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#include <stdio.h>
#include <string.h>
#include <ctype.h>
typedef struct chunk {
struct chunk *next;
char *limit;
char *avail;
} Chunk;
Chunk first = { NULL, NULL, NULL };
Chunk *arena = &first;
void *arena_getmem(n)
int n;
{
char *q;
char *p = arena->avail;
n = (n + 3) & ~3; /* ensuring alignment to 4 bytes */
q = p + n;
if (q <= arena->limit) {
arena->avail = q;
return p;
}
{
Chunk *ap = arena;
Chunk *np = ap->next;
while (np) {
char *v = sizeof(Chunk) + (char *) np;
if (v + n <= np->limit) {
np->avail = v + n;
arena = np;
return v;
}
ap = np;
np = ap->next;
}
{
int m = n + 10000;
np = (Chunk *) malloc(m);
np->limit = m + (char *) np;
np->avail = n + sizeof(Chunk) + (char *) np;
np->next = NULL;
ap->next = np;
arena = np;
return sizeof(Chunk) + (char *) np;
}
}
}
void arena_free()
{
arena = &first;
}
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