AFLplusplus/include/afl-prealloc.h
2020-03-09 12:21:54 +01:00

121 lines
5.9 KiB
C

/* If we know we'll reuse small elements often, we'll just preallocate a buffer,
* then fall back to malloc */
// TODO: Replace free status check with bitmask+CLZ
#ifndef AFL_PREALLOC_H
#define AFL_PREALLOC_H
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include "debug.h"
typedef enum prealloc_status {
PRE_STATUS_UNUSED = 0, /* free in buf */
PRE_STATUS_USED, /* used in buf */
PRE_STATUS_MALLOC /* system malloc */
} pre_status_t;
/* Adds the entry used for prealloc bookkeeping to this struct */
#define PREALLOCABLE \
; \
pre_status_t pre_status; /* prealloc status of this instance */
/* allocate an element of type *el_ptr, to this variable.
Uses (and reuses) the given prealloc_buf before hitting libc's malloc.
prealloc_buf must be the pointer to an array with type `type`.
`type` must be a struct with uses PREALLOCABLE (a pre_status_t pre_status
member). prealloc_size must be the array size. prealloc_counter must be a
variable initialized with 0 (of any name).
*/
#define PRE_ALLOC(el_ptr, prealloc_buf, prealloc_size, prealloc_counter) \
do { \
\
if ((prealloc_counter) >= (prealloc_size)) { \
\
el_ptr = malloc(sizeof(*el_ptr)); \
el_ptr->pre_status = PRE_STATUS_MALLOC; \
\
} else { \
\
/* Find one of our preallocated elements */ \
u32 i; \
for (i = 0; i < (prealloc_size); i++) { \
\
el_ptr = &((prealloc_buf)[i]); \
if (el_ptr->pre_status == PRE_STATUS_UNUSED) { \
\
(prealloc_counter)++; \
el_ptr->pre_status = PRE_STATUS_USED; \
break; \
\
} \
\
} \
\
} \
\
if (!el_ptr) { FATAL("BUG in list.h -> no element found or allocated!"); } \
\
} while (0);
/* Take a chosen (free) element from the prealloc_buf directly */
#define PRE_ALLOC_FORCE(el_ptr, prealloc_counter) \
do { \
\
if ((el_ptr)->pre_status != PRE_STATUS_UNUSED) { \
\
FATAL("PRE_ALLOC_FORCE element already allocated"); \
\
} \
(el_ptr)->pre_status = PRE_STATUS_USED; \
(prealloc_counter)++; \
\
} while (0);
/* free an preallocated element */
#define PRE_FREE(el_ptr, prealloc_counter) \
do { \
\
switch ((el_ptr)->pre_status) { \
\
case PRE_STATUS_USED: { \
\
(el_ptr)->pre_status = PRE_STATUS_UNUSED; \
(prealloc_counter)--; \
if ((prealloc_counter) < 0) { \
\
FATAL("Inconsistent data in PRE_FREE"); \
\
} \
break; \
\
} \
case PRE_STATUS_MALLOC: { \
\
(el_ptr)->pre_status = PRE_STATUS_UNUSED; \
free((el_ptr)); \
break; \
\
} \
default: { \
\
FATAL("Double Free Detected"); \
break; \
\
} \
\
} \
\
} while (0);
#endif