[svn-r13884] The second step of optimization for compound data for the Chicago

company.  The I/O is optimized when the source and destination 
members are a subset of each other one way or another, and
the order is the same, and no conversion is needed.  For example:
    struct source {            struct destination {
        TYPE1 A;      -->          TYPE1 A;
        TYPE2 B;      -->          TYPE2 B;
        TYPE3 C;      -->          TYPE3 C;
    };                             TYPE4 D;
                                   TYPE5 E;
                               };
    or
    struct destination {       struct source {
        TYPE1 A;      -->          TYPE1 A;
        TYPE2 B;      -->          TYPE2 B;
        TYPE3 C;      -->          TYPE3 C;
    };                             TYPE4 D;
                                   TYPE5 E;
                                };
The optimization is simply moving data from the source to the 
appropriate places in the buffer and bypass the reading of 
the background data and data conversion.

Tested on smirom, liberty, sol, and copper.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/H5Tprivate.h b/src/H5Tprivate.h
index a566a0a..0ac6047 100644
--- a/src/H5Tprivate.h
+++ b/src/H5Tprivate.h
@@ -64,6 +64,18 @@ typedef struct H5T_conv_cb_t {
     void*                       user_data;
 } H5T_conv_cb_t;
 
+/* Values for the optimization of compound data reading and writing.  They indicate
+ * whether the fields of the source and destination are subset of each other and
+ * there is no conversion needed.  It's for the Chicago company.
+ */
+typedef enum {
+    H5T_SUBSET_BADVALUE = -1,   /* Invalid value */
+    H5T_SUBSET_FALSE = 0,       /* Source and destination aren't subset of each other */ 
+    H5T_SUBSET_SRC,             /* Source is the subset of dest and no conversion is needed */
+    H5T_SUBSET_DST,             /* Dest is the subset of source and no conversion is needed */
+    H5T_SUBSET_CAP              /* Must be the last value */
+} H5T_subset_t;
+
 /* Forward declarations for prototype arguments */
 struct H5O_t;