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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* 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 skip list abstract data type.
*
* (See "Skip Lists: A Probabilistic Alternative to Balanced Trees"
* by William Pugh for additional information)
*
* (This implementation has the optimization for reducing key
* key comparisons mentioned in section 3.5 of "A Skip List
* Cookbook" by William Pugh)
*
* (Also, this implementation has a couple of home-grown
* optimizations, including setting the "update" vector to the
* actual 'forward' pointer to update, instead of the node
* containing the forward pointer -QAK)
*
*/
/* Interface initialization */
#define H5_INTERFACE_INIT_FUNC H5SL_init_interface
/* Pablo information */
/* (Put before include files to avoid problems with inline functions) */
#define PABLO_MASK H5SL_mask
/* Private headers needed */
#include "H5private.h" /* Generic Functions */
#include "H5Eprivate.h" /* Error handling */
#include "H5FLprivate.h" /* Free Lists */
#include "H5MMprivate.h" /* Memory management */
#include "H5SLprivate.h" /* Skip list routines */
/* Local Macros */
/* Define the code template for insertions for the "OP" in the H5SL_FIND macro */
#define H5SL_FIND_INSERT_FOUND(SLIST,X,UPDATE,I,ITEM) \
HGOTO_DONE(FAIL);
/* Define the code template for removals for the "OP" in the H5SL_FIND macro */
#define H5SL_FIND_REMOVE_FOUND(SLIST,X,UPDATE,I,ITEM) \
void *tmp; \
\
for(I=0; I<=(int)SLIST->curr_level; I++) { \
if(*UPDATE[I]!=X) \
break; \
*UPDATE[I]=X->forward[I]; \
} /* end for */ \
tmp=X->item; \
H5MM_xfree(X); \
while(SLIST->curr_level>0 && SLIST->header->forward[SLIST->curr_level]==NULL) \
SLIST->curr_level--; \
SLIST->nobjs--; \
HGOTO_DONE(tmp);
/* Define the code template for searches for the "OP" in the H5SL_FIND macro */
#define H5SL_FIND_SEARCH_FOUND(SLIST,X,UPDATE,I,ITEM) \
HGOTO_DONE(X->item);
/* Define a code template for updating the "update" vector for the "DOUPDATE" in the H5SL_FIND macro */
#define H5SL_FIND_YES_UPDATE(X,UPDATE,I) \
UPDATE[I]=&X->forward[I];
/* Define a code template for _NOT_ updating the "update" vector for the "DOUPDATE" in the H5SL_FIND macro */
#define H5SL_FIND_NO_UPDATE(X,UPDATE,I)
/* Macro used to find node for operation */
#define H5SL_FIND(OP,DOUPDATE,SLIST,X,UPDATE,I,TYPE,ITEM,KEY,CHECKED) \
CHECKED=NULL; \
for(I=(int)SLIST->curr_level; I>=0; I--) { \
if(X->forward[I]!=CHECKED) { \
while(X->forward[I] && *(TYPE *)X->forward[I]->key<*(TYPE *)KEY) \
X=X->forward[I]; \
CHECKED=X->forward[I]; \
} /* end if */ \
H5_GLUE3(H5SL_FIND_,DOUPDATE,_UPDATE)(X,UPDATE,I) \
} /* end for */ \
X=X->forward[0]; \
if(X!=NULL && *(TYPE *)X->key==*(TYPE *)key) { \
/* What to do when a node is found */ \
H5_GLUE3(H5SL_FIND_,OP,_FOUND)(SLIST,X,UPDATE,I,ITEM) \
} /* end if */
/* Macro used to insert node */
#define H5SL_INSERT(SLIST,X,UPDATE,I,TYPE,ITEM,KEY,CHECKED) \
H5SL_FIND(INSERT,YES,SLIST,X,UPDATE,I,TYPE,ITEM,KEY,CHECKED)
/* Macro used to remove node */
#define H5SL_REMOVE(SLIST,X,UPDATE,I,TYPE,ITEM,KEY,CHECKED) \
H5SL_FIND(REMOVE,YES,SLIST,X,UPDATE,I,TYPE,ITEM,KEY,CHECKED)
/* Macro used to search for node */
#define H5SL_SEARCH(SLIST,X,UPDATE,I,TYPE,ITEM,KEY,CHECKED) \
H5SL_FIND(SEARCH,NO,SLIST,X,UPDATE,I,TYPE,ITEM,KEY,CHECKED)
/* Private typedefs & structs */
/* Skip list node data structure */
struct H5SL_node_t {
void *key; /* Pointer to node's key */
void *item; /* Pointer to node's item */
