Merge pull request #1931 in HDFFV/hdf5 from feature/references to develop

* commit '9ed9762889fcd05dc230d6652b92fddc5ec880a4':
  Update RELEASE.txt for reference changes
  Fix reference type comparison in h5dump
  Make wrappers, tests and tools use H5Treclaim() instead of H5Dvlen_reclaim()
  Add new H5R API that abstracts object, region and attribute reference types
  Remove ability to loc by ref from H5VL layer
  Add support for retrieving object name by token
  Add H5VL_OBJECT_GET_TYPE to get object type
  Add H5VL_MAX_TOKEN_SIZE and H5VL_token_t
  Adapt Jerome's "file info" H5VL 'get' query to retrieve container token info.
  Fix H5VL_blob_get to return size of blob
  Add 'blob' callbacks to VOL, along with a native implementation to store them in the global heap, and changed the VL datatype conversion code to use blobs.

1 files changed, 474 insertions, 426 deletions

diff --git a/src/H5Tvlen.c b/src/H5Tvlen.c
index bafb47f..0253b01 100644
--- a/src/H5Tvlen.c
+++ b/src/H5Tvlen.c
@@ -16,41 +16,119 @@
  *      datatypes in the H5T interface.
  */
 
-#include "H5Tmodule.h"          /* This source code file is part of the H5T module */
-
+/****************/
+/* Module Setup */
+/****************/
 
-#include "H5private.h"		/* Generic Functions			*/
-#include "H5CXprivate.h"        /* API Contexts                         */
-#include "H5Dprivate.h"		/* Dataset functions			*/
-#include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5HGprivate.h"	/* Global Heaps				*/
-#include "H5Iprivate.h"		/* IDs			  		*/
-#include "H5MMprivate.h"	/* Memory management			*/
-#include "H5Pprivate.h"		/* Property lists			*/
-#include "H5Tpkg.h"		/* Datatypes				*/
-
-/* Local functions */
-static herr_t H5T_vlen_reclaim_recurse(void *elem, const H5T_t *dt, H5MM_free_t free_func, void *free_info);
-static ssize_t H5T_vlen_seq_mem_getlen(const void *_vl);
-static void * H5T_vlen_seq_mem_getptr(void *_vl);
-static htri_t H5T_vlen_seq_mem_isnull(const H5F_t *f, void *_vl);
-static herr_t H5T_vlen_seq_mem_read(H5F_t *f, void *_vl, void *_buf, size_t len);
-static herr_t H5T_vlen_seq_mem_write(H5F_t *f, const H5T_vlen_alloc_info_t *vl_alloc_info, void *_vl, void *_buf, void *_bg, size_t seq_len, size_t base_size);
-static herr_t H5T_vlen_seq_mem_setnull(H5F_t *f, void *_vl, void *_bg);
-static ssize_t H5T_vlen_str_mem_getlen(const void *_vl);
-static void * H5T_vlen_str_mem_getptr(void *_vl);
-static htri_t H5T_vlen_str_mem_isnull(const H5F_t *f, void *_vl);
-static herr_t H5T_vlen_str_mem_read(H5F_t *f, void *_vl, void *_buf, size_t len);
-static herr_t H5T_vlen_str_mem_write(H5F_t *f, const H5T_vlen_alloc_info_t *vl_alloc_info, void *_vl, void *_buf, void *_bg, size_t seq_len, size_t base_size);
-static herr_t H5T_vlen_str_mem_setnull(H5F_t *f, void *_vl, void *_bg);
-static ssize_t H5T_vlen_disk_getlen(const void *_vl);
-static void * H5T_vlen_disk_getptr(void *_vl);
-static htri_t H5T_vlen_disk_isnull(const H5F_t *f, void *_vl);
-static herr_t H5T_vlen_disk_read(H5F_t *f, void *_vl, void *_buf, size_t len);
-static herr_t H5T_vlen_disk_write(H5F_t *f, const H5T_vlen_alloc_info_t *vl_alloc_info, void *_vl, void *_buf, void *_bg, size_t seq_len, size_t base_size);
-static herr_t H5T_vlen_disk_setnull(H5F_t *f, void *_vl, void *_bg);
-
-/* Local variables */
+#include "H5Tmodule.h"          /* This source code file is part of the H5T module */
+#define H5F_FRIEND              /*suppress error about including H5Fpkg   */
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"          /* Generic Functions    */
+#include "H5CXprivate.h"        /* API Contexts         */
+#include "H5Eprivate.h"         /* Error handling       */
+#include "H5Fpkg.h"             /* File                 */
+#include "H5Iprivate.h"         /* IDs                  */
+#include "H5MMprivate.h"        /* Memory management    */
+#include "H5Tpkg.h"             /* Datatypes            */
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Package Typedefs */
+/********************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+/* Memory-based VL sequence callbacks */
+static herr_t H5T__vlen_mem_seq_getlen(H5F_t *f, const void *_vl, size_t *len);
+static void * H5T__vlen_mem_seq_getptr(void *_vl);
+static herr_t H5T__vlen_mem_seq_isnull(const H5F_t *f, void *_vl, hbool_t *isnull);
+static herr_t H5T__vlen_mem_seq_setnull(H5F_t *f, void *_vl, void *_bg);
+static herr_t H5T__vlen_mem_seq_read(H5F_t *f, void *_vl, void *_buf, size_t len);
+static herr_t H5T__vlen_mem_seq_write(H5F_t *f, const H5T_vlen_alloc_info_t *vl_alloc_info, void *_vl, void *_buf, void *_bg, size_t seq_len, size_t base_size);
+
+/* Memory-based VL string callbacks */
+static herr_t H5T__vlen_mem_str_getlen(H5F_t *f, const void *_vl, size_t *len);
+static void * H5T__vlen_mem_str_getptr(void *_vl);
+static herr_t H5T__vlen_mem_str_isnull(const H5F_t *f, void *_vl, hbool_t *isnull);
+static herr_t H5T__vlen_mem_str_setnull(H5F_t *f, void *_vl, void *_bg);
+static herr_t H5T__vlen_mem_str_read(H5F_t *f, void *_vl, void *_buf, size_t len);
+static herr_t H5T__vlen_mem_str_write(H5F_t *f, const H5T_vlen_alloc_info_t *vl_alloc_info, void *_vl, void *_buf, void *_bg, size_t seq_len, size_t base_size);
+
+/* Disk-based VL sequence (and string) callbacks */
+static herr_t H5T__vlen_disk_getlen(H5F_t *f, const void *_vl, size_t *len);
+static herr_t H5T__vlen_disk_isnull(const H5F_t *f, void *_vl, hbool_t *isnull);
+static herr_t H5T__vlen_disk_setnull(H5F_t *f, void *_vl, void *_bg);
+static herr_t H5T__vlen_disk_read(H5F_t *f, void *_vl, void *_buf, size_t len);
+static herr_t H5T__vlen_disk_write(H5F_t *f, const H5T_vlen_alloc_info_t *vl_alloc_info, void *_vl, void *_buf, void *_bg, size_t seq_len, size_t base_size);
+static herr_t H5T__vlen_disk_delete(H5F_t *f, const void *_vl);
+
+
+/*********************/
+/* Public Variables */
+/*********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+/* Class for VL sequences in memory */
+static const H5T_vlen_class_t H5T_vlen_mem_seq_g = {
+    H5T__vlen_mem_seq_getlen,           /* 'getlen' */
+    H5T__vlen_mem_seq_getptr,           /* 'getptr' */
+    H5T__vlen_mem_seq_isnull,           /* 'isnull' */
+    H5T__vlen_mem_seq_setnull,          /* 'setnull' */
+    H5T__vlen_mem_seq_read,             /* 'read' */
+    H5T__vlen_mem_seq_write,            /* 'write' */
+    NULL                                /* 'delete' */
+};
+
+/* Class for VL strings in memory */
+static const H5T_vlen_class_t H5T_vlen_mem_str_g = {
+    H5T__vlen_mem_str_getlen,           /* 'getlen' */
+    H5T__vlen_mem_str_getptr,           /* 'getptr' */
+    H5T__vlen_mem_str_isnull,           /* 'isnull' */
+    H5T__vlen_mem_str_setnull,          /* 'setnull' */
+    H5T__vlen_mem_str_read,             /* 'read' */
+    H5T__vlen_mem_str_write,            /* 'write' */
+    NULL                                /* 'delete' */
+};
+
+/* Class for both VL strings and sequences in file */
+static const H5T_vlen_class_t H5T_vlen_disk_g = {
+    H5T__vlen_disk_getlen,              /* 'getlen' */
+    NULL,                               /* 'getptr' */
+    H5T__vlen_disk_isnull,              /* 'isnull' */
+    H5T__vlen_disk_setnull,             /* 'setnull' */
+    H5T__vlen_disk_read,                /* 'read' */
+    H5T__vlen_disk_write,               /* 'write' */
+    H5T__vlen_disk_delete               /* 'delete' */
+};
 
