added block test

Author: jsbain

blocktest.py

@@ -0,0 +1,67 @@
+# coding: utf-8
+'''
+experiment with blocks.
+
+
+[theArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop){
+    NSLog(@"The object at index %d is %@",idx,obj);
+}];
+'''
+from ctypes import *
+from objc_util import *
+import pdb
+
+NSBlock=ObjCClass('NSBlock')
+from ctypes import *
+
+ENUMCALLBACK=CFUNCTYPE(None, c_void_p,c_void_p, c_uint, POINTER(c_bool))
+
+
+class GenericBlockDescriptor(Structure):
+   _fields_=[('reserved',c_ulong),
+            ('size',c_ulong),
+            ('signature', c_char_p)]
+   def __init__(self,block):
+      self.size=sizeof(block)
+
+class EnumerationBlock(Structure):
+   '''
+   struct Block_literal_1 {
+    void *isa; // initialized to &_NSConcreteStackBlock or &_NSConcreteGlobalBlock
+    int flags;
+    int reserved;
+    void (*invoke)(void *, ...);
+    struct Block_descriptor_1 {
+    unsigned long int reserved;         // NULL
+        unsigned long int size;         // sizeof(struct Block_literal_1)
+        // optional helper functions
+        void (*copy_helper)(void *dst, void *src);     // IFF (1<<25)
+        void (*dispose_helper)(void *src);             // IFF (1<<25)
+        // required ABI.2010.3.16
+        const char *signature;                         // IFF (1<<30)
+    } *descriptor;
+    // imported variables
+   };'''
+   _fields_=  [('isa',c_void_p),
+               ('flags',c_int32),
+               ('reserved',c_int32),
+               ('invoke',ENUMCALLBACK),
+               ('descriptor',POINTER(GenericBlockDescriptor))]
+   def __init__(self,invoke):        
+      self._descriptor=GenericBlockDescriptor(self)
+      self.descriptor=pointer(self._descriptor)
+      self.isa=NSBlock.ptr
+      self.invoke=ENUMCALLBACK(invoke)
+      self.descriptor[0].signature=c_char_p('') # not used
+      self.descriptor[0].size=sizeof(self)
+
+
+def invoke_py(self, obj, ind, stop):
+   print 'The item at index',ind,'is', ObjCInstance(obj)
+   if ObjCInstance(obj).intValue()==-1:
+      print 'stopping here'
+      stop[0]=True
+      
+blk=EnumerationBlock(invoke_py)
+A=ns([4,3,7,9,-1, 5])
+A.enumerateObjectsUsingBlock_(byref(blk))