[svn-r6436] Purpose:

    New internal feature

Description:
    Add internal API for building and working with heaps (H5HP).  This will be
    used for the LRU algorithm in the new metadata cache code.

Platforms tested:
    Tested h5committest {arabica (fortran), eirene (fortran, C++)
	modi4 (parallel, fortran)}
    FreeBSD 4.7 (sleipnir)

3 files changed, 1014 insertions, 9 deletions

diff --git a/src/H5HP.c b/src/H5HP.c
new file mode 100644
index 0000000..325392a
--- /dev/null
+++ b/src/H5HP.c
@@ -0,0 +1,934 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * 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. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Purpose:	Provides a heap abstract data type.
+ *
+ *              (See chapter 11 - "Priority Queues" of _Algorithms_, by
+ *              Sedgewick for additional information)
+ *
+ */
+
+/* Private headers needed */
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5HPprivate.h"	/* Heap routines			*/
+#include "H5FLprivate.h"	/* Memory management functions		*/
+
+/* Pablo information */
+#define PABLO_MASK	H5HP_mask
+
+/* Interface initialization? */
+static int		interface_initialize_g = 0;
+#define INTERFACE_INIT NULL
+
+/* Local Macros */
+#define H5HP_START_SIZE 16      /* Initial number of entries for heaps */
+
+/* Private typedefs & structs */
+
+/* Data structure for entries in the internal heap array */
+typedef struct {
+    int val;            /* Value to be used for heap condition */
+    H5HP_info_t *obj;   /* Pointer to object stored in heap */
+}H5HP_ent_t;
+
+/* Main heap data structure */
+struct H5HP_t {
+    H5HP_type_t type;   /* Type of heap (minimum or maximum value at "top") */
+    size_t nobjs;       /* Number of active objects in heap array */
+    size_t nalloc;      /* Number of allocated locations in heap array */
+    H5HP_ent_t *heap;   /* Pointer to array containing heap entries */
+};
+
+/* Static functions */
+static herr_t H5HP_swim_max(H5HP_t *heap, size_t loc);
+static herr_t H5HP_swim_min(H5HP_t *heap, size_t loc);
+static herr_t H5HP_sink_max(H5HP_t *heap, size_t loc);
+static herr_t H5HP_sink_min(H5HP_t *heap, size_t loc);
+
+/* Declare a free list to manage the H5HP_t struct */
+H5FL_DEFINE_STATIC(H5HP_t);
+
+/* Declare a free list to manage arrays of H5HP_ent_t */
+H5FL_ARR_DEFINE_STATIC(H5HP_ent_t,-1);
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_swim_max
+ PURPOSE
+    Restore heap condition by moving an object upward
+ USAGE
+    herr_t H5HP_swim_max(heap, loc)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        size_t loc;             IN: Location to start from
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Restore the heap condition for the heap's array by "swimming" the object
+    at a location upward.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    This routine is for "maximum" value heaps.
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+static herr_t
+H5HP_swim_max(H5HP_t *heap, size_t loc)
+{
+    int val;                    /* Temporary copy value of object to move in heap */
+    H5HP_info_t *obj;           /* Temporary pointer to object to move in heap */
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOINIT(H5HP_swim_max);
+
+    /* Get copies of the information about the object to move in the heap */
+    val=heap->heap[loc].val;
+    obj=heap->heap[loc].obj;
+
+    /* Move object up in heap until it's reached the maximum location possible */
+    while(heap->heap[loc/2].val < val) {
+        /* Move object "above" current location in heap down */
+        heap->heap[loc].val=heap->heap[loc/2].val;
+        heap->heap[loc].obj=heap->heap[loc/2].obj;
+
+        /* Update heap location for object which moved */
+        heap->heap[loc].obj->heap_loc=loc;
+
+        /* Move to location "above" current location */
+        loc=loc/2;
+    } /* end while */
+
+    /* Put object into heap at correct location */
+    heap->heap[loc].val=val;
+    heap->heap[loc].obj=obj;
+
+    /* Update heap location for object */
+    heap->heap[loc].obj->heap_loc=loc;
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_swim_max() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_swim_min
+ PURPOSE
+    Restore heap condition by moving an object upward
+ USAGE
+    herr_t H5HP_swim_min(heap, loc)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        size_t loc;             IN: Location to start from
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Restore the heap condition for the heap's array by "swimming" the object
+    at a location upward.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    This routine is for "minimum" value heaps.
