cpython/Include/memoryobject.h
2011-01-06 19:15:47 +00:00

79 lines
2.8 KiB
C

/* Memory view object. In Python this is available as "memoryview". */
#ifndef Py_MEMORYOBJECT_H
#define Py_MEMORYOBJECT_H
#ifdef __cplusplus
extern "C" {
#endif
PyAPI_DATA(PyTypeObject) PyMemoryView_Type;
#define PyMemoryView_Check(op) (Py_TYPE(op) == &PyMemoryView_Type)
#ifndef Py_LIMITED_API
/* Get a pointer to the underlying Py_buffer of a memoryview object. */
#define PyMemoryView_GET_BUFFER(op) (&((PyMemoryViewObject *)(op))->view)
/* Get a pointer to the PyObject from which originates a memoryview object. */
#define PyMemoryView_GET_BASE(op) (((PyMemoryViewObject *)(op))->view.obj)
#endif
PyAPI_FUNC(PyObject *) PyMemoryView_GetContiguous(PyObject *base,
int buffertype,
char fort);
/* Return a contiguous chunk of memory representing the buffer
from an object in a memory view object. If a copy is made then the
base object for the memory view will be a *new* bytes object.
Otherwise, the base-object will be the object itself and no
data-copying will be done.
The buffertype argument can be PyBUF_READ, PyBUF_WRITE,
PyBUF_SHADOW to determine whether the returned buffer
should be READONLY, WRITABLE, or set to update the
original buffer if a copy must be made. If buffertype is
PyBUF_WRITE and the buffer is not contiguous an error will
be raised. In this circumstance, the user can use
PyBUF_SHADOW to ensure that a a writable temporary
contiguous buffer is returned. The contents of this
contiguous buffer will be copied back into the original
object after the memoryview object is deleted as long as
the original object is writable and allows setting an
exclusive write lock. If this is not allowed by the
original object, then a BufferError is raised.
If the object is multi-dimensional and if fortran is 'F',
the first dimension of the underlying array will vary the
fastest in the buffer. If fortran is 'C', then the last
dimension will vary the fastest (C-style contiguous). If
fortran is 'A', then it does not matter and you will get
whatever the object decides is more efficient.
A new reference is returned that must be DECREF'd when finished.
*/
PyAPI_FUNC(PyObject *) PyMemoryView_FromObject(PyObject *base);
#ifndef Py_LIMITED_API
PyAPI_FUNC(PyObject *) PyMemoryView_FromBuffer(Py_buffer *info);
/* create new if bufptr is NULL
will be a new bytesobject in base */
#endif
/* The struct is declared here so that macros can work, but it shouldn't
be considered public. Don't access those fields directly, use the macros
and functions instead! */
#ifndef Py_LIMITED_API
typedef struct {
PyObject_HEAD
Py_buffer view;
} PyMemoryViewObject;
#endif
#ifdef __cplusplus
}
#endif
#endif /* !Py_MEMORYOBJECT_H */