Author: Armin Rigo <[email protected]>
Branch:
Changeset: r1015:f93cc8e8f97b
Date: 2012-10-29 08:58 +0100
http://bitbucket.org/cffi/cffi/changeset/f93cc8e8f97b/
Log: Give up trying to reuse one of CPython's buffer or memoryview
classes. Write our own simple class.
diff --git a/c/_cffi_backend.c b/c/_cffi_backend.c
--- a/c/_cffi_backend.c
+++ b/c/_cffi_backend.c
@@ -205,6 +205,8 @@
# define restore_errno_only restore_errno
#endif
+#include "minibuffer.h"
+
#ifdef HAVE_WCHAR_H
# include "wchar_helper.h"
#endif
@@ -4275,17 +4277,7 @@
return NULL;
}
/*WRITE(cd->c_data, size)*/
-#if PY_MAJOR_VERSION < 3 && !defined(PyMemoryView_Check) /* Python 2.6 */
- return PyBuffer_FromReadWriteMemory(cd->c_data, size);
-#else
- {
- Py_buffer view;
- if (PyBuffer_FillInfo(&view, NULL, cd->c_data, size,
- /*readonly=*/0, PyBUF_CONTIG | PyBUF_FORMAT) < 0)
- return NULL;
- return PyMemoryView_FromBuffer(&view);
- }
-#endif
+ return minibuffer_new(cd->c_data, size);
}
static PyObject *b_get_errno(PyObject *self, PyObject *noarg)
@@ -4760,6 +4752,8 @@
INITERROR;
if (PyType_Ready(&CDataIter_Type) < 0)
INITERROR;
+ if (PyType_Ready(&MiniBuffer_Type) < 0)
+ INITERROR;
v = PyCapsule_New((void *)cffi_exports, "cffi", NULL);
if (v == NULL || PyModule_AddObject(m, "_C_API", v) < 0)
diff --git a/c/minibuffer.h b/c/minibuffer.h
new file mode 100644
--- /dev/null
+++ b/c/minibuffer.h
@@ -0,0 +1,151 @@
+
+/* Implementation of a C object with the 'buffer' or 'memoryview'
+ * interface at C-level (as approriate for the version of Python we're
+ * compiling for), but only a minimal but *consistent* part of the
+ * 'buffer' interface at application level.
+ */
+
+typedef struct {
+ PyObject_HEAD
+ char *mb_data;
+ Py_ssize_t mb_size;
+} MiniBufferObj;
+
+static Py_ssize_t mb_length(MiniBufferObj *self)
+{
+ return self->mb_size;
+}
+
+static PyObject *mb_item(MiniBufferObj *self, Py_ssize_t idx)
+{
+ if (idx < 0 || idx >= self->mb_size ) {
+ PyErr_SetString(PyExc_IndexError, "buffer index out of range");
+ return NULL;
+ }
+ return PyBytes_FromStringAndSize(self->mb_data + idx, 1);
+}
+
+static PyObject *mb_slice(MiniBufferObj *self,
+ Py_ssize_t left, Py_ssize_t right)
+{
+ Py_ssize_t size = self->mb_size;
+ if (left < 0) left = 0;
+ if (right > size) right = size;
+ if (left > right) left = right;
+ return PyString_FromStringAndSize(self->mb_data + left, right - left);
+}
+
+static int mb_ass_item(MiniBufferObj *self, Py_ssize_t idx, PyObject *other)
+{
+ if (idx < 0 || idx >= self->mb_size) {
+ PyErr_SetString(PyExc_IndexError,
+ "buffer assignment index out of range");
+ return -1;
+ }
+ if (PyBytes_Check(other) && PyBytes_GET_SIZE(other) == 1) {
+ self->mb_data[idx] = PyBytes_AS_STRING(other)[0];
+ return 0;
+ }
+ else {
+ PyErr_Format(PyExc_TypeError,
+ "must assign a "STR_OR_BYTES
+ " of length 1, not %.200s", Py_TYPE(other)->tp_name);
+ return -1;
+ }
+}
+
+static int mb_ass_slice(MiniBufferObj *self,
+ Py_ssize_t left, Py_ssize_t right, PyObject *other)
+{
+ const void *buffer;
+ Py_ssize_t buffer_len, count;
+ Py_ssize_t size = self->mb_size;
+
+ if (PyObject_AsReadBuffer(other, &buffer, &buffer_len) < 0)
+ return -1;
+
+ if (left < 0) left = 0;
+ if (right > size) right = size;
+ if (left > right) left = right;
+
+ count = right - left;
