Files
Terrarum/src/net/torvald/unsafe/UnsafePtr.kt
2024-10-08 00:15:17 +09:00

259 lines
8.6 KiB
Kotlin

package net.torvald.unsafe
import net.torvald.terrarum.App.printdbg
import net.torvald.terrarum.printStackTrace
import sun.misc.Unsafe
import java.io.IOException
import java.io.InputStream
import java.io.OutputStream
class DanglingPointerException(msg: String) : NullPointerException(msg)
class AddressOverflowException(msg: String) : IndexOutOfBoundsException(msg)
/**
* Further read:
* - http://www.docjar.com/docs/api/sun/misc/Unsafe.html
*
* Created by minjaesong on 2019-06-21.
*/
internal object UnsafeHelper {
var unsafeAllocatedSize = 0L
internal set
val unsafe: Unsafe
init {
val unsafeConstructor = Unsafe::class.java.getDeclaredConstructor()
unsafeConstructor.isAccessible = true
unsafe = unsafeConstructor.newInstance()
}
/**
* A factory method to allocate a memory of given size and return its starting address as a pointer.
*/
fun allocate(size: Long): UnsafePtr {
val ptr = unsafe.allocateMemory(size)
printdbg(this, "Allocating 0x${ptr.toString(16)} with size $size, called by:")
printStackTrace(this)
return UnsafePtr(ptr, size)
}
fun memcpy(src: UnsafePtr, fromIndex: Long, dest: UnsafePtr, toIndex: Long, copyLength: Long) =
unsafe.copyMemory(src.ptr + fromIndex, dest.ptr + toIndex, copyLength)
fun memcpy(srcAddress: Long, destAddress: Long, copyLength: Long) =
unsafe.copyMemory(srcAddress, destAddress, copyLength)
fun memcpyRaw(srcObj: Any?, srcPos: Long, destObj: Any?, destPos: Long, len: Long) =
unsafe.copyMemory(srcObj, srcPos, destObj, destPos, len)
fun memcpyFromArrToPtr(srcObj: Any, startIndex: Int, destPos: Long, len: Int) =
unsafe.copyMemory(srcObj, getArrayOffset(srcObj) + startIndex, null, destPos, len.toLong())
fun memcpyFromArrToPtr(srcObj: Any, startIndex: Int, destPos: Long, len: Long) =
unsafe.copyMemory(srcObj, getArrayOffset(srcObj) + startIndex, null, destPos, len)
fun memcpyFromPtrToArr(srcPos: Long, destObj: Any, startIndex: Int, len: Int) =
unsafe.copyMemory(null, srcPos, destObj, getArrayOffset(destObj) + startIndex, len.toLong())
fun memcpyFromPtrToArr(srcPos: Long, destObj: Any, startIndex: Int, len: Long) =
unsafe.copyMemory(null, srcPos, destObj, getArrayOffset(destObj) + startIndex, len)
/**
* The array object in JVM is stored in this memory map:
*
* 0 w 2w *
* | Some identifier | Other identifier | the actual data ... |
*
* (where w = 4 for 32-bit JVM and 8 for 64-bit JVM. If Compressed-OOP is involved, things may get complicated)
*
* @return offset from the array's base memory address (aka pointer) that the actual data begins.
*/
fun getArrayOffset(obj: Any) = unsafe.arrayBaseOffset(obj.javaClass).toLong()
fun addressOf(o: Any): Long {
val array = arrayOf(o)
val baseOffset = unsafe.arrayBaseOffset(Array<Any>::class.java).toLong()
val addressSize = unsafe.addressSize()
val objectAddress = when (addressSize) {
4 -> unsafe.getInt(array, baseOffset).toLong()
8 -> unsafe.getLong(array, baseOffset)
else -> throw Error("unsupported address size: $addressSize")
}
return (objectAddress)
}
}
/**
* To allocate a memory, use UnsafeHelper.allocate(long)
*
* All the getFloat/Int/whatever methods will follow the endianness of your system,
* e.g. it'll be Little Endian on x86, Big Endian on PPC, User-defined on ARM; therefore these functions should not be
* used when the portability matters (e.g. Savefile). In such situations, do byte-wise operations will be needed.
*
* Use of hashCode() is forbidden, use the pointer instead.
