[svn-r26842] Description:

    Cache the dataset's rank & dimension sizes, instead of querying them
frequently, to speed up various checks & algorithms.  Also, a few minor
cleanups.

Tested on:
    MacOSX/64 10.10.2 (amazon) w/serial & parallel
    Linux/32 2.6.18 (jam) w/serial & parallel

10 files changed, 131 insertions, 123 deletions

diff --git a/src/H5Dchunk.c b/src/H5Dchunk.c
index a5cf5b6..e99f00f 100644
--- a/src/H5Dchunk.c
+++ b/src/H5Dchunk.c
@@ -326,8 +326,6 @@ H5D__chunk_direct_write(const H5D_t *dset, hid_t dxpl_id, uint32_t filters, hsiz
     H5F_block_t old_chunk;              /* Offset/length of old chunk */
     H5D_chk_idx_info_t idx_info;        /* Chunked index info */
     hbool_t need_insert = FALSE;        /* Whether the chunk needs to be inserted into the index */
-    int         space_ndims;            /* Dataset's space rank */
-    hsize_t     space_dim[H5O_LAYOUT_NDIMS];    /* Dataset's dataspace dimensions */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC_TAG(dxpl_id, dset->oloc.addr, FAIL)
@@ -338,12 +336,8 @@ H5D__chunk_direct_write(const H5D_t *dset, hid_t dxpl_id, uint32_t filters, hsiz
         if(H5D__alloc_storage(dset, dxpl_id, H5D_ALLOC_WRITE, FALSE, NULL) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize storage")
 
-    /* Retrieve the dataset dimensions */
-    if((space_ndims = H5S_get_simple_extent_dims(dset->shared->space, space_dim, NULL)) < 0)
-         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to get simple dataspace info")
-
     /* Calculate the index of this chunk */
-    if(H5VM_chunk_index((unsigned)space_ndims, offset,
+    if(H5VM_chunk_index(dset->shared->ndims, offset,
             layout->u.chunk.dim, layout->u.chunk.down_chunks, &chunk_idx) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't get chunk index")
 
@@ -475,23 +469,15 @@ done:
 herr_t
 H5D__chunk_set_info(const H5D_t *dset)
 {
-    hsize_t curr_dims[H5O_LAYOUT_NDIMS];    /* Curr. size of dataset dimensions */
-    int sndims;                 /* Rank of dataspace */
-    unsigned ndims;             /* Rank of dataspace */
-    herr_t ret_value = SUCCEED; /* Return value */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity checks */
     HDassert(dset);
 
-    /* Get the dim info for dataset */
-    if((sndims = H5S_get_simple_extent_dims(dset->shared->space, curr_dims, NULL)) < 0)
-	HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get dataspace dimensions")
-    H5_ASSIGN_OVERFLOW(ndims, sndims, int, unsigned);
-
     /* Set the base layout information */
-    if(H5D__chunk_set_info_real(&dset->shared->layout.u.chunk, ndims, curr_dims) < 0)
+    if(H5D__chunk_set_info_real(&dset->shared->layout.u.chunk, dset->shared->ndims, dset->shared->curr_dims) < 0)
 	HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set layout's chunk info")
 
     /* Call the index's "resize" callback */
@@ -519,10 +505,7 @@ static herr_t
 H5D__chunk_construct(H5F_t UNUSED *f, H5D_t *dset)
 {
     const H5T_t *type = dset->shared->type;      /* Convenience pointer to dataset's datatype */
-    hsize_t max_dims[H5O_LAYOUT_NDIMS];          /* Maximum size of data in elements */
-    hsize_t dims[H5O_LAYOUT_NDIMS];              /* Dimension size of data in elements */
     uint64_t chunk_size;        /* Size of chunk in bytes */
-    int ndims;                  /* Rank of dataspace */
     unsigned u;                 /* Local index variable */
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -537,9 +520,7 @@ H5D__chunk_construct(H5F_t UNUSED *f, H5D_t *dset)
         HGOTO_ERROR(H5E_DATASET, H5E_BADVALUE, FAIL, "no chunk information set?")
 