size_t level; /* The level of this node */
struct H5SL_node_t **forward; /* Array of forward pointers from this node */
};
/* Main skip list data structure */
struct H5SL_t {
/* Static values for each list */
H5SL_type_t type; /* Type of skip list */
double p; /* Probability of using a higher level [0..1) */
int p1; /* Probability converted into appropriate value for random # generator on this machine */
size_t max_level; /* Maximum number of levels */
/* Dynamic values for each list */
int curr_level; /* Current top level used in list */
size_t nobjs; /* Number of active objects in skip list */
H5SL_node_t *header; /* Header for nodes in skip list */
};
/* Interface initialization */
static int interface_initialize_g = 0;
#define INTERFACE_INIT H5SL_init_interface
/* Static functions */
static herr_t H5SL_init_interface(void);
static size_t H5SL_random_level(int p1, size_t max_level);
static H5SL_node_t * H5SL_new_node(size_t lvl, void *item, void *key);
/* Declare a free list to manage the H5SL_t struct */
H5FL_DEFINE_STATIC(H5SL_t);
/*--------------------------------------------------------------------------
NAME
H5SL_init_interface
PURPOSE
Initialize interface-specific information
USAGE
herr_t H5SL_init_interface()
RETURNS
Non-negative on success/Negative on failure
DESCRIPTION
Initializes any interface-specific data or routines.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
static herr_t
H5SL_init_interface(void)
{
time_t curr_time; /* Current time, for seeding random number generator */
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_init_interface)
/* Create randomized set of numbers */
curr_time=HDtime(NULL);
HDsrand((unsigned)curr_time);
FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5SL_init_interface() */
/*--------------------------------------------------------------------------
NAME
H5SL_random_level
PURPOSE
Generate a random level
USAGE
size_t H5SL_random_level(p,max_level)
int p1; IN: probability distribution
size_t max_level; IN: Maximum level for node height
RETURNS
Returns non-negative level value
DESCRIPTION
Count elements in a skip list.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
Do we really need a 'random' value, or is a series of nodes with the
correct heights "good enough". We could track the state of the nodes
allocated for this list and issue node heights appropriately (i.e. 1,2,
1,4,1,2,1,8,...) (or would that be 1,1,2,1,1,2,4,... ?)
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
static size_t
H5SL_random_level(int p1, size_t max_level)
{
size_t lvl; /* Level generated */
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_random_level);
/* Account for starting at zero offset */
max_level--;
lvl=0;
while(HDrand()<p1 && lvl < max_level)
lvl++;
FUNC_LEAVE_NOAPI(lvl);
} /* end H5SL_random_level() */
/*--------------------------------------------------------------------------
NAME
H5SL_new_node
PURPOSE
Create a new skip list node
USAGE
H5SL_node_t *H5SL_new_node(lvl,item,key)
size_t lvl; IN: Level for node height
void *item; IN: Pointer to item info for node
void *key; IN: Pointer to key info for node
RETURNS
Returns a pointer to a skip list node on success, NULL on failure.
DESCRIPTION
Create a new skip list node of the specified height, setting the item
and key values internally.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
This routine does _not_ initialize the 'forward' pointers
We should set up a custom free-list for allocating & freeing these sort
of nodes.
