[svn-r14004] Description:

	Fix problem with datatype messages where the version of the format
for a datatype message could depend on the "use the latest format" flag from
the file after it was initially created.

Tested on:
	FreeBSD/32 6.2 (duty)
	FreeBSD/64 6.2 (liberty)
	Linux/32 2.6 (kagiso)
	Mac OS X/32 10.4.10 (amazon)

14 files changed, 889 insertions, 492 deletions

diff --git a/src/H5A.c b/src/H5A.c
index 5bcbd7f..3ac3d52 100644
--- a/src/H5A.c
+++ b/src/H5A.c
@@ -350,6 +350,11 @@ H5A_create(const H5G_loc_t *loc, const char *name, const H5T_t *type,
     if(H5T_set_loc(attr->dt, loc->oloc->file, H5T_LOC_DISK) < 0)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "invalid datatype location")
 
+    /* Set the latest format for datatype, if requested */
+    if(H5F_USE_LATEST_FORMAT(loc->oloc->file))
+        if(H5T_set_latest_version(attr->dt) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set latest version of datatype")
+
     /* Copy the dataspace for the attribute */
     attr->ds = H5S_copy(space, FALSE);
 
diff --git a/src/H5D.c b/src/H5D.c
index 526ee27..6a47908 100644
--- a/src/H5D.c
+++ b/src/H5D.c
@@ -1020,6 +1020,7 @@ H5D_init_type(H5F_t *file, const H5D_t *dset, hid_t type_id, const H5T_t *type)
 {
     htri_t relocatable;                 /* Flag whether the type is relocatable */
     htri_t immutable;                   /* Flag whether the type is immutable */
+    hbool_t use_latest_format;          /* Flag indicating the newest file format should be used */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_init_type)
@@ -1037,15 +1038,23 @@ H5D_init_type(H5F_t *file, const H5D_t *dset, hid_t type_id, const H5T_t *type)
     if((immutable = H5T_is_immutable(type)) < 0)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "can't check datatype?")
 
+    /* Get the file's 'use the latest version of the format' flag */
+    use_latest_format = H5F_USE_LATEST_FORMAT(file);
+
     /* Copy the datatype if it's a custom datatype or if it'll change when it's location is changed */
-    if(!immutable || relocatable) {
+    if(!immutable || relocatable || use_latest_format) {
         /* Copy datatype for dataset */
-        if((dset->shared->type = H5T_copy(type, H5T_COPY_ALL))==NULL)
-            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTCOPY, FAIL, "can't copy datatype")
+        if((dset->shared->type = H5T_copy(type, H5T_COPY_ALL)) == NULL)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy datatype")
 
         /* Mark any datatypes as being on disk now */
         if(H5T_set_loc(dset->shared->type, file, H5T_LOC_DISK) < 0)
-            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "invalid datatype location")
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't set datatype location")
+
+        /* Set the latest format, if requested */
+        if(use_latest_format)
+            if(H5T_set_latest_version(dset->shared->type) < 0)
+                HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set latest version of datatype")
 
         /* Get a datatype ID for the dataset's datatype */
 	if((dset->shared->type_id = H5I_register(H5I_DATATYPE, dset->shared->type)) < 0)
diff --git a/src/H5Odtype.c b/src/H5Odtype.c
index 2bfaccf..1e97687 100644
--- a/src/H5Odtype.c
+++ b/src/H5Odtype.c
@@ -89,31 +89,6 @@ const H5O_msg_class_t H5O_MSG_DTYPE[1] = {{
     H5O_dtype_shared_debug	/* debug the message		*/
 }};
 
-/* This is the version to create all datatypes which don't contain
- * array datatypes (atomic types, compound datatypes without array fields,
- * vlen sequences of objects which aren't arrays, etc.) or VAX byte-ordered
- * objects.
- */
-#define H5O_DTYPE_VERSION_1	1
-
-/* This is the version to create all datatypes which contain H5T_ARRAY
- * class objects (array definitely, potentially compound & vlen sequences also),
- * but not VAX byte-ordered objects.
- */
-#define H5O_DTYPE_VERSION_2	2
-
-/* This is the version to create all datatypes which contain VAX byte-ordered
- * objects (floating-point types, currently) (can also also H5T_ARRAY types
- * also).
- */
-/* This version also packs compound & enum field names without padding */
-/* This version also encodes the member offset of compound fields more efficiently */
-#define H5O_DTYPE_VERSION_3	3
-
-/* The latest version of the format.  Look through the 'encode helper' routine
- *      and 'size' callback for places to change when updating this. */
-#define H5O_DTYPE_VERSION_LATEST H5O_DTYPE_VERSION_3
-
 
 /*-------------------------------------------------------------------------
  * Function:	H5O_dtype_decode_helper
@@ -146,6 +121,7 @@ H5O_dtype_decode_helper(H5F_t *f, const uint8_t **pp, H5T_t *dt)
     version = (flags>>4) & 0x0f;
     if(version < H5O_DTYPE_VERSION_1 || version > H5O_DTYPE_VERSION_3)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTLOAD, FAIL, "bad version number for datatype message")
+    dt->shared->version = version;
     dt->shared->type = (H5T_class_t)(flags & 0x0f);
     flags >>= 8;
 
@@ -515,6 +491,10 @@ done:
  *
  * Purpose:	Encodes a datatype.
  *
+ * Note:	When changing the format of a datatype (or adding a new one),
+ *		remember to change the upgrade version callback
+ *		(H5T_upgrade_version_cb).
+ *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Robb Matzke
@@ -525,14 +505,10 @@ done:
 static herr_t
 H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
 {
-    htri_t      has_array = FALSE;      /* Whether a compound datatype has an array inside it */
-    hbool_t     has_vax = FALSE;        /* Whether VAX floating number exists */
     unsigned	flags = 0;
     char	*hdr = (char *)*pp;
     unsigned	i;
     size_t	n, z;
-    uint8_t     version;                /* version number */
-    hbool_t     use_latest_format;      /* Flag indicating the newest file format should be used */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5O_dtype_encode_helper)
@@ -541,9 +517,6 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
     HDassert(pp && *pp);
     HDassert(dt);
 
-    /* Get the file's 'use the latest version of the format' flag */
-    use_latest_format = H5F_USE_LATEST_FORMAT(f);
-
     /* skip the type and class bit-field for now */
     *pp += 4;
     UINT32ENCODE(*pp, dt->shared->size);
@@ -666,7 +639,7 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
                     break;
                 case H5T_ORDER_VAX:     /*turn on 1st and 6th (reserved before adding VAX) bits*/
                     flags |= 0x41;
-                    has_vax = TRUE;
+                    HDassert(dt->shared->version >= H5O_DTYPE_VERSION_3);
                     break;
                 default:
                     HGOTO_ERROR(H5E_DATATYPE, H5E_UNSUPPORTED, FAIL, "byte order is not supported in file format yet")
@@ -733,10 +706,6 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
             {
                 unsigned offset_nbytes;         /* Size needed to encode member offsets */
 
-                /* Check for an array datatype somewhere within the compound type */
-                if((has_array = H5T_detect_class(dt, H5T_ARRAY)) < 0)
-                    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTENCODE, FAIL, "can't detect array class")
-
                 /* Compute the # of bytes required to store a member offset */
                 offset_nbytes = (H5V_log2_gen((uint64_t)dt->shared->size) + 7) / 8;
 
@@ -745,12 +714,16 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
                  */
                 flags = dt->shared->u.compnd.nmembs & 0xffff;
                 for(i = 0; i < dt->shared->u.compnd.nmembs; i++) {
+                    /* Sanity check */
+                    /* (compound datatypes w/array members must be encoded w/version >= 2) */
+                    HDassert(dt->shared->u.compnd.memb[i].type->shared->type != H5T_ARRAY || dt->shared->version >= H5O_DTYPE_VERSION_2);
+
                     /* Name */
                     HDstrcpy((char*)(*pp), dt->shared->u.compnd.memb[i].name);
 
                     /* Version 3 of the datatype message removed the padding to multiple of 8 bytes */
                     n = HDstrlen(dt->shared->u.compnd.memb[i].name);
-                    if(use_latest_format)
+                    if(dt->shared->version >= H5O_DTYPE_VERSION_3)
                         *pp += n + 1;
                     else {
                         /* Pad name to multiple of 8 bytes */
@@ -761,7 +734,7 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
 
                     /* Member offset */
                     /* (starting with version 3 of the datatype message, use the minimum # of bytes required) */
-                    if(use_latest_format)
+                    if(dt->shared->version >= H5O_DTYPE_VERSION_3)
                         UINT32ENCODE_VAR(*pp, dt->shared->u.compnd.memb[i].offset, offset_nbytes)
                     else
                         UINT32ENCODE(*pp, dt->shared->u.compnd.memb[i].offset)
@@ -770,7 +743,7 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
                      * member information, for better backward compatibility
                      * Write out all zeros for the array information, though...
                      */
-                    if(!has_array && !use_latest_format) {
+                    if(dt->shared->version == H5O_DTYPE_VERSION_1) {
                         unsigned	j;
 
                         /* Dimensionality */
@@ -810,13 +783,13 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
                 HGOTO_ERROR(H5E_DATATYPE, H5E_CANTENCODE, FAIL, "unable to encode parent datatype")
 
             /* Names, each a multiple of eight bytes */
-            for(i=0; i<dt->shared->u.enumer.nmembs; i++) {
+            for(i = 0; i < dt->shared->u.enumer.nmembs; i++) {
                 /* Name */
                 HDstrcpy((char*)(*pp), dt->shared->u.enumer.name[i]);
 
                 /* Version 3 of the datatype message removed the padding to multiple of 8 bytes */
                 n = HDstrlen(dt->shared->u.enumer.name[i]);
-                if(use_latest_format)
+                if(dt->shared->version >= H5O_DTYPE_VERSION_3)
                     *pp += n + 1;
                 else {
                     /* Pad to multiple of 8 bytes */
@@ -882,7 +855,7 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
             *(*pp)++ = dt->shared->u.array.ndims;
 
             /* Drop this information for Version 3 of the format */
-            if(!use_latest_format) {
+            if(dt->shared->version < H5O_DTYPE_VERSION_3) {
                 /* Reserved */
                 *(*pp)++ = '\0';
                 *(*pp)++ = '\0';
@@ -894,7 +867,7 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
                 UINT32ENCODE(*pp, dt->shared->u.array.dim[i]);
 
             /* Drop this information for Version 3 of the format */
-            if(!use_latest_format) {
+            if(dt->shared->version < H5O_DTYPE_VERSION_3) {
                 /* Encode 'fake' array dimension permutations */
                 for(i = 0; i < (unsigned)dt->shared->u.array.ndims; i++)
                     UINT32ENCODE(*pp, i);
@@ -910,21 +883,8 @@ H5O_dtype_encode_helper(const H5F_t *f, uint8_t **pp, const H5T_t *dt)
             break;
     } /* end switch */
 
