cmake学习之判断操作系统版本

[TOC]

概述

集成步骤

将Flatbuffer集成到我们的项目中

if (BUILD_FLAT_BUFFERS_LIB)
    # 官网文档
    # https://google.github.io/flatbuffers/flatbuffers_guide_building.html
    set(FLAT_BUFFERS_NAME flatbuffers)  # 设置FlatBuffers的名称
    set(FLAT_BUFFERS_VERSION v22.10.26)  # 设置FlatBuffers的版本号
    set(FLAT_BUFFERS_BASE_DIR ${LIB_DIR}/${FLAT_BUFFERS_NAME}/${FLAT_BUFFERS_VERSION})   # 设置flatbuffers的根目录
    # 如下表示使用FLAT_BUFFERS源码进行编译
    # 保证FlatBuffers 和项目的其余部分之间使用相同的编译器和链接器设置，因此避免了与使用不兼容库（例如调试/发布）等相关的问题
    if (BUILD_FLAT_BUFFERS_WITH_SOURCE)
        set(FLAT_BUFFERS_SRC_DIR ${FLAT_BUFFERS_BASE_DIR}/src/${FLAT_BUFFERS_NAME}-${FLAT_BUFFERS_VERSION})
        add_subdirectory(${FLAT_BUFFERS_SRC_DIR} ${CMAKE_CURRENT_BINARY_DIR}/flatbuffers-build EXCLUDE_FROM_ALL)
    else ()
        set(FLAT_BUFFERS_INCLUDE_DIR ${FLAT_BUFFERS_BASE_DIR}/include)
        set(FLAT_BUFFERS_LIB_DIR ${QNN_BASE_DIR}/target/${TARGET_OS}-${TARGET_ARCH}-${CMAKE_BUILD_TYPE})   # 根据系统版本设置依赖库的目录
        set(FLAT_BUFFERS_LINK_DIR ${FLAT_BUFFERS_LIB_DIR})
        set(FLAT_BUFFERS_LIB QNN QNN_main)
        include_directories(${FLAT_BUFFERS_INCLUDE_DIR})
        link_directories(${FLAT_BUFFERS_LINK_DIR})
    endif ()
    message(STATUS "[Dependency] flatbuffers FLAT_BUFFERS_INCLUDE_DIR = ${FLAT_BUFFERS_INCLUDE_DIR}")
    message(STATUS "[Dependency] flatbuffers FLAT_BUFFERS_LINK_DIR = ${FLAT_BUFFERS_LINK_DIR}")
    message(STATUS "[Dependency] flatbuffers FLAT_BUFFERS_LIB = ${FLAT_BUFFERS_LIB}")
    message(STATUS "[Dependency] flatbuffers FLAT_BUFFERS_SRC_DIR = ${FLAT_BUFFERS_SRC_DIR}")
endif ()

集成到我们的工程中

# 现在只需根据需要将 flatbuffers 链接到您已经声明的目标。
# 如果 CMake > 2.8.11，flatbuffers 目标会自动携带标题搜索路径。
target_link_libraries（own_project_target PRIVATE flatbuffers）

集成代码

编写FlatBuffers的scheme文件

我们来编写一个FaceIndo.fbs的scheme文件

// 打电话的状态
enum FaceCallStatus:byte { F_CALL_NONE = 0, F_CALL_CALLING}

enum FaceDangerousStatus:byte { F_DANGEROUS_NONE = 0, F_DANGEROUS_SMOKE,F_DANGEROUS_SILENCE,F_DANGEROUS_DRINK,
                           F_DANGEROUS_OPEN_MOUTH,F_COVER_MOUTH,F_FACE_MASK,F_COVER_NONE

struct VPoint3 {
    x:float;
    y:float;
    z:float;
}

struct VAngle {
    yaw:float;
    pitch:float;
    roll:float;
}

table FaceInfo {
    name:string;
    index:short;
    headLocation:VPoint3;
    headDeflection:VAngle;

    faceCount:[ubyte] (deprecated);
    faceFeature:[float];

    stateCallSingle:bool = false;
    stateDangerDriveSingle:FaceDangerousStatus = F_DANGEROUS_NONE;
    eye3dLandmark28Left:[VPoint3];
    eye3dLandmark28Right:[VPoint3];
}

root_type FaceInfo;

关于scheme文件的详细介绍：FlatBuffers的scheme文件解析

编译Schema文件:

