mutter/cogl/cogl-path/tesselator/priorityq.c
2016-04-22 16:44:31 +02:00

262 lines
7.0 KiB
C

/*
* SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
* Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice including the dates of first publication and
* either this permission notice or a reference to
* http://oss.sgi.com/projects/FreeB/
* shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Except as contained in this notice, the name of Silicon Graphics, Inc.
* shall not be used in advertising or otherwise to promote the sale, use or
* other dealings in this Software without prior written authorization from
* Silicon Graphics, Inc.
*/
/*
** Author: Eric Veach, July 1994.
**
*/
#include "gluos.h"
#include <stddef.h>
#include <assert.h>
#include <limits.h> /* LONG_MAX */
#include "memalloc.h"
/* Include all the code for the regular heap-based queue here. */
#include "priorityq-heap.c"
/* Now redefine all the function names to map to their "Sort" versions. */
#include "priorityq-sort.h"
/* really __gl_pqSortNewPriorityQ */
PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) )
{
PriorityQ *pq = (PriorityQ *)memAlloc( sizeof( PriorityQ ));
if (pq == NULL) return NULL;
pq->heap = __gl_pqHeapNewPriorityQ( leq );
if (pq->heap == NULL) {
memFree(pq);
return NULL;
}
pq->keys = (PQHeapKey *)memAlloc( INIT_SIZE * sizeof(pq->keys[0]) );
if (pq->keys == NULL) {
__gl_pqHeapDeletePriorityQ(pq->heap);
memFree(pq);
return NULL;
}
pq->order = NULL;
pq->size = 0;
pq->max = INIT_SIZE;
pq->initialized = FALSE;
pq->leq = leq;
return pq;
}
/* really __gl_pqSortDeletePriorityQ */
void pqDeletePriorityQ( PriorityQ *pq )
{
assert(pq != NULL);
if (pq->heap != NULL) __gl_pqHeapDeletePriorityQ( pq->heap );
if (pq->order != NULL) memFree( pq->order );
if (pq->keys != NULL) memFree( pq->keys );
memFree( pq );
}
#define LT(x,y) (! LEQ(y,x))
#define GT(x,y) (! LEQ(x,y))
#define Swap(a,b) do{PQkey *tmp = *a; *a = *b; *b = tmp;}while(0)
/* really __gl_pqSortInit */
int pqInit( PriorityQ *pq )
{
PQkey **p, **r, **i, **j, *piv;
struct { PQkey **p, **r; } Stack[50], *top = Stack;
unsigned long seed = 2016473283;
/* Create an array of indirect pointers to the keys, so that we
* the handles we have returned are still valid.
*/
/*
pq->order = (PQHeapKey **)memAlloc( (size_t)
(pq->size * sizeof(pq->order[0])) );
*/
pq->order = (PQHeapKey **)memAlloc( (size_t)
((pq->size+1) * sizeof(pq->order[0])) );
/* the previous line is a patch to compensate for the fact that IBM */
/* machines return a null on a malloc of zero bytes (unlike SGI), */
/* so we have to put in this defense to guard against a memory */
/* fault four lines down. from fossum@austin.ibm.com. */
if (pq->order == NULL) return 0;
p = pq->order;
r = p + pq->size - 1;
for( piv = pq->keys, i = p; i <= r; ++piv, ++i ) {
*i = piv;
}
/* Sort the indirect pointers in descending order,
* using randomized Quicksort
*/
top->p = p; top->r = r; ++top;
while( --top >= Stack ) {
p = top->p;
r = top->r;
while( r > p + 10 ) {
seed = seed * 1539415821 + 1;
i = p + seed % (r - p + 1);
piv = *i;
*i = *p;
*p = piv;
i = p - 1;
j = r + 1;
do {
do { ++i; } while( GT( **i, *piv ));
do { --j; } while( LT( **j, *piv ));
Swap( i, j );
} while( i < j );
Swap( i, j ); /* Undo last swap */
if( i - p < r - j ) {
top->p = j+1; top->r = r; ++top;
r = i-1;
} else {
top->p = p; top->r = i-1; ++top;
p = j+1;
}
}
/* Insertion sort small lists */
for( i = p+1; i <= r; ++i ) {
piv = *i;
for( j = i; j > p && LT( **(j-1), *piv ); --j ) {
*j = *(j-1);
}
*j = piv;
}
}
pq->max = pq->size;
pq->initialized = TRUE;
__gl_pqHeapInit( pq->heap ); /* always succeeds */
#ifndef NDEBUG
p = pq->order;
r = p + pq->size - 1;
for( i = p; i < r; ++i ) {
assert( LEQ( **(i+1), **i ));
}
#endif
return 1;
}
/* really __gl_pqSortInsert */
/* returns LONG_MAX iff out of memory */
PQhandle pqInsert( PriorityQ *pq, PQkey keyNew )
{
long curr;
if( pq->initialized ) {
return __gl_pqHeapInsert( pq->heap, keyNew );
}
curr = pq->size;
if( ++ pq->size >= pq->max ) {
PQkey *saveKey= pq->keys;
/* If the heap overflows, double its size. */
pq->max <<= 1;
pq->keys = (PQHeapKey *)memRealloc( pq->keys,
(size_t)
(pq->max * sizeof( pq->keys[0] )));
if (pq->keys == NULL) {
pq->keys = saveKey; /* restore ptr to free upon return */
return LONG_MAX;
}
}
assert(curr != LONG_MAX);
pq->keys[curr] = keyNew;
/* Negative handles index the sorted array. */
return -(curr+1);
}
/* really __gl_pqSortExtractMin */
PQkey pqExtractMin( PriorityQ *pq )
{
PQkey sortMin, heapMin;
if( pq->size == 0 ) {
return __gl_pqHeapExtractMin( pq->heap );
}
sortMin = *(pq->order[pq->size-1]);
if( ! __gl_pqHeapIsEmpty( pq->heap )) {
heapMin = __gl_pqHeapMinimum( pq->heap );
if( LEQ( heapMin, sortMin )) {
return __gl_pqHeapExtractMin( pq->heap );
}
}
do {
-- pq->size;
} while( pq->size > 0 && *(pq->order[pq->size-1]) == NULL );
return sortMin;
}
/* really __gl_pqSortMinimum */
PQkey pqMinimum( PriorityQ *pq )
{
PQkey sortMin, heapMin;
if( pq->size == 0 ) {
return __gl_pqHeapMinimum( pq->heap );
}
sortMin = *(pq->order[pq->size-1]);
if( ! __gl_pqHeapIsEmpty( pq->heap )) {
heapMin = __gl_pqHeapMinimum( pq->heap );
if( LEQ( heapMin, sortMin )) {
return heapMin;
}
}
return sortMin;
}
/* really __gl_pqSortIsEmpty */
int pqIsEmpty( PriorityQ *pq )
{
return (pq->size == 0) && __gl_pqHeapIsEmpty( pq->heap );
}
/* really __gl_pqSortDelete */
void pqDelete( PriorityQ *pq, PQhandle curr )
{
if( curr >= 0 ) {
__gl_pqHeapDelete( pq->heap, curr );
return;
}
curr = -(curr+1);
assert( curr < pq->max && pq->keys[curr] != NULL );
pq->keys[curr] = NULL;
while( pq->size > 0 && *(pq->order[pq->size-1]) == NULL ) {
-- pq->size;
}
}