[svn-r5603] Purpose:

    Bug fix

Description:
    I/O on "Regular" hyperslab selections could fail to transfer correctly
    if the number of elements in the selection's row did now fit "evenly"
    into the buffer being used for the transfer.

Solution:
    Correct the calculation of the block & count offsets within the optimized
    "regular" hyperslab routines.

Platforms tested:
    FreeBSD 4.5 (sleipnir)

3 files changed, 44 insertions, 16 deletions

diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index be279a8..2049ac8 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -35,6 +35,9 @@ Bug Fixes since HDF5-1.4.0
 
 Library
 -------
+    * Fixed bug where regular hyperslab selection could get incorrectly
+      transferred when the number of elements in a row did not fit evenly
+      into the buffer provided.  QAK 2002/06/12
     * Fixed bug (#499) which allowed an "empty" compound or enumerated datatype
       (one with no members) to be used to create a dataset or committed to a
       file.  QAK - 2002/06/11
@@ -302,9 +305,9 @@ New Features
           7 and contains the sizes of the data buffer dimensions. 
         - F90 subroutines h5dwrite_f, h5dread_f, h5awrite_f and h5aread_f were 
           overloaded with "dims" argument to be assumed size array of type 
-          INTEGER(HSIZE_T). We recommend to use the subroutines with the new type. 
-          Module subroutines that accept "dims" as INTEGER array of size 7 will be 
-          depricated in 1.6 release. 
+          INTEGER(HSIZE_T). We recommend to use the subroutines with the new
+          type.  Module subroutines that accept "dims" as INTEGER array of size
+          7 will be deprecated in 1.6 release. 
           EIP - 2002/05/06 
     * C++ API:
         - Added two new member functions: Exception::getFuncName() and
diff --git a/src/H5Shyper.c b/src/H5Shyper.c
index 1d14592..bf035b4 100644
--- a/src/H5Shyper.c
+++ b/src/H5Shyper.c
@@ -968,8 +968,14 @@ H5S_hyper_fread_opt (H5F_t *f, const struct H5O_layout_t *layout,
 
         /* Compute the current "counts" for this location */
         for(i=0; i<ndims; i++) {
-            tmp_count[i] = (file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start)%file_space->select.sel_info.hslab.diminfo[i].stride;
-            tmp_block[i] = (file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start)/file_space->select.sel_info.hslab.diminfo[i].stride;
+            if(file_space->select.sel_info.hslab.diminfo[i].stride==1) {
+                tmp_count[i] = 0;
+                tmp_block[i] = file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start;
+            } /* end if */
+            else {
+                tmp_count[i] = (file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start)/file_space->select.sel_info.hslab.diminfo[i].stride;
+                tmp_block[i] = (file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start)%file_space->select.sel_info.hslab.diminfo[i].stride;
+            } /* end else */
         } /* end for */
 
         /* Compute the initial buffer offset */
@@ -1993,8 +1999,14 @@ H5S_hyper_fwrite_opt (H5F_t *f, const struct H5O_layout_t *layout,
 
         /* Compute the current "counts" for this location */
         for(i=0; i<ndims; i++) {
-            tmp_count[i] = (file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start)%file_space->select.sel_info.hslab.diminfo[i].stride;
-            tmp_block[i] = (file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start)/file_space->select.sel_info.hslab.diminfo[i].stride;
+            if(file_space->select.sel_info.hslab.diminfo[i].stride==1) {
+                tmp_count[i] = 0;
+                tmp_block[i] = file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start;
+            } /* end if */
+            else {
+                tmp_count[i] = (file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start)/file_space->select.sel_info.hslab.diminfo[i].stride;
+                tmp_block[i] = (file_iter->hyp.off[i]-file_space->select.sel_info.hslab.diminfo[i].start)%file_space->select.sel_info.hslab.diminfo[i].stride;
+            } /* end else */
         } /* end for */
 
         /* Compute the initial buffer offset */
@@ -2923,8 +2935,14 @@ H5S_hyper_mread_opt (const void *_buf, size_t elmt_size,
 
         /* Compute the current "counts" for this location */
         for(i=0; i<ndims; i++) {
-            tmp_count[i] = (mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start)%mem_space->select.sel_info.hslab.diminfo[i].stride;
-            tmp_block[i] = (mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start)/mem_space->select.sel_info.hslab.diminfo[i].stride;
+            if(mem_space->select.sel_info.hslab.diminfo[i].stride==1) {
+                tmp_count[i] = 0;
+                tmp_block[i] = mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start;
+            } /* end if */
+            else {
+                tmp_count[i] = (mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start)/mem_space->select.sel_info.hslab.diminfo[i].stride;
+                tmp_block[i] = (mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start)%mem_space->select.sel_info.hslab.diminfo[i].stride;
+            } /* end else */
         } /* end for */
 
