sOut.write(0x80 | (ch & 0x3F)); } i++; } } /** * A locale independent version of toUpperCase. * * @param string input to be converted * @return a US Ascii uppercase version */ public static String toUpperCase(String string) { boolean changed = false; char[] chars = string.toCharArray(); for (int i = 0; i != chars.length; i++) { char ch = chars[i]; if ('a' <= ch && 'z' >= ch) { changed = true; chars[i] = (char) (ch - 'a' + 'A'); } } if (changed) { return new String(chars); } return string; } /** * A locale independent version of toLowerCase. * * @param string input to be converted * @return a US ASCII lowercase version */ public static String toLowerCase(String string) { boolean changed = false; char[] chars = string.toCharArray(); for (int i = 0; i != chars.length; i++) { char ch = chars[i]; if ('A' <= ch && 'Z' >= ch) { changed = true; chars[i] = (char) (ch - 'A' + 'a'); } } if (changed) { return new String(chars); } return string; } public static byte[] toByteArray(char[] chars) { byte[] bytes = new byte[chars.length]; for (int i = 0; i != bytes.length; i++) { bytes[i] = (byte) chars[i]; } return bytes; } public static byte[] toByteArray(String string) { byte[] bytes = new byte[string.length()]; for (int i = 0; i != bytes.length; i++) { char ch = string.charAt(i); bytes[i] = (byte) ch; } return bytes; } public static int toByteArray(String s, byte[] buf, int off) { int count = s.length(); for (int i = 0; i < count; ++i) { char c = s.charAt(i); buf[off + i] = (byte) c; } return count; } /** * Convert an array of 8 bit characters into a string. * * @param bytes 8 bit characters. * @return resulting String. */ public static String fromByteArray(byte[] bytes) { return new String(asCharArray(bytes)); } /** * Do a simple conversion of an array of 8 bit characters into a string. * * @param bytes 8 bit characters. * @return resulting String. */ public static char[] asCharArray(byte[] bytes) { char[] chars = new char[bytes.length]; for (int i = 0; i != chars.length; i++) { chars[i] = (char) (bytes[i] & 0xff); } return chars; } public static String[] split(String input, char delimiter) { Vector v = new Vector(); boolean moreTokens = true; String subString; while (moreTokens) { int tokenLocation = input.indexOf(delimiter); if (tokenLocation > 0) { subString = input.substring(0, tokenLocation); v.addElement(subString); input = input.substring(tokenLocation + 1); } else { moreTokens = false; v.addElement(input); } } String[] res = new String[v.size()]; for (int i = 0; i != res.length; i++) { res[i] = (String) v.elementAt(i); } return res; } public static String lineSeparator() { return LINE_SEPARATOR; } public static StringList newList() { return new StringListImpl(); } private static class StringListImpl implements StringList { private List list = new ArrayList(); public boolean add(String s) { return list.add(s); } public String get(int index) { return (String) list.get(index); } public String set(int index, String element) { return (String) list.set(index, element); } public void add(int index, String element) { list.add(index, element); } public int size() { return list.size(); } public Iterator iterator() { return list.iterator(); } public String[] toStringArray() { String[] strs = new String[this.size()]; for (int i = 0; i != strs.length; i++) { strs[i] = this.get(i); } return strs; } public String[] toStringArray(int from, int to) { String[] strs = new String[to - from]; for (int i = from; i != this.size() && i != to; i++) { strs[i - from] = this.get(i); } return strs; } } }