blob: a54324d28818fc9e4abc9d4d27382be772a04efd (
plain)
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
88
89
|
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "util/coding.h"
#include <algorithm>
#include "rocksdb/slice.h"
#include "rocksdb/slice_transform.h"
namespace ROCKSDB_NAMESPACE {
// conversion' conversion from 'type1' to 'type2', possible loss of data
#if defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable : 4244)
#endif
char* EncodeVarint32(char* dst, uint32_t v) {
// Operate on characters as unsigneds
unsigned char* ptr = reinterpret_cast<unsigned char*>(dst);
static const int B = 128;
if (v < (1 << 7)) {
*(ptr++) = v;
} else if (v < (1 << 14)) {
*(ptr++) = v | B;
*(ptr++) = v >> 7;
} else if (v < (1 << 21)) {
*(ptr++) = v | B;
*(ptr++) = (v >> 7) | B;
*(ptr++) = v >> 14;
} else if (v < (1 << 28)) {
*(ptr++) = v | B;
*(ptr++) = (v >> 7) | B;
*(ptr++) = (v >> 14) | B;
*(ptr++) = v >> 21;
} else {
*(ptr++) = v | B;
*(ptr++) = (v >> 7) | B;
*(ptr++) = (v >> 14) | B;
*(ptr++) = (v >> 21) | B;
*(ptr++) = v >> 28;
}
return reinterpret_cast<char*>(ptr);
}
#if defined(_MSC_VER)
#pragma warning(pop)
#endif
const char* GetVarint32PtrFallback(const char* p, const char* limit,
uint32_t* value) {
uint32_t result = 0;
for (uint32_t shift = 0; shift <= 28 && p < limit; shift += 7) {
uint32_t byte = *(reinterpret_cast<const unsigned char*>(p));
p++;
if (byte & 128) {
// More bytes are present
result |= ((byte & 127) << shift);
} else {
result |= (byte << shift);
*value = result;
return reinterpret_cast<const char*>(p);
}
}
return nullptr;
}
const char* GetVarint64Ptr(const char* p, const char* limit, uint64_t* value) {
uint64_t result = 0;
for (uint32_t shift = 0; shift <= 63 && p < limit; shift += 7) {
uint64_t byte = *(reinterpret_cast<const unsigned char*>(p));
p++;
if (byte & 128) {
// More bytes are present
result |= ((byte & 127) << shift);
} else {
result |= (byte << shift);
*value = result;
return reinterpret_cast<const char*>(p);
}
}
return nullptr;
}
} // namespace ROCKSDB_NAMESPACE
|
