/* Title: Pure/General/bytes.scala
Module: PIDE
Author: Makarius
Immutable byte vectors versus UTF8 strings.
*/
package isabelle
import java.io.{File => JFile, ByteArrayOutputStream, ByteArrayInputStream,
OutputStream, InputStream, FileInputStream, FileOutputStream}
import org.tukaani.xz.{XZInputStream, XZOutputStream}
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 = UTF8.bytes(str)
new Bytes(b, 0, b.length)
}
}
def apply(a: Array[Byte]): Bytes = apply(a, 0, a.length)
def apply(a: Array[Byte], offset: Int, length: Int): Bytes =
if (length == 0) empty
else {
val b = new Array[Byte](length)
System.arraycopy(a, offset, b, 0, length)
new Bytes(b, 0, b.length)
}
/* read */
def read_stream(stream: InputStream, limit: Int = Integer.MAX_VALUE, hint: Int = 1024): Bytes =
if (limit == 0) empty
else {
val out = new ByteArrayOutputStream(if (limit == Integer.MAX_VALUE) hint else limit)
val buf = new Array[Byte](8192)
var m = 0
do {
m = stream.read(buf, 0, buf.size min (limit - out.size))
if (m != -1) out.write(buf, 0, m)
} while (m != -1 && limit > out.size)
new Bytes(out.toByteArray, 0, out.size)
}
def read(file: JFile): Bytes =
using(new FileInputStream(file))(read_stream(_, file.length.toInt))
def read(path: Path): Bytes = read(path.file)
/* write */
def write(file: JFile, bytes: Bytes)
{
val stream = new FileOutputStream(file)
try { bytes.write_stream(stream) } finally { stream.close }
}
def write(path: Path, bytes: Bytes): Unit = write(path.file, bytes)
}
final class Bytes private(
protected val bytes: Array[Byte],
protected val offset: Int,
val length: Int) extends CharSequence
{
/* 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 */
lazy val sha1_digest: SHA1.Digest = SHA1.digest(bytes)
override def toString: String =
{
val str = UTF8.decode_chars(s => s, bytes, offset, offset + length).toString
if (str.contains('\uFFFD')) "Bytes(" + length + ")" else str
}
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)
System.arraycopy(bytes, offset, new_bytes, 0, length)
System.arraycopy(other.bytes, other.offset, new_bytes, length, other.length)
new Bytes(new_bytes, 0, new_bytes.length)
}
/* CharSequence operations */
def charAt(i: Int): Char =
if (0 <= i && i < length) (bytes(offset + i).asInstanceOf[Int] & 0xFF).asInstanceOf[Char]
else throw new IndexOutOfBoundsException
def subSequence(i: Int, j: Int): Bytes =
{
if (0 <= i && i <= j && j <= length) new Bytes(bytes, offset + i, j - i)
else throw new IndexOutOfBoundsException
}
/* streams */
def stream(): ByteArrayInputStream = new ByteArrayInputStream(bytes, offset, length)
def write_stream(stream: OutputStream): Unit = stream.write(bytes, offset, length)
/* XZ data compression */
def uncompress(): Bytes =
using(new XZInputStream(stream()))(Bytes.read_stream(_, hint = length))
def compress(options: XZ.Options = XZ.options()): Bytes =
{
val result = new ByteArrayOutputStream(length)
using(new XZOutputStream(result, options))(write_stream(_))
new Bytes(result.toByteArray, 0, result.size)
}
}