-    /* Set version #, based on actual features used for datatype */
-    /* (unless the "use the latest format" flag is set, which can "upgrade" the
-     *          format of certain encodings)
-     */
-    if(use_latest_format)
-        version = H5O_DTYPE_VERSION_LATEST;
-    else if(has_vax)
-        version = H5O_DTYPE_VERSION_3;
-    else if(has_array)
-        version = H5O_DTYPE_VERSION_2;
-    else
-        version = H5O_DTYPE_VERSION_1;
-
     /* Encode the type's class, version and bit field */
-    *hdr++ = ((unsigned)(dt->shared->type) & 0x0f) | (version << 4);
+    *hdr++ = ((unsigned)(dt->shared->type) & 0x0f) | (dt->shared->version << 4);
     *hdr++ = (flags >> 0) & 0xff;
     *hdr++ = (flags >> 8) & 0xff;
     *hdr++ = (flags >> 16) & 0xff;
@@ -1098,7 +1058,6 @@ static size_t
 H5O_dtype_size(const H5F_t *f, const void *_mesg)
 {
     const H5T_t	*dt = (const H5T_t *)_mesg;
-    hbool_t     use_latest_format;      /* Flag indicating the newest file format should be used */
     unsigned	u;                      /* Local index variable */
     size_t	ret_value;
 
@@ -1107,9 +1066,6 @@ H5O_dtype_size(const H5F_t *f, const void *_mesg)
     HDassert(f);
     HDassert(dt);
 
-    /* Get the file's 'use the latest version of the format' flag */
-    use_latest_format = H5F_USE_LATEST_FORMAT(f);
-
     /* Set the common size information */
     ret_value = 4 +     /* Type, class & flags */
         4;              /* Size of datatype */
@@ -1134,13 +1090,8 @@ H5O_dtype_size(const H5F_t *f, const void *_mesg)
 
         case H5T_COMPOUND:
             {
-                htri_t has_array;      /* Whether a compound datatype has an array inside it */
                 unsigned offset_nbytes;         /* Size needed to encode member offsets */
 
-                /* Check for an array datatype somewhere within the compound type */
-                has_array = H5T_detect_class(dt, H5T_ARRAY);
-                HDassert(has_array >= 0);
-
                 /* Compute the # of bytes required to store a member offset */
                 offset_nbytes = (H5V_log2_gen((uint64_t)dt->shared->size) + 7) / 8;
 
@@ -1151,17 +1102,17 @@ H5O_dtype_size(const H5F_t *f, const void *_mesg)
                     /* Get length of field's name */
                     name_len = HDstrlen(dt->shared->u.compnd.memb[u].name);
 
-                    /* Newer versions of the format don't pad out the name */
-                    if(use_latest_format)
+                    /* Versions of the format >= 3 don't pad out the name */
+                    if(dt->shared->version >= H5O_DTYPE_VERSION_3)
                         ret_value += name_len + 1;
                     else
                         ret_value += ((name_len + 8) / 8) * 8;
 
                     /* Check for encoding array datatype or using the latest file format */
                     /* (starting with version 3 of the datatype message, use the minimum # of bytes required) */
-                    if(use_latest_format)
+                    if(dt->shared->version >= H5O_DTYPE_VERSION_3)
                         ret_value += offset_nbytes; 	/*member offset*/
-                    else if(has_array)
+                    if(dt->shared->version >= H5O_DTYPE_VERSION_2)
                         ret_value += 4; 	/*member offset*/
                     else 
                         ret_value += 4 +	/*member offset*/
@@ -1183,8 +1134,8 @@ H5O_dtype_size(const H5F_t *f, const void *_mesg)
                 /* Get length of field's name */
                 name_len = HDstrlen(dt->shared->u.enumer.name[u]);
 
-                /* Newer versions of the format don't pad out the name */
-                if(use_latest_format)
+                /* Versions of the format >= 3 don't pad out the name */
+                if(dt->shared->version >= H5O_DTYPE_VERSION_3)
                     ret_value += name_len + 1;
                 else
                     ret_value += ((name_len + 8) / 8) * 8;
@@ -1202,10 +1153,10 @@ H5O_dtype_size(const H5F_t *f, const void *_mesg)
 
         case H5T_ARRAY:
             ret_value += 1; /* ndims */
-            if(!use_latest_format)
+            if(dt->shared->version < H5O_DTYPE_VERSION_3)
                 ret_value += 3; /* reserved bytes*/
             ret_value += 4 * dt->shared->u.array.ndims; /* dimensions */
-            if(!use_latest_format)
+            if(dt->shared->version < H5O_DTYPE_VERSION_3)
                 ret_value += 4 * dt->shared->u.array.ndims; /* dimension permutations */
             ret_value += H5O_dtype_size(f, dt->shared->parent);
             break;
diff --git a/src/H5T.c b/src/H5T.c
index a08f010..4e6a7a6 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -260,7 +260,6 @@ H5FL_DEFINE(H5T_shared_t);
 H5FL_DEFINE(H5T_path_t);
 
 /* Static local functions */
-static herr_t H5T_print_stats(H5T_path_t *path, int *nprint/*in,out*/);
 static herr_t H5T_unregister(H5T_pers_t pers, const char *name, H5T_t *src,
                 H5T_t *dst, H5T_conv_t func, hid_t dxpl_id);
 static herr_t H5T_register(H5T_pers_t pers, const char *name, H5T_t *src,
@@ -287,38 +286,38 @@ static H5T_t *H5T_decode(const unsigned char *buf);
 
 /* Define the code template for bitfields for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_BITFIELD_CORE {					      \
-    dt->shared->type = H5T_BITFIELD;						      \
+    dt->shared->type = H5T_BITFIELD;					      \
 }
 
 /* Define the code template for times for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_TIME_CORE {					      \
-    dt->shared->type = H5T_TIME;						      \
+    dt->shared->type = H5T_TIME;					      \
 }
 
 /* Define the code template for types which reset the offset for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_OFFSET_CORE {					      \
-    dt->shared->u.atomic.offset = 0;						      \
+    dt->shared->u.atomic.offset = 0;					      \
 }
 
 /* Define common code for all numeric types (floating-point & int, signed & unsigned) */
 #define H5T_INIT_TYPE_NUM_COMMON(ENDIANNESS) {				      \
-    dt->shared->u.atomic.order = ENDIANNESS;					      \
-    dt->shared->u.atomic.offset = 0;						      \
-    dt->shared->u.atomic.lsb_pad = H5T_PAD_ZERO;				      \
-    dt->shared->u.atomic.msb_pad = H5T_PAD_ZERO;				      \
+    dt->shared->u.atomic.order = ENDIANNESS;				      \
+    dt->shared->u.atomic.offset = 0;					      \
+    dt->shared->u.atomic.lsb_pad = H5T_PAD_ZERO;			      \
+    dt->shared->u.atomic.msb_pad = H5T_PAD_ZERO;			      \
 }
 
 /* Define the code templates for standard floats for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_FLOAT_COMMON(ENDIANNESS) {			      \
     H5T_INIT_TYPE_NUM_COMMON(ENDIANNESS)				      \
-    dt->shared->u.atomic.u.f.sign = 31;						      \
-    dt->shared->u.atomic.u.f.epos = 23;						      \
-    dt->shared->u.atomic.u.f.esize = 8;						      \
-    dt->shared->u.atomic.u.f.ebias = 0x7f;					      \
-    dt->shared->u.atomic.u.f.mpos = 0;						      \
-    dt->shared->u.atomic.u.f.msize = 23;					      \
-    dt->shared->u.atomic.u.f.norm = H5T_NORM_IMPLIED;				      \
-    dt->shared->u.atomic.u.f.pad = H5T_PAD_ZERO;				      \
+    dt->shared->u.atomic.u.f.sign = 31;					      \
+    dt->shared->u.atomic.u.f.epos = 23;					      \
+    dt->shared->u.atomic.u.f.esize = 8;					      \
+    dt->shared->u.atomic.u.f.ebias = 0x7f;				      \
+    dt->shared->u.atomic.u.f.mpos = 0;					      \
+    dt->shared->u.atomic.u.f.msize = 23;				      \
+    dt->shared->u.atomic.u.f.norm = H5T_NORM_IMPLIED;			      \
+    dt->shared->u.atomic.u.f.pad = H5T_PAD_ZERO;			      \
 }
 
 #define H5T_INIT_TYPE_FLOATLE_CORE {					      \
@@ -332,14 +331,14 @@ static H5T_t *H5T_decode(const unsigned char *buf);
 /* Define the code templates for standard doubles for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_DOUBLE_COMMON(ENDIANNESS) {			      \
     H5T_INIT_TYPE_NUM_COMMON(ENDIANNESS)				      \
-    dt->shared->u.atomic.u.f.sign = 63;						      \
-    dt->shared->u.atomic.u.f.epos = 52;						      \
-    dt->shared->u.atomic.u.f.esize = 11;					      \
-    dt->shared->u.atomic.u.f.ebias = 0x03ff;					      \
-    dt->shared->u.atomic.u.f.mpos = 0;						      \
-    dt->shared->u.atomic.u.f.msize = 52;					      \
-    dt->shared->u.atomic.u.f.norm = H5T_NORM_IMPLIED;				      \
-    dt->shared->u.atomic.u.f.pad = H5T_PAD_ZERO;				      \
+    dt->shared->u.atomic.u.f.sign = 63;					      \
+    dt->shared->u.atomic.u.f.epos = 52;					      \
+    dt->shared->u.atomic.u.f.esize = 11;				      \
+    dt->shared->u.atomic.u.f.ebias = 0x03ff;				      \
+    dt->shared->u.atomic.u.f.mpos = 0;					      \
+    dt->shared->u.atomic.u.f.msize = 52;				      \
+    dt->shared->u.atomic.u.f.norm = H5T_NORM_IMPLIED;			      \
+    dt->shared->u.atomic.u.f.pad = H5T_PAD_ZERO;			      \
 }
 
