Add H5Rget_attr() and H5Rget_obj() / Remove H5Rdereference3()

More cleanup to H5R

5 files changed, 528 insertions, 342 deletions

diff --git a/src/H5R.c b/src/H5R.c
index 9df3e9f..dfc6394 100644
--- a/src/H5R.c
+++ b/src/H5R.c
@@ -365,14 +365,14 @@ H5R_create_attr(H5G_loc_t *loc, const char *name, hid_t dxpl_id, const char *att
         HGOTO_ERROR(H5E_REFERENCE, H5E_ARGS, NULL, "attribute name too long")
 
     /* Compute buffer size, allow for the attribute name length and object's OID */
-    buf_size = attr_name_len + 2 + sizeof(haddr_t);
+    buf_size = attr_name_len + sizeof(uint16_t) + sizeof(haddr_t);
 
     /* Allocate the space to store the serialized information */
     if(NULL == (ref = (struct href_t *)H5MM_malloc(sizeof(struct href_t))))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "Cannot allocate memory for reference")
-    if (NULL == (ref->ref.serial.buf = H5MM_malloc((size_t) buf_size)))
+    if (NULL == (ref->ref.serial.buf = H5MM_malloc(buf_size)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, NULL, "Cannot allocate buffer to serialize selection")
-    ref->ref.serial.buf_size = (size_t) buf_size;
+    ref->ref.serial.buf_size = buf_size;
     ref->ref_type = H5R_ATTR;
 
     /* Serialize information for object's OID into buffer */
@@ -404,8 +404,8 @@ done:
 /*-------------------------------------------------------------------------
  * Function:    H5R_create_ext_object
  *
- * Purpose: Creates an external object reference. The LOC and NAME are used to locate
- * the object pointed to.
+ * Purpose: Creates an external object reference. The FILENAME and PATHNAME
+ * are used to locate the object pointed to.
  *
  * Return:  Success:    Reference created
  *          Failure:    NULL
@@ -413,13 +413,10 @@ done:
  *-------------------------------------------------------------------------
  */
 href_t
-H5R_create_ext_object(H5G_loc_t *loc, const char *name, hid_t dxpl_id)
+H5R_create_ext_object(const char *filename, const char *pathname)
 {
-    H5G_loc_t obj_loc;          /* Group hier. location of object */
-    H5G_name_t path;            /* Object group hier. path */
-    H5O_loc_t oloc;             /* Object object location */
-    hbool_t obj_found = FALSE;  /* Object location found */
     size_t filename_len;        /* Length of the file name */
+    size_t pathname_len;        /* Length of the obj path name */
     size_t buf_size;            /* Size of buffer needed to serialize reference */
     uint8_t *p;                 /* Pointer to OID to store */
     struct href_t *ref = NULL;         /* Reference to be returned */
@@ -427,30 +424,23 @@ H5R_create_ext_object(H5G_loc_t *loc, const char *name, hid_t dxpl_id)
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    HDassert(loc);
-    HDassert(name);
-
-    /* Set up object location to fill in */
-    obj_loc.oloc = &oloc;
-    obj_loc.path = &path;
-    H5G_loc_reset(&obj_loc);
-
-    /* Find the object */
-    if(H5G_loc_find(loc, name, &obj_loc, H5P_DEFAULT, dxpl_id) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_NOTFOUND, NULL, "object not found")
-    obj_found = TRUE;
+    HDassert(filename);
+    HDassert(pathname);
 
     /* Need to add name of the file */
-    filename_len = HDstrlen(H5F_OPEN_NAME(loc->oloc->file));
+    filename_len = HDstrlen(filename);
 
-    /* Compute buffer size, allow for the attribute name length and object's OID */
-    buf_size = filename_len + 2 + sizeof(haddr_t);
+    /* Need to add object path name */
+    pathname_len = HDstrlen(pathname);
+
+    /* Compute buffer size, allow for the file name and object path name lengths */
+    buf_size = filename_len + pathname_len + 2 * sizeof(uint16_t);
 
     if(NULL == (ref = (struct href_t *)H5MM_malloc(sizeof(struct href_t))))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "Cannot allocate memory for reference")
-    if (NULL == (ref->ref.serial.buf = H5MM_malloc((size_t) buf_size)))
+    if (NULL == (ref->ref.serial.buf = H5MM_malloc(buf_size)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, NULL, "Cannot allocate buffer to serialize selection")
-    ref->ref.serial.buf_size = (size_t) buf_size;
+    ref->ref.serial.buf_size = buf_size;
     ref->ref_type = H5R_EXT_OBJECT;
 
     /* Serialize information for file name length into the buffer */
@@ -458,17 +448,21 @@ H5R_create_ext_object(H5G_loc_t *loc, const char *name, hid_t dxpl_id)
     UINT16ENCODE(p, filename_len);
 
     /* Copy the file name into the buffer */
-    HDmemcpy(p, H5F_OPEN_NAME(loc->oloc->file), filename_len);
+    HDmemcpy(p, filename, filename_len);
     p += filename_len;
 
-    /* Serialize information for object's OID into buffer */
-    H5F_addr_encode(loc->oloc->file, &p, obj_loc.oloc->addr);
+    /* Serialize information for object path name length into the buffer */
+    UINT16ENCODE(p, pathname_len);
+
+    /* Copy the object path name into the buffer */
+    HDmemcpy(p, pathname, pathname_len);
+
+    /* Sanity check */
+    HDassert((size_t)((p + pathname_len) - (uint8_t *)ref->ref.serial.buf) == buf_size);
 
     ret_value = ref;
 
 done:
-    if(obj_found)
-        H5G_loc_free(&obj_loc);
     if(NULL == ret_value) {
         H5MM_free(ref->ref.serial.buf);
         H5MM_free(ref);
@@ -480,8 +474,9 @@ done:
 /*-------------------------------------------------------------------------
  * Function:    H5R_create_ext_region
  *
- * Purpose: Creates an external region reference. The LOC and NAME are used to locate
- * the object pointed to and the SPACE is used to choose the region pointed to.
+ * Purpose: Creates an external region reference. The FILENAME and PATHNAME
+ * are used to locate the object pointed to and the SPACE is used to choose
+ * the region pointed to.
  *
  * Return:  Success:    Reference created
  *          Failure:    NULL
@@ -489,51 +484,41 @@ done:
  *-------------------------------------------------------------------------
  */
 href_t
-H5R_create_ext_region(H5G_loc_t *loc, const char *name, hid_t dxpl_id, H5S_t *space)
+H5R_create_ext_region(const char *filename, const char *pathname, H5S_t *space)
 {
-    H5G_loc_t obj_loc;          /* Group hier. location of object */
-    H5G_name_t path;            /* Object group hier. path */
-    H5O_loc_t oloc;             /* Object object location */
-    hbool_t obj_found = FALSE;  /* Object location found */
     size_t filename_len;        /* Length of the file name */
-    hssize_t buf_size;          /* Size of buffer needed to serialize selection */
-    uint8_t *p;                 /* Pointer to OID to store */
+    size_t pathname_len;        /* Length of the obj path name */
+    size_t buf_size;            /* Size of buffer needed to serialize selection */
+    size_t space_buf_size;      /* Size of buffer needed to serialize selection */
+    uint8_t *p = NULL;          /* Pointer to OID to store */
     struct href_t *ref = NULL;         /* Reference to be returned */
     struct href_t *ret_value = NULL;   /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    HDassert(loc);
-    HDassert(name);
+    HDassert(filename);
+    HDassert(pathname);
     HDassert(space);
 
