[svn-r13041] Description:

    Migrate "internalish" attribute operations into new source code file.

    Add test & basic support for opening attributes in dense storage (shared
attributes not tested or supported yet).

Tested on:
    Linux/32 2.6 (chicago)
    Linux/64 2.6 (chicago2)

10 files changed, 1106 insertions, 702 deletions

diff --git a/src/H5A.c b/src/H5A.c
index d4ca21b..a7aa381 100644
--- a/src/H5A.c
+++ b/src/H5A.c
@@ -17,6 +17,7 @@
 /****************/
 
 #define H5A_PACKAGE		/*suppress error about including H5Apkg	*/
+#define H5O_PACKAGE		/*suppress error about including H5Opkg	*/
 
 /* Interface initialization */
 #define H5_INTERFACE_INIT_FUNC	H5A_init_interface
@@ -31,6 +32,7 @@
 #include "H5FLprivate.h"	/* Free Lists				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MMprivate.h"	/* Memory management			*/
+#include "H5Opkg.h"             /* Object headers			*/
 #include "H5Sprivate.h"		/* Dataspace functions			*/
 #include "H5SMprivate.h"	/* Shared Object Header Messages	*/
 
@@ -64,8 +66,10 @@ typedef struct H5A_iter_cb1 {
 /********************/
 
 static hid_t H5A_create(const H5G_loc_t *loc, const char *name,
-			const H5T_t *type, const H5S_t *space, hid_t acpl_id, hid_t dxpl_id);
+    const H5T_t *type, const H5S_t *space, hid_t acpl_id, hid_t dxpl_id);
 static hid_t H5A_open(H5G_loc_t *loc, unsigned idx, hid_t dxpl_id);
+static H5A_t *H5A_open_by_name(const H5G_loc_t *loc, const char *name,
+    hid_t dxpl_id);
 static herr_t H5A_write(H5A_t *attr, const H5T_t *mem_type, const void *buf, hid_t dxpl_id);
 static herr_t H5A_read(const H5A_t *attr, const H5T_t *mem_type, void *buf, hid_t dxpl_id);
 static int H5A_get_index(H5O_loc_t *loc, const char *name, hid_t dxpl_id);
@@ -548,7 +552,7 @@ hid_t
 H5Aopen_name(hid_t loc_id, const char *name)
 {
     H5G_loc_t    	loc;            /* Object location */
-    int            	idx;
+    H5A_t               *attr = NULL;   /* Attribute opened */
     hid_t		ret_value;
 
     FUNC_ENTER_API(H5Aopen_name, FAIL)
@@ -562,13 +566,13 @@ H5Aopen_name(hid_t loc_id, const char *name)
     if(!name || !*name)
 	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")
 
-    /* Look up the attribute for the object */
-    if((idx = H5A_get_index(loc.oloc, name, H5AC_ind_dxpl_id)) < 0)
-        HGOTO_ERROR(H5E_ATTR, H5E_BADVALUE, FAIL, "attribute not found")
+    /* Open the attribute on the object header */
+    if(NULL == (attr = H5A_open_by_name(&loc, name, H5AC_ind_dxpl_id)))
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, FAIL, "can't open attribute")
 
-    /* Go do the real work for opening the attribute */
-    if((ret_value = H5A_open(&loc, (unsigned)idx, H5AC_dxpl_id)) < 0)
-	HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, FAIL, "unable to open attribute")
+    /* Register the attribute and get an ID for it */
+    if((ret_value = H5I_register(H5I_ATTR, attr)) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to register attribute for ID")
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -676,7 +680,7 @@ H5A_open(H5G_loc_t *loc, unsigned idx, hid_t dxpl_id)
         HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, FAIL, "unable to open")
     attr->obj_opened = TRUE;
 
-    /* Register the new attribute and get an ID for it */
+    /* Register the attribute and get an ID for it */
     if((ret_value = H5I_register(H5I_ATTR, attr)) < 0)
         HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to register attribute for ID")
 
@@ -690,6 +694,77 @@ done:
 } /* H5A_open() */
 
 
+/*-------------------------------------------------------------------------
+ * Function:	H5A_open_by_name
+ *
+ * Purpose:
+ *      Open an attribute in an object header, according to it's name
+ *      
+ * Usage:
+ *  herr_t H5A_open(loc, name, dxpl_id)
+ *      const H5G_loc_t *loc;   IN: Pointer to group location for object
+ *      const char *name;       IN: Name of attribute to open
+ *      hid_t dxpl_id;          IN: DXPL for operation
+ *
+ * Return: Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		December 11, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static H5A_t *
+H5A_open_by_name(const H5G_loc_t *loc, const char *name, hid_t dxpl_id)
+{
+    H5A_t       *attr = NULL;   /* Attribute from object header */
+    H5A_t       *ret_value;     /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5A_open_by_name)
+
+    /* check args */
+    HDassert(loc);
+    HDassert(name);
+
+    /* Read in attribute from object header */
+    if(NULL == (attr = H5O_attr_open(loc->oloc, name, dxpl_id)))
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, NULL, "unable to load attribute info from object header")
+    attr->initialized = TRUE;
+
+#if defined(H5_USING_PURIFY) || !defined(NDEBUG)
+    /* Clear object location */
+    if(H5O_loc_reset(&(attr->oloc)) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to reset location")
+
+    /* Clear path name */
+    if(H5G_name_reset(&(attr->path)) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to reset path")
+#endif /* H5_USING_PURIFY */
+
+    /* Deep copy of the symbol table entry */
+    if(H5O_loc_copy(&(attr->oloc), loc->oloc, H5_COPY_DEEP) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to copy entry")
+
+    /* Deep copy of the group hier. path */
+    if(H5G_name_copy(&(attr->path), loc->path, H5_COPY_DEEP) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to copy entry")
+
+    /* Hold the symbol table entry (and file) open */
+    if(H5O_open(&(attr->oloc)) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to open")
+    attr->obj_opened = TRUE;
+
+    /* Set return value */
+    ret_value = attr;
+
+done:
+    /* Cleanup on failure */
+    if(ret_value == NULL && attr)
+        (void)H5A_close(attr);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5A_open_by_name() */
+
+
 /*--------------------------------------------------------------------------
  NAME
     H5Awrite
@@ -1200,14 +1275,14 @@ H5Aget_name(hid_t attr_id, size_t buf_size, char *buf)
 
         /* Terminate the string */
         buf[copy_len]='\0';
-    }
+    } /* end if */
 
     /* Set return value */
     ret_value = (ssize_t)nbytes;
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* H5Aget_type() */
+} /* H5Aget_name() */
 
 
 /*-------------------------------------------------------------------------
@@ -1511,9 +1586,12 @@ H5A_copy(H5A_t *_new_attr, const H5A_t *old_attr)
     new_attr->obj_opened = FALSE;
 
     /* Copy the guts of the attribute */
-    new_attr->name = H5MM_xstrdup(old_attr->name);
-    new_attr->dt = H5T_copy(old_attr->dt, H5T_COPY_ALL);
-    new_attr->ds = H5S_copy(old_attr->ds, FALSE);
+    if(NULL == (new_attr->name = H5MM_xstrdup(old_attr->name)))
+	HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, NULL, "unable to copy attribute name")
+    if(NULL == (new_attr->dt = H5T_copy(old_attr->dt, H5T_COPY_ALL)))
+	HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, NULL, "unable to copy attribute datatype")
+    if(NULL == (new_attr->ds = H5S_copy(old_attr->ds, FALSE)))
+	HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, NULL, "unable to copy attribute dataspace")
     /* XXX: Copy the object location and group path? -QAK */
 
     /* Copy the attribute data, if there is any */
@@ -1530,10 +1608,9 @@ H5A_copy(H5A_t *_new_attr, const H5A_t *old_attr)
     ret_value = new_attr;
 
