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Scala example source code file (ByteCodecs.scala)
The ByteCodecs.scala Scala example source code/* __ *\ ** ________ ___ / / ___ Scala API ** ** / __/ __// _ | / / / _ | (c) 2007-2013, LAMP/EPFL ** ** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ ** ** /____/\___/_/ |_/____/_/ | | ** ** |/ ** \* */ package scala package reflect.internal.pickling object ByteCodecs { def avoidZero(src: Array[Byte]): Array[Byte] = { var i = 0 val srclen = src.length var count = 0 while (i < srclen) { if (src(i) == 0x7f) count += 1 i += 1 } val dst = new Array[Byte](srclen + count) i = 0 var j = 0 while (i < srclen) { val in = src(i) if (in == 0x7f) { dst(j) = (0xc0).toByte dst(j + 1) = (0x80).toByte j += 2 } else { dst(j) = (in + 1).toByte j += 1 } i += 1 } dst } def regenerateZero(src: Array[Byte]): Int = { var i = 0 val srclen = src.length var j = 0 while (i < srclen) { val in: Int = src(i) & 0xff if (in == 0xc0 && (src(i + 1) & 0xff) == 0x80) { src(j) = 0x7f i += 2 } else if (in == 0) { src(j) = 0x7f i += 1 } else { src(j) = (in - 1).toByte i += 1 } j += 1 } j } def encode8to7(src: Array[Byte]): Array[Byte] = { val srclen = src.length val dstlen = (srclen * 8 + 6) / 7 val dst = new Array[Byte](dstlen) var i = 0 var j = 0 while (i + 6 < srclen) { var in: Int = src(i) & 0xff dst(j) = (in & 0x7f).toByte var out: Int = in >>> 7 in = src(i + 1) & 0xff dst(j + 1) = (out | (in << 1) & 0x7f).toByte out = in >>> 6 in = src(i + 2) & 0xff dst(j + 2) = (out | (in << 2) & 0x7f).toByte out = in >>> 5 in = src(i + 3) & 0xff dst(j + 3) = (out | (in << 3) & 0x7f).toByte out = in >>> 4 in = src(i + 4) & 0xff dst(j + 4) = (out | (in << 4) & 0x7f).toByte out = in >>> 3 in = src(i + 5) & 0xff dst(j + 5) = (out | (in << 5) & 0x7f).toByte out = in >>> 2 in = src(i + 6) & 0xff dst(j + 6) = (out | (in << 6) & 0x7f).toByte out = in >>> 1 dst(j + 7) = out.toByte i += 7 j += 8 } if (i < srclen) { var in: Int = src(i) & 0xff dst(j) = (in & 0x7f).toByte; j += 1 var out: Int = in >>> 7 if (i + 1 < srclen) { in = src(i + 1) & 0xff dst(j) = (out | (in << 1) & 0x7f).toByte; j += 1 out = in >>> 6 if (i + 2 < srclen) { in = src(i + 2) & 0xff dst(j) = (out | (in << 2) & 0x7f).toByte; j += 1 out = in >>> 5 if (i + 3 < srclen) { in = src(i + 3) & 0xff dst(j) = (out | (in << 3) & 0x7f).toByte; j += 1 out = in >>> 4 if (i + 4 < srclen) { in = src(i + 4) & 0xff dst(j) = (out | (in << 4) & 0x7f).toByte; j += 1 out = in >>> 3 if (i + 5 < srclen) { in = src(i + 5) & 0xff dst(j) = (out | (in << 5) & 0x7f).toByte; j += 1 out = in >>> 2 } } } } } if (j < dstlen) dst(j) = out.toByte } dst } def decode7to8(src: Array[Byte], srclen: Int): Int = { var i = 0 var j = 0 val dstlen = (srclen * 7 + 7) / 8 while (i + 7 < srclen) { var out: Int = src(i).toInt var in: Byte = src(i + 1) src(j) = (out | (in & 0x01) << 7).toByte out = in >>> 1 in = src(i + 2) src(j + 1) = (out | (in & 0x03) << 6).toByte out = in >>> 2 in = src(i + 3) src(j + 2) = (out | (in & 0x07) << 5).toByte out = in >>> 3 in = src(i + 4) src(j + 3) = (out | (in & 0x0f) << 4).toByte out = in >>> 4 in = src(i + 5) src(j + 4) = (out | (in & 0x1f) << 3).toByte out = in >>> 5 in = src(i + 6) src(j + 5) = (out | (in & 0x3f) << 2).toByte out = in >>> 6 in = src(i + 7) src(j + 6) = (out | in << 1).toByte i += 8 j += 7 } if (i < srclen) { var out: Int = src(i).toInt if (i + 1 < srclen) { var in: Byte = src(i + 1) src(j) = (out | (in & 0x01) << 7).toByte; j += 1 out = in >>> 1 if (i + 2 < srclen) { in = src(i + 2) src(j) = (out | (in & 0x03) << 6).toByte; j += 1 out = in >>> 2 if (i + 3 < srclen) { in = src(i + 3) src(j) = (out | (in & 0x07) << 5).toByte; j += 1 out = in >>> 3 if (i + 4 < srclen) { in = src(i + 4) src(j) = (out | (in & 0x0f) << 4).toByte; j += 1 out = in >>> 4 if (i + 5 < srclen) { in = src(i + 5) src(j) = (out | (in & 0x1f) << 3).toByte; j += 1 out = in >>> 5 if (i + 6 < srclen) { in = src(i + 6) src(j) = (out | (in & 0x3f) << 2).toByte; j += 1 out = in >>> 6 } } } } } } if (j < dstlen) src(j) = out.toByte } dstlen } def encode(xs: Array[Byte]): Array[Byte] = avoidZero(encode8to7(xs)) /** * Destructively decodes array xs and returns the length of the decoded array. * * Sometimes returns (length+1) of the decoded array. Example: * * scala> val enc = scala.reflect.generic.ByteCodecs.encode(Array(1,2,3)) * enc: Array[Byte] = Array(2, 5, 13, 1) * * scala> scala.reflect.generic.ByteCodecs.decode(enc) * res43: Int = 4 * * scala> enc * res44: Array[Byte] = Array(1, 2, 3, 0) * * However, this does not always happen. */ def decode(xs: Array[Byte]): Int = { val len = regenerateZero(xs) decode7to8(xs, len) } } Other Scala source code examplesHere is a short list of links related to this Scala ByteCodecs.scala source code file: |
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