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Add PyObject_CheckReadBuffer(), which returns true if its argument 

supports the single-segment readable buffer interface.

Add documentation for this and other PyObject_XXXBuffer() calls.
This commit is contained in:
Jeremy Hylton 2001-11-09 21:59:42 +00:00
parent da4ffeecf5
commit 89c3a22a27
3 changed files with 83 additions and 29 deletions
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39
Doc/api/abstract.tex
View File

@ -867,4 +867,43 @@ if (PyErr_Occurred()) {
else {
/* continue doing useful work */
}
\section{Buffer Protocol \label{buffer}}
\begin{cfuncdesc}{int}{PyObject_AsCharBuffer}{PyObject *obj,
const char **buffer,
int *buffer_len}
Returns a pointer to a read-only memory location useable as character-
based input. The \var{obj} argument must support the single-segment
character buffer interface. On success, returns \code{1}, sets
\var{buffer} to the memory location and \var{buffer} to the buffer
length. Returns \code{0} and sets a \exception{TypeError} on error.
\end{cfuncdesc}
\begin{cfuncdesc}{int}{PyObject_AsReadBuffer}{PyObject *obj,
const char **buffer,
int *buffer_len}
Returns a pointer to a read-only memory location containing
arbitrary data. The \var{obj} argument must support the
single-segment readable buffer interface. On success, returns
\code{1}, sets \var{buffer} to the memory location and \var{buffer}
to the buffer length. Returns \code{0} and sets a
\exception{TypeError} on error.
\end{cfuncdesc}
\begin{cfuncdesc}{int}{PyObject_CheckReadBuffer}{PyObject *o}
Returns \code{1} if \var{o} supports the single-segment readable
buffer interface. Otherwise returns \code{0}.
\enc{cfuncdesc}
\begin{cfuncdesc}{int}{PyObject_AsWriteBuffer}{PyObject *obj,
const char **buffer,
int *buffer_len}
Returns a pointer to a writeable memory location. The \var{obj}
argument must support the single-segment, character buffer
interface. On success, returns \code{1}, sets \var{buffer} to the
memory location and \var{buffer} to the buffer length. Returns
\code{0} and sets a \exception{TypeError} on error.
\end{cfuncdesc}
\end{verbatim}

9
Include/abstract.h
View File

@ -468,6 +468,15 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
*/
DL_IMPORT(int) PyObject_CheckReadBuffer(PyObject *obj);
/*
Checks whether an arbitrary object supports the (character,
single segment) buffer interface. Returns 1 on success, 0
on failure.
*/
DL_IMPORT(int) PyObject_AsReadBuffer(PyObject *obj,
const void **buffer,
int *buffer_len);

64
Objects/abstract.c
View File

@ -182,27 +182,37 @@ int PyObject_AsCharBuffer(PyObject *obj,
return -1;
}
pb = obj->ob_type->tp_as_buffer;
if ( pb == NULL ||
if (pb == NULL ||
pb->bf_getcharbuffer == NULL ||
pb->bf_getsegcount == NULL ) {
pb->bf_getsegcount == NULL) {
PyErr_SetString(PyExc_TypeError,
"expected a character buffer object");
goto onError;
return -1;
}
if ( (*pb->bf_getsegcount)(obj,NULL) != 1 ) {
if ((*pb->bf_getsegcount)(obj,NULL) != 1) {
PyErr_SetString(PyExc_TypeError,
"expected a single-segment buffer object");
goto onError;
return -1;
}
len = (*pb->bf_getcharbuffer)(obj,0,&pp);
len = (*pb->bf_getcharbuffer)(obj, 0, &pp);
if (len < 0)
goto onError;
return -1;
*buffer = pp;
*buffer_len = len;
return 0;
}
onError:
return -1;
int
PyObject_CheckReadBuffer(PyObject *obj)
{
PyBufferProcs *pb = obj->ob_type->tp_as_buffer;
if (pb == NULL ||
pb->bf_getreadbuffer == NULL ||
pb->bf_getsegcount == NULL ||
(*pb->bf_getsegcount)(obj, NULL) != 1)
return 0;
return 1;
}
int PyObject_AsReadBuffer(PyObject *obj,
@ -218,27 +228,24 @@ int PyObject_AsReadBuffer(PyObject *obj,
return -1;
}
pb = obj->ob_type->tp_as_buffer;
if ( pb == NULL ||
if (pb == NULL ||
pb->bf_getreadbuffer == NULL ||
pb->bf_getsegcount == NULL ) {
pb->bf_getsegcount == NULL) {
PyErr_SetString(PyExc_TypeError,
"expected a readable buffer object");
goto onError;
return -1;
}
if ( (*pb->bf_getsegcount)(obj,NULL) != 1 ) {
if ((*pb->bf_getsegcount)(obj, NULL) != 1) {
PyErr_SetString(PyExc_TypeError,
"expected a single-segment buffer object");
goto onError;
return -1;
}
len = (*pb->bf_getreadbuffer)(obj,0,&pp);
len = (*pb->bf_getreadbuffer)(obj, 0, &pp);
if (len < 0)
goto onError;
return -1;
*buffer = pp;
*buffer_len = len;
return 0;
onError:
return -1;
}
int PyObject_AsWriteBuffer(PyObject *obj,
@ -254,27 +261,24 @@ int PyObject_AsWriteBuffer(PyObject *obj,
return -1;
}
pb = obj->ob_type->tp_as_buffer;
if ( pb == NULL ||
if (pb == NULL ||
pb->bf_getwritebuffer == NULL ||
pb->bf_getsegcount == NULL ) {
pb->bf_getsegcount == NULL) {
PyErr_SetString(PyExc_TypeError,
"expected a writeable buffer object");
goto onError;
return -1;
}
if ( (*pb->bf_getsegcount)(obj,NULL) != 1 ) {
if ((*pb->bf_getsegcount)(obj, NULL) != 1) {
PyErr_SetString(PyExc_TypeError,
"expected a single-segment buffer object");
goto onError;
return -1;
}
len = (*pb->bf_getwritebuffer)(obj,0,&pp);
if (len < 0)
goto onError;
return -1;
*buffer = pp;
*buffer_len = len;
return 0;
onError:
return -1;
}
/* Operations on numbers */
@ -1980,7 +1984,8 @@ PyObject_GetIter(PyObject *o)
if (f == NULL) {
if (PySequence_Check(o))
return PySeqIter_New(o);
PyErr_SetString(PyExc_TypeError, "iteration over non-sequence");
PyErr_SetString(PyExc_TypeError,
"iteration over non-sequence");
return NULL;
}
else {
@ -2021,3 +2026,4 @@ PyIter_Next(PyObject *iter)
PyErr_Clear();
return result;
}