     /* Set up layout information */
-    if((ndims = H5S_GET_EXTENT_NDIMS(dset->shared->space)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get rank")
-    if(dset->shared->layout.u.chunk.ndims != (unsigned)ndims)
+    if(dset->shared->layout.u.chunk.ndims != dset->shared->ndims)
         HGOTO_ERROR(H5E_DATASET, H5E_BADVALUE, FAIL, "dimensionality of chunks doesn't match the dataspace")
 
     /* Increment # of chunk dimensions, to account for datatype size as last element */
@@ -553,10 +534,6 @@ H5D__chunk_construct(H5F_t UNUSED *f, H5D_t *dset)
     /* Set the last dimension of the chunk size to the size of the datatype */
     dset->shared->layout.u.chunk.dim[dset->shared->layout.u.chunk.ndims - 1] = (uint32_t)H5T_GET_SIZE(type);
 
-    /* Get local copy of dataset dimensions (for sanity checking) */
-    if(H5S_get_simple_extent_dims(dset->shared->space, dims, max_dims) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to query maximum dimensions")
-
     /* Sanity check dimensions */
     for(u = 0; u < dset->shared->layout.u.chunk.ndims - 1; u++) {
         /* Don't allow zero-sized chunk dimensions */
@@ -568,7 +545,7 @@ H5D__chunk_construct(H5F_t UNUSED *f, H5D_t *dset)
          * the maximum dimension size. If any dimension size is zero, there
          * will be no such restriction.
          */
-        if(dims[u] && max_dims[u] != H5S_UNLIMITED && max_dims[u] < dset->shared->layout.u.chunk.dim[u])
+        if(dset->shared->curr_dims[u] && dset->shared->max_dims[u] != H5S_UNLIMITED && dset->shared->max_dims[u] < dset->shared->layout.u.chunk.dim[u])
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "chunk size must be <= maximum dimension size for fixed-sized dimensions")
     } /* end for */
 
@@ -3297,8 +3274,8 @@ H5D__chunk_allocate(const H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite,
     H5D_chunk_coll_info_t chunk_info; /* chunk address information for doing I/O */
 #endif /* H5_HAVE_PARALLEL */
     hbool_t	carry;          /* Flag to indicate that chunk increment carrys to higher dimension (sorta) */
-    int         space_ndims;    /* Dataset's space rank */
-    hsize_t     space_dim[H5O_LAYOUT_NDIMS];    /* Dataset's dataspace dimensions */
+    unsigned    space_ndims;    /* Dataset's space rank */
+    const hsize_t *space_dim;   /* Dataset's dataspace dimensions */
     const uint32_t *chunk_dim = layout->u.chunk.dim; /* Convenience pointer to chunk dimensions */
     unsigned    op_dim;                 /* Current operating dimension */
     H5D_fill_buf_info_t fb_info;        /* Dataset's fill buffer info */
@@ -3313,9 +3290,8 @@ H5D__chunk_allocate(const H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite,
     HDassert(TRUE == H5P_isa_class(dxpl_id, H5P_DATASET_XFER));
 
     /* Retrieve the dataset dimensions */
-    if((space_ndims = H5S_get_simple_extent_dims(dset->shared->space, space_dim, NULL)) < 0)
-         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to get simple dataspace info")
-    space_dim[space_ndims] = layout->u.chunk.dim[space_ndims];
+    space_dim = dset->shared->curr_dims;
+    space_ndims = dset->shared->ndims;
 
     /* The last dimension in chunk_offset is always 0 */
     chunk_offset[space_ndims] = (hsize_t)0;
@@ -3429,7 +3405,7 @@ H5D__chunk_allocate(const H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite,
      * certain dimension, max_unalloc is updated in order to avoid allocating
      * those chunks again.
      */
-    for(op_dim = 0; op_dim < (unsigned)space_ndims; op_dim++) {
+    for(op_dim = 0; op_dim < space_ndims; op_dim++) {
         H5D_chunk_ud_t udata;   /* User data for querying chunk info */
         int i;                  /* Local index variable */
 
@@ -3438,7 +3414,7 @@ H5D__chunk_allocate(const H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite,
             continue;
         else {
             /* Reset the chunk offset indices */
-            HDmemset(chunk_offset, 0, ((unsigned)space_ndims * sizeof(chunk_offset[0])));
+            HDmemset(chunk_offset, 0, (space_ndims * sizeof(chunk_offset[0])));
             chunk_offset[op_dim] = min_unalloc[op_dim];
 
             carry = FALSE;
@@ -3456,7 +3432,7 @@ H5D__chunk_allocate(const H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite,
                 hsize_t chunk_idx;
 
                 /* Calculate the index of this chunk */
-                if(H5VM_chunk_index((unsigned)space_ndims, chunk_offset,
+                if(H5VM_chunk_index(space_ndims, chunk_offset,
                         layout->u.chunk.dim, layout->u.chunk.down_chunks,
                         &chunk_idx) < 0)
                     HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't get chunk index")
@@ -3473,7 +3449,7 @@ H5D__chunk_allocate(const H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite,
                 unsigned u;             /* Local index variable */
                 hbool_t outside_orig = FALSE;
 
