[svn-r2] Oops...

1 files changed, 789 insertions, 0 deletions

diff --git a/src/H5A.c b/src/H5A.c
new file mode 100644
index 0000000..3733bf8
--- /dev/null
+++ b/src/H5A.c
@@ -0,0 +1,789 @@
+/****************************************************************************
+ * NCSA HDF                                                                 *
+ * Software Development Group                                               *
+ * National Center for Supercomputing Applications                          *
+ * University of Illinois at Urbana-Champaign                               *
+ * 605 E. Springfield, Champaign IL 61820                                   *
+ *                                                                          *
+ * For conditions of distribution and use, see the accompanying             *
+ * hdf/COPYING file.                                                        *
+ *                                                                          *
+ ****************************************************************************/
+
+#ifdef RCSID
+static char RcsId[] = "@(#)$Revision$";
+#endif
+
+/* $Id$ */
+
+/*
+FILE
+    atom.c - Internal storage routines for handling "atoms"
+
+REMARKS
+    Atoms are just ID's which allow objects (void *'s currently) to be
+    bundled into "groups" for more general storage.
+
+DESIGN
+    The groups are stored in an array of pointers to store each group in an
+    element. Each "atomic group" node contains a link to a hash table to
+    manage the atoms in each group.  The allowed "atomic groups" are stored
+    in an enum (called group_t) in atom.h.
+
+BUGS/LIMITATIONS
+    Can't interate over the atoms in a group.
+
+LOCAL ROUTINES
+  H5A_find_atom      - Returns a pointer to an atom_info_t from a atom ID
+  H5A_get_atom_node  - Gets an atom node (uses the atom free list)
+  H5A_release_atom_node - Releases an atom node (uses the atom free list)
+EXPORTED ROUTINES
+ Atom Functions:
+  H5Aregister_atom   - Register an object in a group and get an atom for it
+  H5Aatom_object     - Get the object for an atom
+  H5Aatom_group      - Get the group for an atom
+  H5Aremove_atom     - Remove an atom from a group
+  H5Asearch_atom     - Search a group for a particular object
+  H5Ais_reserved     - Check whether an atom is a reserved atom in a group
+ Atom Group Functions:
+  H5Ainit_group      - Initialize a group to store atoms in
+  H5Adestroy_group   - Destroy an atomic group
+ Atom Group Cleanup:
+  H5Ashutdown        - Terminate various static buffers.
+
+AUTHOR
+   Quincey Koziol
+
+MODIFICATION HISTORY
+   1/3/96  - Starting writing specs & coding prototype
+   1/7/96  - Finished coding prototype
+   6/10/97 - Moved into HDF5 library
+*/
+
+#define HDF5_ATOM_MASTER
+#include "hdf5.h"
+#include "H5Aprivate.h"
+
+
+/* Private function prototypes */
+static atom_info_t *H5A_find_atom(hatom_t atm);
+
+static atom_info_t *H5A_get_atom_node(void);
+
+static void H5A_release_atom_node(atom_info_t *atm);
+
+/******************************************************************************
+ NAME
+     H5Ainit_group - Initialize an atomic group
+
+ DESCRIPTION
+    Creates a global atomic group to store atoms in.  If the group has already
+    been initialized, this routine just increments the count of # of
+    initializations and returns without trying to change the size of the hash
+    table.  A specific number of group entries may be reserved to enable
+    "constant" values to be handed out which are valid atoms in the group, but
+    which do not map to any data structures and are not allocated dynamicly
+    later.
