[svn-r12896] Description:

    Move compact storage routines into separate file, to make room for internal
routines that operate on links within group operations.

Tested on:
    Linux/32 2.6 (chicago)

1 files changed, 668 insertions, 0 deletions

diff --git a/src/H5Gcompact.c b/src/H5Gcompact.c
new file mode 100644
index 0000000..50e661b
--- /dev/null
+++ b/src/H5Gcompact.c
@@ -0,0 +1,668 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * 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:		H5Gcompact.c
+ *			Sep  5 2005
+ *			Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *
+ * Purpose:		Functions for handling compact storage.
+ *
+ *-------------------------------------------------------------------------
+ */
+#define H5G_PACKAGE		/*suppress error about including H5Gpkg	  */
+
+
+/* Packages needed by this file... */
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Gpkg.h"		/* Groups		  		*/
+#include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5MMprivate.h"	/* Memory management			*/
+
+/* Private typedefs */
+
+/* User data for link message iteration when building link table */
+typedef struct {
+    H5G_link_table_t *ltable;   /* Pointer to link table to build */
+    size_t curr_lnk;            /* Current link to operate on */
+} H5G_compact_ud1_t;
+
+/* User data for deleting a link in the link messages */
+typedef struct {
+    /* downward */
+    const char *name;           /* Name to search for */
+    H5F_t       *file;          /* File that object header is located within */
+    hid_t       dxpl_id;        /* DXPL during insertion */
+
+    /* upward */
+    H5G_obj_t *obj_type;        /* Type of object deleted */
+} H5G_compact_ud2_t;
+
+/* User data for link message iteration when querying object info */
+typedef struct {
+    /* downward */
+    const char *name;           /* Name to search for */
+    H5F_t       *file;          /* File that object header is located within */
+    hid_t       dxpl_id;        /* DXPL during insertion */
+
+    /* upward */
+    H5G_stat_t *statbuf;        /* Stat buffer for info */
+} H5G_compact_ud3_t;
+
+/* User data for link message iteration when querying object location */
+typedef struct {
+    /* downward */
+    const char *name;           /* Name to search for */
+
+    /* upward */
+    H5O_link_t *lnk;            /* Link struct to fill in */
+    hbool_t found;              /* Flag to indicate that the object was found */
+} H5G_compact_ud4_t;
+
+/* User data for link message iteration when querying soft link value */
+typedef struct {
+    /* downward */
+    const char *name;           /* Name to search for */
+    size_t size;                /* Buffer size for link value */
+
+    /* upward */
+    char *buf;                  /* Buffer to fill with link value */
+} H5G_compact_ud5_t;
+
+/* Private macros */
+
+/* PRIVATE PROTOTYPES */
+static herr_t H5G_compact_build_table_cb(const void *_mesg, unsigned idx, void *_udata);
+static herr_t H5G_compact_build_table(H5O_loc_t *oloc, hid_t dxpl_id,
+    const H5O_linfo_t *linfo, H5L_index_t idx_type, H5_iter_order_t order,
+    H5G_link_table_t *ltable);
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_build_table_cb
+ *
+ * Purpose:	Callback routine for searching 'link' messages for a particular
+ *              name.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Sep  5 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5G_compact_build_table_cb(const void *_mesg, unsigned UNUSED idx, void *_udata)
+{
+    const H5O_link_t *lnk = (const H5O_link_t *)_mesg;  /* Pointer to link */
+    H5G_compact_ud1_t *udata = (H5G_compact_ud1_t *)_udata;     /* 'User data' passed in */
+    herr_t ret_value=H5O_ITER_CONT;             /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5G_compact_build_table_cb)
+
+    /* check arguments */
+    HDassert(lnk);
+    HDassert(udata);
+    HDassert(udata->curr_lnk < udata->ltable->nlinks);