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
static H5SL_node_t *
H5SL_new_node(size_t lvl, void *item, void *key)
{
H5SL_node_t *ret_value; /* New skip list node */
FUNC_ENTER_NOAPI_NOINIT(H5SL_new_node);
/* Allocate the node */
if((ret_value=H5MM_malloc(sizeof(H5SL_node_t)+(sizeof(H5SL_node_t *)*(lvl+1))))==NULL)
HGOTO_ERROR(H5E_SLIST,H5E_NOSPACE,NULL,"memory allocation failed");
/* Initialize node */
ret_value->key=key;
ret_value->item=item;
ret_value->level=lvl;
ret_value->forward=(H5SL_node_t **)((unsigned char *)ret_value+sizeof(H5SL_node_t));
done:
FUNC_LEAVE_NOAPI(ret_value);
} /* end H5SL_new_node() */
/*--------------------------------------------------------------------------
NAME
H5SL_create
PURPOSE
Create a skip list
USAGE
H5SL_t *H5SL_create(void)
RETURNS
Returns a pointer to a skip list on success, NULL on failure.
DESCRIPTION
Create a skip list.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
H5SL_t *
H5SL_create(H5SL_type_t type, double p, size_t max_level)
{
H5SL_t *new_slist=NULL; /* Pointer to new skip list object created */
H5SL_node_t *header; /* Pointer to skip list header node */
size_t u; /* Local index variable */
H5SL_t *ret_value; /* Return value */
FUNC_ENTER_NOAPI(H5SL_create,NULL);
/* Check args */
HDassert(p>0.0 && p<1.0);
HDassert(max_level>0 && max_level<=H5SL_LEVEL_MAX);
HDassert(type>=H5SL_TYPE_INT && type<=H5SL_TYPE_HADDR);
/* Allocate skip list structure */
if((new_slist=H5FL_MALLOC(H5SL_t))==NULL)
HGOTO_ERROR(H5E_SLIST,H5E_NOSPACE,NULL,"memory allocation failed");
/* Set the static internal fields */
new_slist->type=type;
new_slist->p=p;
new_slist->p1=p*RAND_MAX;
new_slist->max_level=max_level;
/* Set the dynamic internal fields */
new_slist->curr_level=-1;
new_slist->nobjs=0;
/* Allocate the header node */
if((header=H5SL_new_node(max_level-1,NULL,NULL))==NULL)
HGOTO_ERROR(H5E_SLIST,H5E_NOSPACE,NULL,"memory allocation failed");
/* Initialize header node's forward pointers */
for(u=0; u<max_level; u++)
header->forward[u]=NULL;
/* Attach the header */
new_slist->header=header;
/* Set the return value */
ret_value=new_slist;
done:
/* Error cleanup */
if(ret_value==NULL) {
if(new_slist!=NULL) {
H5FL_FREE(H5SL_t,new_slist);
} /* end if */
} /* end if */
FUNC_LEAVE_NOAPI(ret_value);
} /* end H5SL_create() */
/*--------------------------------------------------------------------------
NAME
H5SL_count
PURPOSE
Count the number of objects in a skip list
USAGE
ssize_t H5SL_count(slist)
H5SL_t *slist; IN: Pointer to skip list to count
RETURNS
Returns non-negative on success, negative on failure.
DESCRIPTION
Count elements in a skip list.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
ssize_t
H5SL_count(H5SL_t *slist)
{
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_count);
/* Check args */
assert(slist);
/* Check internal consistency */
/* (Pre-condition) */
FUNC_LEAVE_NOAPI(slist->nobjs);
} /* end H5SL_count() */
/*--------------------------------------------------------------------------
NAME
H5SL_insert
PURPOSE
Insert an objects into a skip list
USAGE
herr_t H5SL_insert(slist,item,key)
H5SL_t *slist; IN/OUT: Pointer to skip list
void *item; IN: Item to insert
void *key; IN: Key for item to insert
RETURNS
Returns non-negative on success, negative on failure.
DESCRIPTION
Insert element into a skip list.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
Inserting an item with the same key as an existing object fails.
