base64编码及JNI实现,代码非原创,只做整理和实现JNI端交互

#include <stdlib.h>
#include <stdio.h>
#include <getopt.h>
#include <string.h>
#include "base64.h"
extern "C" {
//Base64 编码
int Base64Encode(unsigned char *OrgString, unsigned char *Base64String, int OrgStringLen) {

    int Base64StringLen = 0;
    static unsigned char Base64Encode[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.@";

    while (OrgStringLen > 0) {
        *Base64String++ = Base64Encode[(OrgString[0] >> 2) & 0x3f];
        if (OrgStringLen > 2) {
            *Base64String++ = Base64Encode[((OrgString[0] & 3) << 4)
                    | (OrgString[1] >> 4)];
            *Base64String++ = Base64Encode[((OrgString[1] & 0xF) << 2)
                    | (OrgString[2] >> 6)];
            *Base64String++ = Base64Encode[OrgString[2] & 0x3F];
        } else {
            switch (OrgStringLen) {
            case 1:
                *Base64String++ = Base64Encode[(OrgString[0] & 3) << 4];
                *Base64String++ = ‘_‘;
                *Base64String++ = ‘_‘;
                break;
            case 2:
                *Base64String++ = Base64Encode[((OrgString[0] & 3) << 4)
                        | (OrgString[1] >> 4)];
                *Base64String++ = Base64Encode[((OrgString[1] & 0x0F) << 2)
                        | (OrgString[2] >> 6)];
                *Base64String++ = ‘_‘;
                break;
            }
        }

        OrgString += 3;
        OrgStringLen -= 3;
        Base64StringLen += 4;
    }

    *Base64String = ‘\0‘;
    return Base64StringLen;
}
//Base64 解码
char GetBase64Value(unsigned char ch) //得到编码值
        {
    if ((ch >= ‘A‘) && (ch <= ‘Z‘))  // A ~ Z
        return ch - ‘A‘;
    if ((ch >= ‘a‘) && (ch <= ‘z‘))  // a ~ z
        return ch - ‘a‘ + 26;
    if ((ch >= ‘0‘) && (ch <= ‘9‘))  // 0 ~ 9
        return ch - ‘0‘ + 52;
    switch (ch)       // 其它字符
    {
    case ‘.‘:
        return 62;
    case ‘@‘:
        return 63;
    case ‘_‘:  //Base64 填充字符
        return 0;
    default:
        return 0;
    }
}
// 解码函数
int Base64Decode(unsigned char *OrgString, unsigned char *Base64String, int Base64StringLen,bool bForceDecode)  //解码函数
   {
    if (Base64StringLen % 4 && !bForceDecode)   //如果不是 4 的倍数,则 Base64 编码有问题
            {
        OrgString[0] = ‘\0‘;
        return -1;
    }
    unsigned char Base64Encode[4];
    int OrgStringLen = 0;

    while (Base64StringLen > 2)  //当待解码个数不足3个时,将忽略它(强制解码时有效)
    {
        Base64Encode[0] = GetBase64Value(Base64String[0]);
        Base64Encode[1] = GetBase64Value(Base64String[1]);
        Base64Encode[2] = GetBase64Value(Base64String[2]);
        Base64Encode[3] = GetBase64Value(Base64String[3]);

        *OrgString++ = (Base64Encode[0] << 2) | (Base64Encode[1] >> 4);
        *OrgString++ = (Base64Encode[1] << 4) | (Base64Encode[2] >> 2);
        *OrgString++ = (Base64Encode[2] << 6) | (Base64Encode[3]);

        Base64String += 4;
        Base64StringLen -= 4;
        OrgStringLen += 3;
    }

    return OrgStringLen;
}
//Base64 函数完毕
}

/*
 * Class:     com_encrypt_EncryptActivity
 * Method:    base64Encrypt
 * Signature: (Ljava/lang/String;)Ljava/lang/String;
 */
JNIEXPORT jstring JNICALL Java_com_encrypt_EncryptActivity_base64Encrypt(
        JNIEnv *env, jobject, jstring str) {
    //接收java端传过来的字符串变量,需要编码的字符串
    const char *string;
    //base64加密后字符串指针
    unsigned char *base64String;
    //接收java端字符串
    string = env->GetStringUTFChars(str, 0);
    //计算出字符串的长度
    int len = strlen(string) + 1;
    //为字符串分配空间，通常为4个字节一组，且加密后长度小于2倍的长度加4
    base64String = new unsigned char[len * 2 + 4];
    //进行base64编码
    Base64Encode((unsigned char *) string, base64String, len);

    __android_log_print(ANDROID_LOG_INFO, "[INFO][Base64Encyrpt]",
            "hello, base64 encode \n%s", (char *) base64String);
    //释放出从java端接收的字符串
    env->ReleaseStringUTFChars(str, string);
    //返回加密的字符串到java端
    return env->NewStringUTF((char *) base64String);
}

/*
 * Class:     com_encrypt_EncryptActivity
 * Method:    base64Decrypt
 * Signature: (Ljava/lang/String;)Ljava/lang/String;
 */
JNIEXPORT jstring JNICALL Java_com_encrypt_EncryptActivity_base64Decrypt(
        JNIEnv *env, jobject, jstring str) {
    //base64解码后字符串指针
    unsigned char *decodeStr;
    //接收java端传过来的字符串变量
    const char *datestring;
    //接收java端字符串
    datestring = env->GetStringUTFChars(str, 0);
    //字符串的长度
    int len = strlen(datestring) + 1;
    //为字符串分配空间
    decodeStr = new unsigned char[len];
    //base64解码
    Base64Decode(decodeStr, (unsigned char *) datestring, len, true);

    __android_log_print(ANDROID_LOG_INFO, "[INFO][Base64Decyrpt]",
            "hello, base64 decode \n