 done:
-    if(ret_value == NULL) {
+    if(ret_value == NULL)
         if(new_attr != NULL && allocated_attr)
             (void)H5A_close(new_attr);
-    } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5A_copy() */
diff --git a/src/H5Adense.c b/src/H5Adense.c
index 7cacf13..b374e79 100644
--- a/src/H5Adense.c
+++ b/src/H5Adense.c
@@ -249,6 +249,100 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5A_dense_open_cb
+ *
+ * Purpose:	Callback when an attribute is located in an index
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Dec 11 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5A_dense_open_cb(const void *_attr, void *_user_attr)
+{
+    const H5A_t *attr = (const H5A_t *)_attr; /* Record from B-tree */
+    H5A_t **user_attr = (H5A_t **)_user_attr; /* User data from v2 B-tree attribute lookup */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5A_dense_open_cb)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(attr);
+    HDassert(user_attr);
+
+    /* Copy attribute information */
+    if(NULL == (*user_attr = H5A_copy(NULL, attr)))
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, H5_ITER_ERROR, "can't copy attribute")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5A_dense_open_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5A_dense_open
+ *
+ * Purpose:	Open an attribute in dense storage structures for an object
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Dec 11 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+H5A_t *
+H5A_dense_open(H5F_t *f, hid_t dxpl_id, const H5O_t *oh, const char *name)
+{
+    H5A_bt2_ud_common_t udata;          /* User data for v2 B-tree modify */
+    H5HF_t *fheap = NULL;               /* Fractal heap handle */
+    H5A_t *ret_value = NULL;            /* Return value */
+
+    FUNC_ENTER_NOAPI(H5A_dense_open, NULL)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(f);
+    HDassert(oh);
+    HDassert(name);
+
+    /* Open the fractal heap */
+    if(NULL == (fheap = H5HF_open(f, dxpl_id, oh->attr_fheap_addr)))
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to open fractal heap")
+
+    /* Create the "udata" information for v2 B-tree record modify */
+    udata.f = f;
+    udata.dxpl_id = dxpl_id;
+    udata.fheap = fheap;
+    udata.name = name;
+    udata.name_hash = H5_checksum_lookup3(name, HDstrlen(name), 0);
+    udata.flags = 0;
+    udata.corder = -1;   /* XXX: None yet */
+    udata.found_op = H5A_dense_open_cb;       /* v2 B-tree comparison callback */
+    udata.found_op_data = &ret_value;
+
+    /* Find & copy the attribute in the 'name' index */
+    if(H5B2_find(f, dxpl_id, H5A_BT2_NAME, oh->name_bt2_addr, &udata, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, NULL, "can't locate attribute in name index")
+
+done:
+    /* Release resources */
+    if(fheap && H5HF_close(fheap, dxpl_id) < 0)
+        HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, NULL, "can't close fractal heap")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5A_dense_open() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5A_dense_insert
  *
  * Purpose:	Insert an attribute into dense storage structures for an object
diff --git a/src/H5Apkg.h b/src/H5Apkg.h
index a8a7dd7..754c215 100644
--- a/src/H5Apkg.h
+++ b/src/H5Apkg.h
@@ -140,11 +140,17 @@ H5_DLL herr_t H5A_free(H5A_t *attr);
 H5_DLL herr_t H5A_close(H5A_t *attr);
 
 /* Attribute "dense" storage routines */
+H5_DLL H5A_t *H5A_dense_open(H5F_t *f, hid_t dxpl_id, const H5O_t *oh,
+    const char *name);
 H5_DLL herr_t H5A_dense_write(H5F_t *f, hid_t dxpl_id, const H5O_t *oh,
     const H5A_t *attr);
 H5_DLL herr_t H5A_dense_iterate(H5F_t *f, hid_t dxpl_id, hid_t loc_id,
     haddr_t attr_fheap_addr, haddr_t name_bt2_addr, unsigned skip,
     unsigned *last_attr, H5A_operator_t op, void *op_data);
 
+/* Attribute object header routines */
+H5_DLL herr_t H5O_attr_reset(void *_mesg);
+H5_DLL herr_t H5O_attr_get_share(const void *_mesg, H5O_shared_t *sh);
+
 #endif /* _H5Apkg_H */
 
diff --git a/src/H5Gdense.c b/src/H5Gdense.c
index cd0b242..86f8353 100644
--- a/src/H5Gdense.c
+++ b/src/H5Gdense.c
@@ -482,12 +482,9 @@ H5G_dense_lookup_cb(const void *_lnk, void *_user_lnk)
     HDassert(lnk);
     HDassert(user_lnk);
 
-    /* Check if we want the link information */
-    if(user_lnk) {
-        /* Copy link information */
-        if(H5O_msg_copy(H5O_LINK_ID, lnk, user_lnk) == NULL)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTCOPY, H5_ITER_ERROR, "can't copy link message")
-    } /* end if */
+    /* Copy link information */
+    if(H5O_msg_copy(H5O_LINK_ID, lnk, user_lnk) == NULL)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTCOPY, H5_ITER_ERROR, "can't copy link message")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5Oattr.c b/src/H5Oattr.c
index 9e22011..5c1aba8 100644
--- a/src/H5Oattr.c
+++ b/src/H5Oattr.c
@@ -21,63 +21,17 @@
 #include "H5Apkg.h"		/* Attributes				*/
 #include "H5Dprivate.h"		/* Datasets				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5FLprivate.h"	/* Free Lists				*/
-#include "H5Gprivate.h"		/* Groups				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MMprivate.h"	/* Memory management			*/
 #include "H5Opkg.h"             /* Object headers			*/
 #include "H5Spkg.h"		/* Dataspaces				*/
 #include "H5SMprivate.h"	/* Shared Object Header Messages	*/
 
