| /* Util.java -- various utility routines. |
| Copyright (C) 2001, 2002, 2003, 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.java.security.util; |
| |
| import java.math.BigInteger; |
| |
| /** |
| * A collection of utility methods used throughout this project. |
| */ |
| public class Util |
| { |
| // Hex charset |
| private static final char[] HEX_DIGITS = "0123456789ABCDEF".toCharArray(); |
| |
| // Base-64 charset |
| private static final String BASE64_CHARS = |
| "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz./"; |
| |
| private static final char[] BASE64_CHARSET = BASE64_CHARS.toCharArray(); |
| |
| /** Trivial constructor to enforce Singleton pattern. */ |
| private Util() |
| { |
| super(); |
| } |
| |
| /** |
| * Returns a string of hexadecimal digits from a byte array. Each byte is |
| * converted to 2 hex symbols; zero(es) included. |
| * <p> |
| * This method calls the method with same name and three arguments as: |
| * <pre> |
| * toString(ba, 0, ba.length); |
| * </pre> |
| * |
| * @param ba the byte array to convert. |
| * @return a string of hexadecimal characters (two for each byte) representing |
| * the designated input byte array. |
| */ |
| public static String toString(byte[] ba) |
| { |
| return toString(ba, 0, ba.length); |
| } |
| |
| /** |
| * Returns a string of hexadecimal digits from a byte array, starting at |
| * <code>offset</code> and consisting of <code>length</code> bytes. Each |
| * byte is converted to 2 hex symbols; zero(es) included. |
| * |
| * @param ba the byte array to convert. |
| * @param offset the index from which to start considering the bytes to |
| * convert. |
| * @param length the count of bytes, starting from the designated offset to |
| * convert. |
| * @return a string of hexadecimal characters (two for each byte) representing |
| * the designated input byte sub-array. |
| */ |
| public static final String toString(byte[] ba, int offset, int length) |
| { |
| char[] buf = new char[length * 2]; |
| for (int i = 0, j = 0, k; i < length;) |
| { |
| k = ba[offset + i++]; |
| buf[j++] = HEX_DIGITS[(k >>> 4) & 0x0F]; |
| buf[j++] = HEX_DIGITS[ k & 0x0F]; |
| } |
| return new String(buf); |
| } |
| |
| /** |
| * Returns a string of hexadecimal digits from a byte array. Each byte is |
| * converted to 2 hex symbols; zero(es) included. The argument is treated as a |
| * large little-endian integer and is returned as a large big-endian integer. |
| * <p> |
| * This method calls the method with same name and three arguments as: |
| * <pre> |
| * toReversedString(ba, 0, ba.length); |
| * </pre> |
| * |
| * @param ba the byte array to convert. |
| * @return a string of hexadecimal characters (two for each byte) representing |
| * the designated input byte array. |
| */ |
| public static String toReversedString(byte[] ba) |
| { |
| return toReversedString(ba, 0, ba.length); |
| } |
| |
| /** |
| * Returns a string of hexadecimal digits from a byte array, starting at |
| * <code>offset</code> and consisting of <code>length</code> bytes. Each |
| * byte is converted to 2 hex symbols; zero(es) included. |
| * <p> |
| * The byte array is treated as a large little-endian integer, and is returned |
| * as a large big-endian integer. |
| * |
| * @param ba the byte array to convert. |
| * @param offset the index from which to start considering the bytes to |
| * convert. |
| * @param length the count of bytes, starting from the designated offset to |
