1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
|
//===-- sanitizer_leb128.h --------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_LEB128_H
#define SANITIZER_LEB128_H
#include "sanitizer_common.h"
#include "sanitizer_internal_defs.h"
namespace __sanitizer {
template <typename T, typename It>
It EncodeSLEB128(T value, It begin, It end) {
bool more;
do {
u8 byte = value & 0x7f;
// NOTE: this assumes that this signed shift is an arithmetic right shift.
value >>= 7;
more = !((((value == 0) && ((byte & 0x40) == 0)) ||
((value == -1) && ((byte & 0x40) != 0))));
if (more)
byte |= 0x80;
if (UNLIKELY(begin == end))
break;
*(begin++) = byte;
} while (more);
return begin;
}
template <typename T, typename It>
It DecodeSLEB128(It begin, It end, T* v) {
T value = 0;
unsigned shift = 0;
u8 byte;
do {
if (UNLIKELY(begin == end))
return begin;
byte = *(begin++);
T slice = byte & 0x7f;
value |= slice << shift;
shift += 7;
} while (byte >= 128);
if (shift < 64 && (byte & 0x40))
value |= (-1ULL) << shift;
*v = value;
return begin;
}
template <typename T, typename It>
It EncodeULEB128(T value, It begin, It end) {
do {
u8 byte = value & 0x7f;
value >>= 7;
if (value)
byte |= 0x80;
if (UNLIKELY(begin == end))
break;
*(begin++) = byte;
} while (value);
return begin;
}
template <typename T, typename It>
It DecodeULEB128(It begin, It end, T* v) {
T value = 0;
unsigned shift = 0;
u8 byte;
do {
if (UNLIKELY(begin == end))
return begin;
byte = *(begin++);
T slice = byte & 0x7f;
value += slice << shift;
shift += 7;
} while (byte >= 128);
*v = value;
return begin;
}
} // namespace __sanitizer
#endif // SANITIZER_LEB128_H
|