 #define H5T_INIT_TYPE_DOUBLELE_CORE {					      \
@@ -353,33 +352,35 @@ static H5T_t *H5T_decode(const unsigned char *buf);
 /* Define the code templates for VAX float for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_FLOATVAX_CORE {			                      \
     H5T_INIT_TYPE_NUM_COMMON(H5T_ORDER_VAX)				      \
-    dt->shared->u.atomic.u.f.sign = 31;						      \
-    dt->shared->u.atomic.u.f.epos = 23;						      \
-    dt->shared->u.atomic.u.f.esize = 8;						      \
-    dt->shared->u.atomic.u.f.ebias = 0x81;					      \
-    dt->shared->u.atomic.u.f.mpos = 0;						      \
-    dt->shared->u.atomic.u.f.msize = 23;					      \
-    dt->shared->u.atomic.u.f.norm = H5T_NORM_IMPLIED;				      \
-    dt->shared->u.atomic.u.f.pad = H5T_PAD_ZERO;				      \
+    dt->shared->u.atomic.u.f.sign = 31;					      \
+    dt->shared->u.atomic.u.f.epos = 23;					      \
+    dt->shared->u.atomic.u.f.esize = 8;					      \
+    dt->shared->u.atomic.u.f.ebias = 0x81;				      \
+    dt->shared->u.atomic.u.f.mpos = 0;					      \
+    dt->shared->u.atomic.u.f.msize = 23;				      \
+    dt->shared->u.atomic.u.f.norm = H5T_NORM_IMPLIED;			      \
+    dt->shared->u.atomic.u.f.pad = H5T_PAD_ZERO;			      \
+    dt->shared->version = H5O_DTYPE_VERSION_3;				      \
 }
 
 /* Define the code templates for VAX double for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_DOUBLEVAX_CORE {                                        \
     H5T_INIT_TYPE_NUM_COMMON(H5T_ORDER_VAX)				      \
-    dt->shared->u.atomic.u.f.sign = 63;						      \
-    dt->shared->u.atomic.u.f.epos = 52;						      \
-    dt->shared->u.atomic.u.f.esize = 11;					      \
-    dt->shared->u.atomic.u.f.ebias = 0x0401;					      \
-    dt->shared->u.atomic.u.f.mpos = 0;						      \
-    dt->shared->u.atomic.u.f.msize = 52;					      \
-    dt->shared->u.atomic.u.f.norm = H5T_NORM_IMPLIED;				      \
-    dt->shared->u.atomic.u.f.pad = H5T_PAD_ZERO;				      \
+    dt->shared->u.atomic.u.f.sign = 63;					      \
+    dt->shared->u.atomic.u.f.epos = 52;					      \
+    dt->shared->u.atomic.u.f.esize = 11;				      \
+    dt->shared->u.atomic.u.f.ebias = 0x0401;				      \
+    dt->shared->u.atomic.u.f.mpos = 0;					      \
+    dt->shared->u.atomic.u.f.msize = 52;				      \
+    dt->shared->u.atomic.u.f.norm = H5T_NORM_IMPLIED;			      \
+    dt->shared->u.atomic.u.f.pad = H5T_PAD_ZERO;			      \
+    dt->shared->version = H5O_DTYPE_VERSION_3;				      \
 }
 
 /* Define the code templates for standard signed integers for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_SINT_COMMON(ENDIANNESS) {				      \
     H5T_INIT_TYPE_NUM_COMMON(ENDIANNESS)				      \
-    dt->shared->u.atomic.u.i.sign = H5T_SGN_2;					      \
+    dt->shared->u.atomic.u.i.sign = H5T_SGN_2;				      \
 }
 
 #define H5T_INIT_TYPE_SINTLE_CORE {					      \
@@ -407,30 +408,30 @@ static H5T_t *H5T_decode(const unsigned char *buf);
 /* Define a macro for common code for all newly allocate datatypes */
 #define H5T_INIT_TYPE_ALLOC_COMMON(TYPE) {				      \
     dt->sh_loc.type = H5O_SHARE_TYPE_UNSHARED;				      \
-    dt->shared->type = TYPE;							      \
+    dt->shared->type = TYPE;						      \
 }
 
 /* Define the code templates for opaque for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_OPAQ_CORE {					      \
     H5T_INIT_TYPE_ALLOC_COMMON(H5T_OPAQUE)				      \
-    dt->shared->u.opaque.tag = H5MM_xstrdup("");					      \
+    dt->shared->u.opaque.tag = H5MM_xstrdup("");			      \
 }
 
 /* Define the code templates for strings for the "GUTS" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_STRING_COMMON {					      \
     H5T_INIT_TYPE_ALLOC_COMMON(H5T_STRING)				      \
     H5T_INIT_TYPE_NUM_COMMON(H5T_ORDER_NONE)				      \
-    dt->shared->u.atomic.u.s.cset = H5F_DEFAULT_CSET;				      \
+    dt->shared->u.atomic.u.s.cset = H5F_DEFAULT_CSET;			      \
 }
 
 #define H5T_INIT_TYPE_CSTRING_CORE {					      \
     H5T_INIT_TYPE_STRING_COMMON						      \
-    dt->shared->u.atomic.u.s.pad = H5T_STR_NULLTERM;				      \
+    dt->shared->u.atomic.u.s.pad = H5T_STR_NULLTERM;			      \
 }
 
 #define H5T_INIT_TYPE_FORSTRING_CORE {					      \
     H5T_INIT_TYPE_STRING_COMMON						      \
-    dt->shared->u.atomic.u.s.pad = H5T_STR_SPACEPAD;				      \
+    dt->shared->u.atomic.u.s.pad = H5T_STR_SPACEPAD;			      \
 }
 
 /* Define the code templates for references for the "GUTS" in the H5T_INIT_TYPE macro */
@@ -441,20 +442,20 @@ static H5T_t *H5T_decode(const unsigned char *buf);
 
 #define H5T_INIT_TYPE_OBJREF_CORE {					      \
     H5T_INIT_TYPE_REF_COMMON						      \
-    dt->shared->force_conv = TRUE;						      \
-    dt->shared->u.atomic.u.r.rtype = H5R_OBJECT;				      \
-    dt->shared->u.atomic.u.r.loc = H5T_LOC_MEMORY;				      \
+    dt->shared->force_conv = TRUE;					      \
+    dt->shared->u.atomic.u.r.rtype = H5R_OBJECT;			      \
+    dt->shared->u.atomic.u.r.loc = H5T_LOC_MEMORY;			      \
 }
 
 #define H5T_INIT_TYPE_REGREF_CORE {					      \
     H5T_INIT_TYPE_REF_COMMON						      \
-    dt->shared->u.atomic.u.r.rtype = H5R_DATASET_REGION;			      \
+    dt->shared->u.atomic.u.r.rtype = H5R_DATASET_REGION;		      \
 }
 
 /* Define the code templates for the "SIZE_TMPL" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_SET_SIZE(SIZE) {					      \
-    dt->shared->size = SIZE;							      \
-    dt->shared->u.atomic.prec = 8*SIZE;						      \
+    dt->shared->size = SIZE;						      \
+    dt->shared->u.atomic.prec = 8 * SIZE;				      \
 }
 
 #define H5T_INIT_TYPE_NOSET_SIZE(SIZE) {				      \
@@ -463,13 +464,13 @@ static H5T_t *H5T_decode(const unsigned char *buf);
 /* Define the code templates for the "CRT_TMPL" in the H5T_INIT_TYPE macro */
 #define H5T_INIT_TYPE_COPY_CREATE(BASE) {				      \
     /* Base off of existing datatype */					      \
-    if(NULL==(dt = H5T_copy(BASE,H5T_COPY_TRANSIENT)))			      \
+    if(NULL == (dt = H5T_copy(BASE, H5T_COPY_TRANSIENT)))		      \
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTCOPY, FAIL, "duplicating base type failed") \
 }
 
 #define H5T_INIT_TYPE_ALLOC_CREATE(BASE) {				      \
     /* Allocate new datatype info */					      \
-    if (NULL==(dt = H5T_alloc()))				              \
+    if(NULL == (dt = H5T_alloc()))				              \
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed") \
 }
 
@@ -479,14 +480,14 @@ static H5T_t *H5T_decode(const unsigned char *buf);
     H5_GLUE3(H5T_INIT_TYPE_,CRT_TMPL,_CREATE)(BASE)			      \
 									      \
     /* Adjust information for all types */				      \
-    dt->shared->state = H5T_STATE_IMMUTABLE;					      \
+    dt->shared->state = H5T_STATE_IMMUTABLE;				      \
     H5_GLUE3(H5T_INIT_TYPE_,SIZE_TMPL,_SIZE)(SIZE)			      \
 									      \
     /* Adjust information for this type */				      \
     H5_GLUE3(H5T_INIT_TYPE_,GUTS,_CORE)					      \
 									      \
     /* Atomize result */						      \
-    if ((GLOBAL = H5I_register(H5I_DATATYPE, dt)) < 0)			      \
+    if((GLOBAL = H5I_register(H5I_DATATYPE, dt)) < 0)			      \
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREGISTER, FAIL, "unable to register datatype atom") \
 }
 
@@ -3277,7 +3278,7 @@ H5T_copy(const H5T_t *old_dt, H5T_copy_t method)
     /* Copy shared location information if the new type is named or if it is
      * shared in the heap.
      */
-    if(old_dt->sh_loc.type == H5O_SHARE_TYPE_SOHM ||
+    if((old_dt->sh_loc.type == H5O_SHARE_TYPE_SOHM || old_dt->sh_loc.type == H5O_SHARE_TYPE_HERE) ||
             new_dt->shared->state == H5T_STATE_NAMED || new_dt->shared->state == H5T_STATE_OPEN) {
         if(H5O_set_shared(&(new_dt->sh_loc), &(old_dt->sh_loc)) < 0)
             HGOTO_ERROR(H5E_DATATYPE, H5E_CANTCOPY, NULL, "can't copy shared information")
@@ -3357,8 +3358,6 @@ done:
  * Programmer:	Quincey Koziol
  *		Monday, August 29, 2005
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 H5T_t *
@@ -3369,23 +3368,25 @@ H5T_alloc(void)
 
     FUNC_ENTER_NOAPI(H5T_alloc, NULL)
 
-    /* Allocate & initialize new datatype info */
+    /* Allocate & initialize datatype wrapper info */
     if(NULL == (dt = H5FL_CALLOC(H5T_t)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
     H5O_loc_reset(&(dt->oloc));
     H5G_name_reset(&(dt->path));
     H5O_msg_reset_share(H5O_DTYPE_ID, dt);
 
+    /* Allocate & initialize shared datatype structure */
     if(NULL == (dt->shared = H5FL_CALLOC(H5T_shared_t)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+    dt->shared->version = H5O_DTYPE_VERSION_1;
 
     /* Assign return value */
     ret_value = dt;
 
 done:
     if(ret_value == NULL)
-        if(dt != NULL) {
-            if(dt->shared != NULL)
+        if(dt) {
+            if(dt->shared)
                 H5FL_FREE(H5T_shared_t, dt->shared);
             H5FL_FREE(H5T_t, dt);
         } /* end if */
@@ -5071,8 +5072,6 @@ done:
  * Programmer:  Quincey Koziol
  *              Thursday, June 24, 2004
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 htri_t
@@ -5080,323 +5079,124 @@ H5T_is_relocatable(const H5T_t *dt)
 {
     htri_t ret_value = FALSE;
 
-    FUNC_ENTER_NOAPI(H5T_is_relocatable, FAIL);
+    FUNC_ENTER_NOAPI(H5T_is_relocatable, FAIL)
 