| * convert. |
| * @return a string of hexadecimal characters (two for each byte) representing |
| * the designated input byte sub-array. |
| */ |
| public static final String toReversedString(byte[] ba, int offset, int length) |
| { |
| char[] buf = new char[length * 2]; |
| for (int i = offset + length - 1, j = 0, k; i >= offset;) |
| { |
| k = ba[offset + i--]; |
| buf[j++] = HEX_DIGITS[(k >>> 4) & 0x0F]; |
| buf[j++] = HEX_DIGITS[ k & 0x0F]; |
| } |
| return new String(buf); |
| } |
| |
| /** |
| * <p> |
| * Returns a byte array from a string of hexadecimal digits. |
| * </p> |
| * |
| * @param s a string of hexadecimal ASCII characters |
| * @return the decoded byte array from the input hexadecimal string. |
| */ |
| public static byte[] toBytesFromString(String s) |
| { |
| int limit = s.length(); |
| byte[] result = new byte[((limit + 1) / 2)]; |
| int i = 0, j = 0; |
| if ((limit % 2) == 1) |
| result[j++] = (byte) fromDigit(s.charAt(i++)); |
| while (i < limit) |
| { |
| result[j ] = (byte) (fromDigit(s.charAt(i++)) << 4); |
| result[j++] |= (byte) fromDigit(s.charAt(i++)); |
| } |
| return result; |
| } |
| |
| /** |
| * Returns a byte array from a string of hexadecimal digits, interpreting them |
| * as a large big-endian integer and returning it as a large little-endian |
| * integer. |
| * |
| * @param s a string of hexadecimal ASCII characters |
| * @return the decoded byte array from the input hexadecimal string. |
| */ |
| public static byte[] toReversedBytesFromString(String s) |
| { |
| int limit = s.length(); |
| byte[] result = new byte[((limit + 1) / 2)]; |
| int i = 0; |
| if ((limit % 2) == 1) |
| result[i++] = (byte) fromDigit(s.charAt(--limit)); |
| while (limit > 0) |
| { |
| result[i ] = (byte) fromDigit(s.charAt(--limit)); |
| result[i++] |= (byte) (fromDigit(s.charAt(--limit)) << 4); |
| } |
| return result; |
| } |
| |
| /** |
| * Returns a number from <code>0</code> to <code>15</code> corresponding |
| * to the designated hexadecimal digit. |
| * |
| * @param c a hexadecimal ASCII symbol. |
| */ |
| public static int fromDigit(char c) |
| { |
| if (c >= '0' && c <= '9') |
| return c - '0'; |
| else if (c >= 'A' && c <= 'F') |
| return c - 'A' + 10; |
| else if (c >= 'a' && c <= 'f') |
| return c - 'a' + 10; |
| else |
| throw new IllegalArgumentException("Invalid hexadecimal digit: " + c); |
| } |
| |
| /** |
| * Returns a string of 8 hexadecimal digits (most significant digit first) |
| * corresponding to the unsigned integer <code>n</code>. |
| * |
| * @param n the unsigned integer to convert. |
| * @return a hexadecimal string 8-character long. |
| */ |
| public static String toString(int n) |
| { |
| char[] buf = new char[8]; |
| for (int i = 7; i >= 0; i--) |
| { |
| buf[i] = HEX_DIGITS[n & 0x0F]; |
| n >>>= 4; |
| } |
| return new String(buf); |
| } |
| |
| /** |
| * Returns a string of hexadecimal digits from an integer array. Each int is |
| * converted to 4 hex symbols. |
| */ |
| public static String toString(int[] ia) |
| { |
| int length = ia.length; |
| char[] buf = new char[length * 8]; |
| for (int i = 0, j = 0, k; i < length; i++) |
| { |
| k = ia[i]; |
| buf[j++] = HEX_DIGITS[(k >>> 28) & 0x0F]; |
| buf[j++] = HEX_DIGITS[(k >>> 24) & 0x0F]; |
| buf[j++] = HEX_DIGITS[(k >>> 20) & 0x0F]; |
| buf[j++] = HEX_DIGITS[(k >>> 16) & 0x0F]; |
| buf[j++] = HEX_DIGITS[(k >>> 12) & 0x0F]; |
| buf[j++] = HEX_DIGITS[(k >>> 8) & 0x0F]; |
