[pypy-commit] pypy ffi-backend: alignof

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: ffi-backend
Changeset: r55775:c0767a4e786b
Date: 2012-06-23 13:05 +0200
http://bitbucket.org/pypy/pypy/changeset/c0767a4e786b/

Log:	alignof

diff --git a/pypy/module/_ffi_backend/__init__.py b/pypy/module/_ffi_backend/__init__.py
--- a/pypy/module/_ffi_backend/__init__.py
+++ b/pypy/module/_ffi_backend/__init__.py
@@ -16,4 +16,5 @@
         'newp': 'func.newp',
         'cast': 'func.cast',
         'sizeof': 'func.sizeof',
+        'alignof': 'func.alignof',
         }
diff --git a/pypy/module/_ffi_backend/ctypeobj.py b/pypy/module/_ffi_backend/ctypeobj.py
--- a/pypy/module/_ffi_backend/ctypeobj.py
+++ b/pypy/module/_ffi_backend/ctypeobj.py
@@ -71,6 +71,9 @@
         name_position = self.name_position + extra_position
         return name, name_position
 
+    def alignof(self):
+        xxx
+
 
 class W_CTypePtrOrArray(W_CType):
 
@@ -132,6 +135,10 @@
         p = rffi.ptradd(cdata, i * self.ctitem.size)
         return cdataobj.W_CData(self.space, p, self)
 
+    def alignof(self):
+        from pypy.module._ffi_backend import newtype
+        return newtype.alignment_of_pointer
+
 
 class W_CTypeArray(W_CTypePtrOrArray):
 
@@ -141,6 +148,9 @@
         self.length = length
         self.ctptr = ctptr
 
+    def alignof(self):
+        return self.ctitem.alignof()
+
     def newp(self, w_init):
         space = self.space
         datasize = self.size
@@ -209,6 +219,13 @@
 
 class W_CTypePrimitive(W_CType):
 
+    def __init__(self, space, size, name, name_position, align):
+        W_CType.__init__(self, space, size, name, name_position)
+        self.align = align
+
+    def alignof(self):
+        return self.align
+
     def cast_single_char(self, w_ob):
         space = self.space
         s = space.str_w(w_ob)
diff --git a/pypy/module/_ffi_backend/func.py b/pypy/module/_ffi_backend/func.py
--- a/pypy/module/_ffi_backend/func.py
+++ b/pypy/module/_ffi_backend/func.py
@@ -1,7 +1,8 @@
 from pypy.interpreter.error import OperationError, operationerrfmt
 from pypy.interpreter.baseobjspace import Wrappable
 from pypy.interpreter.gateway import interp2app, unwrap_spec
-from pypy.rpython.lltypesystem import lltype, rffi
+from pypy.rpython.lltypesystem import lltype, llmemory, rffi
+from pypy.rlib.objectmodel import we_are_translated
 
 from pypy.module._ffi_backend import ctypeobj, cdataobj
 
@@ -35,3 +36,12 @@
         raise OperationError(space.w_TypeError,
                             space.wrap("expected a 'cdata' or 'ctype' object"))
     return space.wrap(size)
+
+ at unwrap_spec(ctype=ctypeobj.W_CType)
+def alignof(space, ctype):
+    align = ctype.alignof()
+    if not we_are_translated():
+        # obscure hack when untranslated, maybe, approximate, don't use
+        assert isinstance(align, llmemory.FieldOffset)
+        align = rffi.sizeof(align.TYPE.y)
+    return space.wrap(align)
diff --git a/pypy/module/_ffi_backend/newtype.py b/pypy/module/_ffi_backend/newtype.py
--- a/pypy/module/_ffi_backend/newtype.py
+++ b/pypy/module/_ffi_backend/newtype.py
@@ -6,13 +6,19 @@
 from pypy.module._ffi_backend import ctypeobj
 
 
+def alignment(TYPE):
+    S = lltype.Struct('aligncheck', ('x', lltype.Char), ('y', TYPE))
+    return rffi.offsetof(S, 'y')
+
+alignment_of_pointer = alignment(rffi.CCHARP)
+
 # ____________________________________________________________
 
 
 PRIMITIVE_TYPES = {}
 
 def eptype(name, TYPE, ctypecls):
-    PRIMITIVE_TYPES[name] = ctypecls, rffi.sizeof(TYPE)
+    PRIMITIVE_TYPES[name] = ctypecls, rffi.sizeof(TYPE), alignment(TYPE)
 
 eptype("char",        lltype.Char,     ctypeobj.W_CTypePrimitiveChar)
 eptype("signed char", rffi.SIGNEDCHAR, ctypeobj.W_CTypePrimitiveSigned)
@@ -31,10 +37,10 @@
 @unwrap_spec(name=str)
 def new_primitive_type(space, name):
     try:
-        ctypecls, size = PRIMITIVE_TYPES[name]
+        ctypecls, size, align = PRIMITIVE_TYPES[name]
     except KeyError:
         raise OperationError(space.w_KeyError, space.wrap(name))
-    ctype = ctypecls(space, size, name, len(name))
+    ctype = ctypecls(space, size, name, len(name), align)
     return ctype
 
 # ____________________________________________________________