| /* Base64InputStream.java -- base-64 input stream. |
| Copyright (C) 2003, 2004 Free Software Foundation, Inc. |
| |
| This file is 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, 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; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 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.io; |
| |
| import java.io.ByteArrayInputStream; |
| import java.io.ByteArrayOutputStream; |
| import java.io.FilterInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * A filter input stream that decodes data encoded in the Base-64 |
| * encoding scheme. |
| * |
| * @author Casey Marshall (rsdio@metastatic.org) |
| */ |
| public class Base64InputStream extends FilterInputStream |
| { |
| |
| // Constants and fields. |
| // ------------------------------------------------------------------------ |
| |
| /** Base-64 digits. */ |
| private static final String BASE_64 = |
| "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
| |
| /** Base-64 padding character. */ |
| private static final char BASE_64_PAD = '='; |
| |
| /** Decoding state. */ |
| private int state; |
| |
| /** Intermediate decoded value. */ |
| private int temp; |
| |
| /** EOF flag. */ |
| private boolean eof; |
| |
| private final byte[] one = new byte[1]; |
| |
| // Constructors. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * Create a new Base-64 input stream. The input bytes must be the |
| * ASCII characters A-Z, a-z, 0-9, + and /, with optional whitespace, |
| * and will be decoded into a byte stream. |
| * |
| * @param in The source of Base-64 input. |
| */ |
| public Base64InputStream(InputStream in) |
| { |
| super(in); |
| state = 0; |
| temp = 0; |
| eof = false; |
| } |
| |
| // Class method. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * Decode a single Base-64 string to a byte array. |
| * |
| * @param base64 The Base-64 encoded data. |
| * @return The decoded bytes. |
| * @throws IOException If the given data do not compose a valid Base-64 |
| * sequence. |
| */ |
| public static byte[] decode(String base64) throws IOException |
| { |
| Base64InputStream in = |
| new Base64InputStream(new ByteArrayInputStream(base64.getBytes())); |
| ByteArrayOutputStream out = |
| new ByteArrayOutputStream((int) (base64.length() / 0.666)); |
| byte[] buf = new byte[1024]; |
| int len; |
| while ((len = in.read(buf)) != -1) |
| out.write(buf, 0, len); |
| return out.toByteArray(); |
| } |
| |
| // Instance methods. |
| // ------------------------------------------------------------------------ |
| |
| public int available() |
| { |
| return 0; |
| } |
| |
| public int read() throws IOException |
| { |
| if (read(one) == 1) |
| return one[0]; |
| return -1; |
| } |
| |
| public int read(byte[] buf, int off, int len) throws IOException |
| { |
| if (eof) |
| return -1; |
| int count = 0; |
| while (count < len) |
| { |
| int i; |
| while (Character.isWhitespace((char) (i = in.read()))); |
| int pos = BASE_64.indexOf((char) i); |
| if (pos >= 0) |
| { |
| switch (state) |
| { |
| case 0: |
| temp = pos << 2; |
| state = 1; |
| break; |
| case 1: |
| buf[count++] = (byte) (temp | (pos >>> 4)); |
| temp = (pos & 0x0F) << 4; |
| state = 2; |
| break; |
| case 2: |
| buf[count++] = (byte) (temp | (pos >>> 2)); |
| temp = (pos & 0x03) << 6; |
| state = 3; |
| break; |
| case 3: |
| buf[count++] = (byte) (temp | pos); |
| state = 0; |
| break; |
| } |
| } |
| else if (i == BASE_64_PAD) |
| { |
| switch (state) |
| { |
| case 0: |
| case 1: |
| throw new IOException("malformed Base-64 input"); |
| case 2: |
| while (Character.isWhitespace((char) (i = in.read()))); |
| if (i != BASE_64_PAD) |
| throw new IOException("malformed Base-64 input"); |
| case 3: |
| while (Character.isWhitespace((char) (i = in.read()))); |
| } |
| eof = true; |
| break; |
| } |
| else // First non-Base-64 character, consider it end-of-stream. |
| { |
| if (state != 0) |
| throw new IOException("malformed Base-64 input"); |
| eof = true; |
| break; |
| } |
| } |
| return count; |
| } |
| |
| public boolean markSupported() |
| { |
| return false; |
| } |
| |
| public void mark(int markLimit) { } |
| |
| public void reset() throws IOException |
| { |
| throw new IOException("reset not supported"); |
| } |
| |
| public long skip(long n) throws IOException |
| { |
| long skipped; |
| for (skipped = 0; skipped < n; skipped++) |
| if (read() == -1) |
| break; |
| return skipped; |
| } |
| } |