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+static herr_t
+H5HP_swim_min(H5HP_t *heap, size_t loc)
+{
+    int val;                    /* Temporary copy value of object to move in heap */
+    H5HP_info_t *obj;           /* Temporary pointer to object to move in heap */
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOINIT(H5HP_swim_min);
+
+    /* Get copies of the information about the object to move in the heap */
+    val=heap->heap[loc].val;
+    obj=heap->heap[loc].obj;
+
+    /* Move object up in heap until it's reached the minimum location possible */
+    while(heap->heap[loc/2].val > val) {
+        /* Move object "above" current location in heap down */
+        heap->heap[loc].val=heap->heap[loc/2].val;
+        heap->heap[loc].obj=heap->heap[loc/2].obj;
+
+        /* Update heap location for object which moved */
+        heap->heap[loc].obj->heap_loc=loc;
+
+        /* Move to location "above" current location */
+        loc=loc/2;
+    } /* end while */
+
+    /* Put object into heap at correct location */
+    heap->heap[loc].val=val;
+    heap->heap[loc].obj=obj;
+
+    /* Update heap location for object */
+    heap->heap[loc].obj->heap_loc=loc;
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_swim_min() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_sink_max
+ PURPOSE
+    Restore heap condition by moving an object downward
+ USAGE
+    herr_t H5HP_sink_max(heap, loc)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        size_t loc;             IN: Location to start from
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Restore the heap condition for the heap's array by "sinking" the object
+    at a location downward.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    This routine is for "maximum" value heaps.
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+static herr_t
+H5HP_sink_max(H5HP_t *heap, size_t loc)
+{
+    int val;                    /* Temporary copy value of object to move in heap */
+    void *obj;                  /* Temporary pointer to object to move in heap */
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOINIT(H5HP_sink_max);
+
+    /* Get copies of the information about the object to move in the heap */
+    val=heap->heap[loc].val;
+    obj=heap->heap[loc].obj;
+
+    /* Move object up in heap until it's reached the maximum location possible */
+    while((2*loc)<=heap->nobjs) {
+        size_t new_loc=loc*2;   /* New object's potential location area */
+
+        /* Get the greater of the two objects below the location in heap */
+        if(new_loc<heap->nobjs && (heap->heap[new_loc].val < heap->heap[new_loc+1].val))
+            new_loc++;
+
+        /* Check if the object is smaller than the larger of the objects below it */
+        /* If so, its in the correct location now, and we can get out */
+        if(val >= heap->heap[new_loc].val)
+            break;
+
+        /* Move the greater of the two objects below the current location up */
+        heap->heap[loc].val=heap->heap[new_loc].val;
+        heap->heap[loc].obj=heap->heap[new_loc].obj;
+
+        /* Update heap location for object which moved */
+        heap->heap[loc].obj->heap_loc=loc;
+
+        /* Move to location "below" current location */
+        loc=new_loc;
+    } /* end while */
+
+    /* Put object into heap at correct location */
+    heap->heap[loc].val=val;
+    heap->heap[loc].obj=obj;
+
+    /* Update heap location for object */
+    heap->heap[loc].obj->heap_loc=loc;
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_sink_max() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_sink_min
+ PURPOSE
+    Restore heap condition by moving an object downward
+ USAGE
+    herr_t H5HP_sink_min(heap, loc)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        size_t loc;             IN: Location to start from
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Restore the heap condition for the heap's array by "sinking" the object
+    at a location downward.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    This routine is for "minimum" value heaps.