+
+    /* Copy link message into table */
+    if(NULL == H5O_copy(H5O_LINK_ID, lnk, &(udata->ltable->lnks[udata->curr_lnk])))
+        HGOTO_ERROR(H5E_SYM, H5E_CANTCOPY, H5O_ITER_ERROR, "can't copy link message")
+
+    /* Increment current link entry to operate on */
+    udata->curr_lnk++;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_build_table_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_build_table
+ *
+ * Purpose:     Builds a table containing a sorted (alphabetically) list of
+ *              links for a group
+ *
+ * Return:	Success:        Non-negative
+ *		Failure:	Negative
+ *
+ * Programmer:	Quincey Koziol
+ *	        Sep  6, 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5G_compact_build_table(H5O_loc_t *oloc, hid_t dxpl_id, const H5O_linfo_t *linfo,
+    H5L_index_t idx_type, H5_iter_order_t order, H5G_link_table_t *ltable)
+{
+    herr_t	ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5G_compact_build_table)
+
+    /* Sanity check */
+    HDassert(oloc);
+    HDassert(linfo);
+    HDassert(ltable);
+
+    /* Set size of table */
+    H5_CHECK_OVERFLOW(linfo->nlinks, hsize_t, size_t);
+    ltable->nlinks = (size_t)linfo->nlinks;
+
+    /* Allocate space for the table entries */
+    if(ltable->nlinks > 0) {
+        H5G_compact_ud1_t udata;               /* User data for iteration callback */
+
+        if((ltable->lnks = H5MM_malloc(sizeof(H5O_link_t) * ltable->nlinks)) == NULL)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+        /* Set up user data for iteration */
+        udata.ltable = ltable;
+        udata.curr_lnk = 0;
+
+        /* Iterate through the link messages, adding them to the table */
+        if(H5O_iterate(oloc, H5O_LINK_ID, H5G_compact_build_table_cb, &udata, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "error iterating over link messages")
+
+        /* Sort link table in correct iteration order */
+        if(idx_type == H5L_INDEX_NAME) {
+            if(order == H5_ITER_INC)
+                HDqsort(ltable->lnks, ltable->nlinks, sizeof(H5O_link_t), H5G_link_cmp_name_inc);
+            else if(order == H5_ITER_DEC)
+                HDqsort(ltable->lnks, ltable->nlinks, sizeof(H5O_link_t), H5G_link_cmp_name_dec);
+            else
+                HDassert(order == H5_ITER_NATIVE);
+        } /* end if */
+        else {
+            HDassert(idx_type == H5L_INDEX_CRT_ORDER);
+            if(order == H5_ITER_INC)
+                HDqsort(ltable->lnks, ltable->nlinks, sizeof(H5O_link_t), H5G_link_cmp_corder_inc);
+            else if(order == H5_ITER_DEC)
+                HDqsort(ltable->lnks, ltable->nlinks, sizeof(H5O_link_t), H5G_link_cmp_corder_dec);
+            else
+                HDassert(order == H5_ITER_NATIVE);
+        } /* end else */
+    } /* end if */
+    else
+        ltable->lnks = NULL;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_build_table() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_insert
+ *
+ * Purpose:	Insert a new symbol into the table described by GRP_ENT in
+ *		file F.	 The name of the new symbol is NAME and its symbol
+ *		table entry is OBJ_ENT.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Sep  6 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5G_compact_insert(H5O_loc_t *grp_oloc, H5O_link_t *obj_lnk,
+    hid_t dxpl_id)
+{
+    herr_t     ret_value = SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI(H5G_compact_insert, FAIL)
+
+    /* check arguments */
+    HDassert(grp_oloc && grp_oloc->file);
+    HDassert(obj_lnk);
+
+    /* Insert link message into group */
+    if(H5O_modify(grp_oloc, H5O_LINK_ID, H5O_NEW_MESG, 0, H5O_UPDATE_TIME, obj_lnk, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create message")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_insert() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_get_name_by_idx
+ *
+ * Purpose:     Returns the name of objects in the group by giving index.