-/* User data for iteration when converting attributes to dense storage */
-typedef struct {
-    H5F_t      *f;              /* Pointer to file for insertion */
-    hid_t dxpl_id;              /* DXPL during iteration */
-} H5O_iter_cvt_t;
-
-/* User data for iteration when updating an attribute */
-typedef struct {
-    /* down */
-    H5F_t *f;                   /* Pointer to file attribute is in */
-    hid_t dxpl_id;              /* DXPL for operation */
-    H5A_t *attr;                /* Attribute data to update object header with */
-
-    /* up */
-    hbool_t found;              /* Whether the attribute was found */
-} H5O_iter_wrt_t;
-
-/* User data for iteration when renaming an attribute */
-typedef struct {
-    /* down */
-    H5F_t *f;                   /* Pointer to file attribute is in */
-    hid_t dxpl_id;              /* DXPL for operation */
-    const char *old_name;       /* Old name of attribute */
-    const char *new_name;       /* New name of attribute */
-
-    /* up */
-    hbool_t found;              /* Whether the attribute was found */
-} H5O_iter_ren_t;
-
-/* User data for iteration when iterating over attributes */
-typedef struct {
-    /* down */
-    H5F_t *f;                   /* Pointer to file attribute is in */
-    hid_t dxpl_id;              /* DXPL for operation */
-    hid_t loc_id;               /* ID of object being iterated over */
-    unsigned skip;              /* # of attributes to skip over */
-    H5A_operator_t op;          /* Callback routine for each attribute */
-    void *op_data;              /* User data for callback */
-
-    /* up */
-    unsigned count;             /* Count of attributes examined */
-} H5O_iter_itr_t;
-
 /* PRIVATE PROTOTYPES */
 static herr_t H5O_attr_encode(H5F_t *f, uint8_t *p, const void *mesg);
 static void *H5O_attr_decode(H5F_t *f, hid_t dxpl_id, const uint8_t *p);
 static void *H5O_attr_copy(const void *_mesg, void *_dest);
 static size_t H5O_attr_size(const H5F_t *f, const void *_mesg);
-static herr_t H5O_attr_reset(void *_mesg);
 static herr_t H5O_attr_free(void *mesg);
 static herr_t H5O_attr_delete(H5F_t *f, hid_t dxpl_id, const void *_mesg, hbool_t adj_link);
 static herr_t H5O_attr_link(H5F_t *f, hid_t dxpl_id, const void *_mesg);
@@ -86,7 +40,6 @@ static herr_t H5O_attr_pre_copy_file(H5F_t *file_src, const H5O_msg_class_t *typ
 static void *H5O_attr_copy_file(H5F_t *file_src, const H5O_msg_class_t *mesg_type,
     void *native_src, H5F_t *file_dst, hid_t dxpl_id, H5O_copy_t *cpy_info,
     void *udata);
-static herr_t H5O_attr_get_share(const void *_mesg, H5O_shared_t *sh);
 static herr_t H5O_attr_set_share(void *_mesg, const H5O_shared_t *sh);
 static htri_t H5O_attr_is_shared(const void *_mesg);
 static herr_t H5O_attr_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
@@ -639,7 +592,7 @@ H5O_attr_size(const H5F_t *f, const void *_mesg)
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
+herr_t
 H5O_attr_reset(void *_mesg)
 {
     H5A_t                  *attr = (H5A_t *)_mesg;
@@ -1098,7 +1051,7 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
+herr_t
 H5O_attr_get_share(const void *_mesg, H5O_shared_t *sh /*out*/)
 {
     const H5A_t  *mesg = (const H5A_t *)_mesg;
@@ -1271,620 +1224,3 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5O_attr_debug() */
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5O_msg_attr_to_dense_cb
- *
- * Purpose:	Object header iterator callback routine to convert compact
- *              attributes to dense attributes
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Dec  4 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5A_attr_to_dense_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
-    unsigned UNUSED sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/)
-{
-    H5O_iter_cvt_t *udata = (H5O_iter_cvt_t *)_udata;   /* Operator user data */
-    herr_t ret_value = H5_ITER_CONT;   /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5A_attr_to_dense_cb)
-
-    /* check args */
-    HDassert(oh);
-    HDassert(mesg);
-
-    /* Insert attribute into dense storage */
-    if(H5A_dense_insert(udata->f, udata->dxpl_id, oh, mesg->flags, mesg->native) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, H5_ITER_ERROR, "unable to add to dense storage")
-
-    /* Convert message into a null message */
-    if(H5O_release_mesg(udata->f, udata->dxpl_id, oh, mesg, TRUE, FALSE) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, H5_ITER_ERROR, "unable to convert into null message")
-
-    /* Indicate that the object header was modified */
-    *oh_flags_ptr |= H5AC__DIRTIED_FLAG;
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5A_attr_to_dense_cb() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5O_attr_create
- *
- * Purpose:	Create a new attribute in the object header.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		Friday, December  8, 2006
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5O_attr_create(const H5O_loc_t *loc, hid_t dxpl_id, H5A_t *attr)
-{
-    H5O_t *oh = NULL;                   /* Pointer to actual object header */
-    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Metadata cache flags for object header */
-    unsigned mesg_flags = 0;            /* Flags for storing message */
-    htri_t shared_mesg;                 /* Should this message be stored in the Shared Message table? */
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_create)
-
-    /* Check arguments */
-    HDassert(loc);
-    HDassert(attr);
-
-    /* Should this message be written as a SOHM? */
-    if((shared_mesg = H5SM_try_share(loc->file, dxpl_id, H5O_ATTR_ID, attr)) > 0)
-        /* Mark the message as shared */
-        mesg_flags |= H5O_MSG_FLAG_SHARED;
-    else if(shared_mesg < 0)
-	HGOTO_ERROR(H5E_ATTR, H5E_WRITEERROR, FAIL, "error determining if message should be shared")
-
-    /* Protect the object header to iterate over */
-    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
-	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, FAIL, "unable to load object header")
-
-#ifdef QAK
-HDfprintf(stderr, "%s: adding attribute to new-style object header\n", FUNC);
-HDfprintf(stderr, "%s: oh->nattrs = %Hu\n", FUNC, oh->nattrs);
-HDfprintf(stderr, "%s: oh->max_compact = %u\n", FUNC, oh->max_compact);
-HDfprintf(stderr, "%s: oh->min_dense = %u\n", FUNC, oh->min_dense);
-#endif /* QAK */
-    /* Check for switching to "dense" attribute storage */
-    if(oh->version > H5O_VERSION_1 && oh->nattrs == oh->max_compact &&
-            !H5F_addr_defined(oh->attr_fheap_addr)) {
-        H5O_iter_cvt_t udata;           /* User data for callback */
-        H5O_mesg_operator_t op;         /* Wrapper for operator */
-#ifdef QAK
-HDfprintf(stderr, "%s: converting attributes to dense storage\n", FUNC);
-#endif /* QAK */
-
-        /* Create dense storage for attributes */
-        if(H5A_dense_create(loc->file, dxpl_id, oh) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to create dense storage for attributes")
-
-        /* Set up user data for callback */
-        udata.f = loc->file;
-        udata.dxpl_id = dxpl_id;
-
-        /* Iterate over existing attributes, moving them to dense storage */
-        op.lib_op = H5A_attr_to_dense_cb;
-        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
-            HGOTO_ERROR(H5E_ATTR, H5E_CANTCONVERT, FAIL, "error converting attributes to dense storage")
-    } /* end if */
-
-    /* Increment attribute count */
-    oh->nattrs++;
-
-    /* Check for storing attribute with dense storage */
-    if(H5F_addr_defined(oh->attr_fheap_addr)) {
-        /* Insert attribute into dense storage */
-#ifdef QAK
-HDfprintf(stderr, "%s: inserting attribute to dense storage\n", FUNC);
-#endif /* QAK */
-        if(H5A_dense_insert(loc->file, dxpl_id, oh, mesg_flags, attr) < 0)
-            HGOTO_ERROR(H5E_ATTR, H5E_CANTINSERT, FAIL, "unable to add to dense storage")
-    } /* end if */
-    else {
-        /* Append new message to object header */
-        if(H5O_msg_append_real(loc->file, dxpl_id, oh, H5O_MSG_ATTR, mesg_flags, 0, attr, &oh_flags) < 0)
-            HGOTO_ERROR(H5E_ATTR, H5E_CANTINSERT, FAIL, "unable to create new attribute in header")
-    } /* end else */
-
-    /* Update the modification time, if any */
-    if(H5O_touch_oh(loc->file, dxpl_id, oh, FALSE, &oh_flags) < 0)
-        HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
-
-done:
-    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
-        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, FAIL, "unable to release object header")
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_attr_create */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5O_attr_write_cb
- *
- * Purpose:	Object header iterator callback routine to update an
- *              attribute stored compactly.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Dec  4 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5O_attr_write_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
-    unsigned UNUSED sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/)
-{
-    H5O_iter_wrt_t *udata = (H5O_iter_wrt_t *)_udata;   /* Operator user data */
-    herr_t ret_value = H5_ITER_CONT;   /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_write_cb)
-
-    /* check args */
-    HDassert(oh);
-    HDassert(mesg);
-    HDassert(!udata->found);
-
-    /* Check for shared message */
-    if(mesg->flags & H5O_MSG_FLAG_SHARED) {
-        H5A_t shared_attr;             /* Copy of shared attribute */
-
-	/*
-	 * If the message is shared then then the native pointer points to an
-	 * H5O_MSG_SHARED message.  We use that information to look up the real
-	 * message in the global heap or some other object header.
-	 */
-        if(NULL == H5O_shared_read(udata->f, udata->dxpl_id, mesg->native, H5O_MSG_ATTR, &shared_attr))
-	    HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5_ITER_ERROR, "unable to read shared attribute")
-
-        /* Check for correct attribute message to modify */
-        if(HDstrcmp(shared_attr.name, udata->attr->name) == 0) {
-            htri_t shared_mesg;         /* Whether the message should be shared */
-
-            /* Store new version of message as a SOHM */
-            /* (should always work, since we're not changing the size of the attribute) */
-            if((shared_mesg = H5SM_try_share(udata->f, udata->dxpl_id, H5O_ATTR_ID, udata->attr)) == 0)
-                HGOTO_ERROR(H5E_ATTR, H5E_BADMESG, H5_ITER_ERROR, "attribute changed sharing status")
-            else if(shared_mesg < 0)
-                HGOTO_ERROR(H5E_ATTR, H5E_BADMESG, H5_ITER_ERROR, "can't share attribute")
-
-            /* Remove the old attribut from the SOHM index */
-            if(H5SM_try_delete(udata->f, udata->dxpl_id, H5O_ATTR_ID, mesg->native) < 0)
-                HGOTO_ERROR(H5E_ATTR, H5E_CANTFREE, H5_ITER_ERROR, "unable to delete shared attribute in shared storage")
-
-            /* Extract shared message info from current attribute */
-            if(H5O_attr_get_share(udata->attr, mesg->native) < 0)
-                HGOTO_ERROR(H5E_ATTR, H5E_BADMESG, H5_ITER_ERROR, "can't get shared info")
-
-            /* Indicate that we found the correct attribute */
-            udata->found = TRUE;
-        } /* end if */
-
-        /* Release copy of shared attribute */
-        H5O_attr_reset(&shared_attr);
-    } /* end if */
-    else {
-        /* Check for correct attribute message to modify */
-        if(HDstrcmp(((H5A_t *)mesg->native)->name, udata->attr->name) == 0) {
-            /* Allocate storage for the message's data, if necessary */
-            if(((H5A_t *)mesg->native)->data == NULL)
-                if(NULL == (((H5A_t *)mesg->native)->data = H5FL_BLK_MALLOC(attr_buf, udata->attr->data_size)))
-                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, H5_ITER_ERROR, "memory allocation failed")
-
-            /* Copy the data */
-            HDmemcpy(((H5A_t *)mesg->native)->data, udata->attr->data, udata->attr->data_size);
-
-            /* Indicate that we found the correct attribute */
-            udata->found = TRUE;
-        } /* end if */
-    } /* end else */
-
-    /* Set common info, if we found the correct attribute */
-    if(udata->found) {
-        /* Mark message as dirty */
-        mesg->dirty = TRUE;
-
-        /* Stop iterating */
-        ret_value = H5_ITER_STOP;
-
-        /* Indicate that the object header was modified */
-        *oh_flags_ptr |= H5AC__DIRTIED_FLAG;
-    } /* end if */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_attr_write_cb() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5O_attr_write
- *
- * Purpose:	Write a new value to an attribute.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		Monday, December  4, 2006
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5O_attr_write(const H5O_loc_t *loc, hid_t dxpl_id, H5A_t *attr)
-{
-    H5O_t *oh = NULL;                   /* Pointer to actual object header */
-    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Metadata cache flags for object header */
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_write)
-
-    /* Check arguments */
-    HDassert(loc);
-    HDassert(attr);
-
-    /* Protect the object header to iterate over */
-    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
-	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, FAIL, "unable to load object header")
-
-    /* Check for attributes stored densely */
-    if(H5F_addr_defined(oh->attr_fheap_addr)) {
-        /* Modify the attribute data in dense storage */
-        if(H5A_dense_write(loc->file, dxpl_id, oh, attr) < 0)
-            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "error updating attribute")
-    } /* end if */
-    else {
-        H5O_iter_wrt_t udata;           /* User data for callback */
-        H5O_mesg_operator_t op;         /* Wrapper for operator */
-
-        /* Set up user data for callback */
-        udata.f = loc->file;
-        udata.dxpl_id = dxpl_id;
-        udata.attr = attr;
-        udata.found = FALSE;
-
-        /* Iterate over attributes, to locate correct one to update */
-        op.lib_op = H5O_attr_write_cb;
-        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