| buf[j++] = HEX_DIGITS[(k >>> 4) & 0x0F]; |
| buf[j++] = HEX_DIGITS[ k & 0x0F]; |
| } |
| return new String(buf); |
| } |
| |
| /** |
| * Returns a string of 16 hexadecimal digits (most significant digit first) |
| * corresponding to the unsigned long <code>n</code>. |
| * |
| * @param n the unsigned long to convert. |
| * @return a hexadecimal string 16-character long. |
| */ |
| public static String toString(long n) |
| { |
| char[] b = new char[16]; |
| for (int i = 15; i >= 0; i--) |
| { |
| b[i] = HEX_DIGITS[(int)(n & 0x0FL)]; |
| n >>>= 4; |
| } |
| return new String(b); |
| } |
| |
| /** |
| * Similar to the <code>toString()</code> method except that the Unicode |
| * escape character is inserted before every pair of bytes. Useful to |
| * externalise byte arrays that will be constructed later from such strings; |
| * eg. s-box values. |
| * |
| * @throws ArrayIndexOutOfBoundsException if the length is odd. |
| */ |
| public static String toUnicodeString(byte[] ba) |
| { |
| return toUnicodeString(ba, 0, ba.length); |
| } |
| |
| /** |
| * Similar to the <code>toString()</code> method except that the Unicode |
| * escape character is inserted before every pair of bytes. Useful to |
| * externalise byte arrays that will be constructed later from such strings; |
| * eg. s-box values. |
| * |
| * @throws ArrayIndexOutOfBoundsException if the length is odd. |
| */ |
| public static final String toUnicodeString(byte[] ba, int offset, int length) |
| { |
| StringBuffer sb = new StringBuffer(); |
| int i = 0; |
| int j = 0; |
| int k; |
| sb.append('\n').append("\""); |
| while (i < length) |
| { |
| sb.append("\\u"); |
| k = ba[offset + i++]; |
| sb.append(HEX_DIGITS[(k >>> 4) & 0x0F]); |
| sb.append(HEX_DIGITS[ k & 0x0F]); |
| k = ba[offset + i++]; |
| sb.append(HEX_DIGITS[(k >>> 4) & 0x0F]); |
| sb.append(HEX_DIGITS[ k & 0x0F]); |
| if ((++j % 8) == 0) |
| sb.append("\"+").append('\n').append("\""); |
| } |
| sb.append("\"").append('\n'); |
| return sb.toString(); |
| } |
| |
| /** |
| * Similar to the <code>toString()</code> method except that the Unicode |
| * escape character is inserted before every pair of bytes. Useful to |
| * externalise integer arrays that will be constructed later from such |
| * strings; eg. s-box values. |
| * |
| * @throws ArrayIndexOutOfBoundsException if the length is not a multiple of |
| * 4. |
| */ |
| public static String toUnicodeString(int[] ia) |
| { |
| StringBuffer sb = new StringBuffer(); |
| int i = 0; |
| int j = 0; |
| int k; |
| sb.append('\n').append("\""); |
| while (i < ia.length) |
| { |
| k = ia[i++]; |
| sb.append("\\u"); |
| sb.append(HEX_DIGITS[(k >>> 28) & 0x0F]); |
| sb.append(HEX_DIGITS[(k >>> 24) & 0x0F]); |
| sb.append(HEX_DIGITS[(k >>> 20) & 0x0F]); |
| sb.append(HEX_DIGITS[(k >>> 16) & 0x0F]); |
| sb.append("\\u"); |
| sb.append(HEX_DIGITS[(k >>> 12) & 0x0F]); |
| sb.append(HEX_DIGITS[(k >>> 8) & 0x0F]); |
| sb.append(HEX_DIGITS[(k >>> 4) & 0x0F]); |
| sb.append(HEX_DIGITS[ k & 0x0F]); |
| if ((++j % 4) == 0) |
| sb.append("\"+").append('\n').append("\""); |
| } |
| sb.append("\"").append('\n'); |
| return sb.toString(); |
| } |
| |
| public static byte[] toBytesFromUnicode(String s) |
| { |
| int limit = s.length() * 2; |
| byte[] result = new byte[limit]; |
| char c; |
| for (int i = 0; i < limit; i++) |
| { |
| c = s.charAt(i >>> 1); |
| result[i] = (byte)(((i & 1) == 0) ? c >>> 8 : c); |
| } |
| return result; |
| } |
