neujson
JSON parser/generator in C++17
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简介
neujson 是一个 C++ 的 JSON 解析器及生成器。它同时支持 SAX 和 DOM 风格的 API。
文档
安装
克隆 neujson 的源代码
git clone https://github.com/hominsu/neujson.git
编译和安装
下面的命令将在本地构建和安装 neujson：
cd neujson
mkdir -p cmake/build
pushd cmake/build
cmake ../..
make -j
make install
popd
如果你没有安装目录的权限，请使用 sudo：
sudo make install
同时构建示例程序
示例的源代码已经包含在 neujson 的源代码中，你已经在上一步中克隆了源代码，只需要额外添加一个的 cmake 选项：
cmake -DNEUJSON_BUILD_EXAMPLES=ON ../..
同时构建基准测试
构建基准测试，需要使用 git submodule 拉取第三方依赖，并检出到相应的分支，然后添加基准测试的 cmake 选项：
git submodule update --init --recursive
pushd cmake/build
cmake -DNEUJSON_BUILD_BENCHMARK=ON ../..
...
卸载
使用一下命令可以卸载 neujson：
pushd cmake/build
make uninstall
popd
如果你没有安装目录的权限，请使用 sudo：
sudo make uninstall
用法一目了然
此简单例子解析一个 JSON 字符串至一个 document (DOM)，对 DOM 作出简单修改，最终把 DOM 转换（stringify）至 JSON 字符串。
#include <cstdio>
#include "neujson/document.h"
#include "neujson/writer.h"
#include "neujson/string_write_stream.h"
#include "../sample.h"
int main() {
// 1. Parse a JSON string into DOM.
neujson::Document doc;
auto err = doc.parse(kSample[0]);
if (err != neujson::error::PARSE_OK) {
puts(neujson::parseErrorStr(err));
return EXIT_FAILURE;
}
// 2. Modify it by DOM.
auto &s = doc[0]["Longitude"];
s.SetDouble(s.GetDouble() + 100.0);
// 3. Stringify the DOM
neujson::StringWriteStream os;
neujson::Writer<neujson::StringWriteStream> writer(os);
doc.WriteTo(writer);
// Output
fprintf(stdout, "%.*s", static_cast<int>(os.get().length()), os.get().data());
return 0;
}
输出:
[{"precision":"zip","Latitude":37.766800000000003,"Longitude":-22.395899999999997,"Address":"","City":"SAN FRANCISCO","State":"CA","Zip":"94107","Country":"US"},{"precision":"zip","Latitude":37.371991000000001,"Longitude":-122.02602,"Address":"","City":"SUNNYVALE","State":"CA","Zip":"94085","Country":"US"}]
基准性能测试
基准性能测试基于 google benchmark 进行
JSON data
| JSON file | Size | Description |
|---|---|---|
canada.jsonsource | 2199KB | 加拿大边境轮廓，格式为: GeoJSON；包含大量的实数。 |
citm_catalog.jsonsource | 1737KB | 一个带有缩进的大型基准测试文件，用于多个Java JSON解析器基准测试。 |
Sample Results
下面是使用 MacBook Air (M1, 2020) 和 Apple clang 13.1.6 得到的结果
Run on (8 X 24.1212 MHz CPU s)
CPU Caches:
L1 Data 64 KiB (x8)
L1 Instruction 128 KiB (x8)
L2 Unified 4096 KiB (x2)
Load Average: 2.04, 1.78, 1.74
--------------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations
--------------------------------------------------------------------------------------------------------
BM_neujson_read_parse/citm_catalog.json 7.04 ms 7.04 ms 72
BM_nlohmann_read_parse/citm_catalog.json 10.6 ms 10.6 ms 66
BM_rapidjson_read_parse/citm_catalog.json 2.96 ms 2.96 ms 236
BM_neujson_read_parse_write_file/citm_catalog.json 7.92 ms 7.92 ms 88
BM_nlohmann_read_parse_write_file/citm_catalog.json 12.5 ms 12.5 ms 56
BM_rapidjson_read_parse_write_file/citm_catalog.json 4.10 ms 4.10 ms 170
BM_neujson_read_parse_write_string/citm_catalog.json 8.03 ms 8.03 ms 87
BM_nlohmann_read_parse_write_string/citm_catalog.json 12.7 ms 12.7 ms 55
BM_rapidjson_read_parse_write_string/citm_catalog.json 3.90 ms 3.90 ms 180
BM_neujson_read_parse_pretty_write_file/citm_catalog.json 8.84 ms 8.84 ms 79
BM_nlohmann_read_parse_pretty_write_file/citm_catalog.json 13.3 ms 13.3 ms 53
BM_rapidjson_read_parse_pretty_write_file/citm_catalog.json 4.56 ms 4.55 ms 154
BM_neujson_read_parse_pretty_write_string/citm_catalog.json 9.44 ms 9.44 ms 72
BM_nlohmann_read_parse_pretty_write_string/citm_catalog.json 14.2 ms 14.2 ms 50
BM_rapidjson_read_parse_pretty_write_string/citm_catalog.json 4.19 ms 4.19 ms 167
BM_neujson_read_parse/canada.json 31.6 ms 31.6 ms 22
BM_nlohmann_read_parse/canada.json 39.1 ms 39.1 ms 18