-                for(u = 0; u < (unsigned)space_ndims; u++) {
+                for(u = 0; u < space_ndims; u++) {
                     HDassert(chunk_offset[u] < space_dim[u]);
                     if(chunk_offset[u] >= old_dim[u])
                         outside_orig = TRUE;
@@ -4018,14 +3994,13 @@ H5D__chunk_prune_by_extent(H5D_t *dset, hid_t dxpl_id, const hsize_t *old_dim)
     const H5O_layout_t     *layout = &(dset->shared->layout);   /* Dataset's layout */
     const H5D_rdcc_t       *rdcc = &(dset->shared->cache.chunk);	/*raw data chunk cache */
     H5D_rdcc_ent_t         *ent = NULL;	        /* Cache entry  */
-    int                     space_ndims;        /* Dataset's space rank */
-    hsize_t                 space_dim[H5O_LAYOUT_NDIMS]; /* Current dataspace dimensions */
+    unsigned                space_ndims;        /* Dataset's space rank */
+    const hsize_t          *space_dim;          /* Current dataspace dimensions */
     unsigned                op_dim;             /* Current operating dimension */
     hbool_t                 shrunk_dim[H5O_LAYOUT_NDIMS]; /* Dimensions which have shrunk */
     H5D_chunk_it_ud1_t      udata;      /* Chunk index iterator user data */
     hbool_t                 udata_init = FALSE; /* Whether the chunk index iterator user data has been initialized */
     H5D_chunk_common_ud_t   idx_udata;          /* User data for index removal routine */
-    H5D_chunk_ud_t          chk_udata;          /* User data for getting chunk info */
     H5S_t                  *chunk_space = NULL;         /* Dataspace for a chunk */
     hsize_t                 chunk_dim[H5O_LAYOUT_NDIMS];   /* Chunk dimensions */
     hsize_t                 chunk_offset[H5O_LAYOUT_NDIMS]; /* Offset of current chunk */
@@ -4047,10 +4022,8 @@ H5D__chunk_prune_by_extent(H5D_t *dset, hid_t dxpl_id, const hsize_t *old_dim)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't fill dxpl cache")
 
     /* Go get the rank & dimensions (including the element size) */
-    if((space_ndims = H5S_get_simple_extent_dims(dset->shared->space, space_dim,
-            NULL)) < 0)
-	HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get dataset dimensions")
-    space_dim[space_ndims] = layout->u.chunk.dim[space_ndims];
+    space_dim = dset->shared->curr_dims;
+    space_ndims = dset->shared->ndims;
 
     /* The last dimension in chunk_offset is always 0 */
     chunk_offset[space_ndims] = (hsize_t)0;
@@ -4069,14 +4042,14 @@ H5D__chunk_prune_by_extent(H5D_t *dset, hid_t dxpl_id, const hsize_t *old_dim)
     /* (also copy the chunk dimensions into 'hsize_t' array for creating dataspace) */
     /* (also compute the dimensions which have been shrunk) */
     elmts_per_chunk = 1;
-    for(u = 0; u < (unsigned)space_ndims; u++) {
+    for(u = 0; u < space_ndims; u++) {
         elmts_per_chunk *= layout->u.chunk.dim[u];
 	chunk_dim[u] = layout->u.chunk.dim[u];
 	shrunk_dim[u] = space_dim[u] < old_dim[u];
     } /* end for */
 
     /* Create a dataspace for a chunk & set the extent */
-    if(NULL == (chunk_space = H5S_create_simple((unsigned)space_ndims, chunk_dim, NULL)))
+    if(NULL == (chunk_space = H5S_create_simple(space_ndims, chunk_dim, NULL)))
 	HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "can't create simple dataspace")
 
     /* Reset hyperslab start array */
@@ -4160,7 +4133,7 @@ H5D__chunk_prune_by_extent(H5D_t *dset, hid_t dxpl_id, const hsize_t *old_dim)
     if(has_fill)
         for(ent = rdcc->head; ent; ent = ent->next)
             /* Check for chunk offset outside of new dimensions */
-            for(u = 0; u < (unsigned)space_ndims; u++)
+            for(u = 0; u < space_ndims; u++)
                 if((hsize_t)ent->offset[u] >= space_dim[u]) {
                     /* Mark the entry as "deleted" */
                     ent->deleted = TRUE;
@@ -4176,12 +4149,12 @@ H5D__chunk_prune_by_extent(H5D_t *dset, hid_t dxpl_id, const hsize_t *old_dim)
             HDassert((hsize_t) max_mod_chunk_off[op_dim] >= min_mod_chunk_off[op_dim]);
 
