static PyObject *
buffer_from_object(PyObject *base, Py_ssize_t size, Py_ssize_t offset, int readonly)
{
if (offset < 0) {
PyErr_SetString(PyExc_ValueError,
"offset must be zero or positive");
return NULL;
}
if ( PyBuffer_Check(base) && (((PyBufferObject *)base)->b_base) ) {
/* another buffer, refer to the base object */
PyBufferObject *b = (PyBufferObject *)base;
if (b->b_size != Py_END_OF_BUFFER) {
Py_ssize_t base_size = b->b_size - offset;
if (base_size < 0)
base_size = 0;
if (size == Py_END_OF_BUFFER || size > base_size)
size = base_size;
}
offset += b->b_offset;
base = b->b_base;
}
return buffer_from_memory(base, size, offset, NULL, readonly);
}
PyObject *
PyBuffer_FromReadWriteMemory(void *ptr, Py_ssize_t size)
{
return buffer_from_memory(NULL, size, 0, ptr, 0);
}
PyObject *
PyBuffer_FromMemory(void *ptr, int size)
{
return buffer_from_memory(NULL, size, 0, ptr, 1);
}
