/jandcode-utils/src/jandcode/utils/impl/Base64Internal.java

package jandcode.utils.impl;



import java.util.*;



public class Base64Internal {

    private static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray(); //NON-NLS

    private static final int[] IA = new int[256];



    static {

        Arrays.fill(IA, -1);

        for (int i = 0, iS = CA.length; i < iS; i++)

            IA[CA[i]] = i;

        IA['='] = 0;

    }



    // ****************************************************************************************

    // *  char[] version

    // ****************************************************************************************



    /**

     * Encodes a raw byte array into a BASE64 <code>char[]</code> representation i accordance with RFC 2045.

     *

     * @param sArr    The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.

     * @param lineSep Optional "\r\n" after 76 characters, unless end of findFile.<br>

     *                No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a

     *                little faster.

     * @return A BASE64 encoded array. Never <code>null</code>.

     */

    public final static char[] encodeToChar(byte[] sArr, boolean lineSep) {

        // Check special case

        int sLen = sArr != null ? sArr.length : 0;

        if (sLen == 0)

            return new char[0];



        int eLen = (sLen / 3) * 3;              // Length of even 24-bits.

        int cCnt = ((sLen - 1) / 3 + 1) << 2;   // Returned character count

        int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of returned array

        char[] dArr = new char[dLen];



        // Encode even 24-bits

        for (int s = 0, d = 0, cc = 0; s < eLen; ) {

            // Copy next three bytes into lower 24 bits of int, paying attension to sign.

            int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8 | (sArr[s++] & 0xff);



            // Encode the int into four chars

            dArr[d++] = CA[(i >>> 18) & 0x3f];

            dArr[d++] = CA[(i >>> 12) & 0x3f];

            dArr[d++] = CA[(i >>> 6) & 0x3f];

            dArr[d++] = CA[i & 0x3f];



            // Add optional line separator

            if (lineSep && ++cc == 19 && d < dLen - 2) {

                dArr[d++] = '\r';

                dArr[d++] = '\n';

                cc = 0;

            }

        }



        // Pad and encode last bits if source isn't even 24 bits.

        int left = sLen - eLen; // 0 - 2.

        if (left > 0) {

            // Prepare the int

            int i = ((sArr[eLen] & 0xff) << 10) | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);



            // Set last four chars

            dArr[dLen - 4] = CA[i >> 12];

            dArr[dLen - 3] = CA[(i >>> 6) & 0x3f];

            dArr[dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';

            dArr[dLen - 1] = '=';

        }

        return dArr;

    }



    /**

     * Decodes a BASE64 encoded char array. All illegal characters will be ignored and can handle both arrays with

     * and without line separators.

     *

     * @param sArr The source array. <code>null</code> or length 0 will return an empty array.

     * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters

     *         (including '=') isn't divideable by 4.  (I.e. definitely corrupted).

     */

    public final static byte[] decode(char[] sArr) {

        // Check special case

        int sLen = sArr != null ? sArr.length : 0;

        if (sLen == 0)

            return new byte[0];



        // Count illegal characters (including '\r', '\n') to know what size the returned array will be,

        // so we don't have to reallocate & copy it later.

        int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)

        for (int i = 0; i < sLen; i++)  // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.

            if (IA[sArr[i]] < 0)

                sepCnt++;



        // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.

        if ((sLen - sepCnt) % 4 != 0)

            return null;



        int pad = 0;

        for (int i = sLen; i > 1 && IA[sArr[--i]] <= 0; )

            if (sArr[i] == '=')

                pad++;



        int len = ((sLen - sepCnt) * 6 >> 3) - pad;



        byte[] dArr = new byte[len];       // Preallocate byte[] of exact length



        for (int s = 0, d = 0; d < len; ) {

            // Assemble three bytes into an int from four "valid" characters.

            int i = 0;

            for (int j = 0; j < 4; j++) {   // j only increased if a valid char was found.

                int c = IA[sArr[s++]];

                if (c >= 0)

                    i |= c << (18 - j * 6);

                else

                    j--;

            }

            // Add the bytes

            dArr[d++] = (byte) (i >> 16);

            if (d < len) {

                dArr[d++] = (byte) (i >> 8);

                if (d < len)

                    dArr[d++] = (byte) i;

            }

        }

        return dArr;

    }



    /**

     * Decodes a BASE64 encoded char array that is known to be resonably well formatted. The method is about twice as

     * fast as {@link #decode(char[])}. The preconditions are:<br>

     * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>

     * + Line separator must be "\r\n", as specified in RFC 2045

     * + The array must not contain illegal characters within the encoded string<br>

     * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>

     *

     * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.

