[pypy-commit] cffi default: Allow the syntax "a[...]; ", for now only on struct fields.

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r518:8e459b477b6b
Date: 2012-06-26 10:52 +0200
http://bitbucket.org/cffi/cffi/changeset/8e459b477b6b/

Log:	Allow the syntax "a[...];", for now only on struct fields.

diff --git a/cffi/cparser.py b/cffi/cparser.py
--- a/cffi/cparser.py
+++ b/cffi/cparser.py
@@ -7,6 +7,7 @@
                         re.MULTILINE)
 _r_partial_enum = re.compile(r"\.\.\.\s*\}")
 _r_enum_dotdotdot = re.compile(r"__dotdotdot\d+__$")
+_r_partial_array = re.compile(r"\[\s*\.\.\.\s*\]")
 _parser_cache = None
 
 def _get_parser():
@@ -25,6 +26,8 @@
         macroname, macrovalue = match.groups()
         macros[macroname] = macrovalue
     csource = _r_define.sub('', csource)
+    # Replace "[...]" with "[__dotdotdotarray__]"
+    csource = _r_partial_array.sub('[__dotdotdotarray__]', csource)
     # Replace "...}" with "__dotdotdotNUM__}".  This construction should
     # occur only at the end of enums; at the end of structs we have "...;}"
     # and at the end of vararg functions "...);"
@@ -141,7 +144,7 @@
         return model.PointerType(type)
 
     def _get_type(self, typenode, convert_array_to_pointer=False,
-                  force_pointer=False, name=None):
+                  force_pointer=False, name=None, partial_length_ok=False):
         # first, dereference typedefs, if we have it already parsed, we're good
         if (isinstance(typenode, pycparser.c_ast.TypeDecl) and
             isinstance(typenode.type, pycparser.c_ast.IdentifierType) and
@@ -163,7 +166,8 @@
             if typenode.dim is None:
                 length = None
             else:
-                length = self._parse_constant(typenode.dim)
+                length = self._parse_constant(
+                    typenode.dim, partial_length_ok=partial_length_ok)
             return model.ArrayType(self._get_type(typenode.type), length)
         #
         if force_pointer:
@@ -317,23 +321,26 @@
                 # of strings, but is sometimes just one string.  Use
                 # str.join() as a way to cope with both.
                 tp.partial = True
-                if not tp.has_c_name():
-                    raise api.CDefError("%s is partial but has no C name"
-                                        % (tp,))
                 continue
             if decl.bitsize is None:
                 bitsize = -1
             else:
                 bitsize = self._parse_constant(decl.bitsize)
+            self._partial_length = False
+            type = self._get_type(decl.type, partial_length_ok=True)
+            if self._partial_length:
+                tp.partial = True
             fldnames.append(decl.name)
-            fldtypes.append(self._get_type(decl.type))
+            fldtypes.append(type)
             fldbitsize.append(bitsize)
+        if tp.partial and not tp.has_c_name():
+            raise api.CDefError("%s is partial but has no C name" % (tp,))
         tp.fldnames = tuple(fldnames)
         tp.fldtypes = tuple(fldtypes)
         tp.fldbitsize = tuple(fldbitsize)
         return tp
 
-    def _parse_constant(self, exprnode):
+    def _parse_constant(self, exprnode, partial_length_ok=False):
         # for now, limited to expressions that are an immediate number
         # or negative number
         if isinstance(exprnode, pycparser.c_ast.Constant):
@@ -343,6 +350,12 @@
                 exprnode.op == '-'):
             return -self._parse_constant(exprnode.expr)
         #
+        if partial_length_ok:
+            if (isinstance(exprnode, pycparser.c_ast.ID) and
+                    exprnode.name == '__dotdotdotarray__'):
+                self._partial_length = True
+                return None
+        #
         raise api.FFIError("unsupported non-constant or "
                            "not immediately constant expression")
 
diff --git a/testing/test_verify.py b/testing/test_verify.py
--- a/testing/test_verify.py
+++ b/testing/test_verify.py
@@ -267,6 +267,14 @@
     s.a[14] = 4242
     assert lib.bar(s) == 4242
 
+def test_struct_array_guess_length_3():
+    ffi = FFI()
+    ffi.cdef("struct foo_s { int a[...]; };")
+    ffi.verify("struct foo_s { int x; int a[17]; int y; };")
+    assert ffi.sizeof('struct foo_s') == 19 * ffi.sizeof('int')
+    s = ffi.new("struct foo_s")
+    assert ffi.sizeof(s.a) == 17 * ffi.sizeof('int')
+
 def test_global_constants():
     ffi = FFI()
     # use 'static const int', as generally documented, although in this