+ if (count != buffer_len) {
+ PyErr_SetString(PyExc_TypeError,
+ "right operand length must match slice length");
+ return -1;
+ }
+ memcpy(self->mb_data + left, buffer, count);
+ return 0;
+}
+
+static Py_ssize_t mb_getdata(MiniBufferObj *self, Py_ssize_t idx, void **pp)
+{
+ *pp = self->mb_data;
+ return self->mb_size;
+}
+
+static Py_ssize_t mb_getsegcount(MiniBufferObj *self, Py_ssize_t *lenp)
+{
+ if (lenp)
+ *lenp = self->mb_size;
+ return 1;
+}
+
+static int mb_getbuf(MiniBufferObj *self, Py_buffer *view, int flags)
+{
+ return PyBuffer_FillInfo(view, NULL, self->mb_data, self->mb_size,
+ /*readonly=*/0, PyBUF_CONTIG | PyBUF_FORMAT);
+}
+
+static PySequenceMethods mb_as_sequence = {
+ (lenfunc)mb_length, /*sq_length*/
+ (binaryfunc)0, /*sq_concat*/
+ (ssizeargfunc)0, /*sq_repeat*/
+ (ssizeargfunc)mb_item, /*sq_item*/
+ (ssizessizeargfunc)mb_slice, /*sq_slice*/
+ (ssizeobjargproc)mb_ass_item, /*sq_ass_item*/
+ (ssizessizeobjargproc)mb_ass_slice, /*sq_ass_slice*/
+};
+
+static PyBufferProcs mb_as_buffer = {
+ (readbufferproc)mb_getdata,
+ (writebufferproc)mb_getdata,
+ (segcountproc)mb_getsegcount,
+ (charbufferproc)mb_getdata,
+ (getbufferproc)mb_getbuf,
+ (releasebufferproc)0,
+};
+
+static PyTypeObject MiniBuffer_Type = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ "_cffi_backend.buffer",
+ sizeof(MiniBufferObj),
+ 0,
+ (destructor)PyObject_Del, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_compare */
+ 0, /* tp_repr */
+ 0, /* tp_as_number */
+ &mb_as_sequence, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ &mb_as_buffer, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GETCHARBUFFER |
+ Py_TPFLAGS_HAVE_NEWBUFFER, /* tp_flags */
+};
+
+static PyObject *minibuffer_new(char *data, Py_ssize_t size)
+{
+ MiniBufferObj *ob = PyObject_New(MiniBufferObj, &MiniBuffer_Type);
+ if (ob != NULL) {
+ ob->mb_data = data;
+ ob->mb_size = size;
+ }
+ return (PyObject *)ob;
+}
diff --git a/c/test_c.py b/c/test_c.py
--- a/c/test_c.py
+++ b/c/test_c.py
@@ -9,8 +9,6 @@
type_or_class = "type"
mandatory_b_prefix = ''
mandatory_u_prefix = 'u'
- readbuf = lambda buf: buf[:]
- bufchar = lambda x: x
bytechr = chr
class U(object):
def __add__(self, other):
@@ -24,11 +22,6 @@
unichr = chr
mandatory_b_prefix = 'b'
mandatory_u_prefix = ''
- readbuf = lambda buf: buf.tobytes()
- if sys.version_info < (3, 3):
- bufchar = lambda x: bytes([ord(x)])
- else:
- bufchar = ord
bytechr = lambda n: bytes([n])
u = ""
@@ -1815,36 +1808,76 @@
assert (p < s) ^ (p > s)
def test_buffer():
+ import __builtin__
BShort = new_primitive_type("short")
s = newp(new_pointer_type(BShort), 100)
assert sizeof(s) == size_of_ptr()
assert sizeof(BShort) == 2
- assert len(readbuf(buffer(s))) == 2
+ assert len(buffer(s)) == 2
#
BChar = new_primitive_type("char")
BCharArray = new_array_type(new_pointer_type(BChar), None)
c = newp(BCharArray, b"hi there")
+ #
buf = buffer(c)
- assert readbuf(buf) == b"hi there\x00"
+ assert str(buf).startswith('<_cffi_backend.buffer object at 0x')
+ # --mb_length--
assert len(buf) == len(b"hi there\x00")
- assert buf[0] == bufchar('h')
- assert buf[2] == bufchar(' ')
- assert list(buf) == list(map(bufchar, "hi there\x00"))
- buf[2] = bufchar('-')
- assert c[2] == b'-'
- assert readbuf(buf) == b"hi-there\x00"
- c[2] = b'!'