     * @return The decoded array of bytes. May be of length 0.

     */

    public final static byte[] decodeFast(char[] sArr) {

        // Check special case

        int sLen = sArr.length;

        if (sLen == 0)

            return new byte[0];



        int sIx = 0, eIx = sLen - 1;    // Start and end index after trimming.



        // Trim illegal chars from start

        while (sIx < eIx && IA[sArr[sIx]] < 0)

            sIx++;



        // Trim illegal chars from end

        while (eIx > 0 && IA[sArr[eIx]] < 0)

            eIx--;



        // get the padding count (=) (0, 1 or 2)

        int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0;  // Count '=' at end.

        int cCnt = eIx - sIx + 1;   // Content count including possible separators

        int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;



        int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes

        byte[] dArr = new byte[len];       // Preallocate byte[] of exact length



        // Decode all but the last 0 - 2 bytes.

        int d = 0;

        for (int cc = 0, eLen = (len / 3) * 3; d < eLen; ) {

            // Assemble three bytes into an int from four "valid" characters.

            int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12 | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];



            // Add the bytes

            dArr[d++] = (byte) (i >> 16);

            dArr[d++] = (byte) (i >> 8);

            dArr[d++] = (byte) i;



            // If line separator, jump over it.

            if (sepCnt > 0 && ++cc == 19) {

                sIx += 2;

                cc = 0;

            }

        }



        if (d < len) {

            // Decode last 1-3 bytes (incl '=') into 1-3 bytes

            int i = 0;

            for (int j = 0; sIx <= eIx - pad; j++)

                i |= IA[sArr[sIx++]] << (18 - j * 6);



            for (int r = 16; d < len; r -= 8)

                dArr[d++] = (byte) (i >> r);

        }



        return dArr;

    }



    // ****************************************************************************************

    // *  byte[] version

    // ****************************************************************************************



    /**

     * Encodes a raw byte array into a BASE64 <code>byte[]</code> representation i accordance with RFC 2045.

     *

     * @param sArr    The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.

     * @param lineSep Optional "\r\n" after 76 characters, unless end of findFile.<br>

     *                No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a

     *                little faster.

     * @return A BASE64 encoded array. Never <code>null</code>.

     */

    public final static byte[] encodeToByte(byte[] sArr, boolean lineSep) {

        // Check special case

        int sLen = sArr != null ? sArr.length : 0;

        if (sLen == 0)

            return new byte[0];



        int eLen = (sLen / 3) * 3;                              // Length of even 24-bits.

        int cCnt = ((sLen - 1) / 3 + 1) << 2;                   // Returned character count

        int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of returned array

        byte[] dArr = new byte[dLen];



        // Encode even 24-bits

        for (int s = 0, d = 0, cc = 0; s < eLen; ) {

            // Copy next three bytes into lower 24 bits of int, paying attension to sign.

            int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8 | (sArr[s++] & 0xff);



            // Encode the int into four chars

            dArr[d++] = (byte) CA[(i >>> 18) & 0x3f];

            dArr[d++] = (byte) CA[(i >>> 12) & 0x3f];

            dArr[d++] = (byte) CA[(i >>> 6) & 0x3f];

            dArr[d++] = (byte) CA[i & 0x3f];



            // Add optional line separator

            if (lineSep && ++cc == 19 && d < dLen - 2) {

                dArr[d++] = '\r';

                dArr[d++] = '\n';

                cc = 0;

            }

        }



        // Pad and encode last bits if source isn't an even 24 bits.

        int left = sLen - eLen; // 0 - 2.

        if (left > 0) {

            // Prepare the int

            int i = ((sArr[eLen] & 0xff) << 10) | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);



            // Set last four chars

            dArr[dLen - 4] = (byte) CA[i >> 12];

            dArr[dLen - 3] = (byte) CA[(i >>> 6) & 0x3f];

            dArr[dLen - 2] = left == 2 ? (byte) CA[i & 0x3f] : (byte) '=';

            dArr[dLen - 1] = '=';

        }

        return dArr;

    }



    /**

     * Decodes a BASE64 encoded byte array. All illegal characters will be ignored and can handle both arrays with

     * and without line separators.

