diff options
Diffstat (limited to 'src/H5Sselect.c')
| -rw-r--r-- | src/H5Sselect.c | 50 |
1 files changed, 16 insertions, 34 deletions
diff --git a/src/H5Sselect.c b/src/H5Sselect.c index c931304..87ac308 100644 --- a/src/H5Sselect.c +++ b/src/H5Sselect.c @@ -2170,27 +2170,24 @@ done: Note that if m > n, it is possible that the starting point in the buffer associated with the memory dataspace will have to be - adjusted to match the projected dataspace. If the buf parameter - is not NULL, the function must return an adjusted buffer base - address in *adj_buf_ptr. + adjusted to match the projected dataspace. In this case, the amount + of adjustment to be applied to the buffer will be returned via the + buf_adj parameter, if supplied. USAGE htri_t H5S_select_construct_projection(base_space, new_space_ptr, new_space_rank, - buf, - adj_buf_ptr) + element_size, + buf_adj) const H5S_t *base_space; IN: Ptr to Dataspace to project H5S_t ** new_space_ptr; OUT: Ptr to location in which to return the address of the projected space int new_space_rank; IN: Rank of the projected space. - const void * buf; IN: Base address of the buffer - associated with the base space. - May be NULL. - void ** adj_buf_ptr; OUT: If buf != NULL, store the base - address of the section of buf - that is described by *new_space_ptr - in *adj_buf_ptr. + hsize_t element_size; IN: size of each element in the selection + ptrdiff_t buf_adj; OUT: amount of adjustment to be applied + to buffer associated with memory + dataspace RETURNS Non-negative on success/Negative on failure. @@ -2200,9 +2197,6 @@ done: projection of the supplied dataspace and associated selection into the specified rank. Return it in *new_space_ptr. - If buf is supplied, computes the base address of the projected - selection in buf, and stores the base address in *adj_buf_ptr. - GLOBAL VARIABLES COMMENTS, BUGS, ASSUMPTIONS The selection in the supplied base_space has thickness 1 in all @@ -2214,7 +2208,7 @@ done: --------------------------------------------------------------------------*/ herr_t H5S_select_construct_projection(H5S_t *base_space, H5S_t **new_space_ptr, unsigned new_space_rank, - const void *buf, void const **adj_buf_ptr, hsize_t element_size) + hsize_t element_size, ptrdiff_t *buf_adj) { H5S_t * new_space = NULL; /* New dataspace constructed */ hsize_t base_space_dims[H5S_MAX_RANK]; /* Current dimensions of base dataspace */ @@ -2233,7 +2227,6 @@ H5S_select_construct_projection(H5S_t *base_space, H5S_t **new_space_ptr, unsign HDassert(new_space_ptr != NULL); HDassert((new_space_rank != 0) || (H5S_GET_SELECT_NPOINTS(base_space) <= 1)); HDassert(new_space_rank <= H5S_MAX_RANK); - HDassert((buf == NULL) || (adj_buf_ptr != NULL)); HDassert(element_size > 0); /* Get the extent info for the base dataspace */ @@ -2396,26 +2389,15 @@ H5S_select_construct_projection(H5S_t *base_space, H5S_t **new_space_ptr, unsign /* load the address of the new space into *new_space_ptr */ *new_space_ptr = new_space; - /* now adjust the buffer if required */ - if (buf != NULL) { + /* return the buffer adjustment amount if required */ + if (buf_adj != NULL) { if (new_space_rank < base_space_rank) { - /* a bit of pointer magic here: - * - * Since we can't do pointer arithmetic on void pointers, we first - * cast buf to a pointer to byte -- i.e. uint8_t. - * - * We then multiply the projected space element offset we - * calculated earlier by the supplied element size, add this - * value to the type cast buf pointer, cast the result back - * to a pointer to void, and assign the result to *adj_buf_ptr. - */ - *adj_buf_ptr = (const void *)(((const uint8_t *)buf) + - ((size_t)(projected_space_element_offset * element_size))); - } /* end if */ + *buf_adj = (ptrdiff_t)(projected_space_element_offset * element_size); + } else /* No adjustment necessary */ - *adj_buf_ptr = buf; - } /* end if */ + *buf_adj = 0; + } done: /* Cleanup on error */ |