1 /*
2 * Copyright (c) Huawei Technologies Co., Ltd. 2023. All rights reserved.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15 #ifndef VARINT_ENCODE_H
16 #define VARINT_ENCODE_H
17 #include <cinttypes>
18 #include <cstddef>
19 #include <type_traits>
20 #include <cstdint>
21
22 namespace OHOS {
23 namespace Developtools {
24 namespace Profiler {
25 namespace ProtoEncoder {
26 constexpr uint32_t VARINT32_SIZE = 4;
27 constexpr uint32_t VARINT32_ENCODE_SIZE = 5;
28 constexpr uint32_t VARINT64_SIZE = 8;
29 constexpr uint32_t VARINT64_ENCODE_SIZE = 10;
30 constexpr uint32_t VARINT_ENCODE_MAX_SIZE = VARINT64_ENCODE_SIZE;
31
32 constexpr uint32_t VARINT_MAX_1BYTE = (1u << (7 * 1)) - 1;
33 constexpr uint32_t VARINT_MAX_2BYTE = (1u << (7 * 2)) - 1;
34 constexpr uint32_t VARINT_MAX_3BYTE = (1u << (7 * 3)) - 1;
35 constexpr uint32_t VARINT_MAX_4BYTE = (1u << (7 * 4)) - 1;
36
37 constexpr uint8_t VARINT_PAYLOAD_BITS = 7;
38 constexpr uint8_t VARINT_MASK_PAYLOAD = 0x7F;
39 constexpr uint8_t VARINT_MASK_MSB = 0x80;
40
GetPackedVarintLenSize(uint32_t itemCount,uint32_t itemSize,uint32_t & len)41 inline uint32_t GetPackedVarintLenSize(uint32_t itemCount, uint32_t itemSize, uint32_t& len)
42 {
43 len = itemCount;
44 if (itemSize == VARINT32_SIZE) {
45 len = itemCount * VARINT32_ENCODE_SIZE;
46 } else if (itemSize == VARINT64_SIZE) {
47 len = itemCount * VARINT64_ENCODE_SIZE;
48 } // else bool is 1 byte
49
50 const uint32_t one = 1;
51 const uint32_t two = 2;
52 const uint32_t three = 3;
53 const uint32_t four = 4;
54 if (len <= VARINT_MAX_1BYTE) {
55 return one;
56 } else if (len <= VARINT_MAX_2BYTE) {
57 return two;
58 } else if (len <= VARINT_MAX_3BYTE) {
59 return three;
60 } else if (len <= VARINT_MAX_4BYTE) {
61 return four;
62 }
63
64 return 0; // illegal, too large
65 }
66
67 template<typename T>
EncodeZigZag(T v)68 inline typename std::make_unsigned<T>::type EncodeZigZag(T v)
69 {
70 if (v >= 0) {
71 return ((typename std::make_unsigned<T>::type)(v) << 1);
72 }
73
74 return ((typename std::make_unsigned<T>::type)(~v) << 1) + 1;
75 }
76
77 template<typename T>
EncodeVarint(uint8_t * buf,T v)78 inline uint32_t EncodeVarint(uint8_t* buf, T v)
79 {
80 // https://developers.google.com/protocol-buffers/docs/encoding
81 // Unsigned Integers and Signed Integers(intN)
82 uint64_t value = static_cast<uint64_t>(v);
83 uint32_t size = 0;
84 while (value > static_cast<uint64_t>(VARINT_MAX_1BYTE)) {
85 buf[size] = (VARINT_MASK_PAYLOAD & value) | VARINT_MASK_MSB;
86 size++;
87 value >>= VARINT_PAYLOAD_BITS;
88 }
89 buf[size] = (VARINT_MASK_PAYLOAD & value);
90 size++;
91
92 return size;
93 }
94
95 template<typename T>
EncodeZigZagVarint(uint8_t * buf,T v)96 inline uint32_t EncodeZigZagVarint(uint8_t* buf, T v)
97 {
98 return EncodeVarint(buf, EncodeZigZag(v));
99 }
100
101 template<typename T>
EncodeVarintPadding(uint8_t * buf,T v,uint32_t paddingSize)102 inline void EncodeVarintPadding(uint8_t* buf, T v, uint32_t paddingSize)
103 {
104 uint32_t size = 0;
105 paddingSize--;
106 while (size < paddingSize) {
107 buf[size] = (VARINT_MASK_PAYLOAD & v) | VARINT_MASK_MSB;
108 size++;
109 v >>= VARINT_PAYLOAD_BITS;
110 }
111 buf[size] = (VARINT_MASK_PAYLOAD & v);
112 }
113 } // namespace ProtoEncoder
114 } // namespace Profiler
115 } // namespace Developtools
116 } // namespace OHOS
117 #endif // VARINT_ENCODE_H
118