Installation Guide

This document describes how to compile and install the RapidJSON optimized for Kunpeng.

Environment Requirements

Software	Version Requirement	Description
OS	openEuler 22.03 LTS SP3	Linux distribution
Compiler	Clang 16.0.6 or later GCC 9.0 or later	C++03 or later. C++11 or later is recommended.
CMake	3.5 or later	Build tool
Git	2.0 or later	Version control
Doxygen	1.8 or later (optional)	Documentation generator tool

Obtaining Code

Run the following commands to obtain code:

git clone -b dev https://gitcode.com/boostkit/rapidjson.git
cd rapidjson

If integrating the optimization via a patch, you can first obtain the upstream RapidJSON source code and then apply the optimization patch from the master branch.
```
git clone https://github.com/Tencent/rapidjson.git
cd rapidjson
git checkout 24b5e7a
git apply /path/to/kunpeng_opti_v1.0.0.patch
```

Compilation and Installation

Create a custom installation directory. You can change the directory as required.

mkdir -p /path/to/install/rapidjson-bin
export RAPIDJSON_INSTALL_DIR=/path/to/install/rapidjson-bin

Configure the build.
1. Create a build directory.
```
mkdir build
cd build
```
2. Configure and build. RapidJSON is a header-only library, so the installation primarily copies header files and CMake configurations.
```
cmake -DCMAKE_BUILD_TYPE=Release \
      -DCMAKE_CXX_FLAGS="-O3" \
      -DCMAKE_INSTALL_PREFIX=${RAPIDJSON_INSTALL_DIR} \
      ..
```
Perform compilation.
- Use all available CPU cores for parallel compilation.
```
cmake --build . --parallel $(nproc)
```
- Alternatively, specify the number of cores (for example, 32 cores).
```
cmake --build . --parallel 32
```
Start installation.
```
cmake --install .
```

Verify the installation directory.

ls -la ${RAPIDJSON_INSTALL_DIR}

Command output:

total 16
drwxr-xr-x.  4 user user 4096 May 30 12:19 .
drwxr-xr-x. 33 user user 4096 May 30 16:39 ..
drwxr-xr-x.  3 user user 4096 May 30 12:19 include
drwxr-xr-x.  3 user user 4096 May 30 12:19 lib

Check the header files.

ls -la ${RAPIDJSON_INSTALL_DIR}/include/rapidjson

Command output:

-rw-r--r--. 1 user user  ... document.h
-rw-r--r--. 1 user user  ... reader.h
-rw-r--r--. 1 user user  ... writer.h
-rw-r--r--. 1 user user  ... stringbuffer.h

Compilation Option Description

Common CMake Options

Option	Default Value	Description
`-DRAPIDJSON_BUILD_DOC`	OFF	Specifies whether to build documentation.
`-DRAPIDJSON_BUILD_EXAMPLES`	ON	Specifies whether to build examples.
`-DRAPIDJSON_BUILD_TESTS`	ON	Specifies whether to build tests.
`-DCMAKE_BUILD_TYPE`	Release	Specifies the build type (Release or Debug).
`-DCMAKE_CXX_FLAGS`	-	Specifies additional compilation flags (`-O3` recommended).

Performance Optimization Compilation Flag

Recommended compilation flag for the Arm architecture (Kunpeng processors).

cmake -DCMAKE_CXX_FLAGS="-O3 -march=armv8.2-a" ..

# Enables the NEON string scan path (typically available by default on AArch64).
cmake -DCMAKE_CXX_FLAGS="-O3 -march=armv8.2-a+simd -DRAPIDJSON_NEON" ..

Running Test

Ensure you are in the build directory.
- If the directory is not in the build directory, run the following command to go to the build directory.
```
cd build
```
- If the directory is already in the build directory, go to the next step.
Select any of the following methods:
- Run all tests.
```
ctest --verbose
```
- Run a specific test.
```
ctest -R unittest
```
- Run tests in parallel.
```
ctest --parallel $(nproc)
```