+
+ RETURNS
+    Returns SUCCEED if successful and FAIL otherwise
+
+*******************************************************************************/
+intn H5Ainit_group(group_t grp,      /* IN: Group to initialize */
+    intn hash_size,                 /* IN: Minimum hash table size to use for group */
+    uintn reserved                  /* IN: Number of hash table entries to reserve */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5Ainit_group");	/* for HERROR */
+#endif /* LATER */
+    atom_group_t *grp_ptr=NULL;     /* ptr to the atomic group */
+    intn ret_value=SUCCEED;
+
+    PABLO_TRACE_ON(H5A_mask, ID_H5Ainit_group);
+
+    if((grp<=BADGROUP || grp>=MAXGROUP) && hash_size>0)
+        HGOTO_DONE(FAIL);
+
+#ifdef HASH_SIZE_POWER_2
+    /* If anyone knows a faster test for a power of two, please change this silly code -QAK */
+    if(!(hash_size==2 || hash_size==4 || hash_size==8 || hash_size==16
+            || hash_size==32 || hash_size==64 || hash_size==128 || hash_size==256
+            || hash_size==512 || hash_size==1024 || hash_size==2048
+            || hash_size==4096 || hash_size==8192 || hash_size==16374
+            || hash_size==32768 || hash_size==65536 || hash_size==131072
+            || hash_size==262144 || hash_size==524288 || hash_size==1048576
+            || hash_size==2097152 || hash_size==4194304 || hash_size==8388608
+            || hash_size==16777216 || hash_size==33554432 || hash_size==67108864
+            || hash_size==134217728 || hash_size==268435456))
+        HGOTO_DONE(FAIL);
+#endif /* HASH_SIZE_POWER_2 */
+
+    if(atom_group_list[grp]==NULL)
+      {     /* Allocate the group information */
+          grp_ptr=(atom_group_t *)HDcalloc(1,sizeof(atom_group_t));
+          if(grp_ptr==NULL)
+              HGOTO_DONE(FAIL);
+          atom_group_list[grp]=grp_ptr;
+      } /* end if */
+    else /* Get the pointer to the existing group */
+        grp_ptr=atom_group_list[grp];
+
+    if(grp_ptr->count==0)
+      {     /* Initialize the atom group structure */
+        grp_ptr->hash_size=hash_size;
+        grp_ptr->reserved=reserved;
+        grp_ptr->wrapped=0;
+        grp_ptr->atoms=0;
+        grp_ptr->nextid=0;
+        if((grp_ptr->atom_list=(atom_info_t **)HDcalloc(hash_size,sizeof(atom_info_t *)))==NULL)
+            HGOTO_DONE(FAIL);
+      } /* end if */
+
+    /* Increment the count of the times this group has been initialized */
+    grp_ptr->count++;
+
+#ifdef QAK
+printf("%s: group ID=%d, count=%d, current # of active atoms=%d\n",FUNC,grp,grp_ptr->count,grp_ptr->atoms);
+#endif /* QAK */
+done:
+  if(ret_value == FAIL)   
+    { /* Error condition cleanup */
+        if(grp_ptr!=NULL)
+          {
+            if(grp_ptr->atom_list!=NULL)
+                HDfree(grp_ptr->atom_list);
+            HDfree(grp_ptr);
+          } /* end if */
+    } /* end if */
+
+    /* Normal function cleanup */
+    FUNC_LEAVE(H5A_mask, ID_H5Ainit_group, ret_value);
+}   /* end H5Ainit_group() */
+
+/******************************************************************************
+ NAME
+     H5Adestroy_group - Destroy an atomic group
+
+ DESCRIPTION
+    Destroys an atomic group which atoms are stored in.  If the group still
+    has atoms which are registered, this routine fails.  If there have been
+    multiple initializations of the group, this routine just decrements the
+    count of initializations and does not check the atoms out-standing.