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+static herr_t
+H5HP_sink_min(H5HP_t *heap, size_t loc)
+{
+    int val;                    /* Temporary copy value of object to move in heap */
+    void *obj;                  /* Temporary pointer to object to move in heap */
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOINIT(H5HP_sink_min);
+
+    /* Get copies of the information about the object to move in the heap */
+    val=heap->heap[loc].val;
+    obj=heap->heap[loc].obj;
+
+    /* Move object up in heap until it's reached the maximum location possible */
+    while((2*loc)<=heap->nobjs) {
+        size_t new_loc=loc*2;   /* New object's potential location area */
+
+        /* Get the lesser of the two objects below the location in heap */
+        if(new_loc<heap->nobjs && (heap->heap[new_loc].val > heap->heap[new_loc+1].val))
+            new_loc++;
+
+        /* Check if the object is greater than the larger of the objects below it */
+        /* If so, its in the correct location now, and we can get out */
+        if(val <= heap->heap[new_loc].val)
+            break;
+
+        /* Move the greater of the two objects below the current location up */
+        heap->heap[loc].val=heap->heap[new_loc].val;
+        heap->heap[loc].obj=heap->heap[new_loc].obj;
+
+        /* Update heap location for object which moved */
+        heap->heap[loc].obj->heap_loc=loc;
+
+        /* Move to location "below" current location */
+        loc=new_loc;
+    } /* end while */
+
+    /* Put object into heap at correct location */
+    heap->heap[loc].val=val;
+    heap->heap[loc].obj=obj;
+
+    /* Update heap location for object */
+    heap->heap[loc].obj->heap_loc=loc;
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_sink_min() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_create
+ PURPOSE
+    Create a heap
+ USAGE
+    H5HP_t *H5HP_create(heap_type)
+        H5HP_type_t heap_type;          IN: Type of heap to create
+
+ RETURNS
+    Returns a pointer to a heap on success, NULL on failure.
+ DESCRIPTION
+    Create a priority queue.  The SIZE is used to set the initial number of
+    entries allocated.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+H5HP_t *
+H5HP_create(H5HP_type_t heap_type)
+{
+    H5HP_t *new_heap=NULL;      /* Pointer to new heap object created */
+    H5HP_t *ret_value;          /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_create,NULL);
+
+    /* Check args */
+    assert(heap_type==H5HP_MIN_HEAP || heap_type==H5HP_MAX_HEAP);
+
+    /* Allocate ref-counted string structure */
+    if((new_heap=H5FL_MALLOC(H5HP_t))==NULL)
+        HGOTO_ERROR(H5E_HEAP,H5E_NOSPACE,NULL,"memory allocation failed");
+
+    /* Allocate the array to store the heap entries */
+    if((new_heap->heap=H5FL_ARR_MALLOC(H5HP_ent_t, H5HP_START_SIZE+1))==NULL)
+        HGOTO_ERROR(H5E_HEAP,H5E_NOSPACE,NULL,"memory allocation failed");
+
+    /* Set the internal fields */
+    new_heap->type=heap_type;
+    new_heap->nobjs=0;
+    new_heap->nalloc=H5HP_START_SIZE+1;
+
+    /* Set the information in the 0'th location based on the type of heap */
+    if(heap_type==H5HP_MIN_HEAP) {
+        /* Set the value in the '0' location to be the minimum value, to
+         * simplify the algorithms
+         */
+        new_heap->heap[0].val=INT_MIN;
+        new_heap->heap[0].obj=NULL;
+    } /* end if */
+    else {
+        /* Set the value in the '0' location to be the maximum value, to
+         * simplify the algorithms
+         */
+        new_heap->heap[0].val=INT_MAX;
+        new_heap->heap[0].obj=NULL;
+    } /* end else */
+
+    /* Set the return value */
+    ret_value=new_heap;
+
+done:
+    /* Error cleanup */
+    if(ret_value==NULL) {
+        if(new_heap!=NULL) {
+            if(new_heap->heap!=NULL)
+                H5FL_ARR_FREE(H5HP_ent_t,new_heap->heap);
+            H5FL_FREE(H5HP_t,new_heap);
+        } /* end if */
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_create() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_count
+ PURPOSE
+    Check the number of elements in a heap
+ USAGE
+    ssize_t H5HP_count(heap)
+        const H5HP_t *heap;     IN: Pointer to heap to query
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Checks the number of elements in heap
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+ssize_t
+H5HP_count(const H5HP_t *heap)
+{
+    ssize_t ret_value;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_count,FAIL);
+
+    /* Check args */
+    assert(heap);
+
+    /* Check internal consistency */
+    /* (Pre-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    /* Return the number of objects in the heap */
+    ret_value=heap->nobjs;
+
+done:
+    /* No post-condition check necessary, since heap is constant */
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_count() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_insert
+ PURPOSE
+    Insert an object into a heap, with an initial value
+ USAGE
+    herr_t H5HP_insert(heap, val, obj)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        int val;                IN: Initial value for object in heap
+        void *obj;              IN: Pointer to object to insert into heap