 
 
@@ -194,32 +272,21 @@ H5T__vlen_set_loc(const H5T_t *dt, H5F_t *f, H5T_loc_t loc)
                 dt->shared->u.vlen.loc = H5T_LOC_MEMORY;
 
                 if(dt->shared->u.vlen.type == H5T_VLEN_SEQUENCE) {
-                    /* size in memory, disk size is different */
+                    /* Size in memory, disk size is different */
                     dt->shared->size = sizeof(hvl_t);
 
                     /* Set up the function pointers to access the VL sequence in memory */
-                    dt->shared->u.vlen.getlen = H5T_vlen_seq_mem_getlen;
-                    dt->shared->u.vlen.getptr = H5T_vlen_seq_mem_getptr;
-                    dt->shared->u.vlen.isnull = H5T_vlen_seq_mem_isnull;
-                    dt->shared->u.vlen.read = H5T_vlen_seq_mem_read;
-                    dt->shared->u.vlen.write = H5T_vlen_seq_mem_write;
-                    dt->shared->u.vlen.setnull = H5T_vlen_seq_mem_setnull;
-                }
+                    dt->shared->u.vlen.cls = &H5T_vlen_mem_seq_g;
+                } /* end if */
                 else if(dt->shared->u.vlen.type == H5T_VLEN_STRING) {
-                    /* size in memory, disk size is different */
+                    /* Size in memory, disk size is different */
                     dt->shared->size = sizeof(char *);
 
                     /* Set up the function pointers to access the VL string in memory */
-                    dt->shared->u.vlen.getlen = H5T_vlen_str_mem_getlen;
-                    dt->shared->u.vlen.getptr = H5T_vlen_str_mem_getptr;
-                    dt->shared->u.vlen.isnull = H5T_vlen_str_mem_isnull;
-                    dt->shared->u.vlen.read = H5T_vlen_str_mem_read;
-                    dt->shared->u.vlen.write = H5T_vlen_str_mem_write;
-                    dt->shared->u.vlen.setnull = H5T_vlen_str_mem_setnull;
-                }
-                else {
+                    dt->shared->u.vlen.cls = &H5T_vlen_mem_str_g;
+                } /* end else-if */
+                else
                     HDassert(0 && "Invalid VL type");
-                }
 
                 /* Reset file ID (since this VL is in memory) */
                 dt->shared->u.vlen.f = NULL;
@@ -234,18 +301,13 @@ H5T__vlen_set_loc(const H5T_t *dt, H5F_t *f, H5T_loc_t loc)
                 /*
                  * Size of element on disk is 4 bytes for the length, plus the size
                  * of an address in this file, plus 4 bytes for the size of a heap
-                 * ID.  Memory size is different
+                 * ID.  Memory size is different.
                  */
                 dt->shared->size = 4 + (size_t)H5F_SIZEOF_ADDR(f) + 4;
 
                 /* Set up the function pointers to access the VL information on disk */
                 /* VL sequences and VL strings are stored identically on disk, so use the same functions */
-                dt->shared->u.vlen.getlen = H5T_vlen_disk_getlen;
-                dt->shared->u.vlen.getptr = H5T_vlen_disk_getptr;
-                dt->shared->u.vlen.isnull = H5T_vlen_disk_isnull;
-                dt->shared->u.vlen.read = H5T_vlen_disk_read;
-                dt->shared->u.vlen.write = H5T_vlen_disk_write;
-                dt->shared->u.vlen.setnull = H5T_vlen_disk_setnull;
+                dt->shared->u.vlen.cls = &H5T_vlen_disk_g;
 
                 /* Set file ID (since this VL is on disk) */
                 dt->shared->u.vlen.f = f;
@@ -255,6 +317,13 @@ H5T__vlen_set_loc(const H5T_t *dt, H5F_t *f, H5T_loc_t loc)
                 /* Allow undefined location. In H5Odtype.c, H5O_dtype_decode sets undefined
                  * location for VL type and leaves it for the caller to decide.
                  */
+                dt->shared->u.vlen.loc = H5T_LOC_BADLOC;
+
+                /* Reset the function pointers to access the VL information */
+                dt->shared->u.vlen.cls = NULL;
+
+                /* Reset file pointer */
+                dt->shared->u.vlen.f = NULL;
                 break;
 
             case H5T_LOC_MAXLOC:
@@ -269,11 +338,11 @@ H5T__vlen_set_loc(const H5T_t *dt, H5F_t *f, H5T_loc_t loc)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-}   /* end H5T__vlen_set_loc() */
+} /* end H5T__vlen_set_loc() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_seq_mem_getlen
+ * Function:	H5T__vlen_mem_seq_getlen
  *
  * Purpose:	Retrieves the length of a memory based VL element.
  *
@@ -284,33 +353,35 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static ssize_t
-H5T_vlen_seq_mem_getlen(const void *_vl)
+static herr_t
+H5T__vlen_mem_seq_getlen(H5F_t H5_ATTR_UNUSED *f, const void *_vl, size_t *len)
 {
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    const hvl_t *vl=(const hvl_t *)_vl;   /* Pointer to the user's hvl_t information */
+    const hvl_t *vl = (const hvl_t *)_vl; /* Pointer to the user's hvl_t information */
 #else
     hvl_t vl;             /* User's hvl_t information */
 #endif
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check parameters, return result */
-#ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    HDassert(vl);
+    /* Check parameter */
+    HDassert(_vl);
+    HDassert(len);
 