-    assert(dt);
+    /* Sanity check */
+    HDassert(dt);
 
-    if(H5T_detect_class(dt, H5T_VLEN))
-        ret_value = TRUE;
-    else if(H5T_detect_class(dt, H5T_REFERENCE))
+    /* VL and reference datatypes are relocatable */
+    if(H5T_detect_class(dt, H5T_VLEN) || H5T_detect_class(dt, H5T_REFERENCE))
         ret_value = TRUE;
 
 done:
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5T_is_relocatable() */
 
 
-
 /*-------------------------------------------------------------------------
- * Function:	H5T_print_stats
- *
- * Purpose:	Print statistics about a conversion path.  Statistics are
- *		printed only if all the following conditions are true:
+ * Function:    H5T_upgrade_version_cb
  *
- * 		1. The library was compiled with H5T_DEBUG defined.
- *		2. Data type debugging is turned on at run time.
- *		3. The path was called at least one time.
+ * Purpose:     H5T_visit callback to Upgrade the version of a datatype
+ *              (if there's any benefit to doing so)
  *
- *		The optional NPRINT argument keeps track of the number of
- *		conversions paths for which statistics have been shown. If
- *		its value is zero then table headers are printed before the
- *		first line of output.
+ * Note:	The behavior below is tightly coupled with the "better"
+ *              encodings for datatype messages in the datatype message
+ *              encoding routine.
  *
- * Return:	Success:	non-negative
- *
- *		Failure:	negative
- *
- * Programmer:	Robb Matzke
- *              Monday, December 14, 1998
+ * Return:	Non-negative on success/Negative on failure
  *
- * Modifications:
+ * Programmer:  Quincey Koziol
+ *              Thursday, July 19, 2007
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_print_stats(H5T_path_t UNUSED * path, int UNUSED * nprint/*in,out*/)
+H5T_upgrade_version_cb(H5T_t *dt, void *op_value)
 {
-#ifdef H5T_DEBUG
-    hsize_t	nbytes;
-    char	bandwidth[32];
-#endif
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5T_upgrade_version_cb)
 
-    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5T_print_stats);
+    /* Sanity check */
+    HDassert(dt);
+    HDassert(op_value);
 
-#ifdef H5T_DEBUG
-    if (H5DEBUG(T) && path->stats.ncalls>0) {
-	if (nprint && 0==(*nprint)++) {
-	    HDfprintf (H5DEBUG(T), "H5T: type conversion statistics:\n");
-	    HDfprintf (H5DEBUG(T), "   %-16s %10s %10s %8s %8s %8s %10s\n",
-		       "Conversion", "Elmts", "Calls", "User",
-		       "System", "Elapsed", "Bandwidth");
-	    HDfprintf (H5DEBUG(T), "   %-16s %10s %10s %8s %8s %8s %10s\n",
-		       "----------", "-----", "-----", "----",
-		       "------", "-------", "---------");
-	}
-        if(path->src && path->dst)
-            nbytes = MAX (H5T_get_size (path->src),
-                          H5T_get_size (path->dst));
-        else if(path->src)
-            nbytes = H5T_get_size (path->src);
-        else if(path->dst)
-            nbytes = H5T_get_size (path->dst);
-        else
-            nbytes = 0;
-	nbytes *= path->stats.nelmts;
-	H5_bandwidth(bandwidth, (double)nbytes,
-		     path->stats.timer.etime);
-	HDfprintf (H5DEBUG(T), "   %-16s %10Hd %10d %8.2f %8.2f %8.2f %10s\n",
-		   path->name,
-		   path->stats.nelmts,
-		   path->stats.ncalls,
-		   path->stats.timer.utime,
-		   path->stats.timer.stime,
-		   path->stats.timer.etime,
-		   bandwidth);
-    }
-#endif
-    FUNC_LEAVE_NOAPI(SUCCEED);
-}
+    /* Special behavior for each type of datatype */
+    switch(dt->shared->type) {
+        case H5T_COMPOUND:
+        case H5T_ARRAY:
+        case H5T_ENUM:
+            /* These types benefit from "upgrading" their version */
+            if(*(unsigned *)op_value > dt->shared->version)
+                dt->shared->version = *(unsigned *)op_value;
+            break;
+
+        default:
+            break;
+    } /* end switch */
 
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5T_upgrade_version_cb() */
+
+
 /*-------------------------------------------------------------------------
- * Function:	H5T_debug
+ * Function:    H5T_upgrade_version
  *
- * Purpose:	Prints information about a data type.
+ * Purpose:     Upgrade the version of a datatype (if there's any benefit to
+ *              doing so) and recursively apply to compound members and/or
+ *              parent datatypes.
  *
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Robb Matzke
- *		Wednesday, January  7, 1998
- *
- * Modifications:
+ * Programmer:  Quincey Koziol
+ *              Thursday, July 19, 2007
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5T_debug(const H5T_t *dt, FILE *stream)
+H5T_upgrade_version(H5T_t *dt, unsigned new_version)
 {
-    const char	*s1="", *s2="";
-    unsigned	i;
-    size_t	k, base_size;
-    uint64_t	tmp;
-    herr_t ret_value=SUCCEED;   /* Return value */
-
-    FUNC_ENTER_NOAPI(H5T_debug, FAIL);
-
-    /* Check args */
-    assert(dt);
-    assert(stream);
-
-    switch (dt->shared->type) {
-        case H5T_INTEGER:
-            s1 = "int";
-            break;
-        case H5T_FLOAT:
-            s1 = "float";
-            break;
-        case H5T_TIME:
-            s1 = "time";
-            break;
-        case H5T_STRING:
-            s1 = "str";
-            break;
-        case H5T_BITFIELD:
-            s1 = "bits";
-            break;
-        case H5T_OPAQUE:
-            s1 = "opaque";
-            break;
-        case H5T_COMPOUND:
-            s1 = "struct";
-            break;
-        case H5T_ENUM:
-            s1 = "enum";
-            break;
-        case H5T_VLEN:
-            if(H5T_IS_VL_STRING(dt->shared))
-                s1 = "str";
-            else
-                s1 = "vlen";
-            break;
-        default:
-            s1 = "";
-            break;
-    }
-
-    switch (dt->shared->state) {
-        case H5T_STATE_TRANSIENT:
-            s2 = "[transient]";
-            break;
-        case H5T_STATE_RDONLY:
-            s2 = "[constant]";
-            break;
-        case H5T_STATE_IMMUTABLE:
-            s2 = "[predefined]";
-            break;
-        case H5T_STATE_NAMED:
-            s2 = "[named,closed]";
-            break;
-        case H5T_STATE_OPEN:
-            s2 = "[named,open]";
-            break;
-    }
-
-    fprintf(stream, "%s%s {nbytes=%lu", s1, s2, (unsigned long)(dt->shared->size));
-
-    if (H5T_IS_ATOMIC(dt->shared)) {
-	switch (dt->shared->u.atomic.order) {
-            case H5T_ORDER_BE:
-                s1 = "BE";
-                break;
-            case H5T_ORDER_LE:
-                s1 = "LE";
-                break;
-            case H5T_ORDER_VAX:
-                s1 = "VAX";
-                break;
-            case H5T_ORDER_NONE:
-                s1 = "NONE";
-                break;
-            default:
-                s1 = "order?";
-                break;
-	}
-	fprintf(stream, ", %s", s1);
-
-	if (dt->shared->u.atomic.offset) {
-	    fprintf(stream, ", offset=%lu",
-		    (unsigned long) (dt->shared->u.atomic.offset));
-	}
-	if (dt->shared->u.atomic.prec != 8 * dt->shared->size) {
-	    fprintf(stream, ", prec=%lu",
-		    (unsigned long) (dt->shared->u.atomic.prec));
-	}
-	switch (dt->shared->type) {
-            case H5T_INTEGER:
-                switch (dt->shared->u.atomic.u.i.sign) {
-                    case H5T_SGN_NONE:
-                        s1 = "unsigned";
-                        break;
-                    case H5T_SGN_2:
-                        s1 = NULL;
-                        break;
-                    default:
-                        s1 = "sign?";
-                        break;
-                }
-                if (s1) fprintf(stream, ", %s", s1);
-                break;
-
-            case H5T_FLOAT:
-                switch (dt->shared->u.atomic.u.f.norm) {
-                    case H5T_NORM_IMPLIED:
-                        s1 = "implied";
-                        break;
-                    case H5T_NORM_MSBSET:
-                        s1 = "msbset";
-                        break;
-                    case H5T_NORM_NONE:
-                        s1 = "no-norm";
-                        break;
-                    default:
-                        s1 = "norm?";
-                        break;
-                }
-                fprintf(stream, ", sign=%lu+1",
-                        (unsigned long) (dt->shared->u.atomic.u.f.sign));
-                fprintf(stream, ", mant=%lu+%lu (%s)",
-                        (unsigned long) (dt->shared->u.atomic.u.f.mpos),
-                        (unsigned long) (dt->shared->u.atomic.u.f.msize), s1);
-                fprintf(stream, ", exp=%lu+%lu",
-                        (unsigned long) (dt->shared->u.atomic.u.f.epos),
-                        (unsigned long) (dt->shared->u.atomic.u.f.esize));
-                tmp = dt->shared->u.atomic.u.f.ebias >> 32;
-                if (tmp) {
-                    size_t hi=(size_t)tmp;
-                    size_t lo =(size_t)(dt->shared->u.atomic.u.f.ebias & 0xffffffff);
-                    fprintf(stream, " bias=0x%08lx%08lx",
-                            (unsigned long)hi, (unsigned long)lo);
-                } else {
-                    size_t lo = (size_t)(dt->shared->u.atomic.u.f.ebias & 0xffffffff);
-                    fprintf(stream, " bias=0x%08lx", (unsigned long)lo);
-                }
-                break;
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-            default:
-                /* No additional info */
-                break;
-	}
+    FUNC_ENTER_NOAPI(H5T_upgrade_version, FAIL)
 
-    } else if (H5T_COMPOUND==dt->shared->type) {
-	/* Compound data type */
-	for (i=0; i<dt->shared->u.compnd.nmembs; i++) {
-	    fprintf(stream, "\n\"%s\" @%lu",
-		    dt->shared->u.compnd.memb[i].name,
-		    (unsigned long) (dt->shared->u.compnd.memb[i].offset));
-	    fprintf(stream, " ");
-	    H5T_debug(dt->shared->u.compnd.memb[i].type, stream);
-	}
-	fprintf(stream, "\n");
+    /* Sanity check */
+    HDassert(dt);
 