*/
internal class UnsafePtr(pointer: Long, allocSize: Long) {
init {
UnsafeHelper.unsafeAllocatedSize += allocSize
}
var destroyed = false
private set
var ptr: Long = pointer
private set
var size: Long = allocSize
private set
fun realloc(newSize: Long) {
UnsafeHelper.unsafeAllocatedSize -= size
ptr = UnsafeHelper.unsafe.reallocateMemory(ptr, newSize)
size = newSize
UnsafeHelper.unsafeAllocatedSize += size
}
fun destroy() {
if (!destroyed) {
printdbg(this, "Destroying pointer $this; called from:")
printStackTrace(this)
UnsafeHelper.unsafe.freeMemory(ptr)
destroyed = true
UnsafeHelper.unsafeAllocatedSize -= size
}
else {
printdbg(this, "Destroy() is called but the pointer $this is already been destroyed; called from:")
printStackTrace(this)
}
}
private inline fun checkNullPtr(index: Long) { // ignore what IDEA says and do inline this
// commenting out because of the suspected (or minor?) performance impact.
// You may break the glass and use this tool when some fucking incomprehensible bugs ("vittujen vitun bugit")
// appear (e.g. getting garbage values when it fucking shouldn't)
// using ifs instead of assertions: inactive assert statements still slows down the app
// if (destroyed) { throw DanglingPointerException("The pointer is already destroyed ($this)") }
// if (index !in 0 until size) { throw AddressOverflowException("Index: $index; alloc size: $size") }
}
operator fun get(index: Long): Byte {
checkNullPtr(index)
return UnsafeHelper.unsafe.getByte(ptr + index)
}
operator fun set(index: Long, value: Byte) {
checkNullPtr(index)
UnsafeHelper.unsafe.putByte(ptr + index, value)
}
// NOTE: get/set multibyte values ARE BYTE-ALIGNED!
fun getDouble(index: Long): Double {
checkNullPtr(index * 8L)
return UnsafeHelper.unsafe.getDouble(ptr + (index * 8L))
}
fun getLong(index: Long): Long {
checkNullPtr(index * 8L)
return UnsafeHelper.unsafe.getLong(ptr + (index * 8L))
}
fun getFloat(index: Long): Float {
checkNullPtr(index * 4L)
return UnsafeHelper.unsafe.getFloat(ptr + (index * 4L))
}
fun getInt(index: Long): Int {
checkNullPtr(index * 4L)
return UnsafeHelper.unsafe.getInt(ptr + (index * 4L))
}
fun getShort(index: Long): Short {
checkNullPtr(index * 2L)
return UnsafeHelper.unsafe.getShort(ptr + (index * 2L))
}
fun getChar(index: Long): Char {
checkNullPtr(index * 2L)
return UnsafeHelper.unsafe.getChar(ptr + (index * 2L))
}
fun setDouble(index: Long, value: Double) {
checkNullPtr(index * 8L)
UnsafeHelper.unsafe.putDouble(ptr + (index * 8L), value)
}
fun setLong(index: Long, value: Long) {
checkNullPtr(index * 8L)
UnsafeHelper.unsafe.putLong(ptr + (index * 8L), value)
}
fun setFloat(index: Long, value: Float) {
checkNullPtr(index * 4L)
UnsafeHelper.unsafe.putFloat(ptr + (index * 4L), value)
}
fun setInt(index: Long, value: Int) {
checkNullPtr(index * 4L)
UnsafeHelper.unsafe.putInt(ptr + (index * 4L), value)
}
fun setShort(index: Long, value: Short) {
checkNullPtr(index * 2L)
UnsafeHelper.unsafe.putShort(ptr + (index * 2L), value)
}
fun setChar(index: Long, value: Char) {
checkNullPtr(index * 2L)
UnsafeHelper.unsafe.putChar(ptr + (index * 2L), value)
}
fun fillWith(byte: Byte) {
UnsafeHelper.unsafe.setMemory(ptr, size, byte)
}
override fun toString() = "0x${ptr.toString(16)} with size $size"
fun toString(prefix: String) = "$prefix 0x${ptr.toString(16)} with size $size"
override fun equals(other: Any?) = this.ptr == (other as UnsafePtr).ptr && this.size == other.size
}
internal class UnsafePtrInputStream(val ptr: UnsafePtr): InputStream() {
private var p = 0L
override fun reset() {
p = 0L
}
override fun read(): Int {
if (p < ptr.size) {
p += 1
return ptr[p - 1].toInt().and(255)
}
else return -1
}
}
internal class UnsafePtrOutputStream(val ptr: UnsafePtr): OutputStream() {
private var p = 0L
override fun write(p0: Int) {
if (p < ptr.size) {
p += 1
ptr[p - 1] = p0.toByte()
}
else throw IOException("Buffer overflow: $p for allocated size ${ptr.size}")
}
override fun write(b: ByteArray, off: Int, len: Int) {
if (p + len >= ptr.size) throw IOException("Buffer overflow: ${p+len} for allocated size ${ptr.size}")
UnsafeHelper.unsafe.copyMemory(b, off.toLong(), null, ptr.ptr + p, len.toLong())
p += len
}
}