- assert buf[2] == bufchar('!')
- assert readbuf(buf) == b"hi!there\x00"
- c[2] = b'-'
- buf[:2] = b'HI'
- assert string(c) == b'HI-there'
- if sys.version_info < (2, 7) or sys.version_info >= (3, 3):
- assert buf[:4:2] == b'H-'
- if '__pypy__' not in sys.builtin_module_names:
- # XXX pypy doesn't support the following assignment so far
- buf[:4:2] = b'XY'
- assert string(c) == b'XIYthere'
+ # --mb_item--
+ for i in range(-12, 12):
+ try:
+ expected = b"hi there\x00"[i]
+ except IndexError:
+ py.test.raises(IndexError, "buf[i]")
+ else:
+ assert buf[i] == expected
+ # --mb_slice--
+ assert buf[:] == b"hi there\x00"
+ for i in range(-12, 12):
+ assert buf[i:] == b"hi there\x00"[i:]
+ assert buf[:i] == b"hi there\x00"[:i]
+ for j in range(-12, 12):
+ assert buf[i:j] == b"hi there\x00"[i:j]
+ # --misc--
+ assert list(buf) == list(b"hi there\x00")
+ # --mb_as_buffer--
+ py.test.raises(TypeError, __builtin__.buffer, c)
+ bf1 = __builtin__.buffer(buf)
+ assert len(bf1) == len(buf) and bf1[3] == "t"
+ if hasattr(__builtin__, 'memoryview'): # Python >= 2.7
+ py.test.raises(TypeError, memoryview, c)
+ mv1 = memoryview(buf)
+ assert len(mv1) == len(buf) and mv1[3] == "t"
+ # --mb_ass_item--
+ expected = list(b"hi there\x00")
+ for i in range(-12, 12):
+ try:
+ expected[i] = chr(i & 0xff)
+ except IndexError:
+ py.test.raises(IndexError, "buf[i] = chr(i & 0xff)")
+ else:
+ buf[i] = chr(i & 0xff)
+ assert list(buf) == expected
+ # --mb_ass_slice--
+ buf[:] = b"hi there\x00"
+ assert list(buf) == list(c) == list(b"hi there\x00")
+ py.test.raises(TypeError, 'buf[:] = b"shorter"')
+ py.test.raises(TypeError, 'buf[:] = b"this is much too long!"')
+ buf[4:2] = b"" # no effect, but should work
+ assert buf[:] == b"hi there\x00"
+ expected = list(b"hi there\x00")
+ x = 0
+ for i in range(-12, 12):
+ for j in range(-12, 12):
+ start = i if i >= 0 else i + len(buf)
+ stop = j if j >= 0 else j + len(buf)
+ start = max(0, min(len(buf), start))
+ stop = max(0, min(len(buf), stop))
+ sample = chr(x & 0xff) * (stop - start)
+ x += 1
+ buf[i:j] = sample
+ expected[i:j] = sample
+ assert list(buf) == expected
def test_getcname():
BUChar = new_primitive_type("unsigned char")
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