package cn.sinata.util
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import java.io.ByteArrayOutputStream
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import java.io.IOException
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object Base64DES {
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private val legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray()
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fun encode(data: ByteArray): String {
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val start = 0
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val len = data.size
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val buf = StringBuffer(data.size * 3 / 2)
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val end = len - 3
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var i = start
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var n = 0
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while (i <= end) {
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val d = data[i].toInt() and 0x0ff shl 16 or (data[i + 1].toInt() and 0x0ff shl 8) or (data[i + 2].toInt() and 0x0ff)
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buf.append(legalChars[d shr 18 and 63])
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buf.append(legalChars[d shr 12 and 63])
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buf.append(legalChars[d shr 6 and 63])
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buf.append(legalChars[d and 63])
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i += 3
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if (n++ >= 14) {
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n = 0
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buf.append(" ")
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}
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}
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if (i == start + len - 2) {
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val d = data[i].toInt() and 0x0ff shl 16 or (data[i + 1].toInt() and 255 shl 8)
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buf.append(legalChars[d shr 18 and 63])
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buf.append(legalChars[d shr 12 and 63])
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buf.append(legalChars[d shr 6 and 63])
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buf.append("=")
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} else if (i == start + len - 1) {
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val d = data[i].toInt() and 0x0ff shl 16
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buf.append(legalChars[d shr 18 and 63])
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buf.append(legalChars[d shr 12 and 63])
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buf.append("==")
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}
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return buf.toString()
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}
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fun decode(s: String): ByteArray {
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var bos: ByteArrayOutputStream? = ByteArrayOutputStream()
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try {
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decode(s, bos!!)
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} catch (e: IOException) {
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throw RuntimeException()
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}
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val decodedBytes = bos.toByteArray()
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try {
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bos.close()
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bos = null
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} catch (ex: IOException) {
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System.err.println("Error while decoding BASE64: " + ex.toString())
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}
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return decodedBytes
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}
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private fun decode(s: String, os: ByteArrayOutputStream) {
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var i = 0
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val len = s.length
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while (true) {
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while (i < len && s[i] <= ' ')
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i++
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if (i == len)
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break
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val tri = ((decode(s[i]) shl 18)
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+ (decode(s[i + 1]) shl 12)
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+ (decode(s[i + 2]) shl 6)
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+ decode(s[i + 3]))
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os.write(tri shr 16 and 255)
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if (s[i + 2] == '=')
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break
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os.write(tri shr 8 and 255)
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if (s[i + 3] == '=')
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break
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os.write(tri and 255)
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i += 4
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}
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}
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private fun decode(c: Char): Int = when (c) {
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in 'A'..'Z' -> c.toInt() - 65
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in 'a'..'z' -> c.toInt() - 97 + 26
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in '0'..'9' -> c.toInt() - 48 + 26 + 26
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else -> when (c) {
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'+' -> 62
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'/' -> 63
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'=' -> 0
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else -> throw RuntimeException("unexpected code: " + c)
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}
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}
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}
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