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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2011 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef TEST
#include <grub/priority_queue.h>
#include <grub/mm.h>
#include <grub/dl.h>
GRUB_MOD_LICENSE ("GPLv3+");
#else
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <queue>
using namespace std;
typedef size_t grub_size_t;
typedef int (*grub_comparator_t) (const void *a, const void *b);
typedef unsigned char grub_uint8_t;
#define grub_malloc malloc
#define grub_memcpy memcpy
#define grub_realloc realloc
#define grub_free free
typedef enum
{
GRUB_ERR_NONE,
grub_errno
} grub_err_t;
#endif
struct grub_priority_queue
{
grub_size_t elsize;
grub_size_t allocated;
grub_size_t used;
grub_comparator_t cmp;
void *els;
};
#ifdef TEST
typedef struct grub_priority_queue *grub_priority_queue_t;
#endif
static inline void *
element (struct grub_priority_queue *pq, grub_size_t k)
{
return ((grub_uint8_t *) pq->els) + k * pq->elsize;
}
static inline void
swap (struct grub_priority_queue *pq, grub_size_t m, grub_size_t n)
{
grub_uint8_t *p1, *p2;
grub_size_t l;
p1 = (grub_uint8_t *) element (pq, m);
p2 = (grub_uint8_t *) element (pq, n);
for (l = pq->elsize; l; l--, p1++, p2++)
{
grub_uint8_t t;
t = *p1;
*p1 = *p2;
*p2 = t;
}
}
static inline grub_size_t
parent (grub_size_t v)
{
return (v - 1) / 2;
}
static inline grub_size_t
left_child (grub_size_t v)
{
return 2 * v + 1;
}
static inline grub_size_t
right_child (grub_size_t v)
{
return 2 * v + 2;
}
void *
grub_priority_queue_top (grub_priority_queue_t pq)
{
if (!pq->used)
return 0;
return element (pq, 0);
}
void
grub_priority_queue_destroy (grub_priority_queue_t pq)
{
grub_free (pq->els);
grub_free (pq);
}
grub_priority_queue_t
grub_priority_queue_new (grub_size_t elsize,
grub_comparator_t cmp)
{
struct grub_priority_queue *ret;
void *els;
els = grub_malloc (elsize * 8);
if (!els)
return 0;
ret = (struct grub_priority_queue *) grub_malloc (sizeof (*ret));
if (!ret)
{
grub_free (els);
return 0;
}
ret->elsize = elsize;
ret->allocated = 8;
ret->used = 0;
ret->cmp = cmp;
ret->els = els;
return ret;
}
/* Heap property: pq->cmp (element (pq, p), element (pq, parent (p))) <= 0. */
grub_err_t
grub_priority_queue_push (grub_priority_queue_t pq, const void *el)
{
grub_size_t p;
if (pq->used == pq->allocated)
{
void *els;
els = grub_realloc (pq->els, pq->elsize * 2 * pq->allocated);
if (!els)
return grub_errno;
pq->allocated *= 2;
pq->els = els;
}
pq->used++;
grub_memcpy (element (pq, pq->used - 1), el, pq->elsize);
for (p = pq->used - 1; p; p = parent (p))
{
if (pq->cmp (element (pq, p), element (pq, parent (p))) <= 0)
break;
swap (pq, p, parent (p));
}
return GRUB_ERR_NONE;
}
void
grub_priority_queue_pop (grub_priority_queue_t pq)
{
grub_size_t p;
swap (pq, 0, pq->used - 1);
pq->used--;
for (p = 0; left_child (p) < pq->used; )
{
grub_size_t c;
if (pq->cmp (element (pq, left_child (p)), element (pq, p)) <= 0
&& (right_child (p) >= pq->used
|| pq->cmp (element (pq, right_child (p)), element (pq, p)) <= 0))
break;
if (right_child (p) >= pq->used
|| pq->cmp (element (pq, left_child (p)),
element (pq, right_child (p))) > 0)
c = left_child (p);
else
c = right_child (p);
swap (pq, p, c);
p = c;
}
}
#ifdef TEST
static int
compar (const void *a_, const void *b_)
{
int a = *(int *) a_;
int b = *(int *) b_;
if (a < b)
return -1;
if (a > b)
return +1;
return 0;
}
int
main (void)
{
priority_queue <int> pq;
grub_priority_queue_t pq2;
int counter;
int s = 0;
pq2 = grub_priority_queue_new (sizeof (int), compar);
if (!pq2)
return 1;
srand (1);
for (counter = 0; counter < 1000000; counter++)
{
int op = rand () % 10;
if (s && *(int *) grub_priority_queue_top (pq2) != pq.top ())
{
printf ("Error at %d\n", counter);
return 2;
}
if (op < 3 && s)
{
grub_priority_queue_pop (pq2);
pq.pop ();
s--;
}
else
{
int v = rand ();
int e;
pq.push (v);
e = grub_priority_queue_push (pq2, &v);
if (e)
return 3;
s++;
}
}
while (s)
{
if (*(int *) grub_priority_queue_top (pq2) != pq.top ())
{
printf ("Error at the end. %d elements remaining.\n", s);
return 4;
}
grub_priority_queue_pop (pq2);
pq.pop ();
s--;
}
printf ("All tests passed successfully\n");
return 0;
}
#endif
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