-    /* Set up object location to fill in */
-    obj_loc.oloc = &oloc;
-    obj_loc.path = &path;
-    H5G_loc_reset(&obj_loc);
-
-    /* Find the object */
-    if(H5G_loc_find(loc, name, &obj_loc, H5P_DEFAULT, dxpl_id) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_NOTFOUND, NULL, "object not found")
-    obj_found = TRUE;
-
     /* Need to add name of the file */
-    filename_len = HDstrlen(H5F_OPEN_NAME(loc->oloc->file));
+    filename_len = HDstrlen(filename);
+
+    /* Need to add object path name */
+    pathname_len = HDstrlen(pathname);
 
     /* Get the amount of space required to serialize the selection */
-    if((buf_size = H5S_SELECT_SERIAL_SIZE(space)) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTINIT, NULL, "Invalid amount of space for serializing selection")
+    if (H5S_encode(space, &p, &space_buf_size) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOPY, NULL, "Unable to serialize selection")
 
-    /* Increase buffer size to allow for the dataset OID */
-    buf_size += (hssize_t)(sizeof(haddr_t) + 2 + filename_len);
+    /* Compute buffer size, allow for the file name and object path name lengths */
+    buf_size = space_buf_size + filename_len + pathname_len + 2 * sizeof(uint16_t);
 
     /* Allocate the space to store the serialized information */
-    H5_CHECK_OVERFLOW(buf_size, hssize_t, size_t);
     if(NULL == (ref = (struct href_t *)H5MM_malloc(sizeof(struct href_t))))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "Cannot allocate memory for reference")
     if (NULL == (ref->ref.serial.buf = H5MM_malloc((size_t) buf_size)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, NULL, "Cannot allocate buffer to serialize selection")
-    ref->ref.serial.buf_size = (size_t) buf_size;
+    ref->ref.serial.buf_size = buf_size;
     ref->ref_type = H5R_EXT_REGION;
 
     /* Serialize information for file name length into the buffer */
@@ -541,21 +526,26 @@ H5R_create_ext_region(H5G_loc_t *loc, const char *name, hid_t dxpl_id, H5S_t *sp
     UINT16ENCODE(p, filename_len);
 
     /* Copy the file name into the buffer */
-    HDmemcpy(p, H5F_OPEN_NAME(loc->oloc->file), filename_len);
+    HDmemcpy(p, filename, filename_len);
     p += filename_len;
 
-    /* Serialize information for dataset OID into buffer */
-    H5F_addr_encode(loc->oloc->file, &p, obj_loc.oloc->addr);
+    /* Serialize information for object path name length into the buffer */
+    UINT16ENCODE(p, pathname_len);
+
+    /* Copy the object path name into the buffer */
+    HDmemcpy(p, pathname, pathname_len);
+    p += pathname_len;
 
     /* Serialize the selection into buffer */
-    if(H5S_SELECT_SERIALIZE(space, &p) < 0)
+    if (H5S_encode(space, &p, &space_buf_size) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOPY, NULL, "Unable to serialize selection")
 
+    /* Sanity check */
+    HDassert((size_t)(p - (uint8_t *)ref->ref.serial.buf) == (size_t)buf_size);
+
     ret_value = ref;
 
 done:
-    if(obj_found)
-        H5G_loc_free(&obj_loc);
     if(NULL == ret_value) {
         H5MM_free(ref->ref.serial.buf);
         H5MM_free(ref);
@@ -567,8 +557,8 @@ done:
 /*-------------------------------------------------------------------------
  * Function:    H5R_create_ext_attr
  *
- * Purpose: Creates an external attribute reference. The LOC, NAME and ATTR_NAME are
- * used to locate the attribute pointed to.
+ * Purpose: Creates an external attribute reference. The FILENAME, PATHNAME
+ * and ATTR_NAME are used to locate the attribute pointed to.
  *
  * Return:  Success:    Reference created
  *          Failure:    NULL
@@ -576,52 +566,42 @@ done:
  *-------------------------------------------------------------------------
  */
 href_t
-H5R_create_ext_attr(H5G_loc_t *loc, const char *name, hid_t dxpl_id, const char *attr_name)
+H5R_create_ext_attr(const char *filename, const char *pathname, const char *attr_name)
 {
-    H5G_loc_t obj_loc;          /* Group hier. location of object */
-    H5G_name_t path;            /* Object group hier. path */
-    H5O_loc_t oloc;             /* Object object location */
-    hbool_t obj_found = FALSE;  /* Object location found */
     size_t filename_len;        /* Length of the file name */
-    size_t buf_size;            /* Size of buffer needed to serialize attribute */
+    size_t pathname_len;        /* Length of the obj path name */
     size_t attr_name_len;       /* Length of the attribute name */
+    size_t buf_size;            /* Size of buffer needed to serialize reference */
     uint8_t *p;                 /* Pointer to OID to store */
     struct href_t *ref = NULL;         /* Reference to be returned */
     struct href_t *ret_value = NULL;   /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    HDassert(loc);
-    HDassert(name);
+    HDassert(filename);
+    HDassert(pathname);
     HDassert(attr_name);
 
-    /* Set up object location to fill in */
-    obj_loc.oloc = &oloc;
-    obj_loc.path = &path;
-    H5G_loc_reset(&obj_loc);
-
-    /* Find the object */
-    if(H5G_loc_find(loc, name, &obj_loc, H5P_DEFAULT, dxpl_id) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_NOTFOUND, NULL, "object not found")
-    obj_found = TRUE;
-
     /* Need to add name of the file */
-    filename_len = HDstrlen(H5F_OPEN_NAME(loc->oloc->file));
+    filename_len = HDstrlen(filename);
+
+    /* Need to add object path name */
+    pathname_len = HDstrlen(pathname);
 
     /* Get the amount of space required to serialize the attribute name */
     attr_name_len = HDstrlen(attr_name);
     if(attr_name_len >= H5R_MAX_ATTR_REF_NAME_LEN)
         HGOTO_ERROR(H5E_REFERENCE, H5E_ARGS, NULL, "attribute name too long")
 
-    /* Compute buffer size, allow for the attribute name length and object's OID */
-    buf_size = filename_len + 2 + attr_name_len + 2 + sizeof(haddr_t);
+    /* Compute buffer size, allow for the file name and object path name lengths */
+    buf_size = filename_len + pathname_len + attr_name_len + 3 * sizeof(uint16_t);
 
     /* Allocate the space to store the serialized information */
     if(NULL == (ref = (struct href_t *)H5MM_malloc(sizeof(struct href_t))))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "Cannot allocate memory for reference")
-    if (NULL == (ref->ref.serial.buf = H5MM_malloc((size_t) buf_size)))
+    if (NULL == (ref->ref.serial.buf = H5MM_malloc(buf_size)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, NULL, "Cannot allocate buffer to serialize selection")
-    ref->ref.serial.buf_size = (size_t) buf_size;
+    ref->ref.serial.buf_size = buf_size;
     ref->ref_type = H5R_EXT_ATTR;
 
     /* Serialize information for file name length into the buffer */
@@ -629,11 +609,15 @@ H5R_create_ext_attr(H5G_loc_t *loc, const char *name, hid_t dxpl_id, const char
     UINT16ENCODE(p, filename_len);
 
     /* Copy the file name into the buffer */
-    HDmemcpy(p, H5F_OPEN_NAME(loc->oloc->file), filename_len);
+    HDmemcpy(p, filename, filename_len);
     p += filename_len;
 
-    /* Serialize information for object's OID into buffer */
-    H5F_addr_encode(loc->oloc->file, &p, obj_loc.oloc->addr);
+    /* Serialize information for object path name length into the buffer */
+    UINT16ENCODE(p, pathname_len);
+
+    /* Copy the object path name into the buffer */
+    HDmemcpy(p, pathname, pathname_len);
+    p += pathname_len;
 