-    FUNC_LEAVE_NOAPI((ssize_t)vl->len)
+#ifdef H5_NO_ALIGNMENT_RESTRICTIONS
+    *len = vl->len;
 #else
-    HDassert(_vl);
     H5MM_memcpy(&vl, _vl, sizeof(hvl_t));
 
-    FUNC_LEAVE_NOAPI((ssize_t)vl.len)
+    *len = vl.len;
 #endif
-}   /* end H5T_vlen_seq_mem_getlen() */
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5T__vlen_mem_seq_getlen() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_seq_mem_getptr
+ * Function:	H5T__vlen_mem_seq_getptr
  *
  * Purpose:	Retrieves the pointer for a memory based VL element.
  *
@@ -322,15 +393,15 @@ H5T_vlen_seq_mem_getlen(const void *_vl)
  *-------------------------------------------------------------------------
  */
 static void *
-H5T_vlen_seq_mem_getptr(void *_vl)
+H5T__vlen_mem_seq_getptr(void *_vl)
 {
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    const hvl_t *vl=(const hvl_t *)_vl;   /* Pointer to the user's hvl_t information */
+    const hvl_t *vl = (const hvl_t *)_vl; /* Pointer to the user's hvl_t information */
 #else
     hvl_t vl;             /* User's hvl_t information */
 #endif
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     /* check parameters, return result */
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
@@ -343,48 +414,82 @@ H5T_vlen_seq_mem_getptr(void *_vl)
 
     FUNC_LEAVE_NOAPI(vl.p)
 #endif
-}   /* end H5T_vlen_seq_mem_getptr() */
+} /* end H5T__vlen_mem_seq_getptr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_seq_mem_isnull
+ * Function:	H5T__vlen_mem_seq_isnull
  *
  * Purpose:	Checks if a memory sequence is the "null" sequence
  *
- * Return:	TRUE/FALSE on success/Negative on failure
+ * Return:	Non-negative on success / Negative on failure
  *
  * Programmer:	Quincey Koziol
  *		Saturday, November 8, 2003
  *
  *-------------------------------------------------------------------------
  */
-static htri_t
-H5T_vlen_seq_mem_isnull(const H5F_t H5_ATTR_UNUSED *f, void *_vl)
+static herr_t
+H5T__vlen_mem_seq_isnull(const H5F_t H5_ATTR_UNUSED *f, void *_vl, hbool_t *isnull)
 {
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    const hvl_t *vl=(const hvl_t *)_vl;   /* Pointer to the user's hvl_t information */
+    const hvl_t *vl = (const hvl_t *)_vl;   /* Pointer to the user's hvl_t information */
 #else
     hvl_t vl;             /* User's hvl_t information */
 #endif
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check parameters, return result */
-#ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    HDassert(vl);
+    /* Check parameters */
+    HDassert(_vl);
 
-    FUNC_LEAVE_NOAPI((vl->len==0 || vl->p==NULL) ? TRUE : FALSE)
+#ifdef H5_NO_ALIGNMENT_RESTRICTIONS
+    *isnull = ((vl->len == 0 || vl->p == NULL) ? TRUE : FALSE);
 #else
-    HDassert(_vl);
     H5MM_memcpy(&vl, _vl, sizeof(hvl_t));
 
-    FUNC_LEAVE_NOAPI((vl.len==0 || vl.p==NULL) ? TRUE : FALSE)
+    *isnull = ((vl.len == 0 || vl.p == NULL) ? TRUE : FALSE);
 #endif
-}   /* end H5T_vlen_seq_mem_isnull() */
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5T__vlen_mem_seq_isnull() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5T__vlen_mem_seq_setnull
+ *
+ * Purpose:	Sets a VL info object in memory to the "nil" value
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		Saturday, November 8, 2003
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5T__vlen_mem_seq_setnull(H5F_t H5_ATTR_UNUSED *f, void *_vl, void H5_ATTR_UNUSED *_bg)
+{
+    hvl_t vl;                       /* Temporary hvl_t to use during operation */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* check parameters */
+    HDassert(_vl);
+
+    /* Set the "nil" hvl_t */
+    vl.len = 0;
+    vl.p = NULL;
+
+    /* Set pointer in user's buffer with memcpy, to avoid alignment issues */
+    H5MM_memcpy(_vl, &vl, sizeof(hvl_t));
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5T__vlen_mem_seq_setnull() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_seq_mem_read
+ * Function:	H5T__vlen_mem_seq_read
  *
  * Purpose:	"Reads" the memory based VL sequence into a buffer
  *
@@ -396,36 +501,36 @@ H5T_vlen_seq_mem_isnull(const H5F_t H5_ATTR_UNUSED *f, void *_vl)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_seq_mem_read(H5F_t H5_ATTR_UNUSED *f, void *_vl, void *buf, size_t len)
+H5T__vlen_mem_seq_read(H5F_t H5_ATTR_UNUSED *f, void *_vl, void *buf, size_t len)
 {
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    const hvl_t *vl=(const hvl_t *)_vl;   /* Pointer to the user's hvl_t information */
+    const hvl_t *vl = (const hvl_t *)_vl;   /* Pointer to the user's hvl_t information */
 #else
     hvl_t vl;             /* User's hvl_t information */
 #endif
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     /* check parameters, copy data */
     HDassert(buf);
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
     HDassert(vl && vl->p);
 
-    H5MM_memcpy(buf,vl->p,len);
+    H5MM_memcpy(buf, vl->p, len);
 #else
     HDassert(_vl);
     H5MM_memcpy(&vl, _vl, sizeof(hvl_t));
     HDassert(vl.p);
 
-    H5MM_memcpy(buf,vl.p,len);
+    H5MM_memcpy(buf, vl.p, len);
 #endif
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-}   /* end H5T_vlen_seq_mem_read() */
+} /* end H5T__vlen_mem_seq_read() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_seq_mem_write
+ * Function:	H5T__vlen_mem_seq_write
  *
  * Purpose:	"Writes" the memory based VL sequence from a buffer
  *
@@ -437,104 +542,104 @@ H5T_vlen_seq_mem_read(H5F_t H5_ATTR_UNUSED *f, void *_vl, void *buf, size_t len)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_seq_mem_write(H5F_t H5_ATTR_UNUSED *f, const H5T_vlen_alloc_info_t *vl_alloc_info, void *_vl, void *buf, void H5_ATTR_UNUSED *_bg, size_t seq_len, size_t base_size)
+H5T__vlen_mem_seq_write(H5F_t H5_ATTR_UNUSED *f, const H5T_vlen_alloc_info_t *vl_alloc_info, void *_vl, void *buf, void H5_ATTR_UNUSED *_bg, size_t seq_len, size_t base_size)
 {
     hvl_t vl;                       /* Temporary hvl_t to use during operation */
-    size_t len;
-    herr_t      ret_value=SUCCEED;       /* Return value */
+    herr_t ret_value = SUCCEED;     /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* check parameters */
     HDassert(_vl);
     HDassert(buf);
 
