neujson
JSON parser/generator in C++17
Explore the docs » (you are here)
View Demo · Report Bug · Request Feature
Description
neujson is a JSON parser and generator for C++. It supports both SAX and DOM style API.
Document
Install
clone the neujson repo
git clone https://github.com/hominsu/neujson.git
Build and install
The following commands build and locally install neujson:
cd neujson
mkdir -p cmake/build
pushd cmake/build
cmake ../..
make -j
make install
popd
If you didn't have root access use sudo to install neujson instead:
sudo make install
Build with example
The example code is part of the neujson repo source, which you cloned as part of the steps of the previous section, just add a cmake option:
cmake -DNEUJSON_BUILD_EXAMPLES=ON ../..
Build with benchmark
To build with benchmark，use git submodule to fetch all the data from that third party project and check out the appropriate commit first, then add the benchmark CMake option:
git submodule update --init --recursive
pushd cmake/build
cmake -DNEUJSON_BUILD_BENCHMARK=ON ../..
...
Uninstall
The following commands uninstall neujson:
pushd cmake/build
make uninstall
popd
If you didn't have root access use sudo to uninstall neujson instead:
sudo make uninstall
Usage at a glance
This simple example parses a JSON string into a document (DOM), make a simple modification of the DOM, and finally stringify the DOM to a JSON string.
#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;
}
Output:
[{"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"}]
Benchmark
The benchmark is base on the google benchmark
JSON data
| JSON file | Size | Description |
|---|---|---|
canada.jsonsource | 2199KB | Contour of Canada border in GeoJSON format. Contains a lot of real numbers. |
citm_catalog.jsonsource | 1737KB | A big benchmark file with indentation used in several Java JSON parser benchmarks. |
Sample Results
The followings are some snapshots from the results of MacBook Air (M1, 2020) with Apple clang 13.1.6
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
The followings are some snapshots from the results of i5-9500 with gcc 8.5.0 (Red Hat 8.5.0-10) in CentOS-8-Stream
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
Reference
RapidJSON: A fast JSON parser/generator for C++ with both SAX/DOM style API
Acknowledgment
Special thanks to JetBrains for licensing free All Products Pack for this open source projects
Contributors ✨
Thanks goes to these wonderful people (emoji key):
 HominSu 💻 📖 🎨 💡 🚇 📦 ⚠️ |
This project follows the all-contributors specification. Contributions of any kind welcome!