     /* Serialize information for attribute name length into the buffer */
     UINT16ENCODE(p, attr_name_len);
@@ -647,8 +631,6 @@ H5R_create_ext_attr(H5G_loc_t *loc, const char *name, hid_t dxpl_id, const char
     ret_value = ref;
 
 done:
-    if(obj_found)
-        H5G_loc_free(&obj_loc);
     if(NULL == ret_value) {
         H5MM_free(ref->ref.serial.buf);
         H5MM_free(ref);
@@ -764,8 +746,8 @@ done:
 /*-------------------------------------------------------------------------
  * Function:    H5Rcreate_ext_object
  *
- * Purpose: Creates an external object reference. The LOC_ID and NAME are
- * used to locate the object pointed to.
+ * Purpose: Creates an external object reference. The FILENAME and PATHNAME
+ * are used to locate the object pointed to.
  *
  * Return:  Success:    Reference created
  *          Failure:    NULL
@@ -773,20 +755,19 @@ done:
  *-------------------------------------------------------------------------
  */
 href_t
-H5Rcreate_ext_object(hid_t loc_id, const char *name)
+H5Rcreate_ext_object(const char *filename, const char *pathname)
 {
-    H5G_loc_t loc; /* File location */
     href_t    ret_value = NULL; /* Return value */
 
     FUNC_ENTER_API(NULL)
 
     /* Check args */
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a location")
-    if(!name || !*name)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no name given")
+    if(!filename || !*filename)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no filename given")
+    if(!pathname || !*pathname)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no pathname given")
 
-    if(NULL == (ret_value = H5R_create_ext_object(&loc, name, H5AC_dxpl_id)))
+    if(NULL == (ret_value = H5R_create_ext_object(filename, pathname)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTINIT, NULL, "unable to create object reference")
 
 done:
@@ -796,8 +777,8 @@ done:
 /*-------------------------------------------------------------------------
  * Function:    H5Rcreate_ext_region
  *
- * Purpose: Creates an external region reference. The LOC_ID and NAME are
- * used to locate the object pointed to and the SPACE_ID is used to choose
+ * Purpose: Creates an external region reference. The FILENAME and PATHNAME
+ * are used to locate the object pointed to and the SPACE_ID is used to choose
  * the region pointed to.
  *
  * Return:  Success:    Reference created
@@ -806,25 +787,24 @@ done:
  *-------------------------------------------------------------------------
  */
 href_t
-H5Rcreate_ext_region(hid_t loc_id, const char *name, hid_t space_id)
+H5Rcreate_ext_region(const char *filename, const char *pathname, hid_t space_id)
 {
-    H5G_loc_t loc; /* File location */
     H5S_t      *space = NULL;   /* Pointer to dataspace containing region */
     href_t     ret_value = NULL; /* Return value */
 
     FUNC_ENTER_API(NULL)
 
     /* Check args */
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a location")
-    if(!name || !*name)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no name given")
+    if(!filename || !*filename)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no filename given")
+    if(!pathname || !*pathname)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no pathname given")
     if(space_id == H5I_BADID)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "reference region dataspace id must be valid")
     if(space_id != H5I_BADID && (NULL == (space = (H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE))))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a dataspace")
 
-    if(NULL == (ret_value = H5R_create_ext_region(&loc, name, H5AC_dxpl_id, space)))
+    if(NULL == (ret_value = H5R_create_ext_region(filename, pathname, space)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTINIT, NULL, "unable to create region reference")
 
 done:
@@ -834,8 +814,8 @@ done:
 /*-------------------------------------------------------------------------
  * Function:    H5Rcreate_ext_attr
  *
- * Purpose: Creates an external attribute reference. The LOC_ID, NAME and
- * ATTR_NAME are used to locate the attribute pointed to.
+ * Purpose: Creates an external attribute reference. The FILENAME, PATHNAME
+ * and ATTR_NAME are used to locate the attribute pointed to.
  *
  * Return:  Success:    Reference created
  *          Failure:    NULL
@@ -843,22 +823,21 @@ done:
  *-------------------------------------------------------------------------
  */
 href_t
-H5Rcreate_ext_attr(hid_t loc_id, const char *name, const char *attr_name)
+H5Rcreate_ext_attr(const char *filename, const char *pathname, const char *attr_name)
 {
-    H5G_loc_t loc; /* File location */
     href_t    ret_value = NULL; /* Return value */
 
     FUNC_ENTER_API(NULL)
 
     /* Check args */
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a location")
-    if(!name || !*name)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no name given")
+    if(!filename || !*filename)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no filename given")
+    if(!pathname || !*pathname)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no pathname given")
     if(!attr_name || !*attr_name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "no attribute name given")
 
-    if(NULL == (ret_value = H5R_create_ext_attr(&loc, name, H5AC_dxpl_id, attr_name)))
+    if(NULL == (ret_value = H5R_create_ext_attr(filename, pathname, attr_name)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTINIT, NULL, "unable to create atribute reference")
 
 done:
@@ -1049,7 +1028,7 @@ done:
 } /* end H5Requal() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5R__dereference
+ * Function:    H5R__get_object
  *
  * Purpose: Given a reference to some object, open that object and return an
  * ID for that object.
@@ -1059,14 +1038,15 @@ done:
  *-------------------------------------------------------------------------
  */
 hid_t
-H5R__dereference(H5F_t *file, hid_t oapl_id, hid_t dxpl_id, href_t _ref, hbool_t app_ref)
+H5R__get_object(H5F_t *file, hid_t oapl_id, hid_t dxpl_id, href_t _ref, hbool_t app_ref)
 {
     H5O_loc_t oloc;                 /* Object location */
     H5G_name_t path;                /* Path of object */
     H5G_loc_t loc;                  /* Group location */
-    char *attr_name = NULL;         /* Name of the attribute (for attribute references) */
+    char *pathname = NULL;          /* Path name of the object (for external references) */
     unsigned rc;                    /* Reference count of object */
     H5O_type_t obj_type;            /* Type of object */
+    hbool_t ext_ref = FALSE;        /* External reference */
     const uint8_t *p = NULL;        /* Pointer to OID to store */
     struct href_t *ref = (struct href_t *) _ref; /* Reference */
     hid_t ret_value = H5I_BADID;    /* Return value */
@@ -1081,176 +1061,159 @@ H5R__dereference(H5F_t *file, hid_t oapl_id, hid_t dxpl_id, href_t _ref, hbool_t
     H5O_loc_reset(&oloc);
     oloc.file = file;
 
+    /* Construct a group location for opening the object */
+    H5G_name_reset(&path);
+    loc.oloc = &oloc;
+    loc.path = &path;
+
+    /* Point to reference buffer now */
+    p = (const uint8_t *)ref->ref.serial.buf;
+
+    /* Decode reference */
     switch (ref->ref_type) {
+        case H5R_OBJECT:
+            oloc.addr = ref->ref.addr;
+            if(!H5F_addr_defined(oloc.addr) || oloc.addr == 0)
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Undefined reference pointer")
+            break;
+        case H5R_REGION:
+        case H5R_ATTR:
+            /* Get the object oid for the dataset */
+            H5F_addr_decode(oloc.file, &p, &(oloc.addr));
+            break;
         case H5R_EXT_OBJECT:
         case H5R_EXT_REGION:
         case H5R_EXT_ATTR:
         {
             size_t filename_len; /* Length of the file name */
+            size_t pathname_len; /* Length of the obj path name */
 
             /* Get the file name length */
-            p = (const uint8_t *)ref->ref.serial.buf;
             UINT16DECODE(p, filename_len);
             HDassert(filename_len < H5R_MAX_ATTR_REF_NAME_LEN);
 