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
herr_t
H5SL_insert(H5SL_t *slist, void *item, void *key)
{
H5SL_node_t **update[H5SL_LEVEL_MAX]; /* 'update' vector */
H5SL_node_t *checked; /* Pointer to last node checked */
H5SL_node_t *x; /* Current node to examine */
size_t lvl; /* Level of new node */
int i; /* Local index value */
herr_t ret_value=SUCCEED; /* Return value */
FUNC_ENTER_NOAPI_NOINIT(H5SL_insert);
/* Check args */
assert(slist);
assert(key);
/* Check internal consistency */
/* (Pre-condition) */
/* Insert item into skip list */
/* Work through the forward pointers for a node, finding the node at each
* level that is before the location to insert
*/
x=slist->header;
switch(slist->type) {
case H5SL_TYPE_INT:
H5SL_INSERT(slist,x,update,i,int,item,key,checked)
break;
case H5SL_TYPE_HADDR:
H5SL_INSERT(slist,x,update,i,haddr_t,item,key,checked)
break;
} /* end switch */
/* 'key' must not have been found in existing list, if we get here */
/* Generate level for new node */
lvl=H5SL_random_level(slist->p1,slist->max_level);
if((int)lvl>slist->curr_level) {
/* Cap the increase in the current level to just one greater */
lvl=slist->curr_level+1;
/* Set the update pointer correctly */
update[lvl]=&slist->header->forward[lvl];
/* Increase the maximum level of the list */
slist->curr_level=(int)lvl;
} /* end if */
/* Create new node of proper level */
if((x=H5SL_new_node(lvl,item,key))==NULL)
HGOTO_ERROR(H5E_SLIST,H5E_NOSPACE,FAIL,"can't create new skip list node");
/* Link the new node into the existing list */
for(i=0; i<=(int)lvl; i++) {
x->forward[i]=*update[i];
*update[i]=x;
} /* end for */
/* Increment the number of nodes in the skip list */
slist->nobjs++;
done:
FUNC_LEAVE_NOAPI(ret_value);
} /* end H5SL_insert() */
/*--------------------------------------------------------------------------
NAME
H5SL_search
PURPOSE
Search for objects into a skip list
USAGE
void *H5SL_search(slist,key)
H5SL_t *slist; IN/OUT: Pointer to skip list
void *key; IN: Key for item to search for
RETURNS
Returns pointer to item on success, NULL on failure
DESCRIPTION
Search for an object in a skip list, according to it's key
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
void *
H5SL_search(H5SL_t *slist, void *key)
{
H5SL_node_t *checked; /* Pointer to last node checked */
H5SL_node_t *x; /* Current node to examine */
int i; /* Local index value */
void *ret_value; /* Return value */
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_search);
/* Check args */
assert(slist);
assert(key);
/* Check internal consistency */
/* (Pre-condition) */
/* Insert item into skip list */
/* Work through the forward pointers for a node, finding the node at each
* level that is before the location to insert
*/
x=slist->header;
switch(slist->type) {
case H5SL_TYPE_INT:
H5SL_SEARCH(slist,x,-,i,int,-,key,checked)
break;
case H5SL_TYPE_HADDR:
H5SL_SEARCH(slist,x,-,i,haddr_t,-,key,checked)
break;
} /* end switch */
/* 'key' must not have been found in existing list, if we get here */
ret_value=NULL;
done:
FUNC_LEAVE_NOAPI(ret_value);
} /* end H5SL_search() */
/*--------------------------------------------------------------------------
NAME
H5SL_remove
PURPOSE
Removes an object from a skip list
USAGE
void *H5SL_remove(slist,key)
H5SL_t *slist; IN/OUT: Pointer to skip list
void *key; IN: Key for item to remove
RETURNS
Returns pointer to item removed on success, NULL on failure.
