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#include "c.h"
struct block {
struct block *next;
char *limit;
char *avail;
};
union align {
long l;
char *p;
double d;
int (*f)(void);
};
union header {
struct block b;
union align a;
};
#ifdef PURIFY
union header *arena[3];
void *allocate(unsigned long n, unsigned a) {
union header *new = malloc(sizeof *new + n);
assert(a < NELEMS(arena));
if (new == NULL) {
error("insufficient memory\n");
exit(1);
}
new->b.next = (void *)arena[a];
arena[a] = new;
return new + 1;
}
void deallocate(unsigned a) {
union header *p, *q;
assert(a < NELEMS(arena));
for (p = arena[a]; p; p = q) {
q = (void *)p->b.next;
free(p);
}
arena[a] = NULL;
}
void *newarray(unsigned long m, unsigned long n, unsigned a) {
return allocate(m*n, a);
}
#else
static struct block
first[] = { { NULL }, { NULL }, { NULL } },
*arena[] = { &first[0], &first[1], &first[2] };
static struct block *freeblocks;
void *allocate(unsigned long n, unsigned a) {
struct block *ap;
assert(a < NELEMS(arena));
assert(n > 0);
ap = arena[a];
n = roundup(n, sizeof (union align));
while (n > ap->limit - ap->avail) {
if ((ap->next = freeblocks) != NULL) {
freeblocks = freeblocks->next;
ap = ap->next;
} else
{
unsigned m = sizeof (union header) + n + roundup(10*1024, sizeof (union align));
ap->next = malloc(m);
ap = ap->next;
if (ap == NULL) {
error("insufficient memory\n");
exit(1);
}
ap->limit = (char *)ap + m;
}
ap->avail = (char *)((union header *)ap + 1);
ap->next = NULL;
arena[a] = ap;
}
ap->avail += n;
return ap->avail - n;
}
void *newarray(unsigned long m, unsigned long n, unsigned a) {
return allocate(m*n, a);
}
void deallocate(unsigned a) {
assert(a < NELEMS(arena));
arena[a]->next = freeblocks;
freeblocks = first[a].next;
first[a].next = NULL;
arena[a] = &first[a];
}
#endif
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