             /* Reset the chunk offset indices */
-            HDmemset(chunk_offset, 0, ((unsigned)space_ndims * sizeof(chunk_offset[0])));
+            HDmemset(chunk_offset, 0, (space_ndims * sizeof(chunk_offset[0])));
             chunk_offset[op_dim] = min_mod_chunk_off[op_dim];
 
             /* Initialize "dims_outside_fill" array */
             ndims_outside_fill = 0;
-            for(u = 0; u < (unsigned)space_ndims; u++)
+            for(u = 0; u < space_ndims; u++)
                 if((hssize_t)chunk_offset[u] > max_fill_chunk_off[u]) {
                     dims_outside_fill[u] = TRUE;
                     ndims_outside_fill++;
@@ -4196,7 +4169,7 @@ H5D__chunk_prune_by_extent(H5D_t *dset, hid_t dxpl_id, const hsize_t *old_dim)
             int i;	                        /* Local index variable */
 
             /* Calculate the index of this chunk */
-            if(H5VM_chunk_index((unsigned)space_ndims, chunk_offset,
+            if(H5VM_chunk_index(space_ndims, chunk_offset,
                     layout->u.chunk.dim, layout->u.chunk.down_chunks,
                     &(chk_io_info.store->chunk.index)) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't get chunk index")
@@ -4210,12 +4183,14 @@ H5D__chunk_prune_by_extent(H5D_t *dset, hid_t dxpl_id, const hsize_t *old_dim)
                     HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to write fill value")
             } /* end if */
             else {
+                H5D_chunk_ud_t          chk_udata;          /* User data for getting chunk info */
+
 #ifndef NDEBUG
                 /* Make sure this chunk is really outside the new dimensions */
                 {
                     hbool_t outside_dim = FALSE;
 
-                    for(u = 0; u < (unsigned)space_ndims; u++)
+                    for(u = 0; u < space_ndims; u++)
                         if(chunk_offset[u] >= space_dim[u]) {
                             outside_dim = TRUE;
                             break;
@@ -4501,7 +4476,7 @@ H5D__chunk_update_cache(H5D_t *dset, hid_t dxpl_id)
     HDassert(dset->shared->layout.u.chunk.ndims > 0 && dset->shared->layout.u.chunk.ndims <= H5O_LAYOUT_NDIMS);
 
     /* Get the rank */
-    rank = dset->shared->layout.u.chunk.ndims-1;
+    rank = dset->shared->layout.u.chunk.ndims - 1;
     HDassert(rank > 0);
 
     /* 1-D dataset's chunks can't have their index change */
diff --git a/src/H5Dcompact.c b/src/H5Dcompact.c
index 789beab..1d8b97c 100644
--- a/src/H5Dcompact.c
+++ b/src/H5Dcompact.c
@@ -174,11 +174,8 @@ H5D__compact_construct(H5F_t *f, H5D_t *dset)
     hssize_t stmp_size;         /* Temporary holder for raw data size */
     hsize_t tmp_size;           /* Temporary holder for raw data size */
     hsize_t max_comp_data_size; /* Max. allowed size of compact data */
-    hsize_t dim[H5O_LAYOUT_NDIMS];      /* Current size of data in elements */
-    hsize_t max_dim[H5O_LAYOUT_NDIMS];  /* Maximum size of data in elements */
-    int ndims;                          /* Rank of dataspace */
-    int i;                              /* Local index variable */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    unsigned u;                 /* Local index variable */
+    herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_STATIC
 
@@ -187,11 +184,9 @@ H5D__compact_construct(H5F_t *f, H5D_t *dset)
     HDassert(dset);
 
     /* Check for invalid dataset dimensions */
-    if((ndims = H5S_get_simple_extent_dims(dset->shared->space, dim, max_dim)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get dataspace dimensions")
-    for(i = 0; i < ndims; i++)
-        if(max_dim[i] > dim[i])
-            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "extendible compact dataset")
+    for(u = 0; u < dset->shared->ndims; u++)
+        if(dset->shared->max_dims[u] > dset->shared->curr_dims[u])
+            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "extendible compact dataset not allowed")
 