+
+ RETURNS
+    Returns SUCCEED if successful and FAIL otherwise
+
+*******************************************************************************/
+intn H5Adestroy_group(group_t grp       /* IN: Group to destroy */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5Adestroy_group");	/* for HERROR */
+#endif /* LATER */
+    atom_group_t *grp_ptr=NULL;     /* ptr to the atomic group */
+    intn ret_value=SUCCEED;
+
+    PABLO_TRACE_ON(H5A_mask, ID_H5Adestroy_group);
+
+    if(grp<=BADGROUP || grp>=MAXGROUP)
+        HGOTO_DONE(FAIL);
+
+    grp_ptr=atom_group_list[grp];
+    if(grp_ptr==NULL || grp_ptr->count<=0)
+        HGOTO_DONE(FAIL);
+
+#ifdef QAK
+printf("%s: group ID=%d, count=%d, current # of active atoms=%d\n",FUNC,grp,grp_ptr->count,grp_ptr->atoms);
+#endif /* QAK */
+    /* Decrement the number of users of the atomic group */
+    if((--(grp_ptr->count))==0)
+      {
+#ifdef ATOMS_ARE_CACHED
+      {
+        uintn i;
+
+        for(i=0; i<ATOM_CACHE_SIZE; i++)
+            if(ATOM_TO_GROUP(atom_id_cache[i])==grp)
+              {
+                atom_id_cache[i]=(-1);
+                atom_obj_cache[i]=NULL;
+              } /* end if */
+      } /* end block */
+#endif /* ATOMS_ARE_CACHED */
+        HDfree(grp_ptr->atom_list);
+      } /* end if */
+
+done:
+  if(ret_value == FAIL)   
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+    /* Normal function cleanup */
+    FUNC_LEAVE(H5A_mask, ID_H5Adestroy_group, ret_value);
+}   /* end H5Adestroy_group() */
+
+/******************************************************************************
+ NAME
+     H5Aregister_atom - Register an object in a group and get an atom for it.
+
+ DESCRIPTION
+    Registers an object in a group and returns an atom for it.  This routine
+    does _not_ check for unique-ness of the objects, if you register an object
+    twice, you will get two different atoms for it.  This routine does make
+    certain that each atom in a group is unique.  Atoms are created by getting
+    a unique number for the group the atom is in and incorporating the group
+    into the atom which is returned to the user.
+
+ RETURNS
+    Returns atom if successful and FAIL otherwise
+
+*******************************************************************************/
+hatom_t H5Aregister_atom(group_t grp,     /* IN: Group to register the object in */
+    const VOIDP object                    /* IN: Object to attach to atom */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5Aregister_atom");	/* for HERROR */
+#endif /* LATER */
+    atom_group_t *grp_ptr=NULL;     /* ptr to the atomic group */
+    atom_info_t *atm_ptr=NULL;      /* ptr to the new atom */
+    hatom_t atm_id;                  /* new atom ID */
+    uintn hash_loc;                 /* new item's hash table location */
+    hatom_t ret_value=SUCCEED;
+
+    PABLO_TRACE_ON(H5A_mask, ID_H5Aregister_atom);
+
+    if(grp<=BADGROUP || grp>=MAXGROUP)
+        HGOTO_DONE(FAIL);
+
+    grp_ptr=atom_group_list[grp];
+    if(grp_ptr==NULL || grp_ptr->count<=0)
+        HGOTO_DONE(FAIL);
+
+    if((atm_ptr=H5A_get_atom_node())==NULL)
+        HGOTO_DONE(FAIL);
+
+    /* Create the atom & it's ID */
+    atm_id=MAKE_ATOM(grp,grp_ptr->nextid);
+    atm_ptr->id=atm_id;
+    atm_ptr->obj_ptr=object;
+    atm_ptr->next=NULL;
+
+    /* hash bucket already full, prepend to front of chain */
+    hash_loc=grp_ptr->nextid%(uintn)grp_ptr->hash_size;
+    if(grp_ptr->atom_list[hash_loc]!=NULL)
+        atm_ptr->next=grp_ptr->atom_list[hash_loc];
+
+    /* Insert into the group */
+    grp_ptr->atom_list[hash_loc]=atm_ptr;
+    grp_ptr->atoms++;
+    grp_ptr->nextid++;
+
+    /*
+     * This next section of code checks for the 'nextid' getting too large and
+     * wrapping around, thus necessitating checking for duplicate atoms being
+     * handed out.