+ *
+ * Return:	Success:        Non-negative, length of name
+ *		Failure:	Negative
+ *
+ * Programmer:	Quincey Koziol
+ *	        Sep  6, 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+ssize_t
+H5G_compact_get_name_by_idx(H5O_loc_t *oloc, hid_t dxpl_id,
+    const H5O_linfo_t *linfo, H5L_index_t idx_type, H5_iter_order_t order,
+    hsize_t idx, char* name, size_t size)
+{
+    H5G_link_table_t    ltable = {0, NULL};         /* Link table */
+    ssize_t		ret_value;      /* Return value */
+
+    FUNC_ENTER_NOAPI(H5G_compact_get_name_by_idx, FAIL)
+
+    /* Sanity check */
+    HDassert(oloc);
+
+    /* Build table of all link messages */
+    if(H5G_compact_build_table(oloc, dxpl_id, linfo, idx_type, order, &ltable) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create link message table")
+
+    /* Check for going out of bounds */
+    if(idx >= ltable.nlinks)
+	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "index out of bound")
+
+    /* Get the length of the name */
+    ret_value = (ssize_t)HDstrlen(ltable.lnks[idx].name);
+
+    /* Copy the name into the user's buffer, if given */
+    if(name) {
+        HDstrncpy(name, ltable.lnks[idx].name, MIN((size_t)(ret_value + 1), size));
+        if((size_t)ret_value >= size)
+            name[size - 1]='\0';
+    } /* end if */
+
+done:
+    /* Release link table */
+    if(ltable.lnks)
+        /* Free link table information */
+        if(H5G_link_release_table(&ltable) < 0)
+            HDONE_ERROR(H5E_SYM, H5E_CANTFREE, FAIL, "unable to release link table")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_get_name_by_idx() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_get_type_by_idx
+ *
+ * Purpose:     Returns the type of objects in the group by giving index.
+ *
+ * Return:	Success:        Non-negative
+ *		Failure:	Negative
+ *
+ * Programmer:	Quincey Koziol
+ *	        Sep 12, 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+H5G_obj_t
+H5G_compact_get_type_by_idx(H5O_loc_t *oloc, hid_t dxpl_id, const H5O_linfo_t *linfo,
+    hsize_t idx)
+{
+    H5G_link_table_t    ltable = {0, NULL};         /* Link table */
+    H5G_obj_t		ret_value;      /* Return value */
+
+    FUNC_ENTER_NOAPI(H5G_compact_get_type_by_idx, H5G_UNKNOWN)
+
+    /* Sanity check */
+    HDassert(oloc);
+
+    /* Build table of all link messages */
+    if(H5G_compact_build_table(oloc, dxpl_id, linfo, H5L_INDEX_NAME, H5_ITER_INC, &ltable) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, H5G_UNKNOWN, "can't create link message table")
+
+    /* Check for going out of bounds */
+    if(idx >= ltable.nlinks)
+	HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, H5G_UNKNOWN, "index out of bound")
+
+    /* Determine type of object */
+    if(ltable.lnks[idx].type == H5L_TYPE_SOFT)
+        ret_value = H5G_LINK;
+    else if(ltable.lnks[idx].type >= H5L_TYPE_UD_MIN)
+        ret_value = H5G_UDLINK;
+    else if(ltable.lnks[idx].type == H5L_TYPE_HARD){
+        H5O_loc_t tmp_oloc;             /* Temporary object location */
+
+        /* Build temporary object location */
+        tmp_oloc.file = oloc->file;
+        tmp_oloc.addr = ltable.lnks[idx].u.hard.addr;
+
+        /* Get the type of the object */
+        if((ret_value = H5O_obj_type(&tmp_oloc, dxpl_id)) == H5G_UNKNOWN)
+            HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "can't determine object type")
+    } else {
+        HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "unknown link type")
+    } /* end else */
+
+done:
+    /* Release link table */
+    if(ltable.lnks)
+        /* Free link table information */
+        if(H5G_link_release_table(&ltable) < 0)
+            HDONE_ERROR(H5E_SYM, H5E_CANTFREE, H5G_UNKNOWN, "unable to release link table")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_get_type_by_idx() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_remove_cb
+ *
+ * Purpose:	Callback routine for deleting 'link' message for a particular
+ *              name.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Sep  5 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5G_compact_remove_cb(const void *_mesg, unsigned UNUSED idx, void *_udata)
+{
+    const H5O_link_t *lnk = (const H5O_link_t *)_mesg;  /* Pointer to link */
+    H5G_compact_ud2_t *udata = (H5G_compact_ud2_t *)_udata;     /* 'User data' passed in */
