mirror of
https://github.com/cookiengineer/audacity
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92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
/* mem.c -- fast memory allocation/deallocation module */
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/* Allocate large chunks of memory using malloc. From the chunks,
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allocate memory as needed on long-word boundaries. Memory is
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freed by linking memory onto a freelist. An array of freelists,
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one for each size, is maintained and checked before going to the
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chunck for more memory. The freelist array only holds lists of
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nodes up to a certain size. After that, malloc is used directly.
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*/
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/* CHANGE LOG
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----------------------------------------------------------------------
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28-Apr-03 | DM : fix #includes for portability
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----------------------------------------------------------------------
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*/
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#include "switches.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include "cext.h"
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#include "userio.h"
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/* how many bytes in the largest node managed in mem_free_list array */
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#define MAX_SIZE_FOR_FREELIST 256
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long *mem_free_list[MAX_SIZE_FOR_FREELIST/4];
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#define MEM_CHUNK_SIZE 4096
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char *mem_chunk;
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long mem_chunk_remaining = 0;
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void meminit()
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{
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int i;
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for (i = 0; i < MAX_SIZE_FOR_FREELIST/4; i++) {
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mem_free_list[i] = NULL;
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}
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}
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void *memget(register size_t size)
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{
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if (size > MAX_SIZE_FOR_FREELIST) {
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/* gprintf(TRANS, "memget calling MALLOC\n"); */
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return MALLOC(size);
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} else {
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long **p = mem_free_list + ((size - 1) >> 2);
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if (*p) {
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register long *result = *p;
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*p = (long *) *result;
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/* gprintf(TRANS, "memget->%lx\n", result); */
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return (char *) result;
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} else if ((size_t) mem_chunk_remaining >= size) {
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register char *result = mem_chunk;
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size = (size + 3) & ~3; /* round up to multiple of 4 */
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mem_chunk += size;
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mem_chunk_remaining -= size;
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/* gprintf(TRANS, "memget->%lx\n", result); */
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return result;
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/* note that we throw away remaining chunk when there isn't enough */
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} else if ((mem_chunk = (char *) MALLOC(MEM_CHUNK_SIZE))) {
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register char *result = mem_chunk;
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/* gprintf(TRANS, "mem_chunk at %lx\n", mem_chunk); */
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size = (size + 3) & ~3; /* round up to multiple of 4 */
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mem_chunk += size;
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mem_chunk_remaining = MEM_CHUNK_SIZE - size;
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/* gprintf(TRANS, "memget->%lx\n", result); */
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return result;
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} else {
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return NULL;
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}
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}
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}
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void memfree(register void *ptr, register size_t size)
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{
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register long **p = (long **) ptr;
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if (size > MAX_SIZE_FOR_FREELIST) {
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FREE(ptr);
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} else {
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register long **head_ptr = mem_free_list + ((size - 1) >> 2);
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*p = *head_ptr;
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*head_ptr = (long *) p;
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}
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}
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