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/* Title: Pure/General/bytes.scala
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Module: PIDE
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Author: Makarius
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Immutable byte vectors versus UTF8 strings.
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*/
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package isabelle
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import java.io.{File => JFile, OutputStream, FileInputStream}
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object Bytes
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{
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val empty: Bytes = new Bytes(Array[Byte](), 0, 0)
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def apply(s: CharSequence): Bytes =
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{
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val str = s.toString
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if (str.isEmpty) empty
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else {
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val bytes = str.getBytes(UTF8.charset)
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new Bytes(bytes, 0, bytes.length)
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}
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}
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/* read */
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def read(file: JFile): Bytes =
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{
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var i = 0
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var m = 0
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val n = file.length.toInt
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val bytes = new Array[Byte](n)
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val stream = new FileInputStream(file)
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try {
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do {
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m = stream.read(bytes, i, n - i)
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if (m != -1) i += m
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} while (m != -1 && n > i)
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}
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finally { stream.close }
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new Bytes(bytes, 0, bytes.length)
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}
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}
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final class Bytes private(
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protected val bytes: Array[Byte],
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protected val offset: Int,
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val length: Int)
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{
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/* equality */
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override def equals(that: Any): Boolean =
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{
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that match {
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case other: Bytes =>
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if (this eq other) true
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else if (length != other.length) false
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else (0 until length).forall(i => bytes(offset + i) == other.bytes(other.offset + i))
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case _ => false
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}
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}
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private lazy val hash: Int =
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{
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var h = 0
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for (i <- offset until offset + length) {
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val b = bytes(i).asInstanceOf[Int] & 0xFF
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h = 31 * h + b
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}
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h
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}
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override def hashCode(): Int = hash
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/* content */
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def sha1_digest: SHA1.Digest = SHA1.digest(bytes)
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override def toString: String = new String(bytes, offset, length, UTF8.charset)
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def isEmpty: Boolean = length == 0
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def +(other: Bytes): Bytes =
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if (other.isEmpty) this
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else if (isEmpty) other
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else {
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val new_bytes = new Array[Byte](length + other.length)
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java.lang.System.arraycopy(bytes, offset, new_bytes, 0, length)
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java.lang.System.arraycopy(other.bytes, other.offset, new_bytes, length, other.length)
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new Bytes(new_bytes, 0, new_bytes.length)
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}
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/* write */
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def write(stream: OutputStream): Unit = stream.write(bytes, offset, length)
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}
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