+     */
+    if(grp_ptr->nextid>(uintn)ATOM_MASK || grp_ptr->wrapped!=0)
+      {
+        if(grp_ptr->wrapped==0)
+          {
+            grp_ptr->wrapped=1;       /* set the "wrapped around" flag if it isn't already */
+            grp_ptr->nextid=grp_ptr->reserved;    /* re-start the ID counter */
+          } /* end if */
+        do {
+            hatom_t next_atom=MAKE_ATOM(grp,grp_ptr->nextid);      /* new atom to check for */
+            atom_info_t *curr_atm;  /* ptr to the current atom */
+
+            curr_atm=grp_ptr->atom_list[(uintn)ATOM_TO_LOC(grp_ptr->nextid,grp_ptr->hash_size)];
+            if(curr_atm==NULL)    /* Ha! this is not likely... */
+                break;
+
+            while(curr_atm!=NULL)
+              {
+                  if(curr_atm->id==next_atom)
+                      break;
+                  curr_atm=curr_atm->next;
+              } /* end while */
+            if(curr_atm==NULL)    /* must not have found a match */
+                break;
+            grp_ptr->nextid++;
+         } while(grp_ptr->nextid<=(uintn)ATOM_MASK);
+        if(grp_ptr->nextid>(uintn)ATOM_MASK)  /* All the atoms are gone! */
+            HGOTO_DONE(FAIL);
+      } /* end if */
+
+    ret_value=atm_id;
+
+done:
+  if(ret_value == FAIL)   
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+    /* Normal function cleanup */
+    FUNC_LEAVE(H5A_mask, ID_H5Aregister_atom, ret_value);
+}   /* end H5Aregister_atom() */
+
+/******************************************************************************
+ NAME
+     H5Aatom_object - Returns to the object ptr for the atom 
+
+ DESCRIPTION
+    Retrieves the object ptr which is associated with the atom.
+
+ RETURNS
+    Returns object ptr if successful and NULL otherwise
+
+*******************************************************************************/
+VOIDP H5Aatom_object(hatom_t atm   /* IN: Atom to retrieve object for */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5Aatom_object");	/* for HERROR */
+#endif /* LATER */
+#ifdef ATOMS_ARE_CACHED
+    uintn i;                        /* local counter */
+#endif /* ATOMS_ARE_CACHED */
+    atom_info_t *atm_ptr=NULL;      /* ptr to the new atom */
+    VOIDP ret_value=NULL;
+
+    PABLO_TRACE_ON(H5A_mask, ID_H5Aatom_object);
+
+#ifdef ATOMS_ARE_CACHED
+    /* Look for the atom in the cache first */
+    for(i=0; i<ATOM_CACHE_SIZE; i++)
+        if(atom_id_cache[i]==atm)
+          {
+            ret_value=atom_obj_cache[i];
+            if(i>0)
+              { /* Implement a simple "move forward" caching scheme */
+                hatom_t t_atom=atom_id_cache[i-1];
+                VOIDP  t_obj=atom_obj_cache[i-1];
+
+                atom_id_cache[i-1]=atom_id_cache[i];
+                atom_obj_cache[i-1]=atom_obj_cache[i];
+                atom_id_cache[i]=t_atom;
+                atom_obj_cache[i]=t_obj;
+              } /* end if */
+            HGOTO_DONE(ret_value);
+          } /* end if */
+#endif /* ATOMS_ARE_CACHED */
+
+    /* General lookup of the atom */
+    if((atm_ptr=H5A_find_atom(atm))==NULL)
+        HGOTO_DONE(NULL);
+
+    /* Check if we've found the correct atom */
+    if(atm_ptr!=NULL)
+        ret_value=atm_ptr->obj_ptr;
+
+done:
+  if(ret_value == NULL)   
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+    /* Normal function cleanup */
+    FUNC_LEAVE(H5A_mask, ID_H5Aatom_object, ret_value);
+}   /* end H5Aatom_object() */
+
+/******************************************************************************
+ NAME
+     H5Aatom_group - Returns to the group for the atom 
+
+ DESCRIPTION
+    Retrieves the group which is associated with the atom.
