Created
November 9, 2021 21:04
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Present a 64-bit long Int in a URI-safe Base 64 encoding, in scala
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| /* | |
| Usage: | |
| > UriBase64Long(1234567891011L).mkString | |
| val res41: String = dqTp5Kaa | |
| > Range(0,8).map(_=>Random.nextLong()).flatMap(UriBase64Long(_)).mkString | |
| val res42: String = 6MO_7T1drnVveBdcHYG08PcCDyx5QlyU@~T8UpTr6Go02cjd7@IJBYSHk0EttfhS | |
| */ | |
| class UriBase64Long(start:Long) extends Iterator[Char] { | |
| import UriBase64Long._ | |
| var remainder = start | |
| var nextsLeft = UriBase64Long.itrCount | |
| override def hasNext = (nextsLeft!=0) | |
| override def next():Char = { | |
| val thisChar = remainder & UriBase64Long.bitMask | |
| remainder = remainder >>> 7 | |
| nextsLeft = nextsLeft - 1; | |
| UriBase64Long.dict(thisChar.toInt) | |
| } | |
| } | |
| object UriBase64Long { | |
| val dict = Seq( 'a'->'z', 'A'->'Z', '0'->'9').flatMap( p => Range(p._1, p._2) ).map(_.toChar).mkString + "-~_@$" | |
| val dictSize = dict.size | |
| private val bitMask = 63 // 7 bits | |
| private val itrCount = 64/8 // Long is a 64-bit integer | |
| def apply( aLong:Long ) = new UriBase64Long(aLong) | |
| } | |
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