-    if(seq_len!=0) {
-        len=seq_len*base_size;
+    if(seq_len) {
+        size_t len = seq_len * base_size;       /* Sequence size */
 
         /* Use the user's memory allocation routine is one is defined */
-        if(vl_alloc_info->alloc_func!=NULL) {
-            if(NULL==(vl.p=(vl_alloc_info->alloc_func)(len,vl_alloc_info->alloc_info)))
-                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for VL data")
+        if(vl_alloc_info->alloc_func != NULL) {
+            if(NULL == (vl.p = (vl_alloc_info->alloc_func)(len, vl_alloc_info->alloc_info)))
+                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTALLOC, FAIL, "application memory allocation routine failed for VL data")
           } /* end if */
-        else {  /* Default to system malloc */
+        else    /* Default to system malloc */
             if(NULL == (vl.p = HDmalloc(len)))
-                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for VL data")
-          } /* end else */
+                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTALLOC, FAIL, "memory allocation failed for VL data")
 
         /* Copy the data into the newly allocated buffer */
-        H5MM_memcpy(vl.p,buf,len);
-
+        H5MM_memcpy(vl.p, buf, len);
     } /* end if */
     else
-        vl.p=NULL;
+        vl.p = NULL;
 
     /* Set the sequence length */
-    vl.len=seq_len;
+    vl.len = seq_len;
 
     /* Set pointer in user's buffer with memcpy, to avoid alignment issues */
-    H5MM_memcpy(_vl,&vl,sizeof(hvl_t));
+    H5MM_memcpy(_vl, &vl, sizeof(hvl_t));
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-}   /* end H5T_vlen_seq_mem_write() */
+} /* end H5T__vlen_mem_seq_write() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_seq_mem_setnull
+ * Function:	H5T__vlen_mem_str_getlen
  *
- * Purpose:	Sets a VL info object in memory to the "nil" value
+ * Purpose:	Retrieves the length of a memory based VL string.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		Saturday, November 8, 2003
+ *		Wednesday, June 2, 1999
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_seq_mem_setnull(H5F_t H5_ATTR_UNUSED *f, void *_vl, void H5_ATTR_UNUSED *_bg)
+H5T__vlen_mem_str_getlen(H5F_t H5_ATTR_UNUSED *f, const void *_vl, size_t *len)
 {
-    hvl_t vl;                       /* Temporary hvl_t to use during operation */
+#ifdef H5_NO_ALIGNMENT_RESTRICTIONS
+    const char *s = *(const char * const *)_vl; /* Pointer to the user's string information */
+#else
+    const char *s = NULL;       /* Pointer to the user's string information */
+#endif
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     /* check parameters */
     HDassert(_vl);
 
-    /* Set the "nil" hvl_t */
-    vl.len=0;
-    vl.p=NULL;
+#ifndef H5_NO_ALIGNMENT_RESTRICTIONS
+    H5MM_memcpy(&s, _vl, sizeof(char *));
+#endif
 
-    /* Set pointer in user's buffer with memcpy, to avoid alignment issues */
-    H5MM_memcpy(_vl,&vl,sizeof(hvl_t));
+    *len = HDstrlen(s);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-}   /* end H5T_vlen_seq_mem_setnull() */
+} /* end H5T__vlen_mem_str_getlen() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_str_mem_getlen
+ * Function:	H5T__vlen_mem_str_getptr
  *
- * Purpose:	Retrieves the length of a memory based VL string.
+ * Purpose:	Retrieves the pointer for a memory based VL string.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Non-NULL on success/NULL on failure
  *
  * Programmer:	Quincey Koziol
- *		Wednesday, June 2, 1999
+ *		Saturday, June 12, 2004
  *
  *-------------------------------------------------------------------------
  */
-static ssize_t
-H5T_vlen_str_mem_getlen(const void *_vl)
+static void *
+H5T__vlen_mem_str_getptr(void *_vl)
 {
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    const char *s=*(const char * const *)_vl;   /* Pointer to the user's string information */
+    char *s = *(char **)_vl;   /* Pointer to the user's string information */
 #else
-    const char *s = NULL;       /* Pointer to the user's string information */
+    char *s = NULL;     /* Pointer to the user's string information */
 #endif
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     /* check parameters */
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
@@ -544,78 +649,71 @@ H5T_vlen_str_mem_getlen(const void *_vl)
     H5MM_memcpy(&s, _vl, sizeof(char *));
 #endif
 
-    FUNC_LEAVE_NOAPI((ssize_t)HDstrlen(s))
-}   /* end H5T_vlen_str_mem_getlen() */
+    FUNC_LEAVE_NOAPI(s)
+} /* end H5T__vlen_mem_str_getptr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_str_mem_getptr
+ * Function:	H5T__vlen_mem_str_isnull
  *
- * Purpose:	Retrieves the pointer for a memory based VL string.
+ * Purpose:	Checks if a memory string is a NULL pointer
  *
- * Return:	Non-NULL on success/NULL on failure
+ * Return:	Non-negative on success / Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		Saturday, June 12, 2004
+ *		Saturday, November 8, 2003
  *
  *-------------------------------------------------------------------------
  */
-static void *
-H5T_vlen_str_mem_getptr(void *_vl)
+static herr_t
+H5T__vlen_mem_str_isnull(const H5F_t H5_ATTR_UNUSED *f, void *_vl, hbool_t *isnull)
 {
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    char *s=*(char **)_vl;   /* Pointer to the user's string information */
+    char *s = *(char **)_vl;   /* Pointer to the user's string information */
 #else
     char *s = NULL;     /* Pointer to the user's string information */
 #endif
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check parameters */
-#ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    HDassert(s);
-#else
-    HDassert(_vl);
+#ifndef H5_NO_ALIGNMENT_RESTRICTIONS
     H5MM_memcpy(&s, _vl, sizeof(char *));
 #endif
 
-    FUNC_LEAVE_NOAPI(s)
-}   /* end H5T_vlen_str_mem_getptr() */
+    *isnull = (s == NULL ? TRUE : FALSE);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5T__vlen_mem_str_isnull() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_str_mem_isnull
+ * Function:	H5T__vlen_mem_str_setnull
  *
- * Purpose:	Checks if a memory string is a NULL pointer
+ * Purpose:	Sets a VL info object in memory to the "null" value
  *
- * Return:	TRUE/FALSE on success/Negative on failure
+ * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
  *		Saturday, November 8, 2003
  *
  *-------------------------------------------------------------------------
  */
-static htri_t
-H5T_vlen_str_mem_isnull(const H5F_t H5_ATTR_UNUSED *f, void *_vl)
+static herr_t
+H5T__vlen_mem_str_setnull(H5F_t H5_ATTR_UNUSED *f, void *_vl, void H5_ATTR_UNUSED *_bg)
 {
-#ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    char *s=*(char **)_vl;   /* Pointer to the user's string information */
-#else
-    char *s = NULL;     /* Pointer to the user's string information */
-#endif
+    char *t = NULL;                   /* Pointer to temporary buffer allocated */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
-#ifndef H5_NO_ALIGNMENT_RESTRICTIONS
-    H5MM_memcpy(&s, _vl, sizeof(char *));
-#endif
+    /* Set pointer in user's buffer with memcpy, to avoid alignment issues */
+    H5MM_memcpy(_vl, &t, sizeof(char *));
 