-            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "error updating attribute")
-
-        /* Check that we found the attribute */
-        if(!udata.found)
-            HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, FAIL, "can't locate open attribute?")
-    } /* end else */
-
-    /* Update the modification time, if any */
-    if(H5O_touch_oh(loc->file, dxpl_id, oh, FALSE, &oh_flags) < 0)
-        HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
-
-done:
-    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
-        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, FAIL, "unable to release object header")
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_attr_write */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5O_attr_rename_dup_cb
- *
- * Purpose:	Object header iterator callback routine to check for
- *              duplicate name during rename
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Dec  5 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5O_attr_rename_dup_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
-    unsigned UNUSED sequence, unsigned UNUSED *oh_flags_ptr, void *_udata/*in,out*/)
-{
-    H5O_iter_ren_t *udata = (H5O_iter_ren_t *)_udata;   /* Operator user data */
-    herr_t ret_value = H5_ITER_CONT;   /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_rename_dup_cb)
-
-    /* check args */
-    HDassert(oh);
-    HDassert(mesg);
-    HDassert(!udata->found);
-
-    /* Check for shared message */
-    if(mesg->flags & H5O_MSG_FLAG_SHARED) {
-        H5A_t shared_attr;              /* Copy of shared attribute */
-
-	/*
-	 * If the message is shared then then the native pointer points to an
-	 * H5O_MSG_SHARED message.  We use that information to look up the real
-	 * message in the global heap or some other object header.
-	 */
-        if(NULL == H5O_shared_read(udata->f, udata->dxpl_id, mesg->native, H5O_MSG_ATTR, &shared_attr))
-	    HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5_ITER_ERROR, "unable to read shared attribute")
-
-        /* Check for existing attribute with new name */
-        if(HDstrcmp(shared_attr.name, udata->new_name) == 0) {
-            /* Indicate that we found an existing attribute with the new name*/
-            udata->found = TRUE;
-
-            /* Stop iterating */
-            ret_value = H5_ITER_STOP;
-        } /* end if */
-
-        /* Release copy of shared attribute */
-        H5O_attr_reset(&shared_attr);
-    } /* end if */
-    else {
-        /* Check for existing attribute with new name */
-        if(HDstrcmp(((H5A_t *)mesg->native)->name, udata->new_name) == 0) {
-            /* Indicate that we found an existing attribute with the new name*/
-            udata->found = TRUE;
-
-            /* Stop iterating */
-            ret_value = H5_ITER_STOP;
-        } /* end if */
-    } /* end else */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_attr_rename_dup_cb() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5O_attr_rename_mod_cb
- *
- * Purpose:	Object header iterator callback routine to change name of
- *              attribute during rename
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Dec  5 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5O_attr_rename_mod_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
-    unsigned UNUSED sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/)
-{
-    H5O_iter_ren_t *udata = (H5O_iter_ren_t *)_udata;   /* Operator user data */
-    herr_t ret_value = H5_ITER_CONT;   /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_rename_mod_cb)
-
-    /* check args */
-    HDassert(oh);
-    HDassert(mesg);
-    HDassert(!udata->found);
-
-    /* Check for shared message */
-    if(mesg->flags & H5O_MSG_FLAG_SHARED) {
-        H5A_t shared_attr;             /* Copy of shared attribute */
-
-	/*
-	 * If the message is shared then then the native pointer points to an
-	 * H5O_MSG_SHARED message.  We use that information to look up the real
-	 * message in the global heap or some other object header.
-	 */
-        if(NULL == H5O_shared_read(udata->f, udata->dxpl_id, mesg->native, H5O_MSG_ATTR, &shared_attr))
-	    HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5_ITER_ERROR, "unable to read shared attribute")
-
-        /* Check for correct attribute message to modify */
-        if(HDstrcmp(shared_attr.name, udata->old_name) == 0) {
-/* XXX: fix me */
-HDfprintf(stderr, "%s: renaming a shared attribute not supported yet!\n", FUNC);
-HGOTO_ERROR(H5E_ATTR, H5E_UNSUPPORTED, H5_ITER_ERROR, "renaming a shared attribute not supported yet")
-        } /* end if */
-
-        /* Release copy of shared attribute */
-        H5O_attr_reset(&shared_attr);
-    } /* end if */
-    else {
-        /* Find correct attribute message to rename */
-        if(HDstrcmp(((H5A_t *)mesg->native)->name, udata->old_name) == 0) {
-            /* Change the name for the attribute */
-            H5MM_xfree(((H5A_t *)mesg->native)->name);
-            ((H5A_t *)mesg->native)->name = H5MM_xstrdup(udata->new_name);
-
-            /* Indicate that we found an existing attribute with the old name*/
-            udata->found = TRUE;
-
-            /* Mark message as dirty */
-            mesg->dirty = TRUE;
-
-            /* Stop iterating */
-            ret_value = H5_ITER_STOP;
-
-            /* Indicate that the object header was modified */
-            *oh_flags_ptr |= H5AC__DIRTIED_FLAG;
-        } /* end if */
-    } /* end else */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_attr_rename_mod_cb() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5O_attr_rename
- *
- * Purpose:	Rename an attribute.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		Tuesday, December  5, 2006
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5O_attr_rename(const H5O_loc_t *loc, hid_t dxpl_id, const char *old_name, const char *new_name)
-{
-    H5O_t *oh = NULL;                   /* Pointer to actual object header */
-    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Metadata cache flags for object header */
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_rename)
-
-    /* Check arguments */
-    HDassert(loc);
-    HDassert(old_name);
-    HDassert(new_name);
-
-    /* Protect the object header to iterate over */
-    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
-	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, FAIL, "unable to load object header")
-
-    /* Check for attributes stored densely */
-    if(H5F_addr_defined(oh->attr_fheap_addr)) {
-/* XXX: fix me */
-HDfprintf(stderr, "%s: renaming attributes in dense storage not supported yet!\n", FUNC);
-HGOTO_ERROR(H5E_ATTR, H5E_UNSUPPORTED, FAIL, "renaming attributes in dense storage not supported yet")
-    } /* end if */
-    else {
-        H5O_iter_ren_t udata;           /* User data for callback */
-        H5O_mesg_operator_t op;         /* Wrapper for operator */
-
-        /* Set up user data for callback */
-        udata.f = loc->file;
-        udata.dxpl_id = dxpl_id;
-        udata.old_name = old_name;
-        udata.new_name = new_name;
-        udata.found = FALSE;
-
-        /* Iterate over attributes, to check if "new name" exists already */
-        op.lib_op = H5O_attr_rename_dup_cb;
-        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
-            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "error updating attribute")
-
-        /* If the new name was found, indicate an error */
-        if(udata.found)
-            HGOTO_ERROR(H5E_ATTR, H5E_EXISTS, FAIL, "attribute with new name already exists")
-
-        /* Iterate over attributes again, to actually rename attribute with old name */
-        op.lib_op = H5O_attr_rename_mod_cb;
-        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
-            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "error updating attribute")
-    } /* end else */
-
-    /* Update the modification time, if any */
-    if(H5O_touch_oh(loc->file, dxpl_id, oh, FALSE, &oh_flags) < 0)
-        HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
-
-done:
-    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
-        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, FAIL, "unable to release object header")
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_attr_rename */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5O_attr_iterate
- *
- * Purpose:	Iterate over attributes for an object.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		Tuesday, December  5, 2006
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5O_attr_iterate(hid_t loc_id, const H5O_loc_t *loc, hid_t dxpl_id,
-    unsigned skip, unsigned *last_attr, H5A_operator_t op, void *op_data)
-{
-    H5O_t *oh = NULL;                   /* Pointer to actual object header */
-    haddr_t attr_fheap_addr;            /* Address of fractal heap for dense attribute storage */
-    haddr_t name_bt2_addr;              /* Address of v2 B-tree for name index on dense attribute storage */
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_iterate)
-
-    /* Check arguments */
-    HDassert(loc);
-    HDassert(op);
-
-    /* Protect the object header to iterate over */
-    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_READ)))
-	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, FAIL, "unable to load object header")
-
-    /* Retrieve the information about dense attribute storage */
-    if(oh->version > H5O_VERSION_1 && H5F_addr_defined(oh->attr_fheap_addr)) {
-        attr_fheap_addr = oh->attr_fheap_addr;
-        name_bt2_addr = oh->name_bt2_addr;
-    } /* end if */
-    else
-        attr_fheap_addr = name_bt2_addr = HADDR_UNDEF;
-
-    /* Release the object header */
-    if(H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, H5AC__NO_FLAGS_SET) < 0)
-        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, FAIL, "unable to release object header")
-    oh = NULL;
-
-    /* Check for attributes stored densely */
-    if(H5F_addr_defined(attr_fheap_addr)) {
-        if((ret_value = H5A_dense_iterate(loc->file, dxpl_id, loc_id, attr_fheap_addr,
-                name_bt2_addr, skip, last_attr, op, op_data)) < 0)
-            HERROR(H5E_ATTR, H5E_BADITER, "error iterating over attributes");
-    } /* end if */
-    else {
-        unsigned idx;           /* Current attribute to operate on */
-
-        /* Check for skipping over too many attributes */
-        if((int)skip < H5O_msg_count(loc, H5O_ATTR_ID, dxpl_id)) {
-            H5A_t found_attr;           /* Copy of attribute for callback */
-
-            /* Read each attribute and call application's callback */
-            /* (this could be made more efficient by iterating over the
-             *  attribute header messages with H5O_msg_iterate, but then
-             *  the object header would be locked during the callback into
-             *  the application code, causing problems if they attempt to
-             *  do anything with the object the attribute is on - QAK)
-             */
-            idx = skip;
-            while(H5O_msg_read(loc, H5O_ATTR_ID, (int)idx, &found_attr, dxpl_id) != NULL) {
-                /* Call application's callback */
-                idx++;
-                if((ret_value = (op)(loc_id, found_attr.name, op_data)) != 0) {
-                    H5A_free(&found_attr);
-                    break;
-                } /* end if */
-                H5A_free(&found_attr);
-            } /* end while */
-
-            /* Clear error stack from running off end of attributes */
-            if(ret_value == 0)
-                H5E_clear_stack(NULL);
-        } /* end if */
-        else
-            if(skip > 0)
-                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index specified")
-
-        /* Update last attribute looked at */
-        if(last_attr)
-            *last_attr = idx;
-    } /* end else */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_attr_iterate */
-
diff --git a/src/H5Oattribute.c b/src/H5Oattribute.c
new file mode 100644
index 0000000..3c440b6
--- /dev/null
+++ b/src/H5Oattribute.c
@@ -0,0 +1,892 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5Oattribute.c
+ *			Dec 11 2006
+ *			Quincey Koziol <koziol@hdfgroup.org>
+ *
+ * Purpose:		Object header attribute routines.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5A_PACKAGE		/*suppress error about including H5Apkg	  */
+#define H5O_PACKAGE		/*suppress error about including H5Opkg	  */
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Apkg.h"		/* Attributes	  			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5MMprivate.h"	/* Memory management			*/
+#include "H5Opkg.h"             /* Object headers			*/
+#include "H5SMprivate.h"	/* Shared Object Header Messages	*/
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+/* User data for iteration when converting attributes to dense storage */
+typedef struct {
+    H5F_t      *f;              /* Pointer to file for insertion */
+    hid_t dxpl_id;              /* DXPL during iteration */
+} H5O_iter_cvt_t;
+
+/* User data for iteration when opening an attribute */
+typedef struct {
+    /* down */
+    H5F_t *f;                   /* Pointer to file attribute is in */
+    hid_t dxpl_id;              /* DXPL for operation */
+    const char *name;           /* Name of attribute to open */
+
+    /* up */
+    H5A_t *attr;                /* Attribute data to update object header with */
+} H5O_iter_opn_t;
+
+/* User data for iteration when updating an attribute */
+typedef struct {
+    /* down */
+    H5F_t *f;                   /* Pointer to file attribute is in */
+    hid_t dxpl_id;              /* DXPL for operation */
+    H5A_t *attr;                /* Attribute data to update object header with */
+
+    /* up */
+    hbool_t found;              /* Whether the attribute was found */
+} H5O_iter_wrt_t;
+
+/* User data for iteration when renaming an attribute */
+typedef struct {
+    /* down */
+    H5F_t *f;                   /* Pointer to file attribute is in */
+    hid_t dxpl_id;              /* DXPL for operation */
+    const char *old_name;       /* Old name of attribute */
+    const char *new_name;       /* New name of attribute */