             /* Skip the file name */
             p += filename_len;
+
+            /* Get the path name length */
+            UINT16DECODE(p, pathname_len);
+
+            /* Allocate space for the path name */
+            if(NULL == (pathname = (char *)H5MM_malloc(pathname_len + 1)))
+                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, FAIL, "memory allocation failed")
+
+            /* Get the path name */
+            HDmemcpy(pathname, p, pathname_len);
+            pathname[pathname_len] = '\0';
+
+            /* Skip the path name */
+            p += pathname_len;
+
+            /* Mark as external reference */
+            ext_ref = TRUE;
         }
             break;
-        case H5R_OBJECT:
-        case H5R_REGION:
-        case H5R_ATTR:
         case H5R_BADTYPE:
         case H5R_MAXTYPE:
         default:
-            break;
+            HDassert("unknown reference type" && 0);
+            HGOTO_ERROR(H5E_REFERENCE, H5E_UNSUPPORTED, FAIL, "internal error (unknown reference type)")
     }
 
-    switch(ref->ref_type) {
-        case H5R_OBJECT:
-            oloc.addr = ref->ref.addr;
-            if(!H5F_addr_defined(oloc.addr) || oloc.addr == 0)
-                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Undefined reference pointer")
-            break;
+    /* Get object location */
+    if (ext_ref) {
+        H5G_loc_t file_loc;  /* File root group location */
+
+        /* Construct a group location for root group of the file */
+        if (FAIL == H5G_root_loc(file, &file_loc))
+            HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, FAIL, "unable to create location for file")
+
+        /* Find the object's location */
+        if (H5G_loc_find(&file_loc, pathname, &loc/*out*/, H5P_LINK_ACCESS_DEFAULT, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, FAIL, "object not found")
+
+        /* Find the object's type */
+        if (H5O_obj_type(loc.oloc, &obj_type, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "cannot get object type")
+    } else {
+        /* Get the # of links for object, and its type */
+        /* (To check to make certain that this object hasn't been deleted since the reference was created) */
+        if(H5O_get_rc_and_type(&oloc, dxpl_id, &rc, &obj_type) < 0 || 0 == rc)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_LINKCOUNT, FAIL, "dereferencing deleted object")
+    }
 
-        case H5R_EXT_OBJECT:
-        case H5R_EXT_REGION:
-        case H5R_REGION:
+    /* Open the object */
+    switch(obj_type) {
+        case H5O_TYPE_GROUP:
         {
-            /* Get the object oid for the dataset */
-            if (!p) p = (const uint8_t *)ref->ref.serial.buf;
-            H5F_addr_decode(oloc.file, &p, &(oloc.addr));
+            H5G_t *group;               /* Pointer to group to open */
+
+            if(NULL == (group = H5G_open(&loc, dxpl_id)))
+                HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "not found")
+
+            /* Create an atom for the group */
+            if((ret_value = H5I_register(H5I_GROUP, group, app_ref)) < 0) {
+                H5G_close(group);
+                HGOTO_ERROR(H5E_SYM, H5E_CANTREGISTER, FAIL, "can't register group")
+            } /* end if */
         } /* end case */
         break;
 
-        case H5R_EXT_ATTR:
-        case H5R_ATTR:
+        case H5O_TYPE_NAMED_DATATYPE:
         {
-            size_t attr_name_len; /* Length of the attribute name */
-
-            /* Get the object oid for the dataset */
-            if (!p) p = (const uint8_t *)ref->ref.serial.buf;
-            H5F_addr_decode(oloc.file, &p, &(oloc.addr));
-
-            /* Get the attribute name length */
-            UINT16DECODE(p, attr_name_len);
-            HDassert(attr_name_len < H5R_MAX_ATTR_REF_NAME_LEN);
+            H5T_t *type;                /* Pointer to datatype to open */
 
-            /* Allocate space for the attribute name */
-            if(NULL == (attr_name = (char *)H5MM_malloc(attr_name_len + 1)))
-                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, FAIL, "memory allocation failed")
+            if(NULL == (type = H5T_open(&loc, dxpl_id)))
+                HGOTO_ERROR(H5E_DATATYPE, H5E_NOTFOUND, FAIL, "not found")
 
-            /* Get the attribute name */
-            HDmemcpy(attr_name, p, attr_name_len);
-            attr_name[attr_name_len] = '\0';
+            /* Create an atom for the datatype */
+            if((ret_value = H5I_register(H5I_DATATYPE, type, app_ref)) < 0) {
+                H5T_close(type);
+                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREGISTER, FAIL, "can't register datatype")
+            } /* end if */
         } /* end case */
         break;
 
-        case H5R_BADTYPE:
-        case H5R_MAXTYPE:
-        default:
-            HDassert("unknown reference type" && 0);
-            HGOTO_ERROR(H5E_REFERENCE, H5E_UNSUPPORTED, FAIL, "internal error (unknown reference type)")
-    } /* end switch */
-
-    /* Get the # of links for object, and its type */
-    /* (To check to make certain that this object hasn't been deleted since the reference was created) */
-    if(H5O_get_rc_and_type(&oloc, dxpl_id, &rc, &obj_type) < 0 || 0 == rc)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_LINKCOUNT, FAIL, "dereferencing deleted object")
+        case H5O_TYPE_DATASET:
+        {
+            H5D_t *dset;                /* Pointer to dataset to open */
 
-    /* Construct a group location for opening the object */
-    H5G_name_reset(&path);
-    loc.oloc = &oloc;
-    loc.path = &path;
+            /* Get correct property list */
+            if(H5P_DEFAULT == oapl_id)
+                oapl_id = H5P_DATASET_ACCESS_DEFAULT;
+            else if(TRUE != H5P_isa_class(oapl_id, H5P_DATASET_ACCESS))
+                HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not dataset access property list")
 
-    /* Open an attribute */
-    if(H5R_ATTR == ref->ref_type || H5R_EXT_ATTR == ref->ref_type) {
-        H5A_t *attr;            /* Attribute opened */
+            /* Open the dataset */
+            if(NULL == (dset = H5D_open(&loc, oapl_id, dxpl_id)))
+                HGOTO_ERROR(H5E_DATASET, H5E_NOTFOUND, FAIL, "not found")
 
-        /* Open the attribute */
-        if(NULL == (attr = H5A_open(&loc, attr_name, dxpl_id)))
-            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENOBJ, FAIL, "can't open attribute")
+            /* Create an atom for the dataset */
+            if((ret_value = H5I_register(H5I_DATASET, dset, app_ref)) < 0) {
+                H5D_close(dset);
+                HGOTO_ERROR(H5E_DATASET, H5E_CANTREGISTER, FAIL, "can't register dataset")
+            } /* end if */
 