到我们编写的scheme文件保存为FaceInfo.fbs文件夹下，执行：

flatc --cpp FaceInfo.fbs
flatc --java FaceInfo.fbs

实例程序

//
// Created by Frewen.Wang on 2022/11/19.
//
#include "FaceInfo_generated.h"
#include "aura/baselib/utils/AuraLog.h"

using namespace aura::aura_vision;

const char *TAG = "demo_flatbuffers";

/**
 * 参考文档：https://github.com/google/flatbuffers/blob/master/samples/sample_binary.cpp
 * @param argc
 * @param argv
 * @return
 */
int main(int argc, const char *argv[]) {
    // Build up a serialized buffer algorithmically:
    flatbuffers::FlatBufferBuilder builder;
    // 创建FaceInfo的String字段:name
    auto name = builder.CreateString("MyFace");
    // 创建FaceInfo的short字段:name
    short index = 123;
    // 创建FaceIndo的struct字段：headLocation
    auto headLocation = VPoint3(1.0f, 2.0f, 3.0f);
    auto headDeflection = VAngle(1.0f, 2.0f, 3.0f);
    // 创建FaceInfo的Vector<float>字段：faceFeature
    float face_feature[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    auto faceFeature = builder.CreateVector(face_feature, 10);

    auto point1 = builder.CreateStruct(VPoint3(1.0f, 2.0f, 3.0f));
    auto point2 = builder.CreateStruct(VPoint3(4.0f, 5.0f, 6.0f));
    auto point3 = builder.CreateStruct(VPoint3(7.0f, 8.0f, 9.0f));
    std::vector<flatbuffers::Offset<const VPoint3 *>> eye3dLandmark28LeftVector;
    eye3dLandmark28LeftVector.push_back(point1);
    eye3dLandmark28LeftVector.push_back(point2);
    eye3dLandmark28LeftVector.push_back(point3);
    auto eye3dLandmark28Lefts = builder.CreateVector(eye3dLandmark28LeftVector);
    std::vector<flatbuffers::Offset<const VPoint3 *>> eye3dLandmark28RightVector;
    eye3dLandmark28RightVector.push_back(point1);
    eye3dLandmark28RightVector.push_back(point2);
    eye3dLandmark28RightVector.push_back(point3);
    auto eye3dLandmark28Rights = builder.CreateVector(eye3dLandmark28RightVector);

    auto gestureName1 = builder.CreateString("gesture1");
    short gestureIndex1 = 12345;
    auto gestureName2 = builder.CreateString("gesture2");
    short gestureIndex2 = 6789;
    auto gesture1 = CreateGestureInfo(builder, gestureName1, gestureIndex1);
    auto gesture2 = CreateGestureInfo(builder, gestureName2, gestureIndex2);

    // Create a FlatBuffer's `vector` from the `std::vector`.
    // 创建FaceInfo的Table型数组对象：gesture_info_list
    std::vector<flatbuffers::Offset<GestureInfo>> gestureVector;
    gestureVector.push_back(gesture1);
    gestureVector.push_back(gesture2);
    auto gestureList = builder.CreateVector(gestureVector);

    // 开始序列化根节点对象
    builder.Finish(faceInfo);
    // 我们通过此方法就可以进行序列化对象数据，然我们就可以将*buffer存储到硬盘上
    uint8_t *buffer = builder.GetBufferPointer();
    ALOGD(TAG, "serialization object success");

    // 我们现在有了一个可以存储在磁盘上或通过网络发送的 FlatBuffer。
    // ** file/network code goes here :) **
    // access builder.GetBufferPointer() for builder.GetSize() bytes

    // 下面，我们立即访问序列化之后的buffer数据（就好像我们刚刚收到它一样）。
    auto newFaceInfo = GetFaceInfo(buffer);
    // Get and test some scalar types from the FlatBuffer.
    assert(newFaceInfo->name()->str() == "MyFace");
    ALOGD(TAG, "deserialization object name:%s", newFaceInfo->name()->str().c_str());
    assert(newFaceInfo->index() == 123);

    auto newHeadLocation = newFaceInfo->head_deflection();
    assert(newHeadLocation);
    assert(newHeadLocation->yaw() == 1.0);
    assert(newHeadLocation->pitch() == 2.0);
    assert(newHeadLocation->roll() == 3.0);

    ALOGD(TAG, "deserialization object success");
}