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Inserts a OBJ into a HEAP, with an initial VALue.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5HP_insert(H5HP_t *heap, int val, void *obj)
+{
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_insert,FAIL);
+
+    /* Check args */
+    assert(heap);
+    assert(obj);
+
+    /* Check internal consistency */
+    /* (Pre-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    /* Increment number of objects in heap */
+    heap->nobjs++;
+
+    /* Check if we need to allocate more room for heap array */
+    if(heap->nobjs>=heap->nalloc) {
+        size_t n = MAX(H5HP_START_SIZE, 2*(heap->nalloc-1)) + 1;
+        H5HP_ent_t *new_heap = H5FL_ARR_REALLOC(H5HP_ent_t,heap->heap, n);
+
+        if (!new_heap)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to extend heap array");
+        heap->heap = new_heap;
+        heap->nalloc = n;
+    } /* end if */
+
+    /* Insert new object at end of heap */
+    heap->heap[heap->nobjs].val=val;
+    heap->heap[heap->nobjs].obj=obj;
+    heap->heap[heap->nobjs].obj->heap_loc=heap->nobjs;
+
+    /* Restore heap condition */
+    if(heap->type==H5HP_MAX_HEAP) {
+        if(H5HP_swim_max(heap,heap->nobjs)<0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTINSERT, FAIL, "unable to restore heap condition");
+    } /* end if */
+    else {
+        if(H5HP_swim_min(heap,heap->nobjs)<0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTINSERT, FAIL, "unable to restore heap condition");
+    } /* end else */
+
+done:
+
+    /* Check internal consistency */
+    /* (Post-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_insert() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_top
+ PURPOSE
+    Check the value of the top object in the heap
+ USAGE
+    herr_t H5HP_top(heap, val)
+        const H5HP_t *heap;     IN: Pointer to heap to modify
+        int val;                IN/OUT: Initial value for object in heap
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Checks the value of the top object in a heap
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5HP_top(const H5HP_t *heap, int *val)
+{
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_top,FAIL);
+
+    /* Check args */
+    assert(heap);
+    assert(val);
+
+    /* Check internal consistency */
+    /* (Pre-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    /* Get value of the top object in the heap */
+    *val=heap->heap[1].val;
+
+done:
+
+    /* No post-condition check necessary, since heap is constant */
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_top() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_remove
+ PURPOSE
+    Remove an object into a heap
+ USAGE
+    herr_t H5HP_remove(heap, val, obj)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        int *val;               OUT: Pointer to value of object removed from heap
+        void **obj;             OUT: Pointer to object removed from heap
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Removes the top object on a heap, returning its value and object pointer
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5HP_remove(H5HP_t *heap, int *val, void **obj)
+{
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_remove,FAIL);
+
+    /* Check args */
+    assert(heap);
+    assert(val);
+    assert(obj);
+
+    /* Check internal consistency */
+    /* (Pre-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    /* Check if there are any objects on the heap to remove */
+    if(heap->nobjs==0)
+        HGOTO_ERROR(H5E_HEAP, H5E_NOTFOUND, FAIL, "heap is empty");
+
+    /* Get the information for the top object on the heap */
+    assert(heap->heap[1].obj->heap_loc==1);
+    *val=heap->heap[1].val;
+    *obj=heap->heap[1].obj;
+
+    /* Move the last element in the heap to the top */
+    heap->heap[1].val=heap->heap[heap->nobjs].val;
+    heap->heap[1].obj=heap->heap[heap->nobjs].obj;
+    heap->heap[1].obj->heap_loc=1;
+
+    /* Decrement number of objects in heap */
+    heap->nobjs--;
+
+    /* Restore heap condition, if there are objects on the heap */
+    if(heap->nobjs>0) {
+        if(heap->type==H5HP_MAX_HEAP) {
+            if(H5HP_sink_max(heap,1)<0)
+                HGOTO_ERROR(H5E_HEAP, H5E_CANTDELETE, FAIL, "unable to restore heap condition");
+        } /* end if */
+        else {
+            if(H5HP_sink_min(heap,1)<0)
+                HGOTO_ERROR(H5E_HEAP, H5E_CANTDELETE, FAIL, "unable to restore heap condition");
+        } /* end else */
+    } /* end if */
+
+done:
+
+    /* Check internal consistency */
+    /* (Post-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_remove() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_change
+ PURPOSE
+    Change the priority of an object on a heap
+ USAGE
+    herr_t H5HP_change(heap, val, obj)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        int val;                IN: New priority value for object
+        void *obj;              IN: Pointer to object to modify
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Changes the priority of an object on a heap.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5HP_change(H5HP_t *heap, int val, void *_obj)
+{