-        /* Create an atom for the attribute */
-        if((ret_value = H5I_register(H5I_ATTR, attr, app_ref)) < 0) {
-            H5A_close(attr);
-            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTREGISTER, FAIL, "can't register attribute")
-        } /* end if */
-    } /* end if */
-    else {
-        /* Open the object */
-        switch(obj_type) {
-            case H5O_TYPE_GROUP:
-                {
-                    H5G_t *group;               /* Pointer to group to open */
-
-                    if(NULL == (group = H5G_open(&loc, dxpl_id)))
-                        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "not found")
-
-                    /* Create an atom for the group */
-                    if((ret_value = H5I_register(H5I_GROUP, group, app_ref)) < 0) {
-                        H5G_close(group);
-                        HGOTO_ERROR(H5E_SYM, H5E_CANTREGISTER, FAIL, "can't register group")
-                    } /* end if */
-                } /* end case */
-                break;
-
-            case H5O_TYPE_NAMED_DATATYPE:
-                {
-                    H5T_t *type;                /* Pointer to datatype to open */
-
-                    if(NULL == (type = H5T_open(&loc, dxpl_id)))
-                        HGOTO_ERROR(H5E_DATATYPE, H5E_NOTFOUND, FAIL, "not found")
-
-                    /* Create an atom for the datatype */
-                    if((ret_value = H5I_register(H5I_DATATYPE, type, app_ref)) < 0) {
-                        H5T_close(type);
-                        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREGISTER, FAIL, "can't register datatype")
-                    } /* end if */
-                } /* end case */
-                break;
-
-            case H5O_TYPE_DATASET:
-                {
-                    H5D_t *dset;                /* Pointer to dataset to open */
-
-                    /* Get correct property list */
-                    if(H5P_DEFAULT == oapl_id)
-                        oapl_id = H5P_DATASET_ACCESS_DEFAULT;
-                    else if(TRUE != H5P_isa_class(oapl_id, H5P_DATASET_ACCESS))
-                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not dataset access property list")
-
-                    /* Open the dataset */
-                    if(NULL == (dset = H5D_open(&loc, oapl_id, dxpl_id)))
-                        HGOTO_ERROR(H5E_DATASET, H5E_NOTFOUND, FAIL, "not found")
-
-                    /* Create an atom for the dataset */
-                    if((ret_value = H5I_register(H5I_DATASET, dset, app_ref)) < 0) {
-                        H5D_close(dset);
-                        HGOTO_ERROR(H5E_DATASET, H5E_CANTREGISTER, FAIL, "can't register dataset")
-                    } /* end if */
-
-                    /* TODO Keep ID of the dataset */
+            /* TODO Keep ID of the dataset */
 //                  dset->shared->dset_id = ret_value;
 
-                } /* end case */
-                break;
+        } /* end case */
+        break;
 
-            case H5O_TYPE_UNKNOWN:
-            case H5O_TYPE_NTYPES:
-            default:
-                HGOTO_ERROR(H5E_REFERENCE, H5E_BADTYPE, FAIL, "can't identify type of object referenced")
-         } /* end switch */
-    } /* end else */
+        case H5O_TYPE_UNKNOWN:
+        case H5O_TYPE_NTYPES:
+        default:
+            HGOTO_ERROR(H5E_REFERENCE, H5E_BADTYPE, FAIL, "can't identify type of object referenced")
+    } /* end switch */
 
 done:
-    H5MM_xfree(attr_name);
+    H5MM_xfree(pathname);
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5R__dereference() */
+} /* end H5R__get_object() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5Rdereference3
+ * Function:    H5Rget_object
  *
  * Purpose: Given a reference to some object, open that object and return an
  * ID for that object.
@@ -1260,7 +1223,7 @@ done:
  *-------------------------------------------------------------------------
  */
 hid_t
-H5Rdereference3(hid_t obj_id, hid_t oapl_id, href_t _ref)
+H5Rget_object(hid_t obj_id, hid_t oapl_id, href_t _ref)
 {
     struct href_t *ref = (struct href_t *) _ref; /* Reference */
     H5G_loc_t loc;      /* Group location */
@@ -1278,13 +1241,13 @@ H5Rdereference3(hid_t obj_id, hid_t oapl_id, href_t _ref)
     if(ref->ref_type <= H5R_BADTYPE || ref->ref_type >= H5R_MAXTYPE)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference type")
 
-    /* Dereference */
-    if((ret_value = H5R__dereference(loc.oloc->file, oapl_id, H5AC_ind_dxpl_id, ref, TRUE)) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTINIT, FAIL, "unable to dereference object")
+    /* get_object */
+    if((ret_value = H5R__get_object(loc.oloc->file, oapl_id, H5AC_ind_dxpl_id, ref, TRUE)) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTINIT, FAIL, "unable to get_object object")
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Rdereference3() */
+} /* end H5Rget_object() */
 
 /*-------------------------------------------------------------------------
  * Function:    H5R__get_region
@@ -1320,6 +1283,7 @@ H5R__get_region(H5F_t *file, hid_t dxpl_id, href_t _ref)
 
     if (ref->ref_type == H5R_EXT_REGION) {
         size_t filename_len; /* Length of the file name */
+        size_t pathname_len; /* Length of the obj path name */
 
         /* Get the file name length */
         UINT16DECODE(p, filename_len);
@@ -1327,18 +1291,28 @@ H5R__get_region(H5F_t *file, hid_t dxpl_id, href_t _ref)
 
         /* Skip the file name */
         p += filename_len;
-    }
 
-    /* Get the object oid for the dataset */
-    H5F_addr_decode(oloc.file, &p, &(oloc.addr));
+        /* Get the path name length */
+        UINT16DECODE(p, pathname_len);
+
+        /* Skip the path name */
+        p += pathname_len;
 
-    /* Open and copy the dataset's dataspace */
-    if((ret_value = H5S_read(&oloc, dxpl_id)) == NULL)
-        HGOTO_ERROR(H5E_DATASPACE, H5E_NOTFOUND, NULL, "not found")
+        /* Unserialize the selection */
+        if (NULL == (ret_value = H5S_decode(&p)))
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, NULL, "can't deserialize selection")
+    } else {
+        /* Get the object oid for the dataset */
+        H5F_addr_decode(oloc.file, &p, &(oloc.addr));
 
-    /* Unserialize the selection */
-    if(H5S_SELECT_DESERIALIZE(&ret_value, &p) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, NULL, "can't deserialize selection")
+        /* Open and copy the dataset's dataspace */
+        if((ret_value = H5S_read(&oloc, dxpl_id)) == NULL)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_NOTFOUND, NULL, "not found")
+
+        /* Unserialize the selection */
+        if(H5S_SELECT_DESERIALIZE(&ret_value, &p) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, NULL, "can't deserialize selection")
+    }
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1386,6 +1360,147 @@ done:
 } /* end H5Rget_region2() */
 
