Java tutorial
// Copyright (c) 2003-2009, Jodd Team (jodd.org). All Rights Reserved. import java.io.IOException; import java.io.OutputStream; import java.io.Writer; /** * One of the fastest implementation of the Base64 encoding. * Jakarta and others are slower. */ public class Base64 { private static final char[] S_BASE64CHAR = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' }; private static final char S_BASE64PAD = '='; private static final byte[] S_DECODETABLE = new byte[128]; static { for (int i = 0; i < S_DECODETABLE.length; i++) { S_DECODETABLE[i] = Byte.MAX_VALUE; // 127 } for (int i = 0; i < S_BASE64CHAR.length; i++) // 0 to 63 { S_DECODETABLE[S_BASE64CHAR[i]] = (byte) i; } } private static int decode0(char[] ibuf, byte[] obuf, int wp) { int outlen = 3; if (ibuf[3] == S_BASE64PAD) { outlen = 2; } if (ibuf[2] == S_BASE64PAD) { outlen = 1; } int b0 = S_DECODETABLE[ibuf[0]]; int b1 = S_DECODETABLE[ibuf[1]]; int b2 = S_DECODETABLE[ibuf[2]]; int b3 = S_DECODETABLE[ibuf[3]]; switch (outlen) { case 1: obuf[wp] = (byte) (b0 << 2 & 0xfc | b1 >> 4 & 0x3); return 1; case 2: obuf[wp++] = (byte) (b0 << 2 & 0xfc | b1 >> 4 & 0x3); obuf[wp] = (byte) (b1 << 4 & 0xf0 | b2 >> 2 & 0xf); return 2; case 3: obuf[wp++] = (byte) (b0 << 2 & 0xfc | b1 >> 4 & 0x3); obuf[wp++] = (byte) (b1 << 4 & 0xf0 | b2 >> 2 & 0xf); obuf[wp] = (byte) (b2 << 6 & 0xc0 | b3 & 0x3f); return 3; default: throw new RuntimeException("Internal Error"); } } /** * Decode the base64 data. * @param data The base64 encoded data to be decoded * @param off The offset within the encoded data at which to start decoding * @param len The length of data to decode * @return The decoded data */ public static byte[] decode(char[] data, int off, int len) { char[] ibuf = new char[4]; int ibufcount = 0; byte[] obuf = new byte[(len >> 2) * 3 + 3]; int obufcount = 0; for (int i = off; i < off + len; i++) { char ch = data[i]; if (ch == S_BASE64PAD || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) { ibuf[ibufcount++] = ch; if (ibufcount == ibuf.length) { ibufcount = 0; obufcount += decode0(ibuf, obuf, obufcount); } } } if (obufcount == obuf.length) { return obuf; } byte[] ret = new byte[obufcount]; System.arraycopy(obuf, 0, ret, 0, obufcount); return ret; } public static final int BUF_SIZE = 256; /** * Decode the base64 data. * @param data The base64 encoded data to be decoded * @return The decoded data */ public static byte[] decode(String data) { int ibufcount = 0; int slen = data.length(); char[] ibuf = new char[slen < BUF_SIZE + 3 ? slen : BUF_SIZE + 3]; byte[] obuf = new byte[(slen >> 2) * 3 + 3]; int obufcount = 0; int blen; for (int i = 0; i < slen; i += BUF_SIZE) { // buffer may contain unprocessed characters from previous step if (i + BUF_SIZE <= slen) { data.getChars(i, i + BUF_SIZE, ibuf, ibufcount); blen = BUF_SIZE + ibufcount; } else { data.getChars(i, slen, ibuf, ibufcount); blen = slen - i + ibufcount; } for (int j = ibufcount; j < blen; j++) { char ch = ibuf[j]; if (ch == S_BASE64PAD || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) { ibuf[ibufcount++] = ch; // as soon as we have 4 chars process them if (ibufcount == 4) { ibufcount = 0; obufcount += decode0(ibuf, obuf, obufcount); } } } } if (obufcount == obuf.length) { return obuf; } byte[] ret = new byte[obufcount]; System.arraycopy(obuf, 0, ret, 0, obufcount); return ret; } /** * Decode the base64 data. * @param data The base64 encoded data to be decoded * @param off The offset within the encoded data at which to start decoding * @param len The length of data to decode * @param ostream The OutputStream to which the decoded data should be * written */ public static void decode(char[] data, int off, int len, OutputStream ostream) throws IOException { char[] ibuf = new char[4]; int ibufcount = 0; byte[] obuf = new byte[3]; for (int i = off; i < off + len; i++) { char ch = data[i]; if (ch == S_BASE64PAD || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) { ibuf[ibufcount++] = ch; if (ibufcount == ibuf.length) { ibufcount = 0; int obufcount = decode0(ibuf, obuf, 0); ostream.write(obuf, 0, obufcount); } } } } /** * Decode the base64 data. * @param data The base64 encoded data to be decoded * @param ostream The OutputStream to which the decoded data should be * written */ public static void decode(String data, OutputStream ostream) throws IOException { char[] ibuf = new char[BUF_SIZE + 4]; byte[] obuf = new byte[3]; int slen = data.length(); int blen; int ibufcount = 0; for (int i = 0; i < slen; i += BUF_SIZE) { // buffer may contain unprocessed characters from previous step if (i + BUF_SIZE <= slen) { data.getChars(i, i + BUF_SIZE, ibuf, ibufcount); blen = BUF_SIZE + ibufcount; } else { data.getChars(i, slen, ibuf, ibufcount); blen = slen - i + ibufcount; } for (int j = ibufcount; j < blen; j++) { char ch = ibuf[j]; if (ch == S_BASE64PAD || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) { ibuf[ibufcount++] = ch; // as sson as we have 4 chars process them if (ibufcount == 4) { ibufcount = 0; int obufcount = decode0(ibuf, obuf, 0); ostream.write(obuf, 0, obufcount); } } } } } /** * Returns base64 representation of specified byte array. * @param data The data to be encoded * @return The base64 encoded data */ public static String encode(byte[] data) { return encode(data, 0, data.length); } public static String encode(String s) { return encode(s.getBytes(), 0, s.length()); } /** * Returns base64 representation of specified byte array. * @param data The data to be encoded * @param off The offset within the data at which to start encoding * @param len The length of the data to encode * @return The base64 encoded data */ public static String encode(byte[] data, int off, int len) { if (len <= 0) { return ""; } char[] out = new char[(len / 3 << 2) + 4]; int rindex = off; int windex = 0; int rest = len; while (rest >= 3) { int i = ((data[rindex] & 0xff) << 16) + ((data[rindex + 1] & 0xff) << 8) + (data[rindex + 2] & 0xff); out[windex++] = S_BASE64CHAR[i >> 18]; out[windex++] = S_BASE64CHAR[(i >> 12) & 0x3f]; out[windex++] = S_BASE64CHAR[(i >> 6) & 0x3f]; out[windex++] = S_BASE64CHAR[i & 0x3f]; rindex += 3; rest -= 3; } if (rest == 1) { int i = data[rindex] & 0xff; out[windex++] = S_BASE64CHAR[i >> 2]; out[windex++] = S_BASE64CHAR[(i << 4) & 0x3f]; out[windex++] = S_BASE64PAD; out[windex++] = S_BASE64PAD; } else if (rest == 2) { int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff); out[windex++] = S_BASE64CHAR[i >> 10]; out[windex++] = S_BASE64CHAR[(i >> 4) & 0x3f]; out[windex++] = S_BASE64CHAR[(i << 2) & 0x3f]; out[windex++] = S_BASE64PAD; } return new String(out, 0, windex); } /** * Outputs base64 representation of the specified byte array to a byte stream. * @param data The data to be encoded * @param off The offset within the data at which to start encoding * @param len The length of the data to encode * @param ostream The OutputStream to which the encoded data should be * written */ public static void encode(byte[] data, int off, int len, OutputStream ostream) throws IOException { if (len <= 0) { return; } byte[] out = new byte[4]; int rindex = off; int rest = len; while (rest >= 3) { int i = ((data[rindex] & 0xff) << 16) + ((data[rindex + 1] & 0xff) << 8) + (data[rindex + 2] & 0xff); out[0] = (byte) S_BASE64CHAR[i >> 18]; out[1] = (byte) S_BASE64CHAR[(i >> 12) & 0x3f]; out[2] = (byte) S_BASE64CHAR[(i >> 6) & 0x3f]; out[3] = (byte) S_BASE64CHAR[i & 0x3f]; ostream.write(out, 0, 4); rindex += 3; rest -= 3; } if (rest == 1) { int i = data[rindex] & 0xff; out[0] = (byte) S_BASE64CHAR[i >> 2]; out[1] = (byte) S_BASE64CHAR[(i << 4) & 0x3f]; out[2] = (byte) S_BASE64PAD; out[3] = (byte) S_BASE64PAD; ostream.write(out, 0, 4); } else if (rest == 2) { int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff); out[0] = (byte) S_BASE64CHAR[i >> 10]; out[1] = (byte) S_BASE64CHAR[(i >> 4) & 0x3f]; out[2] = (byte) S_BASE64CHAR[(i << 2) & 0x3f]; out[3] = (byte) S_BASE64PAD; ostream.write(out, 0, 4); } } /** * Outputs base64 representation of the specified byte array to a character stream. * @param data The data to be encoded * @param off The offset within the data at which to start encoding * @param len The length of the data to encode * @param writer The Writer to which the encoded data should be * written */ public static void encode(byte[] data, int off, int len, Writer writer) throws IOException { if (len <= 0) { return; } char[] out = new char[4]; int rindex = off; int rest = len; int output = 0; while (rest >= 3) { int i = ((data[rindex] & 0xff) << 16) + ((data[rindex + 1] & 0xff) << 8) + (data[rindex + 2] & 0xff); out[0] = S_BASE64CHAR[i >> 18]; out[1] = S_BASE64CHAR[(i >> 12) & 0x3f]; out[2] = S_BASE64CHAR[(i >> 6) & 0x3f]; out[3] = S_BASE64CHAR[i & 0x3f]; writer.write(out, 0, 4); rindex += 3; rest -= 3; output += 4; if (output % 76 == 0) { writer.write("\n"); } } if (rest == 1) { int i = data[rindex] & 0xff; out[0] = S_BASE64CHAR[i >> 2]; out[1] = S_BASE64CHAR[(i << 4) & 0x3f]; out[2] = S_BASE64PAD; out[3] = S_BASE64PAD; writer.write(out, 0, 4); } else if (rest == 2) { int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff); out[0] = S_BASE64CHAR[i >> 10]; out[1] = S_BASE64CHAR[(i >> 4) & 0x3f]; out[2] = S_BASE64CHAR[(i << 2) & 0x3f]; out[3] = S_BASE64PAD; writer.write(out, 0, 4); } } }