-    FUNC_LEAVE_NOAPI(s==NULL ? TRUE : FALSE)
-}   /* end H5T_vlen_str_mem_isnull() */
+    FUNC_LEAVE_NOAPI(SUCCEED) /*lint !e429 The pointer in 't' has been copied */
+} /* end H5T__vlen_mem_str_setnull() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_str_mem_read
+ * Function:	H5T__vlen_mem_str_read
  *
  * Purpose:	"Reads" the memory based VL string into a buffer
  *
@@ -627,17 +725,17 @@ H5T_vlen_str_mem_isnull(const H5F_t H5_ATTR_UNUSED *f, void *_vl)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_str_mem_read(H5F_t H5_ATTR_UNUSED *f, void *_vl, void *buf, size_t len)
+H5T__vlen_mem_str_read(H5F_t H5_ATTR_UNUSED *f, void *_vl, void *buf, size_t len)
 {
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
-    char *s=*(char **)_vl;   /* Pointer to the user's string information */
+    char *s = *(char **)_vl;   /* Pointer to the user's string information */
 #else
     char *s;      /* Pointer to the user's string information */
 #endif
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
-    if(len>0) {
+    if(len > 0) {
         /* check parameters */
         HDassert(buf);
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS
@@ -647,15 +745,15 @@ H5T_vlen_str_mem_read(H5F_t H5_ATTR_UNUSED *f, void *_vl, void *buf, size_t len)
         H5MM_memcpy(&s, _vl, sizeof(char *));
 #endif
 
-        H5MM_memcpy(buf,s,len);
+        H5MM_memcpy(buf, s, len);
     } /* end if */
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-}   /* end H5T_vlen_str_mem_read() */
+} /* end H5T__vlen_mem_str_read() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_str_mem_write
+ * Function:	H5T__vlen_mem_str_write
  *
  * Purpose:	"Writes" the memory based VL string from a buffer
  *
@@ -667,154 +765,171 @@ H5T_vlen_str_mem_read(H5F_t H5_ATTR_UNUSED *f, void *_vl, void *buf, size_t len)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_str_mem_write(H5F_t H5_ATTR_UNUSED *f, const H5T_vlen_alloc_info_t *vl_alloc_info,
+H5T__vlen_mem_str_write(H5F_t H5_ATTR_UNUSED *f, const H5T_vlen_alloc_info_t *vl_alloc_info,
     void *_vl, void *buf, void H5_ATTR_UNUSED *_bg, size_t seq_len, size_t base_size)
 {
     char *t;                        /* Pointer to temporary buffer allocated */
     size_t len;                     /* Maximum length of the string to copy */
-    herr_t      ret_value=SUCCEED;  /* Return value */
+    herr_t ret_value = SUCCEED;     /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* check parameters */
     HDassert(buf);
 
     /* Use the user's memory allocation routine if one is defined */
-    if(vl_alloc_info->alloc_func!=NULL) {
-        if(NULL==(t = (char *)(vl_alloc_info->alloc_func)((seq_len+1)*base_size,vl_alloc_info->alloc_info)))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for VL data")
-      } /* end if */
-    else {  /* Default to system malloc */
+    if(vl_alloc_info->alloc_func != NULL) {
+        if(NULL == (t = (char *)(vl_alloc_info->alloc_func)((seq_len + 1) * base_size, vl_alloc_info->alloc_info)))
+            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTALLOC, FAIL, "application memory allocation routine failed for VL data")
+    } /* end if */
+    else        /* Default to system malloc */
         if(NULL == (t = (char *)HDmalloc((seq_len + 1) * base_size)))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for VL data")
-      } /* end else */
+            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTALLOC, FAIL, "memory allocation failed for VL data")
 
-    len=(seq_len*base_size);
-    H5MM_memcpy(t,buf,len);
-    t[len]='\0';
+    /* 'write' the string into the buffer, with memcpy() */
+    len = (seq_len * base_size);
+    H5MM_memcpy(t, buf, len);
+    t[len] = '\0';
 
     /* Set pointer in user's buffer with memcpy, to avoid alignment issues */
-    H5MM_memcpy(_vl,&t,sizeof(char *));
+    H5MM_memcpy(_vl, &t, sizeof(char *));
 
 done:
     FUNC_LEAVE_NOAPI(ret_value) /*lint !e429 The pointer in 't' has been copied */
-}   /* end H5T_vlen_str_mem_write() */
+} /* end H5T__vlen_mem_str_write() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_str_mem_setnull
+ * Function:	H5T__vlen_disk_getlen
  *
- * Purpose:	Sets a VL info object in memory to the "null" value
+ * Purpose:	Retrieves the length of a disk based VL element.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		Saturday, November 8, 2003
+ *		Wednesday, June 2, 1999
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_str_mem_setnull(H5F_t H5_ATTR_UNUSED *f, void *_vl, void H5_ATTR_UNUSED *_bg)
+H5T__vlen_disk_getlen(H5F_t H5_ATTR_UNUSED *f, const void *_vl, size_t *seq_len)
 {
-    char *t=NULL;                   /* Pointer to temporary buffer allocated */
+    const uint8_t *vl = (const uint8_t *)_vl; /* Pointer to the user's hvl_t information */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
-    /* Set pointer in user's buffer with memcpy, to avoid alignment issues */
-    H5MM_memcpy(_vl,&t,sizeof(char *));
+    /* Check parameters */
+    HDassert(vl);
+    HDassert(seq_len);
 
-    FUNC_LEAVE_NOAPI(SUCCEED) /*lint !e429 The pointer in 't' has been copied */
-}   /* end H5T_vlen_str_mem_setnull() */
+    /* Get length of sequence (different from blob size) */
+    UINT32DECODE(vl, *seq_len);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5T__vlen_disk_getlen() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_disk_getlen
+ * Function:	H5T__vlen_disk_isnull
  *
- * Purpose:	Retrieves the length of a disk based VL element.
+ * Purpose:	Checks if a disk VL info object is the "nil" object
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Non-negative on success / Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		Wednesday, June 2, 1999
+ *		Saturday, November 8, 2003
  *
  *-------------------------------------------------------------------------
  */
-static ssize_t
-H5T_vlen_disk_getlen(const void *_vl)
+static herr_t
+H5T__vlen_disk_isnull(const H5F_t *f, void *_vl, hbool_t *isnull)
 {
-    const uint8_t *vl=(const uint8_t *)_vl; /* Pointer to the disk VL information */
-    size_t	seq_len = 0;    /* Sequence length */
+    H5VL_object_t *vol_obj = NULL;/* Object info */
+    hid_t file_id = H5I_INVALID_HID;
+    uint8_t *vl = (uint8_t *)_vl; /* Pointer to the user's hvl_t information */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC
 
-    /* check parameters */
+    /* Check parameters */
+    HDassert(f);
     HDassert(vl);
+    HDassert(isnull);
 
-    UINT32DECODE(vl, seq_len);
+    /* Skip the sequence's length */
+    vl += 4;
 