-    } else if (H5T_VLEN==dt->shared->type) {
-        switch(dt->shared->u.vlen.loc) {
-            case H5T_LOC_MEMORY:
-                fprintf(stream, ", loc=memory");
-                break;
+    /* Iterate over entire datatype, upgrading the version of components, if it's useful */
+    if(H5T_visit(dt, (H5T_VISIT_SIMPLE | H5T_VISIT_COMPLEX_LAST), H5T_upgrade_version_cb, &new_version) < 0)
+        HGOTO_ERROR(H5E_DATATYPE, H5E_BADITER, FAIL, "iteration to upgrade datatype encoding version failed")
 
-            case H5T_LOC_DISK:
-                fprintf(stream, ", loc=disk");
-                break;
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5T_upgrade_version() */
 
-            default:
-                fprintf(stream, ", loc=UNKNOWN");
-                break;
-        } /* end switch */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5T_set_latest_version
+ *
+ * Purpose:     Set the encoding for a datatype to the latest version.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              Thursday, July 19, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5T_set_latest_version(H5T_t *dt)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-        if(H5T_IS_VL_STRING(dt->shared)) {
-            /* Variable length string datatype */
-            fprintf(stream, ", variable-length");
-        } /* end if */
-        else {
-            /* Variable length sequence datatype */
-            fprintf(stream, " VLEN ");
-            H5T_debug(dt->shared->parent, stream);
-            fprintf(stream, "\n");
-        } /* end else */
- 
-    } else if (H5T_ENUM==dt->shared->type) {
-	/* Enumeration data type */
-	fprintf(stream, " ");
-	H5T_debug(dt->shared->parent, stream);
-	base_size = dt->shared->parent->shared->size;
-	for (i=0; i<dt->shared->u.enumer.nmembs; i++) {
-	    fprintf(stream, "\n\"%s\" = 0x", dt->shared->u.enumer.name[i]);
-	    for (k=0; k<base_size; k++) {
-		fprintf(stream, "%02lx",
-			(unsigned long)(dt->shared->u.enumer.value+i*base_size+k));
-	    }
-	}
-	fprintf(stream, "\n");
+    FUNC_ENTER_NOAPI(H5T_set_latest_version, FAIL)
 
-    } else if (H5T_OPAQUE==dt->shared->type) {
-	fprintf(stream, ", tag=\"%s\"", dt->shared->u.opaque.tag);
+    /* Sanity check */
+    HDassert(dt);
 
-    } else {
-	/* Unknown */
-	fprintf(stream, "unknown class %d\n", (int)(dt->shared->type));
-    }
-    fprintf(stream, "}");
+    /* Upgrade the format version for the datatype to the latest */
+    if(H5T_upgrade_version(dt, H5O_DTYPE_VERSION_LATEST) < 0)
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "can't upgrade datatype encoding")
 
 done:
-    FUNC_LEAVE_NOAPI(ret_value);
-}
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5T_set_latest_version() */
 
diff --git a/src/H5Tarray.c b/src/H5Tarray.c
index 05b8dc4..cef8f66 100644
--- a/src/H5Tarray.c
+++ b/src/H5Tarray.c
@@ -158,12 +158,13 @@ H5T_array_create(H5T_t *base, unsigned ndims, const hsize_t dim[/* ndims */])
     /* Set the array's size (number of elements * element datatype's size) */
     ret_value->shared->size = ret_value->shared->parent->shared->size * ret_value->shared->u.array.nelem;
 
-    /*
-     * Set the "force conversion" flag if the base datatype indicates
-     */
+    /* Set the "force conversion" flag if the base datatype indicates */
     if(base->shared->force_conv == TRUE)
         ret_value->shared->force_conv = TRUE;
 
+    /* Array datatypes need a later version of the datatype object header message */
+    ret_value->shared->version = MAX(base->shared->version, H5O_DTYPE_VERSION_2);
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 }   /* end H5T_array_create */
@@ -220,7 +221,7 @@ done:
  *-------------------------------------------------------------------------
  */
 int
-H5T_get_array_ndims(H5T_t *dt)
+H5T_get_array_ndims(const H5T_t *dt)
 {
     FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5T_get_array_ndims)
 
@@ -283,7 +284,7 @@ done:
  *-------------------------------------------------------------------------
  */
 int
-H5T_get_array_dims(H5T_t *dt, hsize_t dims[])
+H5T_get_array_dims(const H5T_t *dt, hsize_t dims[])
 {
     unsigned u;         /* Local index variable */
     int	ret_value;	/* return value			*/
diff --git a/src/H5Tcommit.c b/src/H5Tcommit.c
index 4c5d802..dba5524 100644
--- a/src/H5Tcommit.c
+++ b/src/H5Tcommit.c
@@ -314,6 +314,11 @@ H5T_commit(H5F_t *file, H5T_t *type, hid_t tcpl_id, hid_t dxpl_id)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTRESET, FAIL, "unable to initialize path")
     loc_init = TRUE;
 
+    /* Set the latest format, if requested */
+    if(H5F_USE_LATEST_FORMAT(file))
+        if(H5T_set_latest_version(type) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set latest version of datatype")
+
     /* Calculate message size infomation, for creating object header */
     dtype_size = H5O_msg_size_f(file, tcpl_id, H5O_DTYPE_ID, type, (size_t)0);
     HDassert(dtype_size);
diff --git a/src/H5Tcompound.c b/src/H5Tcompound.c
index fbaacfc..660a76d 100644
--- a/src/H5Tcompound.c
+++ b/src/H5Tcompound.c
@@ -30,9 +30,6 @@
 #include "H5MMprivate.h"	/*memory management			  */
 #include "H5Tpkg.h"		/*data-type functions			  */
 
-/* Local macros */
-#define H5T_COMPND_INC	64	/*typical max numb of members per struct */
-
 /* Static local functions */
 static herr_t H5T_pack(const H5T_t *dt);
 
@@ -416,59 +413,56 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5T_insert(const H5T_t *parent, const char *name, size_t offset, const H5T_t *member)
+H5T_insert(H5T_t *parent, const char *name, size_t offset, const H5T_t *member)
 {
     unsigned	idx, i;
     size_t	total_size;
-    herr_t      ret_value=SUCCEED;       /* Return value */
+    herr_t      ret_value = SUCCEED;       /* Return value */
 
     FUNC_ENTER_NOAPI(H5T_insert, FAIL)
 
     /* check args */
-    assert(parent && H5T_COMPOUND == parent->shared->type);
-    assert(H5T_STATE_TRANSIENT==parent->shared->state);
-    assert(member);
-    assert(name && *name);
+    HDassert(parent && H5T_COMPOUND == parent->shared->type);
+    HDassert(H5T_STATE_TRANSIENT == parent->shared->state);
+    HDassert(member);
+    HDassert(name && *name);
 
     /* Does NAME already exist in PARENT? */
-    for (i=0; i<parent->shared->u.compnd.nmembs; i++) {
-	if (!HDstrcmp(parent->shared->u.compnd.memb[i].name, name))
+    for(i = 0; i < parent->shared->u.compnd.nmembs; i++)
+	if(!HDstrcmp(parent->shared->u.compnd.memb[i].name, name))
 	    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINSERT, FAIL, "member name is not unique")
-    }
 
     /* Does the new member overlap any existing member ? */
-    total_size=member->shared->size;
-    for (i=0; i<parent->shared->u.compnd.nmembs; i++) {
-	if ((offset <= parent->shared->u.compnd.memb[i].offset &&
+    total_size = member->shared->size;
+    for(i = 0; i < parent->shared->u.compnd.nmembs; i++)
+	if((offset <= parent->shared->u.compnd.memb[i].offset &&
                  offset + total_size > parent->shared->u.compnd.memb[i].offset) ||
                 (parent->shared->u.compnd.memb[i].offset <= offset &&
                  parent->shared->u.compnd.memb[i].offset +
                  parent->shared->u.compnd.memb[i].size > offset))
 	    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINSERT, FAIL, "member overlaps with another member")
-    }
 
     /* Does the new member overlap the end of the compound type? */
-    if(offset+total_size>parent->shared->size)
+    if((offset + total_size) > parent->shared->size)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINSERT, FAIL, "member extends past end of compound type")
 
     /* Increase member array if necessary */
-    if (parent->shared->u.compnd.nmembs >= parent->shared->u.compnd.nalloc) {
-        unsigned na = parent->shared->u.compnd.nalloc + H5T_COMPND_INC;
-        H5T_cmemb_t *x = H5MM_realloc (parent->shared->u.compnd.memb,
-                           na * sizeof(H5T_cmemb_t));
+    if(parent->shared->u.compnd.nmembs >= parent->shared->u.compnd.nalloc) {
+        unsigned na = MAX(1, parent->shared->u.compnd.nalloc * 2);
+        H5T_cmemb_t *x = H5MM_realloc(parent->shared->u.compnd.memb, na * sizeof(H5T_cmemb_t));
 
-        if (!x)
-            HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+        if(!x)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
         parent->shared->u.compnd.nalloc = na;
         parent->shared->u.compnd.memb = x;
-    }
+    } /* end if */
 
     /* Add member to end of member array */
     idx = parent->shared->u.compnd.nmembs;
     parent->shared->u.compnd.memb[idx].name = H5MM_xstrdup(name);
     parent->shared->u.compnd.memb[idx].offset = offset;
     parent->shared->u.compnd.memb[idx].size = total_size;
-    parent->shared->u.compnd.memb[idx].type = H5T_copy (member, H5T_COPY_ALL);
+    parent->shared->u.compnd.memb[idx].type = H5T_copy(member, H5T_COPY_ALL);
 
     parent->shared->u.compnd.sorted = H5T_SORT_NONE;
     parent->shared->u.compnd.nmembs++;
@@ -476,35 +470,42 @@ H5T_insert(const H5T_t *parent, const char *name, size_t offset, const H5T_t *me
     /* Determine if the compound datatype stayed packed */
     if(parent->shared->u.compnd.packed) {
         /* Check if the member type is packed */
-        if(H5T_is_packed(parent->shared->u.compnd.memb[idx].type)>0) {
-            if(idx==0) {
+        if(H5T_is_packed(parent->shared->u.compnd.memb[idx].type) > 0) {
+            if(idx == 0) {
                 /* If the is the first member, the datatype is not packed
                  * if the first member isn't at offset 0
                  */
-                if(parent->shared->u.compnd.memb[idx].offset>0)
-                    parent->shared->u.compnd.packed=FALSE;
+                if(parent->shared->u.compnd.memb[idx].offset > 0)
+                    parent->shared->u.compnd.packed = FALSE;
             } /* end if */
             else {
                 /* If the is not the first member, the datatype is not
                  * packed if the new member isn't adjoining the previous member
                  */
-                if(parent->shared->u.compnd.memb[idx].offset!=(parent->shared->u.compnd.memb[idx-1].offset+parent->shared->u.compnd.memb[idx-1].size))
-                    parent->shared->u.compnd.packed=FALSE;
+                if(parent->shared->u.compnd.memb[idx].offset != (parent->shared->u.compnd.memb[idx - 1].offset + parent->shared->u.compnd.memb[idx - 1].size))
+                    parent->shared->u.compnd.packed = FALSE;
             } /* end else */
         } /* end if */
         else
-            parent->shared->u.compnd.packed=FALSE;
+            parent->shared->u.compnd.packed = FALSE;
     } /* end if */
 