+    herr_t ret_value = H5O_ITER_CONT;           /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5G_compact_remove_cb)
+
+    /* check arguments */
+    HDassert(lnk);
+    HDassert(udata);
+
+    /* If we've found the right link, get the object type */
+    if(HDstrcmp(lnk->name, udata->name) == 0) {
+        switch(lnk->type)
+        {
+            case H5L_TYPE_HARD:
+                {
+                    H5O_loc_t tmp_oloc;             /* Temporary object location */
+
+                    /* Build temporary object location */
+                    tmp_oloc.file = udata->file;
+                    tmp_oloc.addr = lnk->u.hard.addr;
+
+                    /* Get the type of the object */
+                    /* Note: no way to check for error :-( */
+                    *(udata->obj_type) = H5O_obj_type(&tmp_oloc, udata->dxpl_id);
+                }
+                break;
+
+            case H5L_TYPE_SOFT:
+                *(udata->obj_type) = H5G_LINK;
+                break;
+
+            default:  /* User-defined link */
+                if(lnk->type < H5L_TYPE_UD_MIN)
+                   HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, FAIL, "unknown link type")
+
+                *(udata->obj_type) = H5G_UDLINK;
+        }
+        /* Stop the iteration, we found the correct link */
+        HGOTO_DONE(H5O_ITER_STOP)
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_remove_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_remove
+ *
+ * Purpose:	Remove NAME from links.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, September 19, 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5G_compact_remove(const H5O_loc_t *oloc, const char *name, H5G_obj_t *obj_type,
+    hid_t dxpl_id)
+{
+    H5G_compact_ud2_t udata;               /* Data to pass through OH iteration */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(H5G_compact_remove, FAIL)
+
+    HDassert(oloc && oloc->file);
+    HDassert(name && *name);
+
+    /* Initialize data to pass through object header iteration */
+    udata.name = name;
+    udata.file = oloc->file;
+    udata.dxpl_id = dxpl_id;
+    udata.obj_type = obj_type;
+
+    /* Iterate over the link messages to delete the right one */
+    if(H5O_remove_op(oloc, H5O_LINK_ID, H5O_FIRST, H5G_compact_remove_cb, &udata, TRUE, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTDELETE, FAIL, "unable to delete link message")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_remove() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_iterate
+ *
+ * Purpose:	Iterate over the links in a group
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, October  3, 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5G_compact_iterate(H5O_loc_t *oloc, hid_t dxpl_id, const H5O_linfo_t *linfo, 
+    H5_iter_order_t order, hid_t gid, hbool_t lib_internal, int skip,
+    int *last_obj, H5G_link_iterate_t op, void *op_data)
+{
+    H5G_link_table_t    ltable = {0, NULL};     /* Link table */
+    size_t              u;                      /* Local index variable */
+    herr_t		ret_value;
+
+    FUNC_ENTER_NOAPI(H5G_compact_iterate, FAIL)
+
+    /* Sanity check */
+    HDassert(oloc);
+    HDassert(lib_internal || H5I_GROUP == H5I_get_type(gid));
+    HDassert(op.lib_op);
+
+    /* Build table of all link messages */
+    if(H5G_compact_build_table(oloc, dxpl_id, linfo, H5L_INDEX_NAME, order, &ltable) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create link message table")
+
+    /* Iterate over link messages */
+    for(u = 0, ret_value = H5B_ITER_CONT; u < ltable.nlinks && !ret_value; u++) {
+        if(skip > 0)
+            --skip;
+        else {
+            /* Check for internal callback with link info */
+            if(lib_internal)
+                ret_value = (op.lib_op)(&(ltable.lnks[u]), op_data);
+            else
+                ret_value = (op.app_op)(gid, ltable.lnks[u].name, op_data);
+        } /* end else */
+
+        /* Increment the number of entries passed through */
+        /* (whether we skipped them or not) */
+        (*last_obj)++;
+    } /* end for */
+
+    /* Check for callback failure and pass along return value */
+    if(ret_value < 0)
+        HERROR(H5E_SYM, H5E_CANTNEXT, "iteration operator failed");
+
+done:
+    /* Release link table */
+    if(ltable.lnks)
+        /* Free link table information */
+        if(H5G_link_release_table(&ltable) < 0)
+            HDONE_ERROR(H5E_SYM, H5E_CANTFREE, FAIL, "unable to release link table")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_iterate() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_lookup_cb
+ *
+ * Purpose:	Callback routine for searching 'link' messages for a particular
+ *              name & gettting object location for it
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Sep 20 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5G_compact_lookup_cb(const void *_mesg, unsigned UNUSED idx, void *_udata)
+{
+    const H5O_link_t *lnk = (const H5O_link_t *)_mesg;  /* Pointer to link */
+    H5G_compact_ud4_t *udata = (H5G_compact_ud4_t *)_udata;     /* 'User data' passed in */
+    herr_t ret_value = H5O_ITER_CONT;           /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5G_compact_lookup_cb)
+
+    /* check arguments */
+    HDassert(lnk);
+    HDassert(udata);
+
+    /* Check for name to get information */
+    if(HDstrcmp(lnk->name, udata->name) == 0) {
+        if(udata->lnk) {
+            /* Copy link information */
+            if(NULL == H5O_copy(H5O_LINK_ID, lnk, udata->lnk))
+                HGOTO_ERROR(H5E_SYM, H5E_CANTCOPY, H5O_ITER_ERROR, "can't copy link message")
+        } /* end if */
+
+        /* Indicate that the correct link was found */
+        udata->found = TRUE;
+
+        /* Stop iteration now */
+        HGOTO_DONE(H5O_ITER_STOP)
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_lookup_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_lookup
+ *
+ * Purpose:	Look up an object relative to a group, using link messages.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Sep 20 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5G_compact_lookup(H5O_loc_t *oloc, const char *name, H5O_link_t *lnk,
+    hid_t dxpl_id)
+{
+    H5G_compact_ud4_t udata;               /* User data for iteration callback */
+    herr_t     ret_value = SUCCEED;     /* Return value */
+
+    FUNC_ENTER_NOAPI(H5G_compact_lookup, FAIL)
+
+    /* check arguments */
+    HDassert(lnk && oloc->file);
+    HDassert(name && *name);
+
+    /* Set up user data for iteration */
+    udata.name = name;
+    udata.lnk = lnk;
+    udata.found = FALSE;
+
+    /* Iterate through the link messages, adding them to the table */
+    if(H5O_iterate(oloc, H5O_LINK_ID, H5G_compact_lookup_cb, &udata, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "error iterating over link messages")
+
+    /* Check if we found the link we were looking for */
+    if(!udata.found)
+        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_lookup() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_compact_lookup_by_idx
+ *
+ * Purpose:	Look up an object in a group using link messages,
+ *              according to the order of an index
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Nov  6 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5G_compact_lookup_by_idx(H5O_loc_t *oloc, hid_t dxpl_id, const H5O_linfo_t *linfo,
+    H5L_index_t idx_type, H5_iter_order_t order, hsize_t n, H5O_link_t *lnk)
+{
+    H5G_link_table_t    ltable = {0, NULL};     /* Link table */
+    herr_t     ret_value = SUCCEED;     /* Return value */
+
+    FUNC_ENTER_NOAPI(H5G_compact_lookup_by_idx, FAIL)
+
+    /* check arguments */
+    HDassert(oloc && oloc->file);
+    HDassert(linfo);
+    HDassert(lnk);
+
+    /* Build table of all link messages, sorted according to desired order */
+    if(H5G_compact_build_table(oloc, dxpl_id, linfo, idx_type, order, &ltable) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create link message table")
+
+    /* Check for going out of bounds */
+    if(n >= ltable.nlinks)
+	HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index out of bound")
+
+    /* Copy link information */
+    if(NULL == H5O_copy(H5O_LINK_ID, &ltable.lnks[n], lnk))
+        HGOTO_ERROR(H5E_SYM, H5E_CANTCOPY, H5O_ITER_ERROR, "can't copy link message")
+
+done:
+    /* Release link table */
+    if(ltable.lnks)
+        /* Free link table information */
+        if(H5G_link_release_table(&ltable) < 0)
+            HDONE_ERROR(H5E_SYM, H5E_CANTFREE, FAIL, "unable to release link table")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_compact_lookup_by_idx() */
+