BM_rapidjson_read_parse/canada.json 3.38 ms 3.38 ms 207
BM_neujson_read_parse_write_file/canada.json 68.2 ms 68.2 ms 10
BM_nlohmann_read_parse_write_file/canada.json 47.6 ms 47.6 ms 15
BM_rapidjson_read_parse_write_file/canada.json 12.5 ms 12.5 ms 55
BM_neujson_read_parse_write_string/canada.json 69.4 ms 69.4 ms 10
BM_nlohmann_read_parse_write_string/canada.json 48.5 ms 48.5 ms 14
BM_rapidjson_read_parse_write_string/canada.json 10.7 ms 10.7 ms 63
BM_neujson_read_parse_pretty_write_file/canada.json 72.3 ms 72.3 ms 10
BM_nlohmann_read_parse_pretty_write_file/canada.json 51.2 ms 51.2 ms 14
BM_rapidjson_read_parse_pretty_write_file/canada.json 13.7 ms 13.7 ms 51
BM_neujson_read_parse_pretty_write_string/canada.json 75.9 ms 75.9 ms 9
BM_nlohmann_read_parse_pretty_write_string/canada.json 55.0 ms 55.0 ms 13
BM_rapidjson_read_parse_pretty_write_string/canada.json 12.4 ms 12.4 ms 56
下面是使用 i5-9500 以及 CentOS-8-Stream 和 gcc 8.5.0 (Red Hat 8.5.0-10) 得到的结果
Run on (6 X 4166.48 MHz CPU s)
CPU Caches:
L1 Data 32 KiB (x6)
L1 Instruction 32 KiB (x6)
L2 Unified 256 KiB (x6)
L3 Unified 9216 KiB (x1)
Load Average: 0.80, 0.52, 0.45
--------------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations
--------------------------------------------------------------------------------------------------------
BM_neujson_read_parse/citm_catalog.json 8.59 ms 8.58 ms 74
BM_nlohmann_read_parse/citm_catalog.json 14.7 ms 14.6 ms 48
BM_rapidjson_read_parse/citm_catalog.json 2.38 ms 2.37 ms 293
BM_neujson_read_parse_write_file/citm_catalog.json 10.1 ms 10.1 ms 70
BM_nlohmann_read_parse_write_file/citm_catalog.json 17.5 ms 17.5 ms 40
BM_rapidjson_read_parse_write_file/citm_catalog.json 3.39 ms 3.39 ms 206
BM_neujson_read_parse_write_string/citm_catalog.json 10.9 ms 10.9 ms 65
BM_nlohmann_read_parse_write_string/citm_catalog.json 17.5 ms 17.5 ms 40
BM_rapidjson_read_parse_write_string/citm_catalog.json 3.20 ms 3.19 ms 218
BM_neujson_read_parse_pretty_write_file/citm_catalog.json 11.3 ms 11.3 ms 60
BM_nlohmann_read_parse_pretty_write_file/citm_catalog.json 18.8 ms 18.7 ms 38
BM_rapidjson_read_parse_pretty_write_file/citm_catalog.json 3.70 ms 3.69 ms 189
BM_neujson_read_parse_pretty_write_string/citm_catalog.json 14.5 ms 14.5 ms 49
BM_nlohmann_read_parse_pretty_write_string/citm_catalog.json 18.5 ms 18.5 ms 38
BM_rapidjson_read_parse_pretty_write_string/citm_catalog.json 3.57 ms 3.57 ms 196
BM_neujson_read_parse/canada.json 27.8 ms 27.7 ms 25
BM_nlohmann_read_parse/canada.json 41.8 ms 41.8 ms 17
BM_rapidjson_read_parse/canada.json 4.59 ms 4.58 ms 152
BM_neujson_read_parse_write_file/canada.json 100 ms 100 ms 7
BM_nlohmann_read_parse_write_file/canada.json 53.5 ms 53.4 ms 13
BM_rapidjson_read_parse_write_file/canada.json 13.6 ms 13.6 ms 51
BM_neujson_read_parse_write_string/canada.json 106 ms 106 ms 7
BM_nlohmann_read_parse_write_string/canada.json 53.3 ms 53.3 ms 13
BM_rapidjson_read_parse_write_string/canada.json 11.9 ms 11.9 ms 58
BM_neujson_read_parse_pretty_write_file/canada.json 106 ms 106 ms 7
BM_nlohmann_read_parse_pretty_write_file/canada.json 58.6 ms 58.6 ms 12
BM_rapidjson_read_parse_pretty_write_file/canada.json 14.4 ms 14.4 ms 49
BM_neujson_read_parse_pretty_write_string/canada.json 119 ms 119 ms 6
BM_nlohmann_read_parse_pretty_write_string/canada.json 64.9 ms 64.8 ms 11
BM_rapidjson_read_parse_pretty_write_string/canada.json 12.8 ms 12.8 ms 54
参考
RapidJSON: A fast JSON parser/generator for C++ with both SAX/DOM style API
鸣谢
特别感谢 JetBrains 为本开源项目提供免费的 All Products Pack 授权
Contributors ✨
Thanks goes to these wonderful people (emoji key):
 HominSu 💻 📖 🎨 💡 🚇 📦 ⚠️ |
This project follows the all-contributors specification. Contributions of any kind welcome!