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#include <config.h>
#include "malloca.h"
#if HAVE_ALLOCA
#define MAGIC_NUMBER 0x1415fb4a
#define MAGIC_SIZE sizeof (int)
struct preliminary_header { void *next; char room[MAGIC_SIZE]; };
#define HEADER_SIZE \
(((sizeof (struct preliminary_header) + sa_alignment_max - 1) / sa_alignment_max) * sa_alignment_max)
struct header { void *next; char room[HEADER_SIZE - sizeof (struct preliminary_header) + MAGIC_SIZE]; };
typedef int verify1[2 * (HEADER_SIZE == sizeof (struct header)) - 1];
#define HASH_TABLE_SIZE 257
static void * mmalloca_results[HASH_TABLE_SIZE];
#endif
void *
mmalloca (size_t n)
{
#if HAVE_ALLOCA
size_t nplus = n + HEADER_SIZE;
if (nplus >= n)
{
char *p = (char *) malloc (nplus);
if (p != NULL)
{
size_t slot;
p += HEADER_SIZE;
((int *) p)[-1] = MAGIC_NUMBER;
slot = (unsigned long) p % HASH_TABLE_SIZE;
((struct header *) (p - HEADER_SIZE))->next = mmalloca_results[slot];
mmalloca_results[slot] = p;
return p;
}
}
return NULL;
#else
# if !MALLOC_0_IS_NONNULL
if (n == 0)
n = 1;
# endif
return malloc (n);
#endif
}
#if HAVE_ALLOCA
void
freea (void *p)
{
if (p != NULL)
{
if (((int *) p)[-1] == MAGIC_NUMBER)
{
size_t slot = (unsigned long) p % HASH_TABLE_SIZE;
void **chain = &mmalloca_results[slot];
for (; *chain != NULL;)
{
if (*chain == p)
{
char *p_begin = (char *) p - HEADER_SIZE;
*chain = ((struct header *) p_begin)->next;
free (p_begin);
return;
}
chain = &((struct header *) ((char *) *chain - HEADER_SIZE))->next;
}
}
}
}
#endif
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