diff --git a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/FileBinary.kt b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/FileBinary.kt
index 3154a2cf..db74e8e0 100644
--- a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/FileBinary.kt
+++ b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/FileBinary.kt
@@ -3,13 +3,19 @@ package hep.dataforge.io
 import kotlinx.io.core.ByteReadPacket
 import kotlinx.io.core.Input
 import java.nio.channels.FileChannel
+import java.nio.file.Files
 import java.nio.file.Path
 import java.nio.file.StandardOpenOption
 
 class FileBinary(val path: Path, private val offset: Int = 0) : RandomAccessBinary {
-    override fun <R> read(from: Long, size: Long, block: Input.() -> R): R {
+
+    override val size: ULong
+        get() = (Files.size(path) - offset).toULong()
+
+
+    override fun <R> read(from: UInt, size: UInt, block: Input.() -> R): R {
         FileChannel.open(path, StandardOpenOption.READ).use {
-            val buffer = it.map(FileChannel.MapMode.READ_ONLY, from + offset, size)
+            val buffer = it.map(FileChannel.MapMode.READ_ONLY, (from.toLong() + offset), size.toLong())
             return ByteReadPacket(buffer).block()
         }
     }