-    FUNC_LEAVE_NOAPI((ssize_t)seq_len)
-}   /* end H5T_vlen_disk_getlen() */
+    /* TODO temporary hack to retrieve file object */
+    if((file_id = H5F__get_file_id((H5F_t *)f, FALSE)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+    if(NULL == (vol_obj = H5VL_vol_object(file_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5T_vlen_disk_getptr
- *
- * Purpose:	Retrieves the pointer to a disk based VL element.
- *
- * Return:	Non-NULL on success/NULL on failure
- *
- * Programmer:	Quincey Koziol
- *		Saturday, June 12, 2004
- *
- *-------------------------------------------------------------------------
- */
-static void *
-H5T_vlen_disk_getptr(void H5_ATTR_UNUSED *vl)
-{
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    /* Check if blob ID is "nil" */
+    if(H5VL_blob_specific(vol_obj, vl, H5VL_BLOB_ISNULL, isnull) < 0)
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "unable to check if a blob ID is 'nil'")
 
-    /* check parameters */
-    HDassert(vl);
-
-    FUNC_LEAVE_NOAPI(NULL)
-}   /* end H5T_vlen_disk_getptr() */
+done:
+    if((file_id != H5I_INVALID_HID) && (H5I_dec_ref(file_id) < 0))
+        HDONE_ERROR(H5E_DATATYPE, H5E_CANTDEC, FAIL, "unable to decrement refcount on file id")
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5T__vlen_disk_isnull() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_disk_isnull
+ * Function:	H5T__vlen_disk_setnull
  *
- * Purpose:	Checks if a disk VL info object is the "nil" object
+ * Purpose:	Sets a VL info object on disk to the "nil" value
  *
- * Return:	TRUE/FALSE on success/Negative on failure
+ * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
  *		Saturday, November 8, 2003
  *
  *-------------------------------------------------------------------------
  */
-static htri_t
-H5T_vlen_disk_isnull(const H5F_t *f, void *_vl)
+static herr_t
+H5T__vlen_disk_setnull(H5F_t *f, void *_vl, void *bg)
 {
-    uint8_t *vl = (uint8_t *)_vl; /* Pointer to the disk VL information */
-    haddr_t addr;               /* Sequence's heap address */
+    H5VL_object_t *vol_obj = NULL;/* Object info */
+    hid_t file_id = H5I_INVALID_HID;
+    uint8_t *vl = (uint8_t *)_vl; /* Pointer to the user's hvl_t information */
+    herr_t ret_value = SUCCEED;   /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC
 
     /* check parameters */
+    HDassert(f);
     HDassert(vl);
 
-    /* Skip the sequence's length */
-    vl += 4;
+    /* Free heap object for old data */
+    if(bg != NULL)
+        /* Delete sequence in destination location */
+        if(H5T__vlen_disk_delete(f, bg) < 0)
+            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREMOVE, FAIL, "unable to remove background heap object")
 
-    /* Get the heap address */
-    H5F_addr_decode(f, (const uint8_t **)&vl, &addr);
+    /* Set the length of the sequence */
+    UINT32ENCODE(vl, 0);
+
+    /* TODO temporary hack to retrieve file object */
+    if((file_id = H5F__get_file_id(f, FALSE)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+    if(NULL == (vol_obj = H5VL_vol_object(file_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")
 
-    FUNC_LEAVE_NOAPI(addr == 0 ? TRUE : FALSE)
-}   /* end H5T_vlen_disk_isnull() */
+    /* Set blob ID to "nil" */
+    if(H5VL_blob_specific(vol_obj, vl, H5VL_BLOB_SETNULL) < 0)
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "unable to set a blob ID to 'nil'")
+
+done:
+    if((file_id != H5I_INVALID_HID) && (H5I_dec_ref(file_id) < 0))
+        HDONE_ERROR(H5E_DATATYPE, H5E_CANTDEC, FAIL, "unable to decrement refcount on file id")
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5T__vlen_disk_setnull() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_disk_read
+ * Function:	H5T__vlen_disk_read
  *
  * Purpose:	Reads the disk based VL element into a buffer
  *
@@ -826,40 +941,42 @@ H5T_vlen_disk_isnull(const H5F_t *f, void *_vl)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_disk_read(H5F_t *f, void *_vl, void *buf, size_t H5_ATTR_UNUSED len)
+H5T__vlen_disk_read(H5F_t *f, void *_vl, void *buf, size_t H5_ATTR_UNUSED len)
 {
-    uint8_t *vl=(uint8_t *)_vl;   /* Pointer to the user's hvl_t information */
-    H5HG_t hobjid;
-    herr_t      ret_value=SUCCEED;       /* Return value */
+    H5VL_object_t *vol_obj = NULL;/* Object info */
+    hid_t file_id = H5I_INVALID_HID;
+    const uint8_t *vl = (const uint8_t *)_vl; /* Pointer to the user's hvl_t information */
+    herr_t ret_value = SUCCEED;     /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* check parameters */
+    /* Check parameters */
+    HDassert(f);
     HDassert(vl);
     HDassert(buf);
-    HDassert(f);
 
     /* Skip the length of the sequence */
     vl += 4;
 
-    /* Get the heap information */
-    H5F_addr_decode(f, (const uint8_t **)&vl, &(hobjid.addr));
-    UINT32DECODE(vl, hobjid.idx);
+    /* TODO temporary hack to retrieve file object */
+    if((file_id = H5F__get_file_id(f, FALSE)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+    if(NULL == (vol_obj = H5VL_vol_object(file_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")
 
-    /* Check if this sequence actually has any data */
-    if(hobjid.addr > 0) {
-        /* Read the VL information from disk */
-        if(NULL == H5HG_read(f, &hobjid, buf, NULL))
-            HGOTO_ERROR(H5E_DATATYPE, H5E_READERROR, FAIL, "Unable to read VL information")
-    }
+    /* Retrieve blob */
+    if(H5VL_blob_get(vol_obj, vl, buf, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "unable to get blob")
 
 done:
+    if((file_id != H5I_INVALID_HID) && (H5I_dec_ref(file_id) < 0))
+        HDONE_ERROR(H5E_DATATYPE, H5E_CANTDEC, FAIL, "unable to decrement refcount on file id")
     FUNC_LEAVE_NOAPI(ret_value)
-}   /* end H5T_vlen_disk_read() */
+} /* end H5T__vlen_disk_read() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_disk_write
+ * Function:	H5T__vlen_disk_write
  *
  * Purpose:	Writes the disk based VL element from a buffer
  *
@@ -871,146 +988,129 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_disk_write(H5F_t *f, const H5T_vlen_alloc_info_t H5_ATTR_UNUSED *vl_alloc_info,
+H5T__vlen_disk_write(H5F_t *f, const H5T_vlen_alloc_info_t H5_ATTR_UNUSED *vl_alloc_info,
     void *_vl, void *buf, void *_bg, size_t seq_len, size_t base_size)
 {
-    uint8_t *vl = (uint8_t *)_vl; /*Pointer to the user's hvl_t information*/
-    uint8_t *bg = (uint8_t *)_bg; /*Pointer to the old data hvl_t          */
-    H5HG_t hobjid;              /* New VL sequence's heap ID */
-    size_t len;                 /* Size of new sequence on disk (in bytes) */
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5VL_object_t *vol_obj = NULL;      /* Object info */
+    hid_t file_id = H5I_INVALID_HID;
+    uint8_t *vl = (uint8_t *)_vl;       /* Pointer to the user's hvl_t information */
+    const uint8_t *bg = (const uint8_t *)_bg; /* Pointer to the old data hvl_t */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* check parameters */
     HDassert(vl);
     HDassert(seq_len == 0 || buf);
     HDassert(f);
 