+    H5HP_info_t *obj=(H5HP_info_t *)_obj;       /* Alias for object */
+    size_t obj_loc;             /* Location of object in heap */
+    int old_val;                /* Object's old priority value */
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_change,FAIL);
+
+    /* Check args */
+    assert(heap);
+    assert(obj);
+
+    /* Check internal consistency */
+    /* (Pre-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    /* Get the location of the object in the heap */
+    obj_loc=obj->heap_loc;
+    assert(obj_loc>0 && obj_loc<=heap->nobjs);
+
+    /* Change the heap object's priority */
+    old_val=heap->heap[obj_loc].val;
+    heap->heap[obj_loc].val=val;
+
+    /* Restore heap condition */
+    if(val<old_val) {
+        if(heap->type==H5HP_MAX_HEAP) {
+            if(H5HP_sink_max(heap,obj_loc)<0)
+                HGOTO_ERROR(H5E_HEAP, H5E_CANTCHANGE, FAIL, "unable to restore heap condition");
+        } /* end if */
+        else {
+            if(H5HP_swim_min(heap,obj_loc)<0)
+                HGOTO_ERROR(H5E_HEAP, H5E_CANTCHANGE, FAIL, "unable to restore heap condition");
+        } /* end else */
+    } /* end if */
+    else {
+        if(heap->type==H5HP_MAX_HEAP) {
+            if(H5HP_swim_max(heap,obj_loc)<0)
+                HGOTO_ERROR(H5E_HEAP, H5E_CANTCHANGE, FAIL, "unable to restore heap condition");
+        } /* end if */
+        else {
+            if(H5HP_sink_min(heap,obj_loc)<0)
+                HGOTO_ERROR(H5E_HEAP, H5E_CANTCHANGE, FAIL, "unable to restore heap condition");
+        } /* end else */
+    } /* end else */
+
+done:
+
+    /* Check internal consistency */
+    /* (Post-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_change() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_incr
+ PURPOSE
+    Increment the priority of an object on a heap
+ USAGE
+    herr_t H5HP_incr(heap, amt, obj)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        unsigned amt;           IN: Amount to increase priority by
+        void *obj;              IN: Pointer to object to modify
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Increments the priority of an object on a heap by one.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5HP_incr(H5HP_t *heap, unsigned amt, void *_obj)
+{
+    H5HP_info_t *obj=(H5HP_info_t *)_obj;       /* Alias for object */
+    size_t obj_loc;             /* Location of object in heap */
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_incr,FAIL);
+
+    /* Check args */
+    assert(heap);
+    assert(obj);
+
+    /* Check internal consistency */
+    /* (Pre-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    /* Get the location of the object in the heap */
+    obj_loc=obj->heap_loc;
+    assert(obj_loc>0 && obj_loc<=heap->nobjs);
+
+    /* Change the heap object's priority */
+    heap->heap[obj_loc].val+=amt;
+
+    /* Restore heap condition */
+    if(heap->type==H5HP_MAX_HEAP) {
+        if(H5HP_swim_max(heap,obj_loc)<0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTCHANGE, FAIL, "unable to restore heap condition");
+    } /* end if */
+    else {
+        if(H5HP_sink_min(heap,obj_loc)<0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTCHANGE, FAIL, "unable to restore heap condition");
+    } /* end else */
+
+done:
+
+    /* Check internal consistency */
+    /* (Post-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_incr() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_decr
+ PURPOSE
+    Decrement the priority of an object on a heap
+ USAGE
+    herr_t H5HP_dec(heap, amt, obj)
+        H5HP_t *heap;           IN/OUT: Pointer to heap to modify
+        unsigned amt;           IN: Amount to decrease priority by
+        void *obj;              IN: Pointer to object to modify
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Decrements the priority of an object on a heap by one.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5HP_decr(H5HP_t *heap, unsigned amt, void *_obj)
+{
+    H5HP_info_t *obj=(H5HP_info_t *)_obj;       /* Alias for object */
+    size_t obj_loc;             /* Location of object in heap */
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_decr,FAIL);
+
+    /* Check args */
+    assert(heap);
+    assert(obj);
+
+    /* Check internal consistency */
+    /* (Pre-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    /* Get the location of the object in the heap */
+    obj_loc=obj->heap_loc;
+    assert(obj_loc>0 && obj_loc<=heap->nobjs);
+
+    /* Change the heap object's priority */
+    heap->heap[obj_loc].val-=amt;
+
+    /* Restore heap condition */
+    if(heap->type==H5HP_MAX_HEAP) {
+        if(H5HP_sink_max(heap,obj_loc)<0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTCHANGE, FAIL, "unable to restore heap condition");
+    } /* end if */
+    else {
+        if(H5HP_swim_min(heap,obj_loc)<0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTCHANGE, FAIL, "unable to restore heap condition");
+    } /* end else */
+
+done:
+
+    /* Check internal consistency */
+    /* (Post-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_decr() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5HP_close
+ PURPOSE
+    Close a heap, deallocating it.
