94 lines
2.7 KiB
C
94 lines
2.7 KiB
C
/* mem.c -- fast memory allocation/deallocation module */
|
|
|
|
/* Allocate large chunks of memory using malloc. From the chunks,
|
|
allocate memory as needed on long-word boundaries. Memory is
|
|
freed by linking memory onto a freelist. An array of freelists,
|
|
one for each size, is maintained and checked before going to the
|
|
chunck for more memory. The freelist array only holds lists of
|
|
nodes up to a certain size. After that, malloc is used directly.
|
|
*/
|
|
/* CHANGE LOG
|
|
----------------------------------------------------------------------
|
|
10-Oct-20 | RBD : change to 8-byte alignment
|
|
28-Apr-03 | DM : fix #includes for portability
|
|
----------------------------------------------------------------------
|
|
*/
|
|
|
|
#include "switches.h"
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "cext.h"
|
|
#include "userio.h"
|
|
|
|
/* how many bytes in the largest node managed in mem_free_list array */
|
|
#define MAX_SIZE_FOR_FREELIST 256
|
|
|
|
intptr_t *mem_free_list[MAX_SIZE_FOR_FREELIST/8];
|
|
|
|
#define MEM_CHUNK_SIZE 4096
|
|
char *mem_chunk;
|
|
intptr_t mem_chunk_remaining = 0;
|
|
|
|
void meminit()
|
|
{
|
|
int i;
|
|
for (i = 0; i < MAX_SIZE_FOR_FREELIST/8; i++) {
|
|
mem_free_list[i] = NULL;
|
|
}
|
|
}
|
|
|
|
|
|
void *memget(register size_t size)
|
|
{
|
|
if (size > MAX_SIZE_FOR_FREELIST) {
|
|
/* gprintf(TRANS, "memget calling MALLOC\n"); */
|
|
return MALLOC(size);
|
|
} else {
|
|
/* 8 -> 0, 9 -> 1, 256 -> 31 */
|
|
intptr_t **p = mem_free_list + ((size - 1) >> 3);
|
|
if (*p) {
|
|
intptr_t *result = *p;
|
|
*p = (intptr_t *) *result;
|
|
/* gprintf(TRANS, "memget->%lx\n", result); */
|
|
return (char *) result;
|
|
} else if ((size_t) mem_chunk_remaining >= size) {
|
|
char *result = mem_chunk;
|
|
size = (size + 7) & ~7; /* round up to multiple of 8 */
|
|
mem_chunk += size;
|
|
mem_chunk_remaining -= size;
|
|
/* gprintf(TRANS, "memget->%lx\n", result); */
|
|
return result;
|
|
/* note that we throw away remaining chunk when there isn't enough */
|
|
} else if ((mem_chunk = (char *) MALLOC(MEM_CHUNK_SIZE))) {
|
|
register char *result = mem_chunk;
|
|
/* gprintf(TRANS, "mem_chunk at %lx\n", mem_chunk); */
|
|
size = (size + 7) & ~7; /* round up to multiple of 8 */
|
|
mem_chunk += size;
|
|
mem_chunk_remaining = MEM_CHUNK_SIZE - size;
|
|
/* gprintf(TRANS, "memget->%lx\n", result); */
|
|
return result;
|
|
} else {
|
|
return NULL;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
void memfree(register void *ptr, register size_t size)
|
|
{
|
|
intptr_t **p = (intptr_t **) ptr;
|
|
if (size > MAX_SIZE_FOR_FREELIST) {
|
|
FREE(ptr);
|
|
} else {
|
|
intptr_t **head_ptr = mem_free_list + ((size - 1) >> 3);
|
|
*p = *head_ptr;
|
|
*head_ptr = (intptr_t *) p;
|
|
}
|
|
}
|
|
|
|
|
|
|
|
|