Android Studio NDK 编译 Bsdiff 库

externalNativeBuild {
        cmake {
            path file('src/main/cpp/CMakeLists.txt')
        }
    }

# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html

# Sets the minimum version of CMake required to build your native library.
# This ensures that a certain set of CMake features is available to
# your build.

cmakeminimumrequired(VERSION 3.4.1)

# 查找文件系统中指定模式的路径，如/ 匹配根目录的文件（注意路径）
file(GLOB bzip2 bzip2/.c)

# Specifies a library name, specifies whether the library is STATIC or
# SHARED, and provides relative paths to the source code. You can
# define multiple libraries by adding multiple addlibrary() commands,
# and CMake builds them for you. When you build your app, Gradle
# automatically packages shared libraries with your APK.

addlibrary( # Specifies the name of the library.
        bsdiff

        # Sets the library as a shared library.
        SHARED

        # Provides a relative path to your source file(s).
        bsdiff.c
        bspatch.c
        # 这里名字需要完全匹配，不能你是 cpp 类型文件，这里只写 .c 后缀；会有问题
        diffpatch-lib.cpp
        ${bzip2}
        )

includedirectories(src/main/cpp)

findlibrary( # Defines the name of the path variable that stores the
        # location of the NDK library.
        log-lib

        # Specifies the name of the NDK library that
        # CMake needs to locate.
        log)

# Links your native library against one or more other native libraries.
targetlinklibraries( # Specifies the target library.
        bsdiff

        # Links the log library to the target library.
        ${log-lib})

public class BsdiffUtils {
    static {
        System.loadLibrary("bsdiff");
    }

    //生成差分包
    public static native int diff(String oldFile, String newFile, String patchFile);


    public static native int patch(String oldFile, String patchFile, String newFile);
}

#include <jni.h>
#include <cstdlib>

extern "C" {
int bsdiffmain(int argc, const char argv[]);

int bspatchmain(int argc, const char argv[]);
}

extern "C" JNIEXPORT jint JNICALL
JavacombashellwanglibbsdiffBsdiffUtilsdiff(JNIEnv env, jclass clazz, jstring oldfile,
                                                jstring newfile, jstring patchfile) {

    // for cpp
    const char oldFile = env->GetStringUTFChars(oldfile, 0);
    const char patchFile = env->GetStringUTFChars(patchfile, 0);
    const char newFile = env->GetStringUTFChars(newfile, 0);

    const char argv[] = {"", oldFile, newFile, patchFile};

    int result = bsdiffmain(4, argv);

    env->ReleaseStringUTFChars(oldfile, oldFile);
    env->ReleaseStringUTFChars(patchfile, patchFile);
    env->ReleaseStringUTFChars(newfile, newFile);

    return result;
}

extern "C" JNIEXPORT jint JNICALL
JavacombashellwanglibbsdiffBsdiffUtilspatch(JNIEnv env, jclass clazz, jstring oldfile,
                                                 jstring patchfile, jstring newfile) {

    // for cpp
    const char oldFile = env->GetStringUTFChars(oldfile, 0);
    const char patchFile = env->GetStringUTFChars(patchfile, 0);
    const char newFile = env->GetStringUTFChars(newfile, 0);

    const char argv[] = {"", oldFile, newFile, patchFile};

    int result = bspatchmain(4, argv);


    env->ReleaseStringUTFChars(oldfile, oldFile);
    env->ReleaseStringUTFChars(newfile, newFile);
    env->ReleaseStringUTFChars(patchfile, patchFile);

    return result;
}