     *

     * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.

     * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters

     *         (including '=') isn't divideable by 4. (I.e. definitely corrupted).

     */

    public final static byte[] decode(byte[] sArr) {

        // Check special case

        int sLen = sArr.length;



        // Count illegal characters (including '\r', '\n') to know what size the returned array will be,

        // so we don't have to reallocate & copy it later.

        int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)

        for (int i = 0; i < sLen; i++)      // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.

            if (IA[sArr[i] & 0xff] < 0)

                sepCnt++;



        // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.

        if ((sLen - sepCnt) % 4 != 0)

            return null;



        int pad = 0;

        for (int i = sLen; i > 1 && IA[sArr[--i] & 0xff] <= 0; )

            if (sArr[i] == '=')

                pad++;



        int len = ((sLen - sepCnt) * 6 >> 3) - pad;



        byte[] dArr = new byte[len];       // Preallocate byte[] of exact length



        for (int s = 0, d = 0; d < len; ) {

            // Assemble three bytes into an int from four "valid" characters.

            int i = 0;

            for (int j = 0; j < 4; j++) {   // j only increased if a valid char was found.

                int c = IA[sArr[s++] & 0xff];

                if (c >= 0)

                    i |= c << (18 - j * 6);

                else

                    j--;

            }



            // Add the bytes

            dArr[d++] = (byte) (i >> 16);

            if (d < len) {

                dArr[d++] = (byte) (i >> 8);

                if (d < len)

                    dArr[d++] = (byte) i;

            }

        }



        return dArr;

    }





    /**

     * Decodes a BASE64 encoded byte array that is known to be resonably well formatted. The method is about twice as

     * fast as {@link #decode(byte[])}. The preconditions are:<br>

     * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>

     * + Line separator must be "\r\n", as specified in RFC 2045

     * + The array must not contain illegal characters within the encoded string<br>

     * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>

     *

     * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.

     * @return The decoded array of bytes. May be of length 0.

     */

    public final static byte[] decodeFast(byte[] sArr) {

        // Check special case

        int sLen = sArr.length;

        if (sLen == 0)

            return new byte[0];



        int sIx = 0, eIx = sLen - 1;    // Start and end index after trimming.



        // Trim illegal chars from start

        while (sIx < eIx && IA[sArr[sIx] & 0xff] < 0)

            sIx++;



        // Trim illegal chars from end

        while (eIx > 0 && IA[sArr[eIx] & 0xff] < 0)

            eIx--;



        // get the padding count (=) (0, 1 or 2)

        int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0;  // Count '=' at end.

        int cCnt = eIx - sIx + 1;   // Content count including possible separators

        int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;



        int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes

        byte[] dArr = new byte[len];       // Preallocate byte[] of exact length



        // Decode all but the last 0 - 2 bytes.

        int d = 0;

        for (int cc = 0, eLen = (len / 3) * 3; d < eLen; ) {

            // Assemble three bytes into an int from four "valid" characters.

            int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12 | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];



            // Add the bytes

            dArr[d++] = (byte) (i >> 16);

            dArr[d++] = (byte) (i >> 8);

            dArr[d++] = (byte) i;



            // If line separator, jump over it.

            if (sepCnt > 0 && ++cc == 19) {

                sIx += 2;

                cc = 0;

            }

        }



        if (d < len) {

            // Decode last 1-3 bytes (incl '=') into 1-3 bytes

            int i = 0;

            for (int j = 0; sIx <= eIx - pad; j++)

                i |= IA[sArr[sIx++]] << (18 - j * 6);



            for (int r = 16; d < len; r -= 8)

                dArr[d++] = (byte) (i >> r);

        }



        return dArr;

    }



    // ****************************************************************************************

    // * String version

    // ****************************************************************************************



    /**

     * Encodes a raw byte array into a BASE64 <code>String</code> representation i accordance with RFC 2045.

     *

     * @param sArr    The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.

     * @param lineSep Optional "\r\n" after 76 characters, unless end of findFile.<br>

     *                No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a

     *                little faster.

     * @return A BASE64 encoded array. Never <code>null</code>.

