1 /*
2 * Copyright (c) 2016-present, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 */
9
10 /**
11 * Helper functions for fuzzing.
12 */
13
14 #ifndef FUZZ_HELPERS_H
15 #define FUZZ_HELPERS_H
16
17 #include "fuzz.h"
18 #include "xxhash.h"
19 #include <stdint.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22
23 #ifdef __cplusplus
24 extern "C" {
25 #endif
26
27 #define LZ4_COMMONDEFS_ONLY
28 #ifndef LZ4_SRC_INCLUDED
29 #include "lz4.c" /* LZ4_count, constants, mem */
30 #endif
31
32 #define MIN(a,b) ( (a) < (b) ? (a) : (b) )
33 #define MAX(a,b) ( (a) > (b) ? (a) : (b) )
34
35 #define FUZZ_QUOTE_IMPL(str) #str
36 #define FUZZ_QUOTE(str) FUZZ_QUOTE_IMPL(str)
37
38 /**
39 * Asserts for fuzzing that are always enabled.
40 */
41 #define FUZZ_ASSERT_MSG(cond, msg) \
42 ((cond) ? (void)0 \
43 : (fprintf(stderr, "%s: %u: Assertion: `%s' failed. %s\n", __FILE__, \
44 __LINE__, FUZZ_QUOTE(cond), (msg)), \
45 abort()))
46 #define FUZZ_ASSERT(cond) FUZZ_ASSERT_MSG((cond), "");
47
48 #if defined(__GNUC__)
49 #define FUZZ_STATIC static __inline __attribute__((unused))
50 #elif defined(__cplusplus) || \
51 (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
52 #define FUZZ_STATIC static inline
53 #elif defined(_MSC_VER)
54 #define FUZZ_STATIC static __inline
55 #else
56 #define FUZZ_STATIC static
57 #endif
58
59 /**
60 * Deterministically constructs a seed based on the fuzz input.
61 * Consumes up to the first FUZZ_RNG_SEED_SIZE bytes of the input.
62 */
FUZZ_seed(uint8_t const ** src,size_t * size)63 FUZZ_STATIC uint32_t FUZZ_seed(uint8_t const **src, size_t* size) {
64 uint8_t const *data = *src;
65 size_t const toHash = MIN(FUZZ_RNG_SEED_SIZE, *size);
66 *size -= toHash;
67 *src += toHash;
68 return XXH32(data, toHash, 0);
69 }
70
71 #define FUZZ_rotl32(x, r) (((x) << (r)) | ((x) >> (32 - (r))))
72
FUZZ_rand(uint32_t * state)73 FUZZ_STATIC uint32_t FUZZ_rand(uint32_t *state) {
74 static const uint32_t prime1 = 2654435761U;
75 static const uint32_t prime2 = 2246822519U;
76 uint32_t rand32 = *state;
77 rand32 *= prime1;
78 rand32 += prime2;
79 rand32 = FUZZ_rotl32(rand32, 13);
80 *state = rand32;
81 return rand32 >> 5;
82 }
83
84 /* Returns a random numer in the range [min, max]. */
FUZZ_rand32(uint32_t * state,uint32_t min,uint32_t max)85 FUZZ_STATIC uint32_t FUZZ_rand32(uint32_t *state, uint32_t min, uint32_t max) {
86 uint32_t random = FUZZ_rand(state);
87 return min + (random % (max - min + 1));
88 }
89
90 #ifdef __cplusplus
91 }
92 #endif
93
94 #endif
95
