com.gu.cas.util.BitBashing.scala Maven / Gradle / Ivy
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package com.gu.cas.util
class BitWriter() {
var v: BigInt = 0
var offset = 0
def add(value: Int, bits: Int) {
val bigIntValue = BigInt(value)
val usedBitLength = bigIntValue.bitLength
if (usedBitLength > bits) {
throw new IllegalArgumentException("value "+value+" takes up "+usedBitLength+" bits, allocated only "+bits)
}
v = v | (bigIntValue << offset)
offset += bits
}
}
class BitReader(val v: BigInt) {
var offset = 0
def read(bits: Int): Int = {
val bitMask = BigInt((1<> offset) & bitMask).toInt
offset += bits
value
}
}
object ByteArrayToAlphaStringEncoder {
val radix = 26
val jdkChars = "0123456789abcdefghijklmnop".toList
val alphaChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toList
def from (c1: List[Char], c2: List[Char])(c :Char): Char = {
c2(c1.indexOf(c))
}
def byteArrayToAlphaString(ba: Array[Byte]): String = {
new String(new java.math.BigInteger(addByte(ba)).toString(radix).map(from(jdkChars, alphaChars)))
}
def alphaStringToByteArray(s: String): Array[Byte] = {
stripByte(new java.math.BigInteger(new String(s.map(from(alphaChars, jdkChars))), radix).toByteArray)
}
def addByte(ba: Array[Byte]): Array[Byte] = {
val h = new Array[Byte](1)
h(0) = 0x01
h ++ ba
}
def stripByte(ba: Array[Byte]): Array[Byte] = {
ba.slice(1,ba.size)
}
}