 /*-------------------------------------------------------------------------
+ * Function:    H5R__get_attr
+ *
+ * Purpose: Given a reference to some attribute, open that attribute and
+ * return an ID for that attribute.
+ *
+ * Return:  Valid ID on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+H5A_t *
+H5R__get_attr(H5F_t *file, hid_t dxpl_id, href_t _ref)
+{
+    H5O_loc_t oloc;                 /* Object location */
+    H5G_name_t path;                /* Path of object */
+    H5G_loc_t loc;                  /* Group location */
+    char *pathname = NULL;          /* Path name of the object (for external references) */
+    size_t attr_name_len;           /* Length of the attribute name */
+    char *attr_name = NULL;         /* Attribute name */
+    const uint8_t *p = NULL;        /* Pointer to OID to store */
+    struct href_t *ref = (struct href_t *) _ref; /* Reference */
+    H5A_t *ret_value = NULL;        /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    HDassert(file);
+    HDassert(ref);
+    HDassert((ref->ref_type == H5R_ATTR) || (ref->ref_type == H5R_EXT_ATTR));
+
+    /* Initialize the object location */
+    H5O_loc_reset(&oloc);
+    oloc.file = file;
+
+    /* Construct a group location for opening the object */
+    H5G_name_reset(&path);
+    loc.oloc = &oloc;
+    loc.path = &path;
+
+    /* Point to reference buffer now */
+    p = (const uint8_t *)ref->ref.serial.buf;
+
+    if (ref->ref_type == H5R_EXT_ATTR) {
+        H5G_loc_t file_loc;  /* File root group location */
+        size_t filename_len; /* Length of the file name */
+        size_t pathname_len; /* Length of the obj path name */
+
+        /* Get the file name length */
+        UINT16DECODE(p, filename_len);
+
+        /* Skip the file name */
+        p += filename_len;
+
+        /* Get the path name length */
+        UINT16DECODE(p, pathname_len);
+
+        /* Allocate space for the path name */
+        if(NULL == (pathname = (char *)H5MM_malloc(pathname_len + 1)))
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, NULL, "memory allocation failed")
+
+        /* Get the path name */
+        HDmemcpy(pathname, p, pathname_len);
+        pathname[pathname_len] = '\0';
+
+        /* Skip the path name */
+        p += pathname_len;
+
+        /* Construct a group location for root group of the file */
+        if (FAIL == H5G_root_loc(file, &file_loc))
+            HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, NULL, "unable to create location for file")
+
+        /* Find the object's location */
+        if (H5G_loc_find(&file_loc, pathname, &loc/*out*/, H5P_LINK_ACCESS_DEFAULT, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, NULL, "object not found")
+    } else {
+        /* Get the object oid for the dataset */
+        H5F_addr_decode(oloc.file, &p, &(oloc.addr));
+    }
+
+    /* Get the attribute name length */
+    UINT16DECODE(p, attr_name_len);
+    HDassert(attr_name_len < H5R_MAX_ATTR_REF_NAME_LEN);
+
+    /* Allocate space for the attribute name */
+    if(NULL == (attr_name = (char *)H5MM_malloc(attr_name_len + 1)))
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, NULL, "memory allocation failed")
+
+    /* Get the attribute name */
+    HDmemcpy(attr_name, p, attr_name_len);
+    attr_name[attr_name_len] = '\0';
+
+    /* Open the attribute */
+    if(NULL == (ret_value = H5A_open(&loc, attr_name, dxpl_id)))
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENOBJ, NULL, "can't open attribute")
+
+done:
+    H5MM_xfree(pathname);
+    H5MM_xfree(attr_name);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5R__get_attr() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Rget_attr
+ *
+ * Purpose: Given a reference to some attribute, open that attribute and
+ * return an ID for that attribute.
+ *
+ * Return:  Valid ID on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5Rget_attr(hid_t loc_id, href_t _ref)
+{
+    struct href_t *ref = (struct href_t *) _ref; /* Reference */
+    H5G_loc_t loc;      /* Group location */
+    H5A_t *attr;        /* Attribute */
+    hid_t ret_value;
+
+    FUNC_ENTER_API(FAIL)
+
+    /* Check args */
+    if(H5G_loc(loc_id, &loc) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location")
+    if(ref == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference pointer")
+    if(ref->ref_type != H5R_ATTR && ref->ref_type != H5R_EXT_ATTR)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference type")
+
+    /* Get the attribute */
+    if((attr = H5R__get_attr(loc.oloc->file, H5AC_ind_dxpl_id, ref)) == NULL)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCREATE, FAIL, "unable to open attribute")
+
+    /* Atomize */
+    if((ret_value = H5I_register (H5I_ATTR, attr, TRUE)) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to register attribute atom")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Rget_attr() */
+
+/*-------------------------------------------------------------------------
  * Function:    H5R__get_obj_type
  *
  * Purpose: Given a reference to some object, this function returns the type
@@ -1398,20 +1513,35 @@ done:
 herr_t
 H5R__get_obj_type(H5F_t *file, hid_t dxpl_id, href_t _ref, H5O_type_t *obj_type)
 {
-    H5O_loc_t oloc;             /* Object location */
-    unsigned rc;                /* Reference count of object    */
+    H5O_loc_t oloc;                 /* Object location */
+    H5G_name_t path;                /* Path of object */
+    H5G_loc_t loc;                  /* Group location */
+    char *pathname = NULL;          /* Path name of the object (for external references) */
+    unsigned rc;                    /* Reference count of object */
+    hbool_t ext_ref = FALSE;        /* External reference */
+    const uint8_t *p = NULL;        /* Pointer to OID to store */
     struct href_t *ref = (struct href_t *) _ref; /* Reference */
-    herr_t ret_value = SUCCEED; /* Return value */
+    herr_t ret_value = SUCCEED;     /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    HDassert(ref);
     HDassert(file);
+    HDassert(ref);
+    HDassert(ref->ref_type > H5R_BADTYPE && ref->ref_type < H5R_MAXTYPE);
+    HDassert(obj_type);
 
-    /* Initialize the symbol table entry */
+    /* Initialize the object location */
     H5O_loc_reset(&oloc);
     oloc.file = file;
 
+    /* Construct a group location for opening the object */
+    H5G_name_reset(&path);
+    loc.oloc = &oloc;
+    loc.path = &path;
+
+    /* Point to reference buffer now */
+    p = (const uint8_t *)ref->ref.serial.buf;
+
     switch(ref->ref_type) {
         case H5R_OBJECT:
             /* Get the object oid */
@@ -1419,24 +1549,41 @@ H5R__get_obj_type(H5F_t *file, hid_t dxpl_id, href_t _ref, H5O_type_t *obj_type)
             break;
 
         case H5R_REGION:
-        {
-            const uint8_t *p;   /* Pointer to reference to decode */
-
+        case H5R_ATTR:
             /* Get the object oid for the dataset */
-            p = (const uint8_t *)ref->ref.serial.buf;
             H5F_addr_decode(oloc.file, &p, &(oloc.addr));
-
             break;
-        } /* end case */
 
-        case H5R_ATTR:
+        case H5R_EXT_OBJECT:
+        case H5R_EXT_REGION:
+        case H5R_EXT_ATTR:
         {
-            const uint8_t *p;   /* Pointer to reference to decode */
+            size_t filename_len; /* Length of the file name */
+            size_t pathname_len; /* Length of the obj path name */
 
-            /* Get the object oid for the dataset */
-            p = (const uint8_t *)ref->ref.serial.buf;
-            H5F_addr_decode(oloc.file, &p, &(oloc.addr));
+            /* Get the file name length */
+            UINT16DECODE(p, filename_len);
+            HDassert(filename_len < H5R_MAX_ATTR_REF_NAME_LEN);
 
+            /* Skip the file name */
+            p += filename_len;
+
+            /* Get the path name length */
+            UINT16DECODE(p, pathname_len);
+
+            /* Allocate space for the path name */
+            if(NULL == (pathname = (char *)H5MM_malloc(pathname_len + 1)))
+                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTALLOC, FAIL, "memory allocation failed")
+
+            /* Get the path name */
+            HDmemcpy(pathname, p, pathname_len);
+            pathname[pathname_len] = '\0';
+
+            /* Skip the path name */
+            p += pathname_len;
+
+            /* Mark as external reference */
+            ext_ref = TRUE;
             break;
         } /* end case */
 
@@ -1447,12 +1594,30 @@ H5R__get_obj_type(H5F_t *file, hid_t dxpl_id, href_t _ref, H5O_type_t *obj_type)
             HGOTO_ERROR(H5E_REFERENCE, H5E_UNSUPPORTED, FAIL, "internal error (unknown reference type)")
     } /* end switch */
 
-    /* Get the # of links for object, and its type */
-    /* (To check to make certain that this object hasn't been deleted since the reference was created) */
-    if(H5O_get_rc_and_type(&oloc, dxpl_id, &rc, obj_type) < 0 || 0 == rc)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_LINKCOUNT, FAIL, "dereferencing deleted object")
+    if (ext_ref) {
+        H5G_loc_t file_loc;  /* File root group location */
+
+        /* Construct a group location for root group of the file */
+        if (FAIL == H5G_root_loc(file, &file_loc))
+            HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, FAIL, "unable to create location for file")
+
+        /* Find the object's location */
+        if (H5G_loc_find(&file_loc, pathname, &loc/*out*/, H5P_LINK_ACCESS_DEFAULT, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, FAIL, "object not found")
+
+        /* Find the object's type */
+        if (H5O_obj_type(loc.oloc, obj_type, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "cannot get object type")
+    } else {
+        /* Get the # of links for object, and its type */
+        /* (To check to make certain that this object hasn't been deleted since the reference was created) */
+        if(H5O_get_rc_and_type(&oloc, dxpl_id, &rc, obj_type) < 0 || 0 == rc)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_LINKCOUNT, FAIL, "dereferencing deleted object")
+    }
 
 done:
+    H5MM_xfree(pathname);
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5R__get_obj_type() */
 