DESCRIPTION
Remove element from a skip list.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
void *
H5SL_remove(H5SL_t *slist, void *key)
{
H5SL_node_t **update[H5SL_LEVEL_MAX]; /* 'update' vector */
H5SL_node_t *checked; /* Pointer to last node checked */
H5SL_node_t *x; /* Current node to examine */
int i; /* Local index value */
void *ret_value=NULL; /* Return value */
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_remove);
/* Check args */
assert(slist);
assert(key);
/* Check internal consistency */
/* (Pre-condition) */
/* Remove item from skip list */
/* Work through the forward pointers for a node, finding the node at each
* level that is before the location to remove
*/
x=slist->header;
switch(slist->type) {
case H5SL_TYPE_INT:
H5SL_REMOVE(slist,x,update,i,int,-,key,checked)
break;
case H5SL_TYPE_HADDR:
H5SL_REMOVE(slist,x,update,i,haddr_t,-,key,checked)
break;
} /* end switch */
done:
FUNC_LEAVE_NOAPI(ret_value);
} /* end H5SL_remove() */
/*--------------------------------------------------------------------------
NAME
H5SL_first
PURPOSE
Gets a pointer to the first node in a skip list
USAGE
H5SL_node_t *H5SL_first(slist)
H5SL_t *slist; IN: Pointer to skip list
RETURNS
Returns pointer to first node in skip list on success, NULL on failure.
DESCRIPTION
Retrieves a pointer to the first node in a skip list, for iterating over
the list.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
H5SL_node_t *
H5SL_first(H5SL_t *slist)
{
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_first);
/* Check args */
assert(slist);
/* Check internal consistency */
/* (Pre-condition) */
FUNC_LEAVE_NOAPI(slist->header->forward[0]);
} /* end H5SL_first() */
/*--------------------------------------------------------------------------
NAME
H5SL_next
PURPOSE
Gets a pointer to the next node in a skip list
USAGE
H5SL_node_t *H5SL_next(slist_node)
H5SL_node_t *slist_node; IN: Pointer to skip list node
RETURNS
Returns pointer to node after slist_node in skip list on success, NULL on failure.
DESCRIPTION
Retrieves a pointer to the next node in a skip list, for iterating over
the list.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
H5SL_node_t *
H5SL_next(H5SL_node_t *slist_node)
{
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_next);
/* Check args */
assert(slist_node);
/* Check internal consistency */
/* (Pre-condition) */
FUNC_LEAVE_NOAPI(slist_node->forward[0]);
} /* end H5SL_next() */
/*--------------------------------------------------------------------------
NAME
H5SL_item
PURPOSE
Gets pointer to the 'item' for a skip list node
USAGE
void *H5SL_item(slist_node)
H5SL_node_t *slist_node; IN: Pointer to skip list node
RETURNS
Returns pointer to node 'item' on success, NULL on failure.
DESCRIPTION
Retrieves a node's 'item'
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
void *
H5SL_item(H5SL_node_t *slist_node)
{
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_item);
/* Check args */
assert(slist_node);
/* Check internal consistency */
/* (Pre-condition) */
FUNC_LEAVE_NOAPI(slist_node->item);
} /* end H5SL_item() */
/*--------------------------------------------------------------------------
NAME
H5SL_close
PURPOSE
Close a skip list, deallocating it.
USAGE
herr_t H5SL_close(slist)
H5SL_t *slist; IN/OUT: Pointer to skip list to close
RETURNS
Returns non-negative on success, negative on failure.
DESCRIPTION
Close a skip list, freeing all internal information. Any objects left in
the skip list are not deallocated.
GLOBAL VARIABLES
COMMENTS, BUGS, ASSUMPTIONS
EXAMPLES
REVISION LOG
--------------------------------------------------------------------------*/
herr_t
H5SL_close(H5SL_t *slist)
{
H5SL_node_t *node, *next_node; /* Pointers to skip list nodes */
FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SL_close);
/* Check args */
assert(slist);
/* Check internal consistency */
/* (Pre-condition) */
/* Free skip list nodes */
node=slist->header;
while(node!=NULL) {
next_node=node->forward[0];
H5MM_xfree(node);
node=next_node;
} /* end while */
/* Free skip list object */
H5FL_FREE(H5SL_t,slist);
FUNC_LEAVE_NOAPI(SUCCEED);
} /* end H5SL_close() */
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