-    /* Free heap object for old data.  */
-    if(bg!=NULL) {
-        H5HG_t bg_hobjid;       /* "Background" VL info sequence's ID info */
-
-        /* Skip the length of the sequence and heap object ID from background data. */
-        bg += 4;
-
-        /* Get heap information */
-        H5F_addr_decode(f, (const uint8_t **)&bg, &(bg_hobjid.addr));
-        UINT32DECODE(bg, bg_hobjid.idx);
-
-        /* Free heap object for old data */
-        if(bg_hobjid.addr > 0) {
-            /* Free heap object */
-            if(H5HG_remove(f, &bg_hobjid) < 0)
-                HGOTO_ERROR(H5E_DATATYPE, H5E_WRITEERROR, FAIL, "Unable to remove heap object")
-        }
-    } /* end if */
+    /* Free heap object for old data, if non-NULL */
+    if(bg != NULL)
+        if(H5T__vlen_disk_delete(f, bg) < 0)
+            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREMOVE, FAIL, "unable to remove background heap object")
 
     /* Set the length of the sequence */
     UINT32ENCODE(vl, seq_len);
 
-    /* Write the VL information to disk (allocates space also) */
-    len = (seq_len*base_size);
-    if(H5HG_insert(f, len, buf, &hobjid) < 0)
-        HGOTO_ERROR(H5E_DATATYPE, H5E_WRITEERROR, FAIL, "Unable to write VL information")
+    /* TODO temporary hack to retrieve file object */
+    if((file_id = H5F__get_file_id(f, FALSE)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+    if(NULL == (vol_obj = H5VL_vol_object(file_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")
 
-    /* Encode the heap information */
-    H5F_addr_encode(f, &vl, hobjid.addr);
-    UINT32ENCODE(vl, hobjid.idx);
+    /* Store blob */
+    if(H5VL_blob_put(vol_obj, buf, (seq_len * base_size), vl, NULL) < 0)
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "unable to put blob")
 
 done:
+    if((file_id != H5I_INVALID_HID) && (H5I_dec_ref(file_id) < 0))
+        HDONE_ERROR(H5E_DATATYPE, H5E_CANTDEC, FAIL, "unable to decrement refcount on file id")
     FUNC_LEAVE_NOAPI(ret_value)
-}   /* end H5T_vlen_disk_write() */
+} /* end H5T__vlen_disk_write() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5T_vlen_disk_setnull
+ * Function:	H5T__vlen_disk_delete
  *
- * Purpose:	Sets a VL info object on disk to the "nil" value
+ * Purpose:	Deletes a disk-based VL element
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Non-negative on success / Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		Saturday, November 8, 2003
+ *		Friday, August 15, 2019
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T_vlen_disk_setnull(H5F_t *f, void *_vl, void *_bg)
+H5T__vlen_disk_delete(H5F_t *f, const void *_vl)
 {
-    uint8_t *vl = (uint8_t *)_vl; /*Pointer to the user's hvl_t information*/
-    uint8_t *bg = (uint8_t *)_bg; /*Pointer to the old data hvl_t          */
-    uint32_t seq_len = 0;         /* Sequence length */
-    herr_t ret_value = SUCCEED;   /* Return value */
+    const uint8_t *vl = (const uint8_t *)_vl; /* Pointer to the user's hvl_t information */
+    hid_t file_id = H5I_INVALID_HID;
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* check parameters */
+    /* Check parameters */
     HDassert(f);
-    HDassert(vl);
 
-    /* Free heap object for old data.  */
-    if(bg != NULL) {
-        H5HG_t bg_hobjid;       /* "Background" VL info sequence's ID info */
+    /* Free heap object for old data */
+    if(vl != NULL) {
+        size_t seq_len;             /* VL sequence's length */
 
-        /* Skip the length of the sequence and heap object ID from background data. */
-        bg += 4;
+        /* Get length of sequence */
+        UINT32DECODE(vl, seq_len);
 
-        /* Get heap information */
-        H5F_addr_decode(f, (const uint8_t **)&bg, &(bg_hobjid.addr));
-        UINT32DECODE(bg, bg_hobjid.idx);
+        /* Delete object, if length > 0 */
+        if(seq_len > 0) {
+            H5VL_object_t *vol_obj = NULL; /* Object info */
 
-        /* Free heap object for old data */
-        if(bg_hobjid.addr > 0) {
-            /* Free heap object */
-            if(H5HG_remove(f, &bg_hobjid) < 0)
-                HGOTO_ERROR(H5E_DATATYPE, H5E_WRITEERROR, FAIL, "Unable to remove heap object")
-         } /* end if */
-    } /* end if */
+            /* TODO temporary hack to retrieve file object */
+            if((file_id = H5F__get_file_id(f, FALSE)) < 0)
+                HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+            if(NULL == (vol_obj = H5VL_vol_object(file_id)))
+                HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")
 
-    /* Set the length of the sequence */
-    UINT32ENCODE(vl, seq_len);
-
-    /* Encode the "nil" heap pointer information */
-    H5F_addr_encode(f, &vl, (haddr_t)0);
-    UINT32ENCODE(vl, 0);
+            if(H5VL_blob_specific(vol_obj, (void *)vl, H5VL_BLOB_DELETE) < 0)   /* Casting away 'const' OK -QAK */
+                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREMOVE, FAIL, "unable to delete blob")
+        }
+    } /* end if */
 
 done:
+    if((file_id != H5I_INVALID_HID) && (H5I_dec_ref(file_id) < 0))
+        HDONE_ERROR(H5E_DATATYPE, H5E_CANTDEC, FAIL, "unable to decrement refcount on file id")
     FUNC_LEAVE_NOAPI(ret_value)
-}   /* end H5T_vlen_disk_setnull() */
+} /* end H5T__vlen_disk_delete() */
 
 
-/*--------------------------------------------------------------------------
- NAME
-    H5T_vlen_reclaim_recurse
- PURPOSE
-    Internal recursive routine to free VL datatypes
- USAGE
-    herr_t H5T_vlen_reclaim_recurse(elem,dt)
-        void *elem;  IN/OUT: Pointer to the dataset element
-        H5T_t *dt;   IN: Datatype of dataset element
-
- RETURNS
-    SUCCEED/FAIL
- DESCRIPTION
-    Frees any dynamic memory used by VL datatypes in the current dataset
-    element.  Performs a recursive depth-first traversal of all compound
-    datatypes to free all VL datatype information allocated by any field.
- GLOBAL VARIABLES
- COMMENTS, BUGS, ASSUMPTIONS
- EXAMPLES
- REVISION LOG
---------------------------------------------------------------------------*/
-static herr_t
-H5T_vlen_reclaim_recurse(void *elem, const H5T_t *dt, H5MM_free_t free_func, void *free_info)
+/*-------------------------------------------------------------------------
+ * Function:    H5T_vlen_reclaim
+ *
+ * Purpose: Internal recursive routine to free VL datatypes
+ *
+ * Return:  Non-negative on success / Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *      Friday, August 15, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5T_vlen_reclaim(void *elem, const H5T_t *dt, H5T_vlen_alloc_info_t *alloc_info)
 {
     unsigned u;                     /* Local index variable */
+    H5MM_free_t free_func;          /* Free function */
+    void *free_info;                /* Free info */
     herr_t ret_value = SUCCEED;     /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_NOAPI(FAIL)
 
