java/src/main/java/com/jsoniter/extra/Base64.java at master · iCodeIN/java · GitHub

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package com.jsoniter.extra;

import com.jsoniter.JsonIterator;

import com.jsoniter.spi.Slice;

import com.jsoniter.output.JsonStream;

import java.io.IOException;

import java.util.Arrays;

/** A very fast and memory efficient class to encode and decode to and from BASE64 in full accordance

* with RFC 2045.

* On Windows XP sp1 with 1.4.2_04 and later ;), this encoder and decoder is about 10 times faster

* on small arrays (10 - 1000 bytes) and 2-3 times as fast on larger arrays (10000 - 1000000 bytes)

* compared to <code>sun.misc.Encoder()/Decoder()</code>.

* On byte arrays the encoder is about 20% faster than Jakarta Commons Base64 Codec for encode and

* about 50% faster for decoding large arrays. This implementation is about twice as fast on very small

* arrays (&lt 30 bytes). If source/destination is a <code>String</code> this

* version is about three times as fast due to the fact that the Commons Codec result has to be recoded

* to a <code>String</code> from <code>byte[]</code>, which is very expensive.

* This encode/decode algorithm doesn't create any temporary arrays as many other codecs do, it only

* allocates the resulting array. This produces less garbage and it is possible to handle arrays twice

* as large as algorithms that create a temporary array. (E.g. Jakarta Commons Codec). It is unknown

* whether Sun's <code>sun.misc.Encoder()/Decoder()</code> produce temporary arrays but since performance

* is quite low it probably does.

* The encoder produces the same output as the Sun one except that the Sun's encoder appends

* a trailing line separator if the last character isn't a pad. Unclear why but it only adds to the

* length and is probably a side effect. Both are in conformance with RFC 2045 though.

* Commons codec seem to always att a trailing line separator.

* Note!

* The encode/decode method pairs (types) come in three versions with the exact same algorithm and

* thus a lot of code redundancy. This is to not create any temporary arrays for transcoding to/from different

* format types. The methods not used can simply be commented out.

* There is also a "fast" version of all decode methods that works the same way as the normal ones, but

* har a few demands on the decoded input. Normally though, these fast verions should be used if the source if

* the input is known and it hasn't bee tampered with.

* If you find the code useful or you find a bug, please send me a note at base64 @ miginfocom . com.

* Licence (BSD):

* ==============

* Redistribution and use in source and binary forms, with or without modification,

* are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this list

* of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice, this

* list of conditions and the following disclaimer in the documentation and/or other

* materials provided with the distribution.

* Neither the name of the MiG InfoCom AB nor the names of its contributors may be

* used to endorse or promote products derived from this software without specific

* prior written permission.

* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

* IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,

* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,

* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,

* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY

* OF SUCH DAMAGE.

* @version 2.2

* @author Mikael Grev

* Date: 2004-aug-02

* Time: 11:31:11

abstract class Base64 {

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

static final byte[] BA;

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;

BA = new byte[CA.length];

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

BA[i] = (byte)CA[i];

}

static int encodeToChar(byte[] sArr, char[] dArr, final int start) {

final int sLen = sArr.length;

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

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

// Encode even 24-bits

for (int s = 0, d = start; 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];

}

// 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[start + dLen - 4] = CA[i >> 12];

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

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

dArr[start + dLen - 1] = '=';

}

return dLen;

}

static int encodeToBytes(byte[] sArr, JsonStream stream) throws IOException {

final int sLen = sArr.length;

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

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

// Encode even 24-bits

for (int s = 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

stream.write(BA[(i >>> 18) & 0x3f], BA[(i >>> 12) & 0x3f], BA[(i >>> 6) & 0x3f], BA[i & 0x3f]);

}

// 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

stream.write(BA[i >> 12], BA[(i >>> 6) & 0x3f], left == 2 ? BA[i & 0x3f] : (byte)'=', (byte)'=');

}

return dLen;

}

static void encodeLongBits(long bits, JsonStream stream) throws IOException {

int i = (int) bits;

byte b1 = BA[(i >>> 18) & 0x3f];

byte b2 = BA[(i >>> 12) & 0x3f];

byte b3 = BA[(i >>> 6) & 0x3f];

byte b4 = BA[i & 0x3f];

stream.write((byte)'"', b1, b2, b3, b4);

bits = bits >>> 24;

i = (int) bits;

b1 = BA[(i >>> 18) & 0x3f];

b2 = BA[(i >>> 12) & 0x3f];

b3 = BA[(i >>> 6) & 0x3f];

b4 = BA[i & 0x3f];

stream.write(b1, b2, b3, b4);

bits = (bits >>> 24) << 2;

i = (int) bits;

b1 = BA[i >> 12];

b2 = BA[(i >>> 6) & 0x3f];

b3 = BA[i & 0x3f];

stream.write(b1, b2, b3, (byte)'"');

}

static long decodeLongBits(JsonIterator iter) throws IOException {

Slice slice = iter.readStringAsSlice();

if (slice.len() != 11) {

throw iter.reportError("decodeLongBits", "must be 11 bytes for long bits encoded double");

}

byte[] encoded = slice.data();

int sIx = slice.head();

long i = IA[encoded[sIx++]] << 18 | IA[encoded[sIx++]] << 12 | IA[encoded[sIx++]] << 6 | IA[encoded[sIx++]];

long bits = i;

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

bits = i << 24 | bits;

i = IA[encoded[sIx++]] << 12 | IA[encoded[sIx++]] << 6 | IA[encoded[sIx]];

bits = i << 46 | bits;

return bits;

}

static int findEnd(final byte[] sArr, final int start) {

for (int i = start; i < sArr.length; i++)

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

return i;

return sArr.length;

}

private final static byte[] EMPTY_ARRAY = new byte[0];

static byte[] decodeFast(final byte[] sArr, final int start, final int end) {

// Check special case

int sLen = end - start;

if (sLen == 0)

return EMPTY_ARRAY;

int sIx = start, eIx = end - 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;

}

java/src/main/java/com/jsoniter/extra/Base64.java at master · iCodeIN/java · GitHub

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