+
+ RETURNS
+    Returns group if successful and BADGROUP otherwise
+
+*******************************************************************************/
+group_t H5Aatom_group(hatom_t atm   /* IN: Atom to retrieve group for */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5Aatom_group");	/* for HERROR */
+#endif /* LATER */
+    group_t ret_value=BADGROUP;
+
+    PABLO_TRACE_ON(H5A_mask, ID_H5Aatom_group);
+
+    ret_value=ATOM_TO_GROUP(atm);
+    if(ret_value<=BADGROUP || ret_value>=MAXGROUP)
+        HGOTO_DONE(BADGROUP);
+
+done:
+  if(ret_value == BADGROUP)   
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+    /* Normal function cleanup */
+    FUNC_LEAVE(H5A_mask, ID_H5Aatom_group, ret_value);
+}   /* end H5Aatom_group() */
+
+/******************************************************************************
+ NAME
+     H5Aremove_atom - Removes an atom from a group
+
+ DESCRIPTION
+    Removes an atom from a group.
+
+ RETURNS
+    Returns atom's object if successful and NULL otherwise
+
+*******************************************************************************/
+VOIDP H5Aremove_atom(hatom_t atm   /* IN: Atom to remove */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5Aremove_atom");	/* for HERROR */
+#endif /* LATER */
+    atom_group_t *grp_ptr=NULL;     /* ptr to the atomic group */
+    atom_info_t *curr_atm,          /* ptr to the current atom */
+        *last_atm;                  /* ptr to the last atom */
+    group_t grp;                    /* atom's atomic group */
+    uintn hash_loc;                 /* atom's hash table location */
+#ifdef ATOMS_ARE_CACHED
+    uintn i;                        /* local counting variable */
+#endif /* ATOMS_ARE_CACHED */
+    VOIDP ret_value=NULL;
+
+    PABLO_TRACE_ON(H5A_mask, ID_H5Aremove_atom);
+
+    grp=ATOM_TO_GROUP(atm);
+    if(grp<=BADGROUP || grp>=MAXGROUP)
+        HGOTO_DONE(NULL);
+
+    grp_ptr=atom_group_list[grp];
+    if(grp_ptr==NULL || grp_ptr->count<=0)
+        HGOTO_DONE(NULL);
+
+    /* Get the location in which the atom is located */
+    hash_loc=(uintn)ATOM_TO_LOC(atm,grp_ptr->hash_size);
+    curr_atm=grp_ptr->atom_list[hash_loc];
+    if(curr_atm==NULL)
+        HGOTO_DONE(NULL);
+
+    last_atm=NULL;
+    while(curr_atm!=NULL)
+      {
+          if(curr_atm->id==atm)
+              break;
+          last_atm=curr_atm;
+          curr_atm=curr_atm->next;
+      } /* end while */
+
+    if(curr_atm!=NULL)
+      {
+          if(last_atm==NULL)    /* atom is the first the chain */
+              grp_ptr->atom_list[hash_loc]=curr_atm->next;
+          else
+              last_atm->next=curr_atm->next;
+          ret_value=curr_atm->obj_ptr;
+          H5A_release_atom_node(curr_atm);
+      } /* end if */
+    else    /* couldn't find the atom in the proper place */
+        HGOTO_DONE(NULL);
+    
+#ifdef ATOMS_ARE_CACHED
+    /* Delete object from cache */
+    for(i=0; i<ATOM_CACHE_SIZE; i++)
+        if(atom_id_cache[i]==atm)
+          {
+            atom_id_cache[i]=(-1);
+            atom_obj_cache[i]=NULL;
+            break;  /* we assume there is only one instance in the cache */
+          } /* end if */
+#endif /* ATOMS_ARE_CACHED */
+
+    /* Decrement the number of atoms in the group */
+    (grp_ptr->atoms)--;
+
+done:
+  if(ret_value == NULL)   
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+    /* Normal function cleanup */
+    FUNC_LEAVE(H5A_mask, ID_H5Aremove_atom, ret_value);
+}   /* end H5Aremove_atom() */
+
+/******************************************************************************
+ NAME
+     H5Asearch_atom - Search for an object in a group and get it's pointer.
+
+ DESCRIPTION
+    Searchs for an object in a group and returns the pointer to it.
+    This routine calls the function pointer passed in for each object in the
+    group until it finds a match.  Currently there is no way to resume a
+    search.