-    /*
-     * Set the "force conversion" flag if the field's datatype indicates
-     */
-    if(member->shared->force_conv==TRUE)
-        parent->shared->force_conv=TRUE;
+    /* Set the "force conversion" flag if the field's datatype indicates */
+    if(member->shared->force_conv == TRUE)
+        parent->shared->force_conv = TRUE;
+
+    /* Check for member having a later version than the parent */
+    if(parent->shared->version < member->shared->version)
+        /* Upgrade parent datatype (and all other members also) */
+        /* (can't use a partial datatype and later versions of the format are
+         *  more efficient, so might as well upgrade all members also... -QAK)
+         */
+        if(H5T_upgrade_version(parent, member->shared->version) < 0)
+	    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "can't upgrade member encoding version")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-}
+} /* end H5T_insert() */
 
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5Tdbg.c b/src/H5Tdbg.c
new file mode 100644
index 0000000..88e084d
--- /dev/null
+++ b/src/H5Tdbg.c
@@ -0,0 +1,407 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Module Info: This module contains most of the "core" functionality of
+ *      the H5T interface, including the API initialization code, etc.
+ *      Many routines that are infrequently used, or are specialized for
+ *      one particular datatype class are in another module.
+ */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5Tdbg.c
+ *			Jul 19 2007
+ *			Quincey Koziol <koziol@hdfgroup.org>
+ *
+ * Purpose:		Dump debugging information about a datatype
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5T_PACKAGE		/*suppress error about including H5Tpkg	  */
+
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Tpkg.h"		/* Datatypes         			*/
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Package Typedefs */
+/********************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5T_print_stats
+ *
+ * Purpose:	Print statistics about a conversion path.  Statistics are
+ *		printed only if all the following conditions are true:
+ *
+ * 		1. The library was compiled with H5T_DEBUG defined.
+ *		2. Data type debugging is turned on at run time.
+ *		3. The path was called at least one time.
+ *
+ *		The optional NPRINT argument keeps track of the number of
+ *		conversions paths for which statistics have been shown. If
+ *		its value is zero then table headers are printed before the
+ *		first line of output.
+ *
+ * Return:	Success:	non-negative
+ *
+ *		Failure:	negative
+ *
+ * Programmer:	Robb Matzke
+ *              Monday, December 14, 1998
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5T_print_stats(H5T_path_t UNUSED * path, int UNUSED * nprint/*in,out*/)
+{
+#ifdef H5T_DEBUG
+    hsize_t	nbytes;
+    char	bandwidth[32];
+#endif
+
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5T_print_stats)
+
+#ifdef H5T_DEBUG
+    if(H5DEBUG(T) && path->stats.ncalls > 0) {
+	if(nprint && 0 == (*nprint)++) {
+	    HDfprintf(H5DEBUG(T), "H5T: type conversion statistics:\n");
+	    HDfprintf(H5DEBUG(T), "   %-16s %10s %10s %8s %8s %8s %10s\n",
+		       "Conversion", "Elmts", "Calls", "User",
+		       "System", "Elapsed", "Bandwidth");
+	    HDfprintf(H5DEBUG(T), "   %-16s %10s %10s %8s %8s %8s %10s\n",
+		       "----------", "-----", "-----", "----",
+		       "------", "-------", "---------");
+	}
+        if(path->src && path->dst)
+            nbytes = MAX(H5T_get_size(path->src), H5T_get_size(path->dst));
+        else if(path->src)
+            nbytes = H5T_get_size(path->src);
+        else if(path->dst)
+            nbytes = H5T_get_size(path->dst);
+        else
+            nbytes = 0;
+	nbytes *= path->stats.nelmts;
+	H5_bandwidth(bandwidth, (double)nbytes, path->stats.timer.etime);
+	HDfprintf(H5DEBUG(T), "   %-16s %10Hd %10d %8.2f %8.2f %8.2f %10s\n",
+		   path->name,
+		   path->stats.nelmts,
+		   path->stats.ncalls,
+		   path->stats.timer.utime,
+		   path->stats.timer.stime,
+		   path->stats.timer.etime,
+		   bandwidth);
+    }
+#endif
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5T_print_stats() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5T_debug
+ *
+ * Purpose:	Prints information about a data type.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Robb Matzke
+ *		Wednesday, January  7, 1998
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5T_debug(const H5T_t *dt, FILE *stream)
+{
+    const char	*s1 = "", *s2 = "";
+    unsigned	i;
+
+    FUNC_ENTER_NOAPI_NOFUNC(H5T_debug)
+
+    /* Check args */
+    HDassert(dt);
+    HDassert(stream);
+
+    switch(dt->shared->type) {
+        case H5T_INTEGER:
+            s1 = "int";
+            break;
+
+        case H5T_FLOAT:
+            s1 = "float";
+            break;
+
+        case H5T_TIME:
+            s1 = "time";
+            break;
+
+        case H5T_STRING:
+            s1 = "str";
+            break;
+
+        case H5T_BITFIELD:
+            s1 = "bits";
+            break;
+
+        case H5T_OPAQUE:
+            s1 = "opaque";
+            break;
+
+        case H5T_COMPOUND:
+            s1 = "struct";
+            break;
+
+        case H5T_ENUM:
+            s1 = "enum";
+            break;
+
+        case H5T_VLEN:
+            if(H5T_IS_VL_STRING(dt->shared))
+                s1 = "str";
+            else
+                s1 = "vlen";
+            break;
+
+        default:
+            s1 = "";
+            break;
+    } /* end switch */
+
+    switch(dt->shared->state) {
+        case H5T_STATE_TRANSIENT:
+            s2 = "[transient]";
+            break;
+
+        case H5T_STATE_RDONLY:
+            s2 = "[constant]";
+            break;
+
+        case H5T_STATE_IMMUTABLE:
+            s2 = "[predefined]";
+            break;
+
+        case H5T_STATE_NAMED:
+            s2 = "[named,closed]";
+            break;
+
+        case H5T_STATE_OPEN:
+            s2 = "[named,open]";
+            break;
+    } /* end switch */
+
+    fprintf(stream, "%s%s {nbytes=%lu", s1, s2, (unsigned long)(dt->shared->size));
+
+    if(H5T_IS_ATOMIC(dt->shared)) {
+        uint64_t	tmp;
+
+	switch(dt->shared->u.atomic.order) {
+            case H5T_ORDER_BE:
+                s1 = "BE";
+                break;
+
+            case H5T_ORDER_LE:
+                s1 = "LE";
+                break;
+
+            case H5T_ORDER_VAX:
+                s1 = "VAX";
+                break;
+
+            case H5T_ORDER_NONE:
+                s1 = "NONE";
+                break;
+
+            default:
+                s1 = "order?";
+                break;
+	} /* end switch */
+
+	fprintf(stream, ", %s", s1);
+
+	if(dt->shared->u.atomic.offset)
+	    fprintf(stream, ", offset=%lu",
+		    (unsigned long) (dt->shared->u.atomic.offset));
+	if(dt->shared->u.atomic.prec != 8 * dt->shared->size)
+	    fprintf(stream, ", prec=%lu",
+		    (unsigned long) (dt->shared->u.atomic.prec));
+	switch(dt->shared->type) {
+            case H5T_INTEGER:
+                switch(dt->shared->u.atomic.u.i.sign) {
+                    case H5T_SGN_NONE:
+                        s1 = "unsigned";
+                        break;
+
+                    case H5T_SGN_2:
+                        s1 = NULL;
+                        break;
+
+                    default:
+                        s1 = "sign?";
+                        break;
+
+                } /* end switch */
+                if(s1)
+                    fprintf(stream, ", %s", s1);
+                break;
+
+            case H5T_FLOAT:
+                switch(dt->shared->u.atomic.u.f.norm) {
+                    case H5T_NORM_IMPLIED:
+                        s1 = "implied";
+                        break;
+
+                    case H5T_NORM_MSBSET:
+                        s1 = "msbset";
+                        break;
+
+                    case H5T_NORM_NONE:
+                        s1 = "no-norm";
+                        break;
+
+                    default:
+                        s1 = "norm?";
+                        break;
+                } /* end switch */
+
+                fprintf(stream, ", sign=%lu+1",
+                        (unsigned long)(dt->shared->u.atomic.u.f.sign));
+                fprintf(stream, ", mant=%lu+%lu (%s)",
+                        (unsigned long)(dt->shared->u.atomic.u.f.mpos),
+                        (unsigned long)(dt->shared->u.atomic.u.f.msize), s1);
+                fprintf(stream, ", exp=%lu+%lu",
+                        (unsigned long)(dt->shared->u.atomic.u.f.epos),
+                        (unsigned long)(dt->shared->u.atomic.u.f.esize));
+                tmp = dt->shared->u.atomic.u.f.ebias >> 32;
+                if(tmp) {
+                    size_t hi = (size_t)tmp;
+                    size_t lo = (size_t)(dt->shared->u.atomic.u.f.ebias & 0xffffffff);
+                    fprintf(stream, " bias=0x%08lx%08lx",
+                            (unsigned long)hi, (unsigned long)lo);
+                } else {
+                    size_t lo = (size_t)(dt->shared->u.atomic.u.f.ebias & 0xffffffff);
+                    fprintf(stream, " bias=0x%08lx", (unsigned long)lo);
+                }
+                break;
+
+            default:
+                /* No additional info */
+                break;
+	} /* end switch */
+    } else if(H5T_COMPOUND == dt->shared->type) {
+	/* Compound data type */
+	for(i = 0; i < dt->shared->u.compnd.nmembs; i++) {
+	    fprintf(stream, "\n\"%s\" @%lu",
+		    dt->shared->u.compnd.memb[i].name,
+		    (unsigned long)(dt->shared->u.compnd.memb[i].offset));
+	    fprintf(stream, " ");
+	    H5T_debug(dt->shared->u.compnd.memb[i].type, stream);
+	} /* end for */
+	fprintf(stream, "\n");
+    } else if(H5T_VLEN == dt->shared->type) {
+        switch(dt->shared->u.vlen.loc) {
+            case H5T_LOC_MEMORY:
+                fprintf(stream, ", loc=memory");
+                break;
+
+            case H5T_LOC_DISK:
+                fprintf(stream, ", loc=disk");
+                break;
+
+            default:
+                fprintf(stream, ", loc=UNKNOWN");
+                break;
+        } /* end switch */
+
+        if(H5T_IS_VL_STRING(dt->shared))
+            /* Variable length string datatype */
+            fprintf(stream, ", variable-length");
+        else {
+            /* Variable length sequence datatype */
+            fprintf(stream, " VLEN ");
+            H5T_debug(dt->shared->parent, stream);
+            fprintf(stream, "\n");
+        } /* end else */
+    } else if(H5T_ENUM == dt->shared->type) {
+        size_t	base_size;
+
+	/* Enumeration data type */
+	fprintf(stream, " ");
+	H5T_debug(dt->shared->parent, stream);
+	base_size = dt->shared->parent->shared->size;
+	for(i = 0; i < dt->shared->u.enumer.nmembs; i++) {
+            size_t	k;
+
+	    fprintf(stream, "\n\"%s\" = 0x", dt->shared->u.enumer.name[i]);
+	    for(k = 0; k < base_size; k++)
+		fprintf(stream, "%02lx",
+			(unsigned long)(dt->shared->u.enumer.value + (i * base_size) + k));
+	} /* end for */
+	fprintf(stream, "\n");
+    } else if(H5T_OPAQUE == dt->shared->type) {
+	fprintf(stream, ", tag=\"%s\"", dt->shared->u.opaque.tag);
+    } else {
+	/* Unknown */
+	fprintf(stream, "unknown class %d\n", (int)(dt->shared->type));
+    }
+    fprintf(stream, "}");
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5T_debug() */
+
diff --git a/src/H5Titerate.c b/src/H5Titerate.c
new file mode 100644
index 0000000..15a91e3
--- /dev/null
+++ b/src/H5Titerate.c
@@ -0,0 +1,155 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Module Info: This module contains most of the "core" functionality of
+ *      the H5T interface, including the API initialization code, etc.
+ *      Many routines that are infrequently used, or are specialized for
+ *      one particular datatype class are in another module.
+ */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5Tdbg.c
+ *			Jul 19 2007
+ *			Quincey Koziol <koziol@hdfgroup.org>
+ *
+ * Purpose:		Dump debugging information about a datatype
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5T_PACKAGE		/*suppress error about including H5Tpkg	  */
+
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Tpkg.h"		/* Datatypes         			*/
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Package Typedefs */
+/********************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5T_visit
+ *
+ * Purpose:     Visit a datatype and all it's members and/or parents, making
+ *              a callback for each.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              Thursday, July 19, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5T_visit(H5T_t *dt, unsigned visit_flags, H5T_operator_t op, void *op_value)
+{
+    hbool_t is_complex;                 /* Flag indicating current datatype is "complex" */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(H5T_visit, FAIL)
+
+    /* Sanity check */
+    HDassert(dt);
+    HDassert(op);
+
+    /* Check for complex datatype */
+    is_complex  = H5T_IS_COMPLEX(dt->shared->type);
+
+    /* If the callback is to be made on the datatype first, do that */
+    if(is_complex && (visit_flags & H5T_VISIT_COMPLEX_FIRST))
+        if(op(dt, op_value) < 0)
+            HGOTO_ERROR(H5E_DATATYPE, H5E_BADITER, FAIL, "operator callback failed")
+
+    /* Make callback for each member/child, if requested */
+    switch(dt->shared->type) {
+        case H5T_COMPOUND:
+            {
+                unsigned u;             /* Local index variable */
+
+                /* Visit each member of the compound datatype */
+                for(u = 0; u < dt->shared->u.compnd.nmembs; u++)
+                    if(H5T_visit(dt->shared->u.compnd.memb[u].type, visit_flags, op, op_value) < 0)
+                        HGOTO_ERROR(H5E_DATATYPE, H5E_BADITER, FAIL, "can't visit member datatype")
+            } /* end case */
+            break;
+
+        case H5T_ARRAY:
+        case H5T_VLEN:
+        case H5T_ENUM:
+            /* Visit parent type */
+            if(H5T_visit(dt->shared->parent, visit_flags, op, op_value) < 0)
+                HGOTO_ERROR(H5E_DATATYPE, H5E_BADITER, FAIL, "can't visit parent datatype")
+            break;
+
+        default:
+            /* Visit "simple" datatypes here */
+            if(visit_flags & H5T_VISIT_SIMPLE)
+                if(op(dt, op_value) < 0)
+                    HGOTO_ERROR(H5E_DATATYPE, H5E_BADITER, FAIL, "operator callback failed")
+            break;
+    } /* end switch */
+
+    /* If the callback is to be made on the datatype last, do that */
+    if(is_complex && (visit_flags & H5T_VISIT_COMPLEX_LAST))
+        if(op(dt, op_value) < 0)
+            HGOTO_ERROR(H5E_DATATYPE, H5E_BADITER, FAIL, "operator callback failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5T_iterate() */
+
diff --git a/src/H5Tpkg.h b/src/H5Tpkg.h
index 6b68bf1..4704288 100644
--- a/src/H5Tpkg.h
+++ b/src/H5Tpkg.h
@@ -68,6 +68,45 @@
 #define H5T_IS_ATOMIC(dt)       (!(H5T_IS_COMPLEX((dt)->type) || (dt)->type==H5T_OPAQUE))
 