+
+    /* up */
+    hbool_t found;              /* Whether the attribute was found */
+} H5O_iter_ren_t;
+
+/* User data for iteration when iterating over attributes */
+typedef struct {
+    /* down */
+    H5F_t *f;                   /* Pointer to file attribute is in */
+    hid_t dxpl_id;              /* DXPL for operation */
+    hid_t loc_id;               /* ID of object being iterated over */
+    unsigned skip;              /* # of attributes to skip over */
+    H5A_operator_t op;          /* Callback routine for each attribute */
+    void *op_data;              /* User data for callback */
+
+    /* up */
+    unsigned count;             /* Count of attributes examined */
+} H5O_iter_itr_t;
+
+
+/********************/
+/* Package Typedefs */
+/********************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_msg_attr_to_dense_cb
+ *
+ * Purpose:	Object header iterator callback routine to convert compact
+ *              attributes to dense attributes
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Dec  4 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5A_attr_to_dense_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
+    unsigned UNUSED sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/)
+{
+    H5O_iter_cvt_t *udata = (H5O_iter_cvt_t *)_udata;   /* Operator user data */
+    herr_t ret_value = H5_ITER_CONT;   /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5A_attr_to_dense_cb)
+
+    /* check args */
+    HDassert(oh);
+    HDassert(mesg);
+
+    /* Insert attribute into dense storage */
+    if(H5A_dense_insert(udata->f, udata->dxpl_id, oh, mesg->flags, mesg->native) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, H5_ITER_ERROR, "unable to add to dense storage")
+
+    /* Convert message into a null message */
+    if(H5O_release_mesg(udata->f, udata->dxpl_id, oh, mesg, TRUE, FALSE) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, H5_ITER_ERROR, "unable to convert into null message")
+
+    /* Indicate that the object header was modified */
+    *oh_flags_ptr |= H5AC__DIRTIED_FLAG;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5A_attr_to_dense_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_create
+ *
+ * Purpose:	Create a new attribute in the object header.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		Friday, December  8, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_attr_create(const H5O_loc_t *loc, hid_t dxpl_id, H5A_t *attr)
+{
+    H5O_t *oh = NULL;                   /* Pointer to actual object header */
+    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Metadata cache flags for object header */
+    unsigned mesg_flags = 0;            /* Flags for storing message */
+    htri_t shared_mesg;                 /* Should this message be stored in the Shared Message table? */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_create)
+
+    /* Check arguments */
+    HDassert(loc);
+    HDassert(attr);
+
+    /* Should this message be written as a SOHM? */
+    if((shared_mesg = H5SM_try_share(loc->file, dxpl_id, H5O_ATTR_ID, attr)) > 0)
+        /* Mark the message as shared */
+        mesg_flags |= H5O_MSG_FLAG_SHARED;
+    else if(shared_mesg < 0)
+	HGOTO_ERROR(H5E_ATTR, H5E_WRITEERROR, FAIL, "error determining if message should be shared")
+
+    /* Protect the object header to iterate over */
+    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
+	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, FAIL, "unable to load object header")
+
+#ifdef QAK
+HDfprintf(stderr, "%s: adding attribute to new-style object header\n", FUNC);
+HDfprintf(stderr, "%s: oh->nattrs = %Hu\n", FUNC, oh->nattrs);
+HDfprintf(stderr, "%s: oh->max_compact = %u\n", FUNC, oh->max_compact);
+HDfprintf(stderr, "%s: oh->min_dense = %u\n", FUNC, oh->min_dense);
+#endif /* QAK */
+    /* Check for switching to "dense" attribute storage */
+    if(oh->version > H5O_VERSION_1 && oh->nattrs == oh->max_compact &&
+            !H5F_addr_defined(oh->attr_fheap_addr)) {
+        H5O_iter_cvt_t udata;           /* User data for callback */
+        H5O_mesg_operator_t op;         /* Wrapper for operator */
+#ifdef QAK
+HDfprintf(stderr, "%s: converting attributes to dense storage\n", FUNC);
+#endif /* QAK */
+
+        /* Create dense storage for attributes */
+        if(H5A_dense_create(loc->file, dxpl_id, oh) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to create dense storage for attributes")
+
+        /* Set up user data for callback */
+        udata.f = loc->file;
+        udata.dxpl_id = dxpl_id;
+
+        /* Iterate over existing attributes, moving them to dense storage */
+        op.lib_op = H5A_attr_to_dense_cb;
+        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTCONVERT, FAIL, "error converting attributes to dense storage")
+    } /* end if */
+
+    /* Increment attribute count */
+    oh->nattrs++;
+
+    /* Check for storing attribute with dense storage */
+    if(H5F_addr_defined(oh->attr_fheap_addr)) {
+        /* Insert attribute into dense storage */
+#ifdef QAK
+HDfprintf(stderr, "%s: inserting attribute to dense storage\n", FUNC);
+#endif /* QAK */
+        if(H5A_dense_insert(loc->file, dxpl_id, oh, mesg_flags, attr) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTINSERT, FAIL, "unable to add to dense storage")
+    } /* end if */
+    else {
+        /* Append new message to object header */
+        if(H5O_msg_append_real(loc->file, dxpl_id, oh, H5O_MSG_ATTR, mesg_flags, 0, attr, &oh_flags) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTINSERT, FAIL, "unable to create new attribute in header")
+    } /* end else */
+
+    /* Update the modification time, if any */
+    if(H5O_touch_oh(loc->file, dxpl_id, oh, FALSE, &oh_flags) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
+
+done:
+    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
+        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, FAIL, "unable to release object header")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_create */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_open_cb
+ *
+ * Purpose:	Object header iterator callback routine to open an
+ *              attribute stored compactly.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Dec 11 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_attr_open_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
+    unsigned UNUSED sequence, unsigned UNUSED *oh_flags_ptr, void *_udata/*in,out*/)
+{
+    H5O_iter_opn_t *udata = (H5O_iter_opn_t *)_udata;   /* Operator user data */
+    herr_t ret_value = H5_ITER_CONT;   /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_open_cb)
+
+    /* check args */
+    HDassert(oh);
+    HDassert(mesg);
+    HDassert(!udata->attr);
+
+    /* Check for shared message */
+    if(mesg->flags & H5O_MSG_FLAG_SHARED) {
+        H5A_t shared_attr;             /* Copy of shared attribute */
+
+	/*
+	 * If the message is shared then then the native pointer points to an
+	 * H5O_MSG_SHARED message.  We use that information to look up the real
+	 * message in the global heap or some other object header.
+	 */
+        if(NULL == H5O_shared_read(udata->f, udata->dxpl_id, mesg->native, H5O_MSG_ATTR, &shared_attr))
+	    HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5_ITER_ERROR, "unable to read shared attribute")
+
+        /* Check for correct attribute message to modify */
+        if(HDstrcmp(shared_attr.name, udata->name) == 0) {
+            /* Make a copy of the attribute to return */
+            if(NULL == (udata->attr = H5A_copy(NULL, &shared_attr)))
+                HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, H5_ITER_ERROR, "unable to copy attribute")
+        } /* end if */
+
+        /* Release copy of shared attribute */
+        H5O_attr_reset(&shared_attr);
+    } /* end if */
+    else {
+        /* Check for correct attribute message to modify */
+        if(HDstrcmp(((H5A_t *)mesg->native)->name, udata->name) == 0) {
+            /* Make a copy of the attribute to return */
+            if(NULL == (udata->attr = H5A_copy(NULL, (H5A_t *)mesg->native)))
+                HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, H5_ITER_ERROR, "unable to copy attribute")
+        } /* end if */
+    } /* end else */
+
+    /* Set common info, if we found the correct attribute */
+    if(udata->attr) {
+        /* Stop iterating */
+        ret_value = H5_ITER_STOP;
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_open_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_open
+ *
+ * Purpose:	Open an existing attribute in an object header.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		Monday, December 11, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+H5A_t *
+H5O_attr_open(const H5O_loc_t *loc, const char *name, hid_t dxpl_id)
+{
+    H5O_t *oh = NULL;                   /* Pointer to actual object header */
+    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Metadata cache flags for object header */
+    H5A_t *ret_value;                   /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_open)
+
+    /* Check arguments */
+    HDassert(loc);
+    HDassert(name);
+
+    /* Protect the object header to iterate over */
+    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_READ)))
+	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, NULL, "unable to load object header")
+
+#ifdef QAK
+HDfprintf(stderr, "%s: opening attribute to new-style object header\n", FUNC);
+HDfprintf(stderr, "%s: oh->nattrs = %Hu\n", FUNC, oh->nattrs);
+HDfprintf(stderr, "%s: oh->max_compact = %u\n", FUNC, oh->max_compact);
+HDfprintf(stderr, "%s: oh->min_dense = %u\n", FUNC, oh->min_dense);
+#endif /* QAK */
+    /* Check for opening attribute with dense storage */
+    if(H5F_addr_defined(oh->attr_fheap_addr)) {
+        /* Open attribute in dense storage */
+        if(NULL == (ret_value = H5A_dense_open(loc->file, dxpl_id, oh, name)))
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "can't open attribute")
+    } /* end if */
+    else {
+        H5O_iter_opn_t udata;           /* User data for callback */
+        H5O_mesg_operator_t op;         /* Wrapper for operator */
+
+        /* Set up user data for callback */
+        udata.f = loc->file;
+        udata.dxpl_id = dxpl_id;
+        udata.name = name;
+        udata.attr = NULL;
+
+        /* Iterate over attributes, to locate correct one to update */
+        op.lib_op = H5O_attr_open_cb;
+        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, NULL, "error updating attribute")
+
+        /* Check that we found the attribute */
+        if(!udata.attr)
+            HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, NULL, "can't locate attribute")
+
+        /* Get attribute opened from object header */
+        HDassert(udata.attr);
+        ret_value = udata.attr;
+    } /* end else */
+
+done:
+    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
+        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, NULL, "unable to release object header")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_open */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_write_cb
+ *
+ * Purpose:	Object header iterator callback routine to update an
+ *              attribute stored compactly.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Dec  4 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_attr_write_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
+    unsigned UNUSED sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/)
+{
+    H5O_iter_wrt_t *udata = (H5O_iter_wrt_t *)_udata;   /* Operator user data */
+    herr_t ret_value = H5_ITER_CONT;   /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_write_cb)
+
+    /* check args */
+    HDassert(oh);
+    HDassert(mesg);
+    HDassert(!udata->found);
+
+    /* Check for shared message */
+    if(mesg->flags & H5O_MSG_FLAG_SHARED) {
+        H5A_t shared_attr;             /* Copy of shared attribute */
+
+	/*
+	 * If the message is shared then then the native pointer points to an
+	 * H5O_MSG_SHARED message.  We use that information to look up the real
+	 * message in the global heap or some other object header.
+	 */
+        if(NULL == H5O_shared_read(udata->f, udata->dxpl_id, mesg->native, H5O_MSG_ATTR, &shared_attr))
+	    HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5_ITER_ERROR, "unable to read shared attribute")
+
+        /* Check for correct attribute message to modify */
+        if(HDstrcmp(shared_attr.name, udata->attr->name) == 0) {
+            htri_t shared_mesg;         /* Whether the message should be shared */
+
+            /* Store new version of message as a SOHM */
+            /* (should always work, since we're not changing the size of the attribute) */
+            if((shared_mesg = H5SM_try_share(udata->f, udata->dxpl_id, H5O_ATTR_ID, udata->attr)) == 0)
+                HGOTO_ERROR(H5E_ATTR, H5E_BADMESG, H5_ITER_ERROR, "attribute changed sharing status")
+            else if(shared_mesg < 0)
+                HGOTO_ERROR(H5E_ATTR, H5E_BADMESG, H5_ITER_ERROR, "can't share attribute")
+
+            /* Remove the old attribut from the SOHM index */
+            if(H5SM_try_delete(udata->f, udata->dxpl_id, H5O_ATTR_ID, mesg->native) < 0)
+                HGOTO_ERROR(H5E_ATTR, H5E_CANTFREE, H5_ITER_ERROR, "unable to delete shared attribute in shared storage")
+
+            /* Extract shared message info from current attribute */
+            if(H5O_attr_get_share(udata->attr, mesg->native) < 0)
+                HGOTO_ERROR(H5E_ATTR, H5E_BADMESG, H5_ITER_ERROR, "can't get shared info")
+
+            /* Indicate that we found the correct attribute */
+            udata->found = TRUE;
+        } /* end if */
+
+        /* Release copy of shared attribute */
+        H5O_attr_reset(&shared_attr);
+    } /* end if */
+    else {
+        /* Check for correct attribute message to modify */
+        if(HDstrcmp(((H5A_t *)mesg->native)->name, udata->attr->name) == 0) {
+            /* Allocate storage for the message's data, if necessary */
+            if(((H5A_t *)mesg->native)->data == NULL)
+                if(NULL == (((H5A_t *)mesg->native)->data = H5FL_BLK_MALLOC(attr_buf, udata->attr->data_size)))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, H5_ITER_ERROR, "memory allocation failed")