@@ -1508,6 +1673,7 @@ H5R__get_obj_name(H5F_t *f, hid_t lapl_id, hid_t dxpl_id, hid_t loc_id, href_t _
     hid_t file_id = H5I_BADID;  /* ID for file that the reference is in */
     H5O_loc_t oloc;             /* Object location describing object for reference */
     ssize_t ret_value = -1;     /* Return value */
+    hbool_t ext_ref = FALSE;    /* External reference */
     const uint8_t *p = NULL;    /* Pointer to reference to decode */
     struct href_t *ref = (struct href_t *) _ref; /* Reference */
 
@@ -1521,48 +1687,55 @@ H5R__get_obj_name(H5F_t *f, hid_t lapl_id, hid_t dxpl_id, hid_t loc_id, href_t _
     H5O_loc_reset(&oloc);
     oloc.file = f;
 
-    switch (ref->ref_type) {
+    /* Point to reference buffer now */
+    p = (const uint8_t *)ref->ref.serial.buf;
+
+    /* Get address for reference */
+    switch(ref->ref_type) {
+        case H5R_OBJECT:
+            oloc.addr = ref->ref.addr;
+            break;
+
+        case H5R_REGION:
+        case H5R_ATTR:
+        {
+            /* Get the object oid for the dataset */
+            H5F_addr_decode(oloc.file, &p, &(oloc.addr));
+        } /* end case */
+        break;
+
         case H5R_EXT_OBJECT:
         case H5R_EXT_REGION:
         case H5R_EXT_ATTR:
         {
             size_t filename_len; /* Length of the file name */
+            size_t pathname_len; /* Length of the obj path name */
+            size_t copy_len;
 
             /* Get the file name length */
-            p = (const uint8_t *)ref->ref.serial.buf;
             UINT16DECODE(p, filename_len);
             HDassert(filename_len < H5R_MAX_ATTR_REF_NAME_LEN);
 
             /* Skip the file name */
             p += filename_len;
-        }
-            break;
-        case H5R_OBJECT:
-        case H5R_REGION:
-        case H5R_ATTR:
-        case H5R_BADTYPE:
-        case H5R_MAXTYPE:
-        default:
-            break;
-    }
 
-    /* Get address for reference */
-    switch(ref->ref_type) {
-        case H5R_OBJECT:
-            oloc.addr = ref->ref.addr;
+            /* Get the path name length */
+            UINT16DECODE(p, pathname_len);
+            copy_len = MIN(pathname_len, size - 1);
+
+            /* Get the path name */
+            if (name) {
+                HDmemcpy(name, p, copy_len);
+                name[copy_len] = '\0';
+            }
+
+            ret_value = (ssize_t)(copy_len + 1);
+
+            /* Mark as external reference */
+            ext_ref = TRUE;
+        }
             break;
 
-        case H5R_EXT_OBJECT:
-        case H5R_EXT_REGION:
-        case H5R_REGION:
-        case H5R_EXT_ATTR:
-        case H5R_ATTR:
-        {
-            /* Get the object oid for the dataset */
-            if (!p) p = (const uint8_t *)ref->ref.serial.buf;
-            H5F_addr_decode(oloc.file, &p, &(oloc.addr));
-        } /* end case */
-        break;
         case H5R_BADTYPE:
         case H5R_MAXTYPE:
         default:
@@ -1570,13 +1743,16 @@ H5R__get_obj_name(H5F_t *f, hid_t lapl_id, hid_t dxpl_id, hid_t loc_id, href_t _
             HGOTO_ERROR(H5E_REFERENCE, H5E_UNSUPPORTED, FAIL, "internal error (unknown reference type)")
     } /* end switch */
 
-    /* Retrieve file ID for name search */
-    if((file_id = H5I_get_file_id(loc_id, FALSE)) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "can't retrieve file ID")
+    /* Get object location */
+    if (!ext_ref) {
+        /* Retrieve file ID for name search */
+        if((file_id = H5I_get_file_id(loc_id, FALSE)) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "can't retrieve file ID")
 
-    /* Get name, length, etc. */
-    if((ret_value = H5G_get_name_by_addr(file_id, lapl_id, dxpl_id, &oloc, name, size)) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "can't determine name")
+        /* Get name, length, etc. */
+        if((ret_value = H5G_get_name_by_addr(file_id, lapl_id, dxpl_id, &oloc, name, size)) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "can't determine name")
+    }
 
 done:
     /* Close file ID used for search */
@@ -1654,21 +1830,29 @@ H5R__get_attr_name(H5F_t *f, href_t _ref, char *name, size_t size)
     H5O_loc_reset(&oloc);
     oloc.file = f;
 
+    /* Point to reference buffer now */
+    p = (const uint8_t *)ref->ref.serial.buf;
+
     if (ref->ref_type == H5R_EXT_ATTR) {
         size_t filename_len; /* Length of the file name */
+        size_t pathname_len; /* Length of the obj path name */
 
         /* Get the file name length */
-        p = (const uint8_t *)ref->ref.serial.buf;
         UINT16DECODE(p, filename_len);
         HDassert(filename_len < H5R_MAX_ATTR_REF_NAME_LEN);
 
         /* Skip the file name */
         p += filename_len;
-    }
 
-    /* Get the object oid for the dataset */
-    if (!p) p = (const uint8_t *)ref->ref.serial.buf;
-    H5F_addr_decode(oloc.file, &p, &(oloc.addr));
+        /* Get the path name length */
+        UINT16DECODE(p, pathname_len);
+
+        /* Skip the path name */
+        p += pathname_len;
+    } else {
+        /* Get the object oid for the dataset */
+        H5F_addr_decode(oloc.file, &p, &(oloc.addr));
+    }
 
     /* Get the attribute name length */
     UINT16DECODE(p, attr_name_len);
@@ -1681,7 +1865,7 @@ H5R__get_attr_name(H5F_t *f, href_t _ref, char *name, size_t size)
         name[copy_len] = '\0';
     }
 
-    ret_value = (ssize_t)copy_len;
+    ret_value = (ssize_t)(copy_len + 1);
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5R__get_attr_name() */
@@ -1764,7 +1948,7 @@ H5R__get_file_name(href_t _ref, char *name, size_t size)
                 HDmemcpy(name, p, copy_len);
                 name[copy_len] = '\0';
             }
-            ret_value = (ssize_t)copy_len;
+            ret_value = (ssize_t)(copy_len + 1);
         }
             break;
         case H5R_OBJECT:
@@ -1775,7 +1959,6 @@ H5R__get_file_name(href_t _ref, char *name, size_t size)
         default:
             HDassert("unknown reference type" && 0);
             HGOTO_ERROR(H5E_REFERENCE, H5E_UNSUPPORTED, FAIL, "internal error (unknown reference type)")
-            break;
     } /* end switch */
 
 done:
diff --git a/src/H5Rdeprec.c b/src/H5Rdeprec.c
index 64b61d7..a823b89 100644
--- a/src/H5Rdeprec.c
+++ b/src/H5Rdeprec.c
@@ -129,7 +129,6 @@ H5Rcreate(void *_ref, hid_t loc_id, const char *name, H5R_type_t ref_type, hid_t
         default:
             HDassert("unsupported reference type" && 0);
             HGOTO_ERROR(H5E_REFERENCE, H5E_UNSUPPORTED, FAIL, "internal error (unsupported reference type)")
-            break;
     }
 
     *ref_ptr = ref;
@@ -171,7 +170,7 @@ H5Rdereference1(hid_t obj_id, H5R_type_t ref_type, const void *_ref)
     file = loc.oloc->file;
 