 
+/*
+ * Datatype encoding versions
+ */
+
+/* This is the version to create all datatypes which don't contain
+ * array datatypes (atomic types, compound datatypes without array fields,
+ * vlen sequences of objects which aren't arrays, etc.) or VAX byte-ordered
+ * objects.
+ */
+#define H5O_DTYPE_VERSION_1	1
+
+/* This is the version to create all datatypes which contain H5T_ARRAY
+ * class objects (array definitely, potentially compound & vlen sequences also),
+ * but not VAX byte-ordered objects.
+ */
+#define H5O_DTYPE_VERSION_2	2
+
+/* This is the version to create all datatypes which contain VAX byte-ordered
+ * objects (floating-point types, currently).
+ */
+/* This version also packs compound & enum field names without padding */
+/* This version also encodes the member offset of compound fields more efficiently */
+/* This version also encodes array types more efficiently */
+#define H5O_DTYPE_VERSION_3	3
+
+/* The latest version of the format.  Look through the 'encode helper' routine
+ *      and 'size' callback for places to change when updating this. */
+#define H5O_DTYPE_VERSION_LATEST H5O_DTYPE_VERSION_3
+
+
+/* Flags for visiting datatype */
+#define H5T_VISIT_COMPLEX_FIRST 0x01            /* Visit complex datatype before visiting member/parent datatypes */
+#define H5T_VISIT_COMPLEX_LAST  0x02            /* Visit complex datatype after visiting member/parent datatypes */
+                                                /* (setting both flags will mean visiting complex type twice) */
+#define H5T_VISIT_SIMPLE        0x04            /* Visit simple datatypes (at all) */
+                                                /* (setting H5T_VISIT_SIMPLE and _not_ setting either H5T_VISIT_COMPLEX_FIRST or H5T_VISIT_COMPLEX_LAST will mean visiting _only_ "simple" "leafs" in the "tree" */
+                                                /* (_not_ setting H5T_VISIT_SIMPLE and setting either H5T_VISIT_COMPLEX_FIRST or H5T_VISIT_COMPLEX_LAST will mean visiting all nodes _except_ "simple" "leafs" in the "tree" */
+
+
 /* Define an internal macro for converting between floating number(float and double) and floating number.
  * All Cray compilers don't support denormalized floating values generating exception(?). */
 #if H5_CONVERT_DENORMAL_FLOAT
@@ -314,6 +353,7 @@ typedef struct H5T_shared_t {
     H5T_state_t		state;	/*current state of the type		     */
     H5T_class_t		type;	/*which class of type is this?		     */
     size_t		size;	/*total size of an instance of this type     */
+    unsigned            version;        /* Version of object header message to encode this object with */
     hbool_t		force_conv;/* Set if this type always needs to be converted and H5T_conv_noop cannot be called */
     struct H5T_t	*parent;/*parent type for derived datatypes	     */
     union {
@@ -362,6 +402,9 @@ typedef struct {
     hid_t tcpl_id;              /* Named datatype creation property list */
 } H5T_obj_create_t;
 
+/* Typedef for datatype iteration operations */
+typedef herr_t (*H5T_operator_t)(H5T_t *dt, void *op_data/*in,out*/);
+
 /*
  * Alignment information for native types. A value of N indicates that the
  * data must be aligned on an address ADDR such that 0 == ADDR mod N. When
@@ -458,20 +501,11 @@ H5_DLL herr_t H5T_commit_named(const H5G_loc_t *loc, const char *name,
     H5T_t *dt, hid_t lcpl_id, hid_t tcpl_id, hid_t tapl_id, hid_t dxpl_id);
 H5_DLL H5T_t *H5T_alloc(void);
 H5_DLL herr_t H5T_free(H5T_t *dt);
-H5_DLL H5T_sign_t H5T_get_sign(H5T_t const *dt);
+H5_DLL herr_t H5T_visit(H5T_t *dt, unsigned visit_flags, H5T_operator_t op,
+    void *op_value);
 H5_DLL H5T_t *H5T_get_super(H5T_t *dt);
-H5_DLL char  *H5T_get_member_name(H5T_t const *dt, unsigned membno);
-H5_DLL herr_t H5T_get_member_value(const H5T_t *dt, unsigned membno, void *value);
-H5_DLL int H5T_get_nmembers(const H5T_t *dt);
-H5_DLL herr_t H5T_insert(const H5T_t *parent, const char *name, size_t offset,
-        const H5T_t *member);
-H5_DLL H5T_t *H5T_enum_create(const H5T_t *parent);
-H5_DLL herr_t H5T_enum_insert(const H5T_t *dt, const char *name, const void *value);
-H5_DLL int    H5T_get_array_ndims(H5T_t *dt);
-H5_DLL int    H5T_get_array_dims(H5T_t *dt, hsize_t dims[]);
-H5_DLL herr_t H5T_sort_value(const H5T_t *dt, int *map);
-H5_DLL herr_t H5T_sort_name(const H5T_t *dt, int *map);
 H5_DLL herr_t H5T_set_size(H5T_t *dt, size_t size);
+H5_DLL herr_t H5T_upgrade_version(H5T_t *dt, unsigned new_version);
 
 /* Conversion functions */
 H5_DLL herr_t H5T_conv_noop(hid_t src_id, hid_t dst_id, H5T_cdata_t *cdata,
@@ -1326,6 +1360,9 @@ H5_DLL htri_t H5T_bit_inc(uint8_t *buf, size_t start, size_t size);
 H5_DLL htri_t H5T_bit_dec(uint8_t *buf, size_t start, size_t size);
 H5_DLL void H5T_bit_neg(uint8_t *buf, size_t start, size_t size);
 