+
+            /* Copy the data */
+            HDmemcpy(((H5A_t *)mesg->native)->data, udata->attr->data, udata->attr->data_size);
+
+            /* Indicate that we found the correct attribute */
+            udata->found = TRUE;
+        } /* end if */
+    } /* end else */
+
+    /* Set common info, if we found the correct attribute */
+    if(udata->found) {
+        /* Mark message as dirty */
+        mesg->dirty = TRUE;
+
+        /* Stop iterating */
+        ret_value = H5_ITER_STOP;
+
+        /* Indicate that the object header was modified */
+        *oh_flags_ptr |= H5AC__DIRTIED_FLAG;
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_write_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_write
+ *
+ * Purpose:	Write a new value to an attribute.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		Monday, December  4, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_attr_write(const H5O_loc_t *loc, hid_t dxpl_id, H5A_t *attr)
+{
+    H5O_t *oh = NULL;                   /* Pointer to actual object header */
+    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Metadata cache flags for object header */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_write)
+
+    /* Check arguments */
+    HDassert(loc);
+    HDassert(attr);
+
+    /* Protect the object header to iterate over */
+    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
+	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, FAIL, "unable to load object header")
+
+    /* Check for attributes stored densely */
+    if(H5F_addr_defined(oh->attr_fheap_addr)) {
+        /* Modify the attribute data in dense storage */
+        if(H5A_dense_write(loc->file, dxpl_id, oh, attr) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "error updating attribute")
+    } /* end if */
+    else {
+        H5O_iter_wrt_t udata;           /* User data for callback */
+        H5O_mesg_operator_t op;         /* Wrapper for operator */
+
+        /* Set up user data for callback */
+        udata.f = loc->file;
+        udata.dxpl_id = dxpl_id;
+        udata.attr = attr;
+        udata.found = FALSE;
+
+        /* Iterate over attributes, to locate correct one to update */
+        op.lib_op = H5O_attr_write_cb;
+        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "error updating attribute")
+
+        /* Check that we found the attribute */
+        if(!udata.found)
+            HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, FAIL, "can't locate open attribute?")
+    } /* end else */
+
+    /* Update the modification time, if any */
+    if(H5O_touch_oh(loc->file, dxpl_id, oh, FALSE, &oh_flags) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
+
+done:
+    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
+        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, FAIL, "unable to release object header")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_write */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_rename_dup_cb
+ *
+ * Purpose:	Object header iterator callback routine to check for
+ *              duplicate name during rename
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Dec  5 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_attr_rename_dup_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
+    unsigned UNUSED sequence, unsigned UNUSED *oh_flags_ptr, void *_udata/*in,out*/)
+{
+    H5O_iter_ren_t *udata = (H5O_iter_ren_t *)_udata;   /* Operator user data */
+    herr_t ret_value = H5_ITER_CONT;   /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_rename_dup_cb)
+
+    /* check args */
+    HDassert(oh);
+    HDassert(mesg);
+    HDassert(!udata->found);
+
+    /* Check for shared message */
+    if(mesg->flags & H5O_MSG_FLAG_SHARED) {
+        H5A_t shared_attr;              /* Copy of shared attribute */
+
+	/*
+	 * If the message is shared then then the native pointer points to an
+	 * H5O_MSG_SHARED message.  We use that information to look up the real
+	 * message in the global heap or some other object header.
+	 */
+        if(NULL == H5O_shared_read(udata->f, udata->dxpl_id, mesg->native, H5O_MSG_ATTR, &shared_attr))
+	    HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5_ITER_ERROR, "unable to read shared attribute")
+
+        /* Check for existing attribute with new name */
+        if(HDstrcmp(shared_attr.name, udata->new_name) == 0) {
+            /* Indicate that we found an existing attribute with the new name*/
+            udata->found = TRUE;
+
+            /* Stop iterating */
+            ret_value = H5_ITER_STOP;
+        } /* end if */
+
+        /* Release copy of shared attribute */
+        H5O_attr_reset(&shared_attr);
+    } /* end if */
+    else {
+        /* Check for existing attribute with new name */
+        if(HDstrcmp(((H5A_t *)mesg->native)->name, udata->new_name) == 0) {
+            /* Indicate that we found an existing attribute with the new name*/
+            udata->found = TRUE;
+
+            /* Stop iterating */
+            ret_value = H5_ITER_STOP;
+        } /* end if */
+    } /* end else */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_rename_dup_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_rename_mod_cb
+ *
+ * Purpose:	Object header iterator callback routine to change name of
+ *              attribute during rename
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Dec  5 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_attr_rename_mod_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
+    unsigned UNUSED sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/)
+{
+    H5O_iter_ren_t *udata = (H5O_iter_ren_t *)_udata;   /* Operator user data */
+    herr_t ret_value = H5_ITER_CONT;   /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_rename_mod_cb)
+
+    /* check args */
+    HDassert(oh);
+    HDassert(mesg);
+    HDassert(!udata->found);
+
+    /* Check for shared message */
+    if(mesg->flags & H5O_MSG_FLAG_SHARED) {
+        H5A_t shared_attr;             /* Copy of shared attribute */
+
+	/*
+	 * If the message is shared then then the native pointer points to an
+	 * H5O_MSG_SHARED message.  We use that information to look up the real
+	 * message in the global heap or some other object header.
+	 */
+        if(NULL == H5O_shared_read(udata->f, udata->dxpl_id, mesg->native, H5O_MSG_ATTR, &shared_attr))
+	    HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5_ITER_ERROR, "unable to read shared attribute")
+
+        /* Check for correct attribute message to modify */
+        if(HDstrcmp(shared_attr.name, udata->old_name) == 0) {
+/* XXX: fix me */
+HDfprintf(stderr, "%s: renaming a shared attribute not supported yet!\n", FUNC);
+HGOTO_ERROR(H5E_ATTR, H5E_UNSUPPORTED, H5_ITER_ERROR, "renaming a shared attribute not supported yet")
+        } /* end if */
+
+        /* Release copy of shared attribute */
+        H5O_attr_reset(&shared_attr);
+    } /* end if */
+    else {
+        /* Find correct attribute message to rename */
+        if(HDstrcmp(((H5A_t *)mesg->native)->name, udata->old_name) == 0) {
+            /* Change the name for the attribute */
+            H5MM_xfree(((H5A_t *)mesg->native)->name);
+            ((H5A_t *)mesg->native)->name = H5MM_xstrdup(udata->new_name);
+
+            /* Indicate that we found an existing attribute with the old name*/
+            udata->found = TRUE;
+
+            /* Mark message as dirty */
+            mesg->dirty = TRUE;
+
+            /* Stop iterating */
+            ret_value = H5_ITER_STOP;
+
+            /* Indicate that the object header was modified */
+            *oh_flags_ptr |= H5AC__DIRTIED_FLAG;
+        } /* end if */
+    } /* end else */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_rename_mod_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_rename
+ *
+ * Purpose:	Rename an attribute.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		Tuesday, December  5, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_attr_rename(const H5O_loc_t *loc, hid_t dxpl_id, const char *old_name, const char *new_name)
+{
+    H5O_t *oh = NULL;                   /* Pointer to actual object header */
+    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Metadata cache flags for object header */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_rename)
+
+    /* Check arguments */
+    HDassert(loc);
+    HDassert(old_name);
+    HDassert(new_name);
+
+    /* Protect the object header to iterate over */
+    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
+	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, FAIL, "unable to load object header")
+
+    /* Check for attributes stored densely */
+    if(H5F_addr_defined(oh->attr_fheap_addr)) {
+/* XXX: fix me */
+HDfprintf(stderr, "%s: renaming attributes in dense storage not supported yet!\n", FUNC);
+HGOTO_ERROR(H5E_ATTR, H5E_UNSUPPORTED, FAIL, "renaming attributes in dense storage not supported yet")
+    } /* end if */
+    else {
+        H5O_iter_ren_t udata;           /* User data for callback */
+        H5O_mesg_operator_t op;         /* Wrapper for operator */
+
+        /* Set up user data for callback */
+        udata.f = loc->file;
+        udata.dxpl_id = dxpl_id;
+        udata.old_name = old_name;
+        udata.new_name = new_name;
+        udata.found = FALSE;
+
+        /* Iterate over attributes, to check if "new name" exists already */
+        op.lib_op = H5O_attr_rename_dup_cb;
+        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "error updating attribute")
+
+        /* If the new name was found, indicate an error */
+        if(udata.found)
+            HGOTO_ERROR(H5E_ATTR, H5E_EXISTS, FAIL, "attribute with new name already exists")
+
+        /* Iterate over attributes again, to actually rename attribute with old name */
+        op.lib_op = H5O_attr_rename_mod_cb;
+        if(H5O_msg_iterate_real(loc->file, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "error updating attribute")
+    } /* end else */
+
+    /* Update the modification time, if any */
+    if(H5O_touch_oh(loc->file, dxpl_id, oh, FALSE, &oh_flags) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
+
+done:
+    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
+        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, FAIL, "unable to release object header")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_rename */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_attr_iterate
+ *
+ * Purpose:	Iterate over attributes for an object.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		Tuesday, December  5, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_attr_iterate(hid_t loc_id, const H5O_loc_t *loc, hid_t dxpl_id,
+    unsigned skip, unsigned *last_attr, H5A_operator_t op, void *op_data)
+{
+    H5O_t *oh = NULL;                   /* Pointer to actual object header */
+    haddr_t attr_fheap_addr;            /* Address of fractal heap for dense attribute storage */
+    haddr_t name_bt2_addr;              /* Address of v2 B-tree for name index on dense attribute storage */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_attr_iterate)
+
+    /* Check arguments */
+    HDassert(loc);
+    HDassert(op);
+
+    /* Protect the object header to iterate over */
+    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_READ)))
+	HGOTO_ERROR(H5E_ATTR, H5E_CANTLOAD, FAIL, "unable to load object header")
+
+    /* Retrieve the information about dense attribute storage */
+    if(oh->version > H5O_VERSION_1 && H5F_addr_defined(oh->attr_fheap_addr)) {
+        attr_fheap_addr = oh->attr_fheap_addr;
+        name_bt2_addr = oh->name_bt2_addr;
+    } /* end if */
+    else
+        attr_fheap_addr = name_bt2_addr = HADDR_UNDEF;
+
+    /* Release the object header */
+    if(H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, H5AC__NO_FLAGS_SET) < 0)
+        HDONE_ERROR(H5E_ATTR, H5E_PROTECT, FAIL, "unable to release object header")
+    oh = NULL;
+
+    /* Check for attributes stored densely */
+    if(H5F_addr_defined(attr_fheap_addr)) {
+        if((ret_value = H5A_dense_iterate(loc->file, dxpl_id, loc_id, attr_fheap_addr,
+                name_bt2_addr, skip, last_attr, op, op_data)) < 0)
+            HERROR(H5E_ATTR, H5E_BADITER, "error iterating over attributes");
+    } /* end if */
+    else {
+        unsigned idx;           /* Current attribute to operate on */
+
+        /* Check for skipping over too many attributes */
+        if((int)skip < H5O_msg_count(loc, H5O_ATTR_ID, dxpl_id)) {
+            H5A_t found_attr;           /* Copy of attribute for callback */
+
+            /* Read each attribute and call application's callback */
+            /* (this could be made more efficient by iterating over the
+             *  attribute header messages with H5O_msg_iterate, but then
+             *  the object header would be locked during the callback into
+             *  the application code, causing problems if they attempt to
+             *  do anything with the object the attribute is on - QAK)
+             */
+            idx = skip;
+            while(H5O_msg_read(loc, H5O_ATTR_ID, (int)idx, &found_attr, dxpl_id) != NULL) {
+                /* Call application's callback */
+                idx++;
+                if((ret_value = (op)(loc_id, found_attr.name, op_data)) != 0) {
+                    H5A_free(&found_attr);
+                    break;
+                } /* end if */
+                H5A_free(&found_attr);
+            } /* end while */
+
+            /* Clear error stack from running off end of attributes */
+            if(ret_value == 0)
+                H5E_clear_stack(NULL);
+        } /* end if */
+        else
+            if(skip > 0)
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index specified")
+
+        /* Update last attribute looked at */
+        if(last_attr)
+            *last_attr = idx;
+    } /* end else */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_attr_iterate */
+
diff --git a/src/H5Opkg.h b/src/H5Opkg.h
index eea0102..b4f5b15 100644
--- a/src/H5Opkg.h
+++ b/src/H5Opkg.h
@@ -23,6 +23,7 @@
 #include "H5Oprivate.h"		/* Object headers		  	*/
 
