More Buffer api

ext/Buffer.c

@@ -24,8 +24,8 @@ buffer_allocate(VALUE self, VALUE size, VALUE count, VALUE clear)
 
     p = ALLOC(Buffer);
     memset(p, 0, sizeof(*p));
-    p->memory.size = NUM2LONG(size) * NUM2LONG(count);
-    p->memory.address = malloc(p->memory.size);
+    p->memory.size = NUM2LONG(size) * (count == Qnil ? 1 : NUM2LONG(count));
+    p->memory.address = p->memory.size > 0 ? malloc(p->memory.size) : NULL;
     p->parent = Qnil;
 
     if (p->memory.address == NULL) {
@@ -86,7 +86,9 @@ rb_FFI_Buffer_Init()
 {
     VALUE moduleFFI = rb_define_module("FFI");
     rb_FFI_Buffer_class = classBuffer = rb_define_class_under(moduleFFI, "Buffer", rb_FFI_AbstractMemory_class);
-    rb_define_singleton_method(classBuffer, "__allocate", buffer_allocate, 3);
+    rb_define_singleton_method(classBuffer, "__alloc_inout", buffer_allocate, 3);
+    rb_define_singleton_method(classBuffer, "__alloc_out", buffer_allocate, 3);
+    rb_define_singleton_method(classBuffer, "__alloc_in", buffer_allocate, 3);
     rb_define_method(classBuffer, "inspect", buffer_inspect, 0);
     rb_define_method(classBuffer, "+", buffer_plus, 1);
 }

ext/MemoryPointer.c

@@ -41,15 +41,15 @@ memptr_allocate(VALUE self, VALUE size, VALUE count, VALUE clear)
     p = ALLOC(MemoryPointer);
     memset(p, 0, sizeof(*p));
     p->autorelease = true;
-    p->memory.size = NUM2ULONG(size) * NUM2ULONG(count);
-    p->memory.address = malloc(p->memory.size);
+    p->memory.size = NUM2LONG(size) * (count == Qnil ? 1 : NUM2LONG(count));
+    p->memory.address = p->memory.size > 0 ? malloc(p->memory.size) : NULL;
     p->parent = Qnil;
     p->allocated = true;
 
     if (p->memory.address == NULL) {
         int size = p->memory.size;
         xfree(p);
-        rb_raise(rb_eNoMemError, "Failed to allocate memory size=%u bytes", size);
+        rb_raise(rb_eNoMemError, "Failed to allocate memory size=%ld bytes", size);
     }
     if (TYPE(clear) == T_TRUE) {
         memset(p->memory.address, 0, p->memory.size);

lib/ffi/buffer.rb

@@ -0,0 +1,25 @@
+module FFI
+  class Buffer
+    def self.__calc_size(type)
+      if type.kind_of? Fixnum
+        type
+      elsif type.kind_of? Symbol
+        FFI.type_size(type)
+      else
+        type.size
+      end
+    end
+    def self.new(size, count=nil, clear=true)
+      self.__alloc_inout(self.__calc_size(size), count, clear)
+    end
+    def self.alloc_in(size, count=nil, clear=true)
+      self.__alloc_in(self.__calc_size(size), count, clear)
+    end
+    def self.alloc_out(size, count=nil, clear=true)
+      self.__alloc_out(self.__calc_size(size), count, clear)
+    end
+    def self.alloc_inout(size, count=nil, clear=true)
+      self.__alloc_inout(self.__calc_size(size), count, clear)
+    end
+  end
+end

lib/ffi/ffi.rb

@@ -68,6 +68,7 @@ def initialize(function, library)
 
 require 'ffi/platform'
 require 'ffi/memorypointer'
+require 'ffi/buffer'
 require 'ffi/struct'
 require 'ffi/callback'
 

lib/ffi/memorypointer.rb

@@ -30,7 +30,7 @@ def self.new(type, count=nil, clear=true)
         else
           type.size
         end
-        ptr = self.__allocate(size, count ? count : 1, clear)
+        ptr = self.__allocate(size, count, clear)
         ptr.type_size = size
         if block_given?
           begin