| |
| /** |
| * Dumps a byte array as a string, in a format that is easy to read for |
| * debugging. The string <code>m</code> is prepended to the start of each |
| * line. |
| * <p> |
| * If <code>offset</code> and <code>length</code> are omitted, the whole |
| * array is used. If <code>m</code> is omitted, nothing is prepended to each |
| * line. |
| * |
| * @param data the byte array to be dumped. |
| * @param offset the offset within <i>data</i> to start from. |
| * @param length the number of bytes to dump. |
| * @param m a string to be prepended to each line. |
| * @return a string containing the result. |
| */ |
| public static String dumpString(byte[] data, int offset, int length, String m) |
| { |
| if (data == null) |
| return m + "null\n"; |
| StringBuffer sb = new StringBuffer(length * 3); |
| if (length > 32) |
| sb.append(m).append("Hexadecimal dump of ") |
| .append(length).append(" bytes...\n"); |
| // each line will list 32 bytes in 4 groups of 8 each |
| int end = offset + length; |
| String s; |
| int l = Integer.toString(length).length(); |
| if (l < 4) |
| l = 4; |
| for (; offset < end; offset += 32) |
| { |
| if (length > 32) |
| { |
| s = " " + offset; |
| sb.append(m).append(s.substring(s.length() - l)).append(": "); |
| } |
| int i = 0; |
| for (; i < 32 && offset + i + 7 < end; i += 8) |
| sb.append(toString(data, offset + i, 8)).append(' '); |
| if (i < 32) |
| for (; i < 32 && offset + i < end; i++) |
| sb.append(byteToString(data[offset + i])); |
| sb.append('\n'); |
| } |
| return sb.toString(); |
| } |
| |
| public static String dumpString(byte[] data) |
| { |
| return (data == null) ? "null\n" : dumpString(data, 0, data.length, ""); |
| } |
| |
| public static String dumpString(byte[] data, String m) |
| { |
| return (data == null) ? "null\n" : dumpString(data, 0, data.length, m); |
| } |
| |
| public static String dumpString(byte[] data, int offset, int length) |
| { |
| return dumpString(data, offset, length, ""); |
| } |
| |
| /** |
| * Returns a string of 2 hexadecimal digits (most significant digit first) |
| * corresponding to the lowest 8 bits of <code>n</code>. |
| * |
| * @param n the byte value to convert. |
| * @return a string of 2 hex characters representing the input. |
| */ |
| public static String byteToString(int n) |
| { |
| char[] buf = { HEX_DIGITS[(n >>> 4) & 0x0F], HEX_DIGITS[n & 0x0F] }; |
| return new String(buf); |
| } |
| |
| /** |
| * Converts a designated byte array to a Base-64 representation, with the |
| * exceptions that (a) leading 0-byte(s) are ignored, and (b) the character |
| * '.' (dot) shall be used instead of "+' (plus). |
| * <p> |
| * Used by SASL password file manipulation primitives. |
| * |
| * @param buffer an arbitrary sequence of bytes to represent in Base-64. |
| * @return unpadded (without the '=' character(s)) Base-64 representation of |
| * the input. |
| */ |
| public static final String toBase64(byte[] buffer) |
| { |
| int len = buffer.length, pos = len % 3; |
| byte b0 = 0, b1 = 0, b2 = 0; |
| switch (pos) |
| { |
| case 1: |
| b2 = buffer[0]; |
| break; |
| case 2: |
| b1 = buffer[0]; |
| b2 = buffer[1]; |
| break; |
| } |
| StringBuffer sb = new StringBuffer(); |
| int c; |
| boolean notleading = false; |
| do |
| { |
| c = (b0 & 0xFC) >>> 2; |
| if (notleading || c != 0) |
| { |
| sb.append(BASE64_CHARSET[c]); |
| notleading = true; |
| } |
| c = ((b0 & 0x03) << 4) | ((b1 & 0xF0) >>> 4); |
