Function NpyIter_ResetBasePointers

numpy/core/src/multiarray/nditer_api.c:316–362

NUMPY_API * Resets the iterator to its initial state, with new base data pointers. * This function requires great caution. * * If errmsg is non-NULL, it should point to a variable which will * receive the error message, and no Python exception will be set. * This is so that the function can be called from code not holding * the GIL. Note that cast errors may still lead to the GIL being * g

 * grabbed temporarily.
 */
NPY_NO_EXPORT int
NpyIter_ResetBasePointers(NpyIter *iter, char **baseptrs, char **errmsg)
{
    npy_uint32 itflags = NIT_ITFLAGS(iter);
    /*int ndim = NIT_NDIM(iter);*/
    int iop, nop = NIT_NOP(iter);

    char **resetdataptr = NIT_RESETDATAPTR(iter);
    npy_intp *baseoffsets = NIT_BASEOFFSETS(iter);

    if (itflags&NPY_ITFLAG_BUFFER) {
        /* If buffer allocation was delayed, do it now */
        if (itflags&NPY_ITFLAG_DELAYBUF) {
            if (!npyiter_allocate_buffers(iter, errmsg)) {
                return NPY_FAIL;
            }
            NIT_ITFLAGS(iter) &= ~NPY_ITFLAG_DELAYBUF;
        }
        else {
            if (npyiter_copy_from_buffers(iter) < 0) {
                if (errmsg != NULL) {
                    *errmsg = _reset_cast_error;
                }
                return NPY_FAIL;
            }
        }
    }

    /* The new data pointers for resetting */
    for (iop = 0; iop < nop; ++iop) {
        resetdataptr[iop] = baseptrs[iop] + baseoffsets[iop];
    }

    npyiter_goto_iterindex(iter, NIT_ITERSTART(iter));

    if (itflags&NPY_ITFLAG_BUFFER) {
        /* Prepare the next buffers and set iterend/size */
        if (npyiter_copy_to_buffers(iter, NULL) < 0) {
            if (errmsg != NULL) {
                *errmsg = _reset_cast_error;
            }
            return NPY_FAIL;
        }
    }

    return NPY_SUCCEED;
}

/*NUMPY_API
 * Resets the iterator to a new iterator index range