     /* Dereference */
-    if((ret_value = H5R__dereference(file, H5P_DATASET_ACCESS_DEFAULT, H5AC_ind_dxpl_id, *ref_ptr, TRUE)) < 0)
+    if((ret_value = H5R__get_object(file, H5P_DATASET_ACCESS_DEFAULT, H5AC_ind_dxpl_id, *ref_ptr, TRUE)) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTINIT, FAIL, "unable dereference object")
 
 done:
@@ -208,7 +207,7 @@ H5Rdereference2(hid_t obj_id, hid_t oapl_id, H5R_type_t ref_type, const void *_r
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference type")
 
     /* Dereference */
-    if((ret_value = H5R__dereference(loc.oloc->file, oapl_id, H5AC_ind_dxpl_id, *ref_ptr, TRUE)) < 0)
+    if((ret_value = H5R__get_object(loc.oloc->file, oapl_id, H5AC_ind_dxpl_id, *ref_ptr, TRUE)) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTINIT, FAIL, "unable dereference object")
 
 done:
@@ -381,7 +380,6 @@ ssize_t H5Rget_name(hid_t loc_id, H5R_type_t ref_type, const void *_ref,
         default:
             HDassert("unsupported reference type" && 0);
             HGOTO_ERROR(H5E_REFERENCE, H5E_UNSUPPORTED, FAIL, "internal error (unsupported reference type)")
-            break;
     }
 
 done:
diff --git a/src/H5Rpkg.h b/src/H5Rpkg.h
index 2048d39..08176ac 100644
--- a/src/H5Rpkg.h
+++ b/src/H5Rpkg.h
@@ -32,7 +32,8 @@
 #include "H5Rprivate.h"
 
 /* Other private headers needed by this file */
-#include "H5Fprivate.h"         /* File access				*/
+#include "H5Fprivate.h"         /* File access  */
+#include "H5Aprivate.h"         /* Attributes   */
 
 /**************************/
 /* Package Private Macros */
@@ -68,9 +69,10 @@ struct href_t {
 /* General functions */
 H5_DLL herr_t H5R__get_obj_type(H5F_t *file, hid_t dxpl_id, href_t ref,
     H5O_type_t *obj_type);
-H5_DLL hid_t H5R__dereference(H5F_t *file, hid_t dapl_id, hid_t dxpl_id,
+H5_DLL hid_t H5R__get_object(H5F_t *file, hid_t dapl_id, hid_t dxpl_id,
     href_t ref, hbool_t app_ref);
 H5_DLL struct H5S_t *H5R__get_region(H5F_t *file, hid_t dxpl_id, href_t ref);
+H5_DLL H5A_t *H5R__get_attr(H5F_t *file, hid_t dxpl_id, href_t ref);
 H5_DLL ssize_t H5R__get_obj_name(H5F_t *file, hid_t lapl_id, hid_t dxpl_id,
     hid_t id, href_t ref, char *name, size_t size);
 H5_DLL ssize_t H5R__get_attr_name(H5F_t *file, href_t ref, char *name, size_t size);
diff --git a/src/H5Rprivate.h b/src/H5Rprivate.h
index 0983cb6..47251ba 100644
--- a/src/H5Rprivate.h
+++ b/src/H5Rprivate.h
@@ -32,9 +32,9 @@ struct H5S_t;
 H5_DLL href_t H5R_create_object(H5G_loc_t *loc, const char *name, hid_t dxpl_id);
 H5_DLL href_t H5R_create_region(H5G_loc_t *loc, const char *name, hid_t dxpl_id, struct H5S_t *space);
 H5_DLL href_t H5R_create_attr(H5G_loc_t *loc, const char *name, hid_t dxpl_id, const char *attr_name);
-H5_DLL href_t H5R_create_ext_object(H5G_loc_t *loc, const char *name, hid_t dxpl_id);
-H5_DLL href_t H5R_create_ext_region(H5G_loc_t *loc, const char *name, hid_t dxpl_id, struct H5S_t *space);
-H5_DLL href_t H5R_create_ext_attr(H5G_loc_t *loc, const char *name, hid_t dxpl_id, const char *attr_name);
+H5_DLL href_t H5R_create_ext_object(const char *filename, const char *pathname);
+H5_DLL href_t H5R_create_ext_region(const char *filename, const char *pathname, struct H5S_t *space);
+H5_DLL href_t H5R_create_ext_attr(const char *filename, const char *pathname, const char *attr_name);
 H5_DLL herr_t H5R_destroy(href_t ref);
 
 H5_DLL H5R_type_t H5R_get_type(href_t ref);
diff --git a/src/H5Rpublic.h b/src/H5Rpublic.h
index 4f67bd8..32eeaba 100644
--- a/src/H5Rpublic.h
+++ b/src/H5Rpublic.h
@@ -30,8 +30,8 @@
 typedef enum {
     H5R_BADTYPE     =   (-1),   /*invalid Reference Type                     */
     H5R_OBJECT,                 /*Object reference                           */
-    H5R_DATASET_REGION,         /*For backward compatibility                 */
-    H5R_REGION,                 /*Dataset Region Reference                   */
+    H5R_REGION_COMPAT,          /*For backward compatibility (region)        */
+    H5R_REGION,                 /*Region Reference                           */
     H5R_ATTR,                   /*Attribute Reference                        */
     H5R_EXT_OBJECT,             /*External Object reference                  */
     H5R_EXT_REGION,             /*External Region reference                  */
@@ -55,16 +55,18 @@ extern "C" {
 H5_DLL href_t H5Rcreate_object(hid_t loc_id, const char *name);
 H5_DLL href_t H5Rcreate_region(hid_t loc_id, const char *name, hid_t space_id);
 H5_DLL href_t H5Rcreate_attr(hid_t loc_id, const char *name, const char *attr_name);
-H5_DLL href_t H5Rcreate_ext_object(hid_t loc_id, const char *name);
-H5_DLL href_t H5Rcreate_ext_region(hid_t loc_id, const char *name, hid_t space_id);
-H5_DLL href_t H5Rcreate_ext_attr(hid_t loc_id, const char *name, const char *attr_name);
+H5_DLL href_t H5Rcreate_ext_object(const char *filename, const char *pathname);
+H5_DLL href_t H5Rcreate_ext_region(const char *filename, const char *pathname, hid_t space_id);
+H5_DLL href_t H5Rcreate_ext_attr(const char *filename, const char *pathname, const char *attr_name);
 H5_DLL herr_t H5Rdestroy(href_t ref);
 
 H5_DLL H5R_type_t H5Rget_type(href_t ref);
 H5_DLL htri_t     H5Requal(href_t ref1, href_t ref2);
 
-H5_DLL hid_t      H5Rdereference3(hid_t obj_id, hid_t oapl_id, href_t ref);
+H5_DLL hid_t      H5Rget_object(hid_t loc_id, hid_t oapl_id, href_t ref);
 H5_DLL hid_t      H5Rget_region2(hid_t loc_id, href_t ref);
+H5_DLL hid_t      H5Rget_attr(hid_t loc_id, href_t ref);
+
 H5_DLL herr_t     H5Rget_obj_type3(hid_t loc_id, href_t ref, H5O_type_t *obj_type);
 H5_DLL ssize_t    H5Rget_obj_name(hid_t loc_id, href_t ref, char *name/*out*/, size_t size);
 H5_DLL ssize_t    H5Rget_attr_name(hid_t loc_id, href_t ref, char *name/*out*/, size_t size);
@@ -78,6 +80,7 @@ H5_DLL ssize_t    H5Rget_file_name(href_t ref, char *name/*out*/, size_t size);
 #ifndef H5_NO_DEPRECATED_SYMBOLS
 
 /* Macros */
+#define H5R_DATASET_REGION H5R_REGION_COMPAT
 
 /* Typedefs */