| if (notleading || c != 0) |
| { |
| sb.append(BASE64_CHARSET[c]); |
| notleading = true; |
| } |
| c = ((b1 & 0x0F) << 2) | ((b2 & 0xC0) >>> 6); |
| if (notleading || c != 0) |
| { |
| sb.append(BASE64_CHARSET[c]); |
| notleading = true; |
| } |
| c = b2 & 0x3F; |
| if (notleading || c != 0) |
| { |
| sb.append(BASE64_CHARSET[c]); |
| notleading = true; |
| } |
| if (pos >= len) |
| break; |
| else |
| { |
| try |
| { |
| b0 = buffer[pos++]; |
| b1 = buffer[pos++]; |
| b2 = buffer[pos++]; |
| } |
| catch (ArrayIndexOutOfBoundsException x) |
| { |
| break; |
| } |
| } |
| } |
| while (true); |
| |
| if (notleading) |
| return sb.toString(); |
| return "0"; |
| } |
| |
| /** |
| * The inverse function of the above. |
| * <p> |
| * Converts a string representing the encoding of some bytes in Base-64 to |
| * their original form. |
| * |
| * @param str the Base-64 encoded representation of some byte(s). |
| * @return the bytes represented by the <code>str</code>. |
| * @throws NumberFormatException if <code>str</code> is <code>null</code>, |
| * or <code>str</code> contains an illegal Base-64 character. |
| * @see #toBase64(byte[]) |
| */ |
| public static final byte[] fromBase64(String str) |
| { |
| int len = str.length(); |
| if (len == 0) |
| throw new NumberFormatException("Empty string"); |
| byte[] a = new byte[len + 1]; |
| int i, j; |
| for (i = 0; i < len; i++) |
| try |
| { |
| a[i] = (byte) BASE64_CHARS.indexOf(str.charAt(i)); |
| } |
| catch (ArrayIndexOutOfBoundsException x) |
| { |
| throw new NumberFormatException("Illegal character at #" + i); |
| } |
| i = len - 1; |
| j = len; |
| try |
| { |
| while (true) |
| { |
| a[j] = a[i]; |
| if (--i < 0) |
| break; |
| a[j] |= (a[i] & 0x03) << 6; |
| j--; |
| a[j] = (byte)((a[i] & 0x3C) >>> 2); |
| if (--i < 0) |
| break; |
| a[j] |= (a[i] & 0x0F) << 4; |
| j--; |
| a[j] = (byte)((a[i] & 0x30) >>> 4); |
| if (--i < 0) |
| break; |
| a[j] |= (a[i] << 2); |
| j--; |
| a[j] = 0; |
| if (--i < 0) |
| break; |
| } |
| } |
| catch (Exception ignored) |
| { |
| } |
| try |
| { // ignore leading 0-bytes |
| while (a[j] == 0) |
| j++; |
| } |
| catch (Exception x) |
| { |
| return new byte[1]; // one 0-byte |
| } |
| byte[] result = new byte[len - j + 1]; |
| System.arraycopy(a, j, result, 0, len - j + 1); |
| return result; |
| } |
| |
| // BigInteger utilities ---------------------------------------------------- |
| |
| /** |
| * Treats the input as the MSB representation of a number, and discards |
| * leading zero elements. For efficiency, the input is simply returned if no |
| * leading zeroes are found. |
| * |
| * @param n the {@link BigInteger} to trim. |
| * @return the byte array representation of the designated {@link BigInteger} |
| * with no leading 0-bytes. |
| */ |
| public static final byte[] trim(BigInteger n) |
| { |
| byte[] in = n.toByteArray(); |
| if (in.length == 0 || in[0] != 0) |
| return in; |
| int len = in.length; |
| int i = 1; |
| while (in[i] == 0 && i < len) |
| ++i; |
| byte[] result = new byte[len - i]; |
| System.arraycopy(in, i, result, 0, len - i); |
| return result; |
| } |
| |
| /** |
| * Returns a hexadecimal dump of the trimmed bytes of a {@link BigInteger}. |
| * |
| * @param x the {@link BigInteger} to display. |
| * @return the string representation of the designated {@link BigInteger}. |
| */ |
| public static final String dump(BigInteger x) |
| { |
| return dumpString(trim(x)); |
| } |
| } |