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