         /* Compute the initial buffer offset */
@@ -3752,8 +3770,14 @@ H5S_hyper_mwrite_opt (const void *_tconv_buf, size_t elmt_size,
 
         /* Compute the current "counts" for this location */
         for(i=0; i<ndims; i++) {
-            tmp_count[i] = (mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start)%mem_space->select.sel_info.hslab.diminfo[i].stride;
-            tmp_block[i] = (mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start)/mem_space->select.sel_info.hslab.diminfo[i].stride;
+            if(mem_space->select.sel_info.hslab.diminfo[i].stride==1) {
+                tmp_count[i] = 0;
+                tmp_block[i] = mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start;
+            } /* end if */
+            else {
+                tmp_count[i] = (mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start)/mem_space->select.sel_info.hslab.diminfo[i].stride;
+                tmp_block[i] = (mem_iter->hyp.off[i]-mem_space->select.sel_info.hslab.diminfo[i].start)%mem_space->select.sel_info.hslab.diminfo[i].stride;
+            } /* end else */
         } /* end for */
 
         /* Compute the initial buffer offset */
diff --git a/test/tselect.c b/test/tselect.c
index 7358d5b..c4587cf 100644
--- a/test/tselect.c
+++ b/test/tselect.c
@@ -939,7 +939,7 @@ compare_size_t(const void *s1, const void *s2)
 ** 
 ****************************************************************/
 static void 
-test_select_hyper_stride(void)
+test_select_hyper_stride(hid_t xfer_plist)
 {
     hid_t		fid1;		/* HDF5 File IDs		*/
     hid_t		dataset;	/* Dataset ID			*/
@@ -1026,7 +1026,7 @@ test_select_hyper_stride(void)
     dataset=H5Dcreate(fid1,"Dataset1",H5T_STD_U16LE,sid1,H5P_DEFAULT);
 
     /* Write selection to disk */
-    ret=H5Dwrite(dataset,H5T_NATIVE_USHORT,sid2,sid1,H5P_DEFAULT,wbuf);
+    ret=H5Dwrite(dataset,H5T_NATIVE_USHORT,sid2,sid1,xfer_plist,wbuf);
     CHECK(ret, FAIL, "H5Dwrite");
 
     /* Close memory dataspace */
@@ -1046,7 +1046,7 @@ test_select_hyper_stride(void)
     CHECK(ret, FAIL, "H5Sselect_hyperslab");
 
     /* Read selection from disk */
-    ret=H5Dread(dataset,H5T_NATIVE_USHORT,sid2,sid1,H5P_DEFAULT,rbuf);
+    ret=H5Dread(dataset,H5T_NATIVE_USHORT,sid2,sid1,xfer_plist,rbuf);
     CHECK(ret, FAIL, "H5Dread");
 
     /* Sort the locations into the proper order */
@@ -4996,7 +4996,7 @@ test_select(void)
     CHECK(plist_id, FAIL, "H5Pcreate");
 
     /* test I/O with a very small buffer for reads */
-    ret=H5Pset_buffer(plist_id,128,NULL,NULL);
+    ret=H5Pset_buffer(plist_id,59,NULL,NULL);
     CHECK(ret, FAIL, "H5Pset_buffer");
 
     /* These next tests use the same file */
@@ -5011,7 +5011,8 @@ test_select(void)
 
     /* These next tests use the same file */
     test_select_combo();        /* Test combined hyperslab & element selection code */
-    test_select_hyper_stride(); /* Test strided hyperslab selection code */
+    test_select_hyper_stride(H5P_DEFAULT); /* Test strided hyperslab selection code */
+    test_select_hyper_stride(plist_id); /* Test strided hyperslab selection code */
     test_select_hyper_contig(H5T_STD_U16LE,H5P_DEFAULT); /* Test contiguous hyperslab selection code */
     test_select_hyper_contig(H5T_STD_U16LE,plist_id); /* Test contiguous hyperslab selection code */
     test_select_hyper_contig(H5T_STD_U16BE,H5P_DEFAULT); /* Test contiguous hyperslab selection code */