     /*
      * Compact dataset is stored in dataset object header message of
diff --git a/src/H5Dcontig.c b/src/H5Dcontig.c
index dc09768..e913a3f 100644
--- a/src/H5Dcontig.c
+++ b/src/H5Dcontig.c
@@ -396,10 +396,7 @@ H5D__contig_construct(H5F_t *f, H5D_t *dset)
     size_t dt_size;                     /* Size of datatype */
     hsize_t tmp_size;                   /* Temporary holder for raw data size */
     size_t tmp_sieve_buf_size;          /* Temporary holder for sieve buffer size */
-    hsize_t dim[H5O_LAYOUT_NDIMS];	/* Current size of data in elements */
-    hsize_t max_dim[H5O_LAYOUT_NDIMS];  /* Maximum size of data in elements */
-    int ndims;                          /* Rank of dataspace */
-    int i;                              /* Local index variable */
+    unsigned u;                         /* Local index variable */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC
@@ -415,11 +412,9 @@ H5D__contig_construct(H5F_t *f, H5D_t *dset)
      */
 
     /* Check for invalid dataset dimensions */
-    if((ndims = H5S_get_simple_extent_dims(dset->shared->space, dim, max_dim)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize contiguous storage")
-    for(i = 0; i < ndims; i++)
-        if(max_dim[i] > dim[i])
-            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "extendible contiguous non-external dataset")
+    for(u = 0; u < dset->shared->ndims; u++)
+        if(dset->shared->max_dims[u] > dset->shared->curr_dims[u])
+            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "extendible contiguous non-external dataset not allowed")
 
     /* Retrieve the number of elements in the dataspace */
     if((snelmts = H5S_GET_EXTENT_NPOINTS(dset->shared->space)) < 0)
diff --git a/src/H5Ddeprec.c b/src/H5Ddeprec.c
index 0b2fee6..b3dae7b 100644
--- a/src/H5Ddeprec.c
+++ b/src/H5Ddeprec.c
@@ -341,9 +341,7 @@ static herr_t
 H5D__extend(H5D_t *dataset, const hsize_t *size, hid_t dxpl_id)
 {
     htri_t changed;                     /* Flag to indicate that the dataspace was successfully extended */
-    H5S_t *space;                       /* Dataset's dataspace */
-    int     rank;                       /* Dataspace # of dimensions */
-    hsize_t curr_dims[H5O_LAYOUT_NDIMS];/* Current dimension sizes */
+    hsize_t old_dims[H5S_MAX_RANK];     /* Current (i.e. old, if changed) dimension sizes */
     H5O_fill_t *fill;                   /* Dataset's fill value */
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -364,20 +362,30 @@ H5D__extend(H5D_t *dataset, const hsize_t *size, hid_t dxpl_id)
      */
 
     /* Retrieve the current dimensions */
-    space = dataset->shared->space;
-    if((rank = H5S_get_simple_extent_dims(space, curr_dims, NULL)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get dataset dimensions")
+    HDcompile_assert(sizeof(old_dims) == sizeof(dataset->shared->curr_dims));
+    HDmemcpy(old_dims, dataset->shared->curr_dims, H5S_MAX_RANK * sizeof(old_dims[0]));
 
     /* Increase the size of the data space */
-    if((changed = H5S_extend(space, size)) < 0)
-	HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to increase size of data space")
+    if((changed = H5S_extend(dataset->shared->space, size)) < 0)
+	HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to increase size of dataspace")
 
     /* Updated the dataset's info if the dataspace was successfully extended */
     if(changed) {
+        /* Get the extended dimension sizes */
+        /* (Need to retrieve this here, since the 'size' dimensions could
+         *  extend one dimension but be smaller in a different dimension,
+         *  and the dataspace's extent is the larger of the current and
+         *  'size' dimension values. - QAK)
+         */
+        if(H5S_get_simple_extent_dims(dataset->shared->space, dataset->shared->curr_dims, NULL) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get dataset dimensions")
+
         /* Update the index values for the cached chunks for this dataset */
         if(H5D_CHUNKED == dataset->shared->layout.type) {
+            /* Update general information for chunks */
             if(H5D__chunk_set_info(dataset) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "unable to update # of chunks")
+            /* Update the chunk cache indices */
             if(H5D__chunk_update_cache(dataset, dxpl_id) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to update cached chunk indices")
         } /* end if */
@@ -385,8 +393,7 @@ H5D__extend(H5D_t *dataset, const hsize_t *size, hid_t dxpl_id)
 	/* Allocate space for the new parts of the dataset, if appropriate */
         fill = &dataset->shared->dcpl_cache.fill;
         if(fill->alloc_time == H5D_ALLOC_TIME_EARLY)
-            if(H5D__alloc_storage(dataset, dxpl_id, H5D_ALLOC_EXTEND, FALSE,
-                    curr_dims) < 0)
+            if(H5D__alloc_storage(dataset, dxpl_id, H5D_ALLOC_EXTEND, FALSE, old_dims) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize dataset with fill value")
 
