H5Ztrans: (feature) Improved H5Z_xform_noop() and H5Z_xform_create() … (#933)

* H5Ztrans: (feature) Improved H5Z_xform_noop() and H5Z_xform_create() function

- Made a small improvement for H5Z_xform_noop() function. Now,
  the function will also return TRUE if the data transform function
  expression = "x". For this case, the HDF5 library behaves in a
  similar fashion as the case when no data transform function has been
  specified.
- Improved the inline documentation of the function
  H5Z_xform_create() such it is more inline with the rest of the
  code.

* Committing clang-format changes

* H5Ztrans: (feature) Added 3 tests for improved H5Z_xform_noop() function

- Added serial test with data transform expression = "x" to
  verify the improved H5Z_xform_noop() function behaves as expected.
- Added 2 parallel tests with data transform expression = "x"
  in combination with a filter. Before, these tests will fail but
  with the improved H5Z_xform_noop() function they work and result
  in the expected behavior.
- Small bug fix for one of parallel filter tests.

* Committing clang-format changes

* H5Ztrans: (feature) Added release note about detection of the
           simple data transform function "x".

- Added a brief explanation about the implemented improvement
  of the detection of the simple data transform function "x"
  to the RELEASE.txt file.

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/test/dtransform.c b/test/dtransform.c
index 8d3a8c0..743103f 100644
--- a/test/dtransform.c
+++ b/test/dtransform.c
@@ -582,6 +582,7 @@ test_specials(hid_t file)
     const char *special4 = "-x";
     const char *special5 = "+x";
     const char *special6 = "2e+1*x";
+    const char *special7 = "x";
 
     TESTING("data transform of some special cases")
 
@@ -729,6 +730,32 @@ test_specials(hid_t file)
     if (H5Dclose(dset_id) < 0)
         TEST_ERROR
 
+    /*-----------------------------
+     * Operation 7: x
+     * This operation will be
+     * treated if no function has
+     * been specified.
+     *----------------------------*/
+    if (H5Pset_data_transform(dxpl_id, special7) < 0)
+        TEST_ERROR;
+
+    for (row = 0; row < ROWS; row++)
+        for (col = 0; col < COLS; col++)
+            data_res[row][col] = transformData[row][col];
+
+    if ((dset_id = H5Dcreate2(file, "/special7", H5T_NATIVE_INT, dataspace, H5P_DEFAULT, H5P_DEFAULT,
+                              H5P_DEFAULT)) < 0)
+        TEST_ERROR
+    if (H5Dwrite(dset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, dxpl_id, transformData) < 0)
+        TEST_ERROR
+    if (H5Dread(dset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, read_buf) < 0)
+        TEST_ERROR
+
+    COMPARE_INT(read_buf, data_res)
+
+    if (H5Dclose(dset_id) < 0)
+        TEST_ERROR
+
     if (H5Pclose(dxpl_id) < 0)
         TEST_ERROR
     if (H5Sclose(dataspace) < 0)