+/* Fixed-point functions */
+H5_DLL H5T_sign_t H5T_get_sign(H5T_t const *dt);
+
 /* VL functions */
 H5_DLL H5T_t * H5T_vlen_create(const H5T_t *base);
 H5_DLL htri_t H5T_vlen_set_loc(const H5T_t *dt, H5F_t *f, H5T_loc_t loc);
@@ -1333,13 +1370,31 @@ H5_DLL htri_t H5T_vlen_set_loc(const H5T_t *dt, H5F_t *f, H5T_loc_t loc);
 /* Array functions */
 H5_DLL H5T_t * H5T_array_create(H5T_t *base, unsigned ndims,
         const hsize_t dim[/* ndims */]);
+H5_DLL int    H5T_get_array_ndims(const H5T_t *dt);
+H5_DLL int    H5T_get_array_dims(const H5T_t *dt, hsize_t dims[]);
 
 /* Compound functions */
+H5_DLL herr_t H5T_insert(H5T_t *parent, const char *name, size_t offset,
+        const H5T_t *member);
 H5_DLL H5T_t *H5T_get_member_type(const H5T_t *dt, unsigned membno);
 H5_DLL size_t H5T_get_member_offset(const H5T_t *dt, unsigned membno);
 H5_DLL size_t H5T_get_member_size(const H5T_t *dt, unsigned membno);
 H5_DLL htri_t H5T_is_packed(const H5T_t *dt);
 H5_DLL H5T_subset_t H5T_conv_struct_subset(const H5T_cdata_t *cdata);
 
+/* Enumerated type functions */
+H5_DLL H5T_t *H5T_enum_create(const H5T_t *parent);
+H5_DLL herr_t H5T_enum_insert(const H5T_t *dt, const char *name, const void *value);
+H5_DLL herr_t H5T_get_member_value(const H5T_t *dt, unsigned membno, void *value);
+
+/* Field functions (for both compound & enumerated types) */
+H5_DLL char  *H5T_get_member_name(H5T_t const *dt, unsigned membno);
+H5_DLL int H5T_get_nmembers(const H5T_t *dt);
+H5_DLL herr_t H5T_sort_value(const H5T_t *dt, int *map);
+H5_DLL herr_t H5T_sort_name(const H5T_t *dt, int *map);
+
+/* Debugging functions */
+H5_DLL herr_t H5T_print_stats(H5T_path_t *path, int *nprint/*in,out*/);
+
 #endif /* _H5Tpkg_H */
 
diff --git a/src/H5Tprivate.h b/src/H5Tprivate.h
index 842eced..deeb8ce 100644
--- a/src/H5Tprivate.h
+++ b/src/H5Tprivate.h
@@ -114,6 +114,7 @@ H5_DLL herr_t H5T_vlen_get_alloc_info(hid_t dxpl_id, H5T_vlen_alloc_info_t **vl_
 H5_DLL htri_t H5T_set_loc(H5T_t *dt, H5F_t *f, H5T_loc_t loc);
 H5_DLL htri_t H5T_is_sensible(const H5T_t *dt);
 H5_DLL uint32_t H5T_hash(H5F_t * file, const H5T_t *dt);
+H5_DLL herr_t H5T_set_latest_version(H5T_t *dt);
 
 /* Reference specific functions */
 H5_DLL H5R_type_t H5T_get_ref_type(const H5T_t *dt);
diff --git a/src/H5Tvlen.c b/src/H5Tvlen.c
index 1d71498..bbc698f 100644
--- a/src/H5Tvlen.c
+++ b/src/H5Tvlen.c
@@ -115,20 +115,20 @@ H5Tvlen_create(hid_t base_id)
     H5TRACE1("i", "i", base_id);
 
     /* Check args */
-    if (NULL==(base=H5I_object_verify(base_id,H5I_DATATYPE)))
+    if(NULL == (base = H5I_object_verify(base_id, H5I_DATATYPE)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an valid base datatype")
 
     /* Create up VL datatype */
-    if ((dt=H5T_vlen_create(base))==NULL)
+    if((dt = H5T_vlen_create(base)) == NULL)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "invalid VL location")
 
     /* Atomize the type */
-    if ((ret_value=H5I_register(H5I_DATATYPE, dt))<0)
+    if((ret_value = H5I_register(H5I_DATATYPE, dt)) < 0)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREGISTER, FAIL, "unable to register datatype")
 
 done:
     FUNC_LEAVE_API(ret_value)
-}
+} /* end H5Tvlen_create() */
 
 
 /*-------------------------------------------------------------------------
@@ -157,7 +157,7 @@ H5T_vlen_create(const H5T_t *base)
     FUNC_ENTER_NOAPI_NOINIT(H5T_vlen_create)
 
     /* Check args */
-    assert(base);
+    HDassert(base);
 
     /* Build new type */
     if(NULL == (dt = H5T_alloc()))
@@ -171,19 +171,22 @@ H5T_vlen_create(const H5T_t *base)
     dt->shared->force_conv = TRUE;
     dt->shared->parent = H5T_copy(base, H5T_COPY_ALL);
 
+    /* Inherit encoding version from base type */
+    dt->shared->version = base->shared->version;
+
     /* This is a sequence, not a string */
     dt->shared->u.vlen.type = H5T_VLEN_SEQUENCE;
 
     /* Set up VL information */
-    if (H5T_set_loc(dt, NULL, H5T_LOC_MEMORY)<0)
+    if(H5T_set_loc(dt, NULL, H5T_LOC_MEMORY) < 0)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "invalid datatype location")
 
     /* Set return value */
-    ret_value=dt;
+    ret_value = dt;
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-}
+} /* end H5T_vlen_create() */
 
 
 /*-------------------------------------------------------------------------
@@ -284,7 +287,7 @@ H5T_vlen_set_loc(const H5T_t *dt, H5F_t *f, H5T_loc_t loc)
                 break;
 
             default:
-                HGOTO_ERROR (H5E_DATATYPE, H5E_BADRANGE, FAIL, "invalid VL datatype location")
+                HGOTO_ERROR(H5E_DATATYPE, H5E_BADRANGE, FAIL, "invalid VL datatype location")
         } /* end switch */ /*lint !e788 All appropriate cases are covered */
     } /* end if */
 
diff --git a/src/Makefile.am b/src/Makefile.am
index bef62b6..b52afbc 100755
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -78,10 +78,12 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5R.c H5RC.c  \
         H5RS.c H5S.c H5Sall.c H5Shyper.c H5Smpio.c H5Snone.c H5Spoint.c       \
         H5Sselect.c H5Stest.c H5SL.c H5SM.c H5SMbtree2.c \
-        H5SMcache.c H5SMtest.c H5ST.c H5T.c H5Tarray.c H5Tbit.c H5Tcommit.c \
-        H5Tcompound.c H5Tconv.c H5Tcset.c H5Tdeprec.c H5Tenum.c H5Tfields.c \
+        H5SMcache.c H5SMtest.c H5ST.c \
+        H5T.c H5Tarray.c H5Tbit.c H5Tcommit.c H5Tcompound.c H5Tconv.c \
+        H5Tcset.c H5Tdbg.c H5Tdeprec.c H5Tenum.c H5Tfields.c \
         H5Tfixed.c \
-        H5Tfloat.c H5Tinit.c H5Tnative.c H5Toffset.c H5Toh.c H5Topaque.c \
+        H5Tfloat.c H5Tinit.c H5Titerate.c H5Tnative.c H5Toffset.c H5Toh.c \
+        H5Topaque.c \
         H5Torder.c \
         H5Tpad.c H5Tprecis.c H5Tstrpad.c H5Tvlen.c H5TS.c H5V.c H5WB.c H5Z.c  \
         H5Zdeflate.c H5Zfletcher32.c H5Znbit.c H5Zshuffle.c H5Zszip.c  \
diff --git a/src/Makefile.in b/src/Makefile.in
index 1f82a69..ce657cf 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -111,9 +111,9 @@ am_libhdf5_la_OBJECTS = H5.lo H5checksum.lo H5dbg.lo H5system.lo \
 	H5S.lo H5Sall.lo H5Shyper.lo H5Smpio.lo H5Snone.lo H5Spoint.lo \
 	H5Sselect.lo H5Stest.lo H5SL.lo H5SM.lo H5SMbtree2.lo \
 	H5SMcache.lo H5SMtest.lo H5ST.lo H5T.lo H5Tarray.lo H5Tbit.lo \
-	H5Tcommit.lo H5Tcompound.lo H5Tconv.lo H5Tcset.lo H5Tdeprec.lo \
+	H5Tcommit.lo H5Tcompound.lo H5Tconv.lo H5Tcset.lo H5Tdbg.lo H5Tdeprec.lo \
 	H5Tenum.lo H5Tfields.lo H5Tfixed.lo H5Tfloat.lo H5Tinit.lo \
-	H5Tnative.lo H5Toffset.lo H5Toh.lo H5Topaque.lo H5Torder.lo \
+	H5Titerate.lo H5Tnative.lo H5Toffset.lo H5Toh.lo H5Topaque.lo H5Torder.lo \
 	H5Tpad.lo H5Tprecis.lo H5Tstrpad.lo H5Tvlen.lo H5TS.lo H5V.lo \
 	H5WB.lo H5Z.lo H5Zdeflate.lo H5Zfletcher32.lo H5Znbit.lo \
 	H5Zshuffle.lo H5Zszip.lo H5Zscaleoffset.lo H5Ztrans.lo
@@ -434,9 +434,9 @@ libhdf5_la_SOURCES = H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5RS.c H5S.c H5Sall.c H5Shyper.c H5Smpio.c H5Snone.c H5Spoint.c       \
         H5Sselect.c H5Stest.c H5SL.c H5SM.c H5SMbtree2.c \
         H5SMcache.c H5SMtest.c H5ST.c H5T.c H5Tarray.c H5Tbit.c H5Tcommit.c \
-        H5Tcompound.c H5Tconv.c H5Tcset.c H5Tdeprec.c H5Tenum.c H5Tfields.c \
+        H5Tcompound.c H5Tconv.c H5Tcset.c H5Tdbg.c H5Tdeprec.c H5Tenum.c H5Tfields.c \
         H5Tfixed.c \
-        H5Tfloat.c H5Tinit.c H5Tnative.c H5Toffset.c H5Toh.c H5Topaque.c \
+        H5Tfloat.c H5Tinit.c H5Titerate.c H5Tnative.c H5Toffset.c H5Toh.c H5Topaque.c \
         H5Torder.c \
         H5Tpad.c H5Tprecis.c H5Tstrpad.c H5Tvlen.c H5TS.c H5V.c H5WB.c H5Z.c  \
         H5Zdeflate.c H5Zfletcher32.c H5Znbit.c H5Zshuffle.c H5Zszip.c  \
@@ -745,12 +745,14 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tcompound.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tconv.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tcset.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tdbg.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tdeprec.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tenum.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tfields.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tfixed.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tfloat.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tinit.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Titerate.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Tnative.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Toffset.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Toh.Plo@am__quote@