         /* Mark the dataspace as dirty, for later writing to the file */
diff --git a/src/H5Defl.c b/src/H5Defl.c
index 38c8ccd..355492f 100644
--- a/src/H5Defl.c
+++ b/src/H5Defl.c
@@ -126,14 +126,11 @@ static herr_t
 H5D__efl_construct(H5F_t *f, H5D_t *dset)
 {
     size_t dt_size;                     /* Size of datatype */
-    hsize_t dim[H5O_LAYOUT_NDIMS];	/* Current size of data in elements */
-    hsize_t max_dim[H5O_LAYOUT_NDIMS];  /* Maximum size of data in elements */
     hssize_t stmp_size;                 /* Temporary holder for raw data size */
     hsize_t tmp_size;                   /* Temporary holder for raw data size */
     hsize_t max_points;                 /* Maximum elements */
     hsize_t max_storage;                /* Maximum storage size */
-    int ndims;                          /* Rank of dataspace */
-    int i;                              /* Local index variable */
+    unsigned u;                         /* Local index variable */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC
@@ -149,11 +146,9 @@ H5D__efl_construct(H5F_t *f, H5D_t *dset)
      */
 
     /* Check for invalid dataset dimensions */
-    if((ndims = H5S_get_simple_extent_dims(dset->shared->space, dim, max_dim)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize contiguous storage")
-    for(i = 1; i < ndims; i++)
-        if(max_dim[i] > dim[i])
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "only the first dimension can be extendible")
+    for(u = 1; u < dset->shared->ndims; u++)
+        if(dset->shared->max_dims[u] > dset->shared->curr_dims[u])
+            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "only the first dimension can be extendible")
 
     /* Retrieve the size of the dataset's datatype */
     if(0 == (dt_size = H5T_get_size(dset->shared->type)))
diff --git a/src/H5Dint.c b/src/H5Dint.c
index 8e1fcec..c626475 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -62,6 +62,7 @@ static H5D_shared_t *H5D__new(hid_t dcpl_id, hbool_t creating,
     hbool_t vl_type);
 static herr_t H5D__init_type(H5F_t *file, const H5D_t *dset, hid_t type_id,
     const H5T_t *type);
+static herr_t H5D__cache_dataspace_info(const H5D_t *dset);
 static herr_t H5D__init_space(H5F_t *file, const H5D_t *dset, const H5S_t *space);
 static herr_t H5D__update_oh_info(H5F_t *file, hid_t dxpl_id, H5D_t *dset,
     hid_t dapl_id);
@@ -665,6 +666,41 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5D__cache_dataspace_info
+ *
+ * Purpose:	Cache dataspace info for a dataset
+ *
+ * Return:	Success:    SUCCEED
+ *		Failure:    FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Wednesday, November 19, 2014
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5D__cache_dataspace_info(const H5D_t *dset)
+{
+    int sndims;                         /* Signed number of dimensions of dataspace rank */
+    unsigned u;                         /* Local index value */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity checking */
+    HDassert(dset);
+
+    /* Cache info for dataset's dataspace */
+    if((sndims = H5S_get_simple_extent_dims(dset->shared->space, dset->shared->curr_dims, dset->shared->max_dims)) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't cache dataspace dimensions")
+    dset->shared->ndims = (unsigned)sndims;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D__cache_dataspace_info() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5D__init_space
  *
  * Purpose:	Copy a dataspace for a dataset's use, performing all the
@@ -698,6 +734,10 @@ H5D__init_space(H5F_t *file, const H5D_t *dset, const H5S_t *space)
     if(NULL == (dset->shared->space = H5S_copy(space, FALSE, TRUE)))
         HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy dataspace")
 
+    /* Cache the dataset's dataspace info */
+    if(H5D__cache_dataspace_info(dset) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't cache dataspace info")
+
     /* Set the latest format, if requested */
     if(use_latest_format)
         if(H5S_set_latest_version(dset->shared->space) < 0)
@@ -1251,6 +1291,10 @@ H5D__open_oid(H5D_t *dataset, hid_t dapl_id, hid_t dxpl_id)
     if(NULL == (dataset->shared->space = H5S_read(&(dataset->oloc), dxpl_id)))
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to load dataspace info from dataset header")
 
