Java Byte Array Create toBytes(final byte[] s, final int off, final int len)

Description

to Bytes

License

Open Source License

Declaration

static byte[] toBytes(final byte[] s, final int off, final int len) 

Method Source Code

//package com.java2s;
/*//from  www  .  jav a  2  s  . c om
 * The MIT License
 *
 * Copyright 2015 Karol Bucek
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

public class Main {
    private static final int MAX_3_BUFF_SIZE = 2 * 1024 * 1024;

    static byte[] toBytes(final byte[] s, final int off, final int len) {
        // Starting with PG 9.0, a new hex format is supported
        // that starts with "\x".  Figure out which format we're
        // dealing with here.
        //
        if (s.length < 2 || s[0] != '\\' || s[1] != 'x') {
            return toBytesOctalEscaped(s, off, len);
        }
        return toBytesHexEscaped(s, off, len);
    }

    private static byte[] toBytesOctalEscaped(final byte[] s, final int off, final int len) {
        final byte[] out;
        final int end = off + len;
        int correctSize = len;
        if (len > MAX_3_BUFF_SIZE) {
            // count backslash escapes, they will be either
            // backslashes or an octal escape \\ or \003
            //
            for (int i = off; i < end; ++i) {
                if (s[i] == '\\') {
                    byte next = s[++i];
                    if (next == '\\') {
                        --correctSize;
                    } else {
                        correctSize -= 3;
                    }
                }
            }
            out = new byte[correctSize];
        } else {
            out = new byte[len];
        }

        int pos = 0;
        for (int i = off; i < end; i++) {
            final byte b = s[i];
            if (b == (byte) '\\') {
                final byte b1 = s[++i];
                if (b1 == (byte) '\\') { // escaped \
                    out[pos++] = (byte) '\\';
                } else {
                    int thebyte = (b1 - 48) * 64 + (s[++i] - 48) * 8 + (s[++i] - 48);
                    if (thebyte > 127)
                        thebyte -= 256;
                    out[pos++] = (byte) thebyte;
                }
            } else {
                out[pos++] = b;
            }
        }

        if (pos == correctSize)
            return out;

        final byte[] out2 = new byte[pos];
        System.arraycopy(out, 0, out2, 0, pos);
        return out2;
    }

    private static byte[] toBytesHexEscaped(final byte[] s, final int off, final int len) {
        final byte[] out = new byte[(len - 2) / 2];
        for (int i = 0; i < out.length; i++) {
            final int j = off + (2 + i * 2);
            byte b1 = hexByte(s[j]);
            byte b2 = hexByte(s[j + 1]);
            out[i] = (byte) ((b1 << 4) | b2);
        }
        return out;
    }

    private static byte hexByte(final byte b) {
        // 0-9 == 48-57
        if (b <= 57)
            return (byte) (b - 48);

        // a-f == 97-102
        if (b >= 97)
            return (byte) (b - 97 + 10);

        // A-F == 65-70
        return (byte) (b - 65 + 10);
    }
}

Related

1. toBytes(Byte[] values)
2. toBytes(char c)
3. toBytes(char value)
4. toBytes(char[] cbuf, byte[] bs)
5. toBytes(char[] chars)
6. toBytes(final long n)
7. toBytes(final long val)
8. toBytes(final String hexaString)
9. toBytes(final String str)