org.jetbrains.kotlin.library.impl.ReadBuffer.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
package org.jetbrains.kotlin.library.impl
import java.io.File
import java.lang.ref.SoftReference
import java.nio.ByteBuffer
sealed class ReadBuffer {
abstract val size: Int
abstract fun get(result: ByteArray, offset: Int, length: Int)
abstract var position: Int
abstract val int: Int
abstract val long: Long
abstract class NIOReader(private val buffer: ByteBuffer) : ReadBuffer() {
override val size: Int
get() = buffer.limit()
override fun get(result: ByteArray, offset: Int, length: Int) {
buffer.get(result, offset, length)
}
override var position: Int
get() = buffer.position()
set(value) { buffer.position(value) }
override val int: Int
get() = buffer.int
override val long: Long
get() = buffer.long
}
class MemoryBuffer(bytes: ByteArray) : NIOReader(bytes.buffer)
class DirectFileBuffer(file: File) : NIOReader(file.readBytes().buffer)
class WeakFileBuffer(private val file: File) : ReadBuffer() {
override val size: Int
get() = file.length().toInt()
override fun get(result: ByteArray, offset: Int, length: Int) {
val buf = ensureBuffer()
pos += length
buf.get(result, offset, length)
}
override val int: Int
get(): Int {
val buf = ensureBuffer()
pos += Int.SIZE_BYTES
return buf.int
}
override val long: Long
get(): Long {
val buf = ensureBuffer()
pos += Long.SIZE_BYTES
return buf.long
}
private var pos: Int = 0
override var position: Int
get() = pos.also { assert(it == ensureBuffer().position()) }
set(value) {
val buf = ensureBuffer()
pos = value
buf.position(value)
}
private fun ensureBuffer(): ByteBuffer {
var tmpBuffer = weakBuffer.get()
if (tmpBuffer == null) {
tmpBuffer = file.readBytes().buffer
tmpBuffer.position(pos)
weakBuffer = SoftReference(tmpBuffer)
}
return tmpBuffer
}
private var weakBuffer: SoftReference = SoftReference(null)
}
}