+    /* Sanity checks */
     HDassert(elem);
     HDassert(dt);
+    HDassert(alloc_info);
+
+    free_func = alloc_info->free_func;
+    free_info = alloc_info->free_info;
 
     /* Check the datatype of this element */
     switch(dt->shared->type) {
@@ -1022,8 +1122,8 @@ H5T_vlen_reclaim_recurse(void *elem, const H5T_t *dt, H5MM_free_t free_func, voi
                 /* Calculate the offset member and recurse on it */
                 for(u = 0; u < dt->shared->u.array.nelem; u++) {
                     off = ((uint8_t *)elem) + u * (dt->shared->parent->shared->size);
-                    if(H5T_vlen_reclaim_recurse(off, dt->shared->parent, free_func, free_info) < 0)
-                        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "Unable to free array element")
+                    if(H5T_reclaim_cb(off, dt->shared->parent, 0, NULL, alloc_info) < 0)
+                        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "unable to free array element")
                 } /* end for */
             } /* end if */
             break;
@@ -1037,8 +1137,8 @@ H5T_vlen_reclaim_recurse(void *elem, const H5T_t *dt, H5MM_free_t free_func, voi
 
                     /* Calculate the offset member and recurse on it */
                     off = ((uint8_t *)elem) + dt->shared->u.compnd.memb[u].offset;
-                    if(H5T_vlen_reclaim_recurse(off, dt->shared->u.compnd.memb[u].type, free_func, free_info) < 0)
-                        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "Unable to free compound field")
+                    if(H5T_reclaim_cb(off, dt->shared->u.compnd.memb[u].type, 0, NULL, alloc_info) < 0)
+                        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "unable to free compound field")
                 } /* end if */
             } /* end for */
             break;
@@ -1057,8 +1157,8 @@ H5T_vlen_reclaim_recurse(void *elem, const H5T_t *dt, H5MM_free_t free_func, voi
                         /* Calculate the offset of each array element and recurse on it */
                         while(vl->len > 0) {
                             off = ((uint8_t *)vl->p) + (vl->len - 1) * dt->shared->parent->shared->size;
-                            if(H5T_vlen_reclaim_recurse(off, dt->shared->parent, free_func, free_info) < 0)
-                                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "Unable to free VL element")
+                            if(H5T_reclaim_cb(off, dt->shared->parent, 0, NULL, alloc_info) < 0)
+                                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "unable to free VL element")
                             vl->len--;
                         } /* end while */
                     } /* end if */
@@ -1087,11 +1187,11 @@ H5T_vlen_reclaim_recurse(void *elem, const H5T_t *dt, H5MM_free_t free_func, voi
         case H5T_STRING:
         case H5T_BITFIELD:
         case H5T_OPAQUE:
-        case H5T_REFERENCE:
         case H5T_ENUM:
             break;
 
         /* Should never have these values */
+        case H5T_REFERENCE:
         case H5T_NO_CLASS:
         case H5T_NCLASSES:
         default:
@@ -1102,66 +1202,15 @@ H5T_vlen_reclaim_recurse(void *elem, const H5T_t *dt, H5MM_free_t free_func, voi
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-}   /* end H5T_vlen_reclaim_recurse() */
-
-
-/*--------------------------------------------------------------------------
- NAME
-    H5T_vlen_reclaim
- PURPOSE
-    Default method to reclaim any VL data for a buffer element
- USAGE
-    herr_t H5T_vlen_reclaim(elem,type_id,ndim,point,op_data)
-        void *elem;  IN/OUT: Pointer to the dataset element
-        hid_t type_id;   IN: Datatype of dataset element
-        unsigned ndim;    IN: Number of dimensions in dataspace
-        hsize_t *point; IN: Coordinate location of element in dataspace
-        void *op_data    IN: Operator data
-
- RETURNS
-    SUCCEED/FAIL
- DESCRIPTION
-    Frees any dynamic memory used by VL datatypes in the current dataset
-    element.  Recursively descends compound datatypes to free all VL datatype
-    information allocated by any field.
- GLOBAL VARIABLES
- COMMENTS, BUGS, ASSUMPTIONS
- EXAMPLES
- REVISION LOG
---------------------------------------------------------------------------*/
-herr_t
-H5T_vlen_reclaim(void *elem, hid_t type_id, unsigned H5_ATTR_UNUSED ndim,
-    const hsize_t H5_ATTR_UNUSED *point, void *op_data)
-{
-    H5T_vlen_alloc_info_t *vl_alloc_info = (H5T_vlen_alloc_info_t *)op_data; /* VL allocation info from iterator */
-    H5T_t	*dt;
-    herr_t ret_value = SUCCEED;     /* Return value */
-
-    FUNC_ENTER_NOAPI(FAIL)
-
-    HDassert(elem);
-    HDassert(vl_alloc_info);
-    HDassert(H5I_DATATYPE == H5I_get_type(type_id));
-
-    /* Check args */
-    if(NULL == (dt = (H5T_t *)H5I_object_verify(type_id, H5I_DATATYPE)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a datatype")
-
-    /* Pull the free function and free info pointer out of the op_data and call the recurse datatype free function */
-    if(H5T_vlen_reclaim_recurse(elem, dt, vl_alloc_info->free_func, vl_alloc_info->free_info) < 0)
-        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "can't reclaim vlen elements")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-}   /* end H5T_vlen_reclaim() */
+} /* end H5T_vlen_reclaim() */
 
 
 /*-------------------------------------------------------------------------
  * Function:	H5T_vlen_reclaim_elmt
  *
  * Purpose: Alternative method to reclaim any VL data for a buffer element.
- * 
- *          Use this function when the datatype is already available, but 
+ *
+ *          Use this function when the datatype is already available, but
  *          the allocation info is needed from the context before jumping
  *          into recursion.
  *
@@ -1188,10 +1237,9 @@ H5T_vlen_reclaim_elmt(void *elem, H5T_t *dt)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "unable to retrieve VL allocation info")
 
     /* Recurse on buffer to free dynamic fields */
-    if(H5T_vlen_reclaim_recurse(elem, dt, vl_alloc_info.free_func, vl_alloc_info.free_info) < 0)
+    if(H5T_vlen_reclaim(elem, dt, &vl_alloc_info) < 0)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "can't reclaim vlen elements")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5T_vlen_reclaim_elmt */
-
+} /* H5T_vlen_reclaim_elmt() */