+    /* Cache the dataset's dataspace info */
+    if(H5D__cache_dataspace_info(dataset) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't cache dataspace info")
+
     /* Get a datatype ID for the dataset's datatype */
     if((dataset->shared->type_id = H5I_register(H5I_DATATYPE, dataset->shared->type, FALSE)) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTREGISTER, FAIL, "unable to register type")
@@ -2161,9 +2205,7 @@ done:
 herr_t
 H5D__set_extent(H5D_t *dset, const hsize_t *size, hid_t dxpl_id)
 {
-    H5S_t   *space;                     /* Dataset's dataspace */
-    int     rank;                       /* Dataspace # of dimensions */
-    hsize_t curr_dims[H5O_LAYOUT_NDIMS];/* Current dimension sizes */
+    hsize_t curr_dims[H5S_MAX_RANK];    /* Current dimension sizes */
     htri_t  changed;                    /* Whether the dataspace changed size */
     herr_t  ret_value = SUCCEED;        /* Return value */
 
@@ -2187,29 +2229,30 @@ H5D__set_extent(H5D_t *dset, const hsize_t *size, hid_t dxpl_id)
     if(H5D__check_filters(dset) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't apply filters")
 
-    /* Get the data space */
-    space = dset->shared->space;
-
-    /* Check if we are shrinking or expanding any of the dimensions */
-    if((rank = H5S_get_simple_extent_dims(space, curr_dims, NULL)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get dataset dimensions")
+    /* Keep the current dataspace dimensions for later */
+    HDcompile_assert(sizeof(curr_dims) == sizeof(dset->shared->curr_dims));
+    HDmemcpy(curr_dims, dset->shared->curr_dims, H5S_MAX_RANK * sizeof(curr_dims[0]));
 
-    /* Modify the size of the data space */
-    if((changed = H5S_set_extent(space, size)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")
+    /* Modify the size of the dataspace */
+    if((changed = H5S_set_extent(dset->shared->space, size)) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of dataspace")
 
     /* Don't bother updating things, unless they've changed */
     if(changed) {
-        hbool_t shrink = FALSE;             /* Flag to indicate a dimension has shrank */
-        hbool_t expand = FALSE;             /* Flag to indicate a dimension has grown */
-        unsigned u;                         /* Local index variable */
+        hbool_t shrink = FALSE;         /* Flag to indicate a dimension has shrank */
+        hbool_t expand = FALSE;         /* Flag to indicate a dimension has grown */
+        unsigned u;                     /* Local index variable */
 
         /* Determine if we are shrinking and/or expanding any dimensions */
-        for(u = 0; u < (unsigned)rank; u++) {
+        for(u = 0; u < dset->shared->ndims; u++) {
+            /* Check for various status changes */
             if(size[u] < curr_dims[u])
                 shrink = TRUE;
             if(size[u] > curr_dims[u])
                 expand = TRUE;
+
+            /* Update the cached copy of the dataset's dimensions */
+            dset->shared->curr_dims[u] = size[u];
         } /* end for */
 
         /*-------------------------------------------------------------------------
diff --git a/src/H5Dio.c b/src/H5Dio.c
index 1c77d93..44080dc 100644
--- a/src/H5Dio.c
+++ b/src/H5Dio.c
@@ -302,8 +302,6 @@ H5D__pre_write(H5D_t *dset, hbool_t direct_write, hid_t mem_type_id,
         uint32_t direct_filters;
         hsize_t *direct_offset;
         uint32_t direct_datasize;
-	int      ndims = 0;
-	hsize_t  dims[H5O_LAYOUT_NDIMS];
 	hsize_t  internal_offset[H5O_LAYOUT_NDIMS];
 	unsigned u;                 /* Local index variable */
 
@@ -324,12 +322,9 @@ H5D__pre_write(H5D_t *dset, hbool_t direct_write, hid_t mem_type_id,
 
 	/* The library's chunking code requires the offset terminates with a zero. So transfer the 
          * offset array to an internal offset array */ 
-	if((ndims = H5S_get_simple_extent_dims(dset->shared->space, dims, NULL)) < 0)
-	    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't retrieve dataspace extent dims")
-
-	for(u = 0; u < (unsigned)ndims; u++) {
+	for(u = 0; u < dset->shared->ndims; u++) {
 	    /* Make sure the offset doesn't exceed the dataset's dimensions */
-            if(direct_offset[u] > dims[u])
+            if(direct_offset[u] > dset->shared->curr_dims[u])
 		HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "offset exceeds dimensions of dataset")
 