 /* Other private headers needed by this file */
+#include "H5Aprivate.h"		/* Attributes				*/
 #include "H5ACprivate.h"	/* Metadata cache			*/
 
 /* Object header macros */
@@ -418,6 +419,17 @@ H5_DLL herr_t H5O_release_mesg(H5F_t *f, hid_t dxpl_id, H5O_t *oh,
 H5_DLL void * H5O_shared_read(H5F_t *f, hid_t dxpl_id, const H5O_shared_t *shared,
     const H5O_msg_class_t *type, void *mesg);
 
+/* Attribute operations */
+H5_DLL herr_t H5O_attr_create(const H5O_loc_t *loc, hid_t dxpl_id, H5A_t *attr);
+H5_DLL H5A_t *H5O_attr_open(const H5O_loc_t *loc, const char *name,
+    hid_t dxpl_id);
+H5_DLL herr_t H5O_attr_write(const H5O_loc_t *loc, hid_t dxpl_id,
+    H5A_t *attr);
+H5_DLL herr_t H5O_attr_rename(const H5O_loc_t *loc, hid_t dxpl_id,
+    const char *old_name, const char *new_name);
+H5_DLL herr_t H5O_attr_iterate(hid_t loc_id, const H5O_loc_t *loc, hid_t dxpl_id,
+    unsigned skip, unsigned *last_attr, H5A_operator_t op, void *op_data);
+
 /* These functions operate on object locations */
 H5_DLL H5O_loc_t *H5O_get_loc(hid_t id);
 