+ USAGE
+    herr_t H5HP_close(heap)
+        H5HP_t *heap;            IN/OUT: Pointer to heap to close
+
+ RETURNS
+    Returns non-negative on success, negative on failure.
+ DESCRIPTION
+    Close a heap, freeing all internal information.  Any objects left in
+    the heap are not deallocated.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5HP_close(H5HP_t *heap)
+{
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HP_close,FAIL);
+
+    /* Check args */
+    assert(heap);
+
+    /* Check internal consistency */
+    /* (Pre-condition) */
+    assert(heap->nobjs<heap->nalloc);
+    assert(heap->heap);
+    assert((heap->type==H5HP_MAX_HEAP && heap->heap[0].val==INT_MAX) ||
+        (heap->type==H5HP_MIN_HEAP && heap->heap[0].val==INT_MIN));
+    assert(heap->heap[0].obj==NULL);
+
+    /* Free internal structures for heap */
+    H5FL_ARR_FREE(H5HP_ent_t,heap->heap);
+
+    /* Free actual heap object */
+    H5FL_FREE(H5HP_t,heap);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5HP_close() */
+
diff --git a/src/H5HPprivate.h b/src/H5HPprivate.h
new file mode 100644
index 0000000..2c16ffe
--- /dev/null
+++ b/src/H5HPprivate.h
@@ -0,0 +1,70 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * 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. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * This file contains private information about the H5HP module
+ */
+#ifndef _H5HPprivate_H
+#define _H5HPprivate_H
+
+/**************************************/
+/* Public headers needed by this file */
+/**************************************/
+#ifdef LATER
+#include "H5HPpublic.h"
+#endif /* LATER */
+
+/***************************************/
+/* Private headers needed by this file */
+/***************************************/
+#include "H5private.h"
+
+/************/
+/* Typedefs */
+/************/
+
+/* Typedef for heap struct (defined in H5HP.c) */
+typedef struct H5HP_t H5HP_t;
+
+/* Typedef for objects which can be inserted into heaps */
+/* This _must_ be the first field in objects which can be inserted into heaps */
+typedef struct H5HP_info_t {
+    size_t heap_loc;                    /* Location of object in heap */
+}H5HP_info_t;
+
+/* Typedef for type of heap to create */
+typedef enum {
+    H5HP_MIN_HEAP,      /* Minimum values in heap are at the "top" */
+    H5HP_MAX_HEAP       /* Maximum values in heap are at the "top" */
+} H5HP_type_t;
+
+/**********/
+/* Macros */
+/**********/
+
+/********************/
+/* Private routines */
+/********************/
+H5_DLL H5HP_t *H5HP_create(H5HP_type_t heap_type);
+H5_DLL herr_t H5HP_insert(H5HP_t *heap, int val, void *obj);
+H5_DLL ssize_t H5HP_count(const H5HP_t *heap);
+H5_DLL herr_t H5HP_top(const H5HP_t *heap, int *val);
+H5_DLL herr_t H5HP_remove(H5HP_t *heap, int *val, void **ptr);
+H5_DLL herr_t H5HP_change(H5HP_t *heap, int val, void *obj);