             /* Make sure the offset fall right on a chunk's boundary */
@@ -340,7 +335,7 @@ H5D__pre_write(H5D_t *dset, hbool_t direct_write, hid_t mem_type_id,
 	} /* end for */
 	   
 	/* Terminate the offset with a zero */ 
-	internal_offset[ndims] = 0;
+	internal_offset[dset->shared->ndims] = 0;
 
 	/* write raw data */
 	if(H5D__chunk_direct_write(dset, dxpl_id, direct_filters, internal_offset, direct_datasize, buf) < 0)
diff --git a/src/H5Dmpio.c b/src/H5Dmpio.c
index bd1531d..db487cd 100644
--- a/src/H5Dmpio.c
+++ b/src/H5Dmpio.c
@@ -860,8 +860,7 @@ H5D__link_chunk_collective_io(H5D_io_info_t *io_info, const H5D_type_info_t *typ
             mspace = chunk_info->mspace;
 
             /* Look up address of chunk */
-            if(H5D__chunk_lookup(io_info->dset, io_info->dxpl_id, chunk_info->coords,
-                    chunk_info->index, &udata) < 0)
+            if(H5D__chunk_lookup(io_info->dset, io_info->dxpl_id, chunk_info->coords, chunk_info->index, &udata) < 0)
                 HGOTO_ERROR(H5E_STORAGE, H5E_CANTGET, FAIL, "couldn't get chunk address")
             ctg_store.contig.dset_addr = udata.chunk_block.offset;
         } /* end else */
diff --git a/src/H5Dpkg.h b/src/H5Dpkg.h
index 4ec140f..fa59412 100644
--- a/src/H5Dpkg.h
+++ b/src/H5Dpkg.h
@@ -325,9 +325,9 @@ typedef struct H5D_chunk_info_t {
     uint32_t chunk_points;      /* Number of elements selected in chunk */
     hsize_t coords[H5O_LAYOUT_NDIMS];   /* Coordinates of chunk in file dataset's dataspace */
     H5S_t *fspace;              /* Dataspace describing chunk & selection in it */
-    unsigned fspace_shared;     /* Indicate that the file space for a chunk is shared and shouldn't be freed */
+    hbool_t fspace_shared;      /* Indicate that the file space for a chunk is shared and shouldn't be freed */
     H5S_t *mspace;              /* Dataspace describing selection in memory corresponding to this chunk */
-    unsigned mspace_shared;     /* Indicate that the memory space for a chunk is shared and shouldn't be freed */
+    hbool_t mspace_shared;      /* Indicate that the memory space for a chunk is shared and shouldn't be freed */
 } H5D_chunk_info_t;
 
 /* Main structure holding the mapping between file chunks and memory */
@@ -418,6 +418,11 @@ typedef struct H5D_shared_t {
     H5O_layout_t        layout;         /* Data layout                  */
     hbool_t             checked_filters;/* TRUE if dataset passes can_apply check */
 
+    /* Cached dataspace info */
+    unsigned            ndims;          /* The dataset's dataspace rank */
+    hsize_t             curr_dims[H5S_MAX_RANK];    /* The curr. size of dataset dimensions */
+    hsize_t             max_dims[H5S_MAX_RANK];     /* The max. size of dataset dimensions */ 
+
     /* Buffered/cached information for types of raw data storage*/
     struct {
         H5D_rdcdc_t     contig;         /* Information about contiguous data */
diff --git a/src/H5S.c b/src/H5S.c
index 4a1783e..dd2bb0a 100644
--- a/src/H5S.c
+++ b/src/H5S.c
@@ -2144,14 +2144,13 @@ H5S_extend(H5S_t *space, const hsize_t *size)
     HDassert(size);
 
     /* Check through all the dimensions to see if modifying the dataspace is allowed */
-    for(u = 0; u < space->extent.rank; u++) {
-        if(space->extent.size[u]<size[u]) {
-            if(space->extent.max && H5S_UNLIMITED!=space->extent.max[u] &&
-                    space->extent.max[u]<size[u])
+    for(u = 0; u < space->extent.rank; u++)
+        if(space->extent.size[u] < size[u]) {
+            if(space->extent.max && H5S_UNLIMITED != space->extent.max[u] &&
+                    space->extent.max[u] < size[u])
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "dimension cannot be increased")
             ret_value++;
         } /* end if */
-    } /* end for */
 
     /* Update */
     if(ret_value) {