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index e578377..3c95953 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -31,7 +31,6 @@
 #include "H5Opublic.h"          /* Object header functions              */
 
 /* Public headers needed by this file */
-#include "H5Apublic.h"          /* Attributes				*/
 #include "H5Dpublic.h"          /* Dataset functions                    */
 #include "H5Lpublic.h"		/* Link functions                       */
 #include "H5Spublic.h"		/* Dataspace functions			*/
@@ -375,7 +374,6 @@ typedef herr_t (*H5O_operator_t)(const void *mesg/*in*/, unsigned idx,
 struct H5P_genplist_t;
 struct H5SL_t;
 struct H5O_t;
-struct H5A_t;
 
 /* Object header routines */
 H5_DLL herr_t H5O_init(void);
@@ -463,14 +461,5 @@ H5_DLL herr_t H5O_fill_convert(void *_fill, H5T_t *type, hid_t dxpl_id);
 /* Link operators */
 H5_DLL herr_t H5O_link_delete(H5F_t *f, hid_t dxpl_id, const void *_mesg, hbool_t adj_link);
 
-/* Attribute operations */
-H5_DLL herr_t H5O_attr_create(const H5O_loc_t *loc, hid_t dxpl_id, struct H5A_t *attr);
-H5_DLL herr_t H5O_attr_write(const H5O_loc_t *loc, hid_t dxpl_id,
-    struct H5A_t *attr);
-H5_DLL herr_t H5O_attr_rename(const H5O_loc_t *loc, hid_t dxpl_id,
-    const char *old_name, const char *new_name);
-H5_DLL herr_t H5O_attr_iterate(hid_t loc_id, const H5O_loc_t *loc, hid_t dxpl_id,
-    unsigned skip, unsigned *last_attr, H5A_operator_t op, void *op_data);
-
 #endif /* _H5Oprivate_H */
 
diff --git a/src/Makefile.am b/src/Makefile.am
index c6fe5fd..44c318f 100755
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -58,7 +58,7 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5HFspace.c H5HFstat.c H5HFtest.c H5HFtiny.c \
         H5HG.c H5HGdbg.c H5HL.c H5HLdbg.c H5HP.c H5I.c H5MF.c H5MM.c \
         H5MP.c H5MPtest.c H5L.c H5Lexternal.c H5O.c H5Oalloc.c H5Oattr.c \
-        H5Obogus.c H5Ocache.c \
+        H5Oattribute.c H5Obogus.c H5Ocache.c \
         H5Ocont.c H5Ocopy.c H5Odbg.c H5Odtype.c H5Oefl.c H5Ofill.c H5Oginfo.c \
         H5Olayout.c \
         H5Olinfo.c H5Olink.c H5Omessage.c H5Omtime.c \
diff --git a/src/Makefile.in b/src/Makefile.in
index 92085be..d6910be 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -99,7 +99,7 @@ am_libhdf5_la_OBJECTS = H5.lo H5checksum.lo H5dbg.lo H5system.lo \
 	H5HFspace.lo H5HFstat.lo H5HFtest.lo H5HFtiny.lo H5HG.lo \
 	H5HGdbg.lo H5HL.lo H5HLdbg.lo H5HP.lo H5I.lo H5MF.lo H5MM.lo \
 	H5MP.lo H5MPtest.lo H5L.lo H5Lexternal.lo H5O.lo H5Oalloc.lo \
-	H5Oattr.lo H5Obogus.lo H5Ocache.lo H5Ocont.lo H5Ocopy.lo \
+	H5Oattr.lo H5Oattribute.lo H5Obogus.lo H5Ocache.lo H5Ocont.lo H5Ocopy.lo \
 	H5Odbg.lo H5Odtype.lo H5Oefl.lo H5Ofill.lo H5Oginfo.lo \
 	H5Olayout.lo H5Olinfo.lo H5Olink.lo H5Omessage.lo H5Omtime.lo H5Oname.lo \
 	H5Onull.lo H5Opline.lo H5Osdspace.lo H5Oshared.lo H5Ostab.lo H5Otest.lo \
@@ -414,7 +414,7 @@ libhdf5_la_SOURCES = H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5HFspace.c H5HFstat.c H5HFtest.c H5HFtiny.c \
         H5HG.c H5HGdbg.c H5HL.c H5HLdbg.c H5HP.c H5I.c H5MF.c H5MM.c \
         H5MP.c H5MPtest.c H5L.c H5Lexternal.c H5O.c H5Oalloc.c H5Oattr.c \
-        H5Obogus.c H5Ocache.c \
+        H5Oattribute.c H5Obogus.c H5Ocache.c \
         H5Ocont.c H5Ocopy.c H5Odbg.c H5Odtype.c H5Oefl.c H5Ofill.c H5Oginfo.c \
         H5Olayout.c \
         H5Olinfo.c H5Olink.c H5Omessage.c H5Omtime.c \
@@ -660,6 +660,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5O.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Oalloc.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Oattr.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Oattribute.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Obogus.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Ocache.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Ocont.Plo@am__quote@