Consider pointers with an unknown size to have a size of LONG_MAX

* Which is the same that FFI on MRI does.

Author: eregon

src/main/java/org/truffleruby/core/CoreLibrary.java

@@ -77,6 +77,7 @@
 import org.truffleruby.core.time.RubyTime;
 import org.truffleruby.core.tracepoint.RubyTracePoint;
 import org.truffleruby.extra.RubyAtomicReference;
+import org.truffleruby.extra.ffi.Pointer;
 import org.truffleruby.extra.ffi.RubyPointer;
 import org.truffleruby.language.Nil;
 import org.truffleruby.language.NotProvided;
@@ -808,6 +809,8 @@ private void initializeConstants() {
         setConstant(truffleFFIModule, "TYPE_ENUM", NativeTypes.TYPE_ENUM);
         setConstant(truffleFFIModule, "TYPE_VARARGS", NativeTypes.TYPE_VARARGS);
 
+        setConstant(truffleFFIPointerClass, "UNBOUNDED", Pointer.UNBOUNDED);
+
         setConstant(objectClass, "RUBY_VERSION", frozenUSASCIIString(TruffleRuby.LANGUAGE_VERSION));
         setConstant(objectClass, "RUBY_PATCHLEVEL", 0);
         setConstant(objectClass, "RUBY_REVISION", frozenUSASCIIString(TruffleRuby.LANGUAGE_REVISION));

src/main/java/org/truffleruby/extra/ffi/Pointer.java

@@ -26,6 +26,7 @@ public class Pointer implements AutoCloseable {
 
     public static final Pointer NULL = new Pointer(0);
     public static final long SIZE = Long.BYTES;
+    public static final long UNBOUNDED = Long.MAX_VALUE;
 
     public static final Pointer[] EMPTY_ARRAY = new Pointer[0];
 
@@ -49,7 +50,7 @@ public static Pointer calloc(long size) {
     private FinalizerReference finalizerRef = null;
 
     public Pointer(long address) {
-        this(address, 0);
+        this(address, UNBOUNDED);
     }
 
     public Pointer(long address, long size) {

src/main/ruby/truffleruby/core/truffle/ffi/pointer.rb

@@ -75,7 +75,7 @@ def initialize(type = nil, address)
 
     def initialize_copy(from)
       total = Primitive.pointer_size(from)
-      raise RuntimeError, 'cannot duplicate unbounded memory area' unless total > 0
+      raise RuntimeError, 'cannot duplicate unbounded memory area' unless total != UNBOUNDED
       Primitive.pointer_malloc self, total
       Primitive.pointer_copy_memory address, from.address, total
       self
@@ -87,7 +87,7 @@ def size
     alias_method :total, :size
 
     def clear
-      raise RuntimeError, 'cannot clear unbounded memory area' unless Primitive.pointer_size(self) > 0
+      raise RuntimeError, 'cannot clear unbounded memory area' unless Primitive.pointer_size(self) != UNBOUNDED
       Primitive.pointer_clear self, Primitive.pointer_size(self)
     end
 
@@ -116,7 +116,7 @@ def null?
 
     def +(offset)
       ptr = Pointer.new(address + offset)
-      if Primitive.pointer_size(self) > 0
+      if Primitive.pointer_size(self) != UNBOUNDED
         ptr.total = Primitive.pointer_size(self) - offset
       end
       ptr
@@ -145,7 +145,7 @@ def network_order(start, size)
 
     private def check_bounds(offset, length)
       size = Primitive.pointer_size(self)
-      if offset < 0 || (size > 0 && offset + length > size)
+      if offset < 0 || offset + length > size
         raise IndexError, "Memory access offset=#{offset} size=#{length} is out of bounds"
       end
     end