+H5_DLL herr_t H5HP_incr(H5HP_t *heap, unsigned amt, void *obj);
+H5_DLL herr_t H5HP_decr(H5HP_t *heap, unsigned amt, void *obj);
+H5_DLL herr_t H5HP_close(H5HP_t *heap);
+
+#endif /* _H5HPprivate_H */
+
diff --git a/src/Makefile.in b/src/Makefile.in
index ea0e957..2fe150b 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -33,12 +33,12 @@ LIB_SRC=H5.c H5A.c H5AC.c H5B.c H5D.c H5E.c H5F.c H5Farray.c H5Fcontig.c      \
         H5FDfphdf5.c H5FDgass.c H5FDlog.c H5FDmpio.c H5FDmpiposix.c           \
         H5FDmulti.c H5FDsec2.c H5FDsrb.c H5FDstdio.c H5FDstream.c H5FL.c      \
         H5FO.c H5FP.c H5FPclient.c H5FPserver.c H5FS.c H5G.c H5Gent.c         \
-        H5Gnode.c H5Gstab.c H5HG.c H5HL.c H5I.c H5MF.c H5MM.c H5O.c H5Oattr.c \
-        H5Obogus.c H5Ocont.c H5Odtype.c H5Oefl.c H5Ofill.c H5Olayout.c        \
-        H5Omtime.c H5Oname.c H5Onull.c H5Opline.c H5Osdspace.c     \
+        H5Gnode.c H5Gstab.c H5HG.c H5HL.c H5HP.c H5I.c H5MF.c H5MM.c H5O.c    \
+        H5Oattr.c H5Obogus.c H5Ocont.c H5Odtype.c H5Oefl.c H5Ofill.c          \
+        H5Olayout.c H5Omtime.c H5Oname.c H5Onull.c H5Opline.c H5Osdspace.c    \
         H5Oshared.c H5Ostab.c H5P.c H5Pdcpl.c H5Pdxpl.c H5Pfapl.c H5Pfcpl.c   \
-        H5R.c H5RS.c H5S.c H5Sall.c H5Shyper.c H5Smpio.c H5Snone.c H5Spoint.c \
-        H5Sselect.c H5ST.c H5T.c H5Tarray.c H5Tbit.c H5Tcommit.c              \
+        H5R.c H5RS.c H5S.c H5Sall.c H5Shyper.c H5Smpio.c H5Snone.c     \
+        H5Spoint.c H5Sselect.c H5ST.c H5T.c H5Tarray.c H5Tbit.c H5Tcommit.c   \
         H5Tcompound.c H5Tconv.c H5Tcset.c H5Tenum.c H5Tfields.c H5Tfixed.c    \
         H5Tfloat.c H5Tinit.c H5Tnative.c H5Toffset.c H5Topaque.c H5Torder.c   \
         H5Tpad.c H5Tprecis.c H5Tstrpad.c H5Tvlen.c H5TB.c H5TS.c H5V.c H5Z.c  \
@@ -62,10 +62,11 @@ PUB_HDR=H5public.h H5Apublic.h H5ACpublic.h H5Bpublic.h H5Dpublic.h           \
 PRIVATE_HDR=H5private.h H5Aprivate.h H5Apkg.h H5ACprivate.h H5Bprivate.h      \
         H5Dprivate.h H5Eprivate.h H5Fprivate.h H5FDprivate.h H5FLprivate.h    \
         H5FOprivate.h H5FPprivate.h H5FSprivate.h H5Gprivate.h H5Gpkg.h       \
-        H5HGprivate.h H5HLprivate.h H5Iprivate.h H5MFprivate.h H5MMprivate.h  \
-        H5Oprivate.h H5Pprivate.h H5Ppkg.h H5Rprivate.h H5RSprivate.h         \
-        H5Sprivate.h H5STprivate.h H5Tprivate.h H5TBprivate.h H5Tpkg.h        \
-        H5TSprivate.h H5Vprivate.h H5Zprivate.h H5config.h
+        H5HGprivate.h H5HLprivate.h H5HPprivate.h H5Iprivate.h H5MFprivate.h  \
+        H5MMprivate.h H5Oprivate.h H5Opkg.h H5Pprivate.h H5Ppkg.h             \
+        H5Rprivate.h H5RSprivate.h H5Sprivate.h H5STprivate.h    \
+        H5Tprivate.h H5TBprivate.h H5Tpkg.h H5TSprivate.h H5Vprivate.h        \
+        H5Zprivate.h H5config.h
 
 ## Number format detection
 ## The LD_LIBRARY_PATH setting is a klutch.