1 /*
2 * Copyright (c) Meta Platforms, Inc. and affiliates.
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 * You may select, at your option, one of the above-listed licenses.
9 */
10
11 #include "fuzz_helpers.h"
12 #include "fuzz_data_producer.h"
13
14 struct FUZZ_dataProducer_s{
15 const uint8_t *data;
16 size_t size;
17 };
18
FUZZ_dataProducer_create(const uint8_t * data,size_t size)19 FUZZ_dataProducer_t *FUZZ_dataProducer_create(const uint8_t *data, size_t size) {
20 FUZZ_dataProducer_t *producer = FUZZ_malloc(sizeof(FUZZ_dataProducer_t));
21
22 producer->data = data;
23 producer->size = size;
24 return producer;
25 }
26
FUZZ_dataProducer_free(FUZZ_dataProducer_t * producer)27 void FUZZ_dataProducer_free(FUZZ_dataProducer_t *producer) { free(producer); }
28
FUZZ_dataProducer_uint32Range(FUZZ_dataProducer_t * producer,uint32_t min,uint32_t max)29 uint32_t FUZZ_dataProducer_uint32Range(FUZZ_dataProducer_t *producer, uint32_t min,
30 uint32_t max) {
31 uint32_t range = max - min;
32 uint32_t rolling = range;
33 uint32_t result = 0;
34
35 FUZZ_ASSERT(min <= max);
36
37 while (rolling > 0 && producer->size > 0) {
38 uint8_t next = *(producer->data + producer->size - 1);
39 producer->size -= 1;
40 result = (result << 8) | next;
41 rolling >>= 8;
42 }
43
44 if (range == 0xffffffff) {
45 return result;
46 }
47
48 return min + result % (range + 1);
49 }
50
FUZZ_dataProducer_uint32(FUZZ_dataProducer_t * producer)51 uint32_t FUZZ_dataProducer_uint32(FUZZ_dataProducer_t *producer) {
52 return FUZZ_dataProducer_uint32Range(producer, 0, 0xffffffff);
53 }
54
FUZZ_dataProducer_int32Range(FUZZ_dataProducer_t * producer,int32_t min,int32_t max)55 int32_t FUZZ_dataProducer_int32Range(FUZZ_dataProducer_t *producer,
56 int32_t min, int32_t max)
57 {
58 FUZZ_ASSERT(min <= max);
59
60 if (min < 0)
61 return (int)FUZZ_dataProducer_uint32Range(producer, 0, max - min) + min;
62
63 return FUZZ_dataProducer_uint32Range(producer, min, max);
64 }
65
FUZZ_dataProducer_remainingBytes(FUZZ_dataProducer_t * producer)66 size_t FUZZ_dataProducer_remainingBytes(FUZZ_dataProducer_t *producer){
67 return producer->size;
68 }
69
FUZZ_dataProducer_rollBack(FUZZ_dataProducer_t * producer,size_t remainingBytes)70 void FUZZ_dataProducer_rollBack(FUZZ_dataProducer_t *producer, size_t remainingBytes)
71 {
72 FUZZ_ASSERT(remainingBytes >= producer->size);
73 producer->size = remainingBytes;
74 }
75
FUZZ_dataProducer_empty(FUZZ_dataProducer_t * producer)76 int FUZZ_dataProducer_empty(FUZZ_dataProducer_t *producer) {
77 return producer->size == 0;
78 }
79
FUZZ_dataProducer_contract(FUZZ_dataProducer_t * producer,size_t newSize)80 size_t FUZZ_dataProducer_contract(FUZZ_dataProducer_t *producer, size_t newSize)
81 {
82 const size_t effectiveNewSize = newSize > producer->size ? producer->size : newSize;
83
84 size_t remaining = producer->size - effectiveNewSize;
85 producer->data = producer->data + remaining;
86 producer->size = effectiveNewSize;
87 return remaining;
88 }
89
FUZZ_dataProducer_reserveDataPrefix(FUZZ_dataProducer_t * producer)90 size_t FUZZ_dataProducer_reserveDataPrefix(FUZZ_dataProducer_t *producer)
91 {
92 size_t producerSliceSize = FUZZ_dataProducer_uint32Range(
93 producer, 0, producer->size);
94 return FUZZ_dataProducer_contract(producer, producerSliceSize);
95 }
96