     */

    public final static String encodeToString(byte[] sArr, boolean lineSep) {

        // Reuse char[] since we can't create a String incrementally anyway and StringBuffer/Builder would be slower.

        return new String(encodeToChar(sArr, lineSep));

    }



    /**

     * Decodes a BASE64 encoded <code>String</code>. All illegal characters will be ignored and can handle both strings with

     * and without line separators.<br>

     * <b>Note!</b> It can be up to about 2x the speed to call <code>decode(str.toCharArray())</code> instead. That

     * will create a temporary array though. This version will use <code>str.charAt(i)</code> to iterate the string.

     *

     * @param str The source string. <code>null</code> or length 0 will return an empty array.

     * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters

     *         (including '=') isn't divideable by 4.  (I.e. definitely corrupted).

     */

    public final static byte[] decode(String str) {

        // Check special case

        int sLen = str != null ? str.length() : 0;

        if (sLen == 0)

            return new byte[0];



        // Count illegal characters (including '\r', '\n') to know what size the returned array will be,

        // so we don't have to reallocate & copy it later.

        int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)

        for (int i = 0; i < sLen; i++)  // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.

            if (IA[str.charAt(i)] < 0)

                sepCnt++;



        // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.

        if ((sLen - sepCnt) % 4 != 0)

            return null;



        // Count '=' at end

        int pad = 0;

        for (int i = sLen; i > 1 && IA[str.charAt(--i)] <= 0; )

            if (str.charAt(i) == '=')

                pad++;



        int len = ((sLen - sepCnt) * 6 >> 3) - pad;



        byte[] dArr = new byte[len];       // Preallocate byte[] of exact length



        for (int s = 0, d = 0; d < len; ) {

            // Assemble three bytes into an int from four "valid" characters.

            int i = 0;

            for (int j = 0; j < 4; j++) {   // j only increased if a valid char was found.

                int c = IA[str.charAt(s++)];

                if (c >= 0)

                    i |= c << (18 - j * 6);

                else

                    j--;

            }

            // Add the bytes

            dArr[d++] = (byte) (i >> 16);

            if (d < len) {

                dArr[d++] = (byte) (i >> 8);

                if (d < len)

                    dArr[d++] = (byte) i;

            }

        }

        return dArr;

    }



    /**

     * Decodes a BASE64 encoded string that is known to be resonably well formatted. The method is about twice as

     * fast as {@link #decode(String)}. The preconditions are:<br>

     * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>

     * + Line separator must be "\r\n", as specified in RFC 2045

     * + The array must not contain illegal characters within the encoded string<br>

     * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>

     *

     * @param s The source string. Length 0 will return an empty array. <code>null</code> will throw an exception.

     * @return The decoded array of bytes. May be of length 0.

     */

    public final static byte[] decodeFast(String s) {

        // Check special case

        int sLen = s.length();

        if (sLen == 0)

            return new byte[0];



        int sIx = 0, eIx = sLen - 1;    // Start and end index after trimming.



        // Trim illegal chars from start

        while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0)

            sIx++;



        // Trim illegal chars from end

        while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0)

            eIx--;



        // get the padding count (=) (0, 1 or 2)

        int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2 : 1) : 0;  // Count '=' at end.

        int cCnt = eIx - sIx + 1;   // Content count including possible separators

        int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1 : 0;



        int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes

        byte[] dArr = new byte[len];       // Preallocate byte[] of exact length



        // Decode all but the last 0 - 2 bytes.

        int d = 0;

        for (int cc = 0, eLen = (len / 3) * 3; d < eLen; ) {

            // Assemble three bytes into an int from four "valid" characters.

            int i = IA[s.charAt(sIx++)] << 18 | IA[s.charAt(sIx++)] << 12 | IA[s.charAt(sIx++)] << 6 | IA[s.charAt(sIx++)];



            // Add the bytes

            dArr[d++] = (byte) (i >> 16);

            dArr[d++] = (byte) (i >> 8);

            dArr[d++] = (byte) i;



            // If line separator, jump over it.

            if (sepCnt > 0 && ++cc == 19) {

                sIx += 2;

                cc = 0;

            }

        }



        if (d < len) {

            // Decode last 1-3 bytes (incl '=') into 1-3 bytes

            int i = 0;

            for (int j = 0; sIx <= eIx - pad; j++)

                i |= IA[s.charAt(sIx++)] << (18 - j * 6);



            for (int r = 16; d < len; r -= 8)

                dArr[d++] = (byte) (i >> r);

        }



        return dArr;

    }

}