+
+ RETURNS
+    Returns pointer an atom's object if successful and NULL otherwise
+
+*******************************************************************************/
+VOIDP H5Asearch_atom(group_t grp,        /* IN: Group to search for the object in */
+    H5Asearch_func_t func,               /* IN: Ptr to the comparison function */
+    const VOIDP key                     /* IN: pointer to key to compare against */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5Asearch_atom");	/* for HERROR */
+#endif /* LATER */
+    atom_group_t *grp_ptr=NULL;     /* ptr to the atomic group */
+    atom_info_t *atm_ptr=NULL;      /* ptr to the new atom */
+    intn i;                         /* local counting variable */
+    VOIDP ret_value=NULL;
+
+    PABLO_TRACE_ON(H5A_mask, ID_H5Asearch_atom);
+
+    if(grp<=BADGROUP || grp>=MAXGROUP)
+        HGOTO_DONE(NULL);
+
+    grp_ptr=atom_group_list[grp];
+    if(grp_ptr==NULL || grp_ptr->count<=0)
+        HGOTO_DONE(NULL);
+
+    /* Start at the beginning of the array */
+    for(i=0; i<grp_ptr->hash_size; i++)
+      {
+        atm_ptr=grp_ptr->atom_list[i];
+        while(atm_ptr!=NULL)
+          {
+              if((*func)(atm_ptr->obj_ptr,key))
+                  HGOTO_DONE(atm_ptr->obj_ptr); /* found the item we are looking for */
+              atm_ptr=atm_ptr->next;
+          } /* end while */
+      } /* end for */
+
+done:
+  if(ret_value == NULL)
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+    /* Normal function cleanup */
+    FUNC_LEAVE(H5A_mask, ID_H5Asearch_atom, ret_value);
+}   /* end H5Asearch_atom() */
+
+/******************************************************************************
+ NAME
+     H5Ais_reserved - Check whether an atom is a reserved atom in a group
+
+ DESCRIPTION
+    Determines the group an atom belongs to and checks if the atom is a
+    reserved atom in the group.
+
+ RETURNS
+    Returns BTRUE/BFALSE/BFAIL
+
+*******************************************************************************/
+intn H5Ais_reserved(hatom_t atm      /* IN: Group to search for the object in */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5Ais_reserved");	/* for HERROR */
+#endif /* LATER */
+    atom_group_t *grp_ptr=NULL;     /* ptr to the atomic group */
+    group_t grp;                    /* atom's atomic group */
+    hbool_t ret_value=BFAIL;
+
+    PABLO_TRACE_ON(H5A_mask, ID_H5Ais_reserved);
+
+    grp=ATOM_TO_GROUP(atm);
+    if(grp<=BADGROUP || grp>=MAXGROUP)
+        HGOTO_DONE(BFAIL);
+
+    grp_ptr=atom_group_list[grp];
+    if(grp_ptr==NULL)
+        HGOTO_DONE(BFAIL);
+
+    /* Get the location in which the atom is located */
+    if((atm&ATOM_MASK)<grp_ptr->reserved)
+        ret_value=BTRUE;
+    else
+        ret_value=BFALSE;
+
+done:
+  if(ret_value == BFAIL)
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+    /* Normal function cleanup */
+    FUNC_LEAVE(H5A_mask, ID_H5Ais_reserved, ret_value);
+}   /* end H5Ais_reserved() */
+
+/******************************************************************************
+ NAME
+     H5A_find_atom - Finds a atom in a group
+
+ DESCRIPTION
+    Retrieves the atom ptr which is associated with the atom.
+
+ RETURNS
+    Returns atom ptr if successful and NULL otherwise
+
+*******************************************************************************/
+static atom_info_t *H5A_find_atom(hatom_t atm   /* IN: Atom to retrieve atom for */
+)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5A_find_atom");	/* for HERROR */
+#endif /* LATER */
+    atom_group_t *grp_ptr=NULL;     /* ptr to the atomic group */
+    atom_info_t *atm_ptr=NULL;      /* ptr to the new atom */
+    group_t grp;                    /* atom's atomic group */
+    uintn hash_loc;                 /* atom's hash table location */
+    atom_info_t *ret_value=NULL;
+
+
+    grp=ATOM_TO_GROUP(atm);
+    if(grp<=BADGROUP || grp>=MAXGROUP)
+        HGOTO_DONE(NULL);
+
+    grp_ptr=atom_group_list[grp];
+    if(grp_ptr==NULL || grp_ptr->count<=0)
+        HGOTO_DONE(NULL);
+
+    /* Get the location in which the atom is located */
+    hash_loc=(uintn)ATOM_TO_LOC(atm,grp_ptr->hash_size);
+    atm_ptr=grp_ptr->atom_list[hash_loc];
+    if(atm_ptr==NULL)
+        HGOTO_DONE(NULL);
+
+    while(atm_ptr!=NULL)
+      {
+          if(atm_ptr->id==atm)
+              break;
+          atm_ptr=atm_ptr->next;
+      } /* end while */
+    ret_value=atm_ptr;
+
+#ifdef ATOMS_ARE_CACHED
+    atom_id_cache[ATOM_CACHE_SIZE-1]=atm;
+    atom_obj_cache[ATOM_CACHE_SIZE-1]=atm_ptr->obj_ptr;
+#endif /* ATOMS_ARE_CACHED */
+
+done:
+  if(ret_value == NULL)   
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+  /* Normal function cleanup */
+
+  return ret_value;
+}   /* end H5A_find_atom() */
+
+/******************************************************************************
+ NAME
+     H5A_get_atom_node - Gets an atom node
+
+ DESCRIPTION
+    Either gets an atom node from the free list (if there is one available)
+    or allocate a node.
+
+ RETURNS
+    Returns atom ptr if successful and NULL otherwise
+
+*******************************************************************************/
+static atom_info_t *H5A_get_atom_node(void)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5A_get_atom_node");	/* for HERROR */
+#endif /* LATER */
+    atom_info_t *ret_value=NULL;
+
+    if(atom_free_list!=NULL)
+      {
+        ret_value=atom_free_list;
+        atom_free_list=atom_free_list->next;
+      } /* end if */
+    else
+      {
+        if((ret_value=(atom_info_t *)HDmalloc(sizeof(atom_info_t)))==NULL)
+            HGOTO_DONE(NULL);
+      } /* end else */
+
+done:
+  if(ret_value == NULL)   
+    { /* Error condition cleanup */
+
+    } /* end if */
+
+  /* Normal function cleanup */
+
+  return ret_value;
+}   /* end H5A_get_atom_node() */
+
+/******************************************************************************
+ NAME
+     H5A_release_atom_node - Releases an atom node
+
+ DESCRIPTION
+    Puts an atom node into the free list
+
+ RETURNS
+    No return value
+
+*******************************************************************************/
+static void H5A_release_atom_node(atom_info_t *atm)
+{
+#ifdef LATER
+    CONSTR(FUNC, "H5A_release_atom_node");	/* for HERROR */
+#endif /* LATER */
+
+    /* Insert the atom at the beginning of the free list */
+    atm->next=atom_free_list;
+    atom_free_list=atm;
+}   /* end H5A_release_atom_node() */
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5Ashutdown
+ PURPOSE
+    Terminate various static buffers.
+ USAGE
+    intn H5Ashutdown()
+ RETURNS
+    Returns SUCCEED/FAIL
+ DESCRIPTION
+    Free various buffers allocated in the H5A routines.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    Should only ever be called by the "atexit" function HDFend
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+intn 
+H5Ashutdown(void)
+{
+    atom_info_t *curr;
+    intn i;
+
+    /* Release the free-list if it exists */
+    if(atom_free_list!=NULL)
+      {
+        while(atom_free_list!=NULL)
+          {
+            curr=atom_free_list;
+            atom_free_list=atom_free_list->next;
+            HDfree(curr);
+          } /* end while */
+      } /* end if */
+
+    for(i=0; i<(intn)MAXGROUP; i++)
+        if(atom_group_list[i]!=NULL)
+          {
+            HDfree(atom_group_list[i]);
+            atom_group_list[i]=NULL;
+          } /* end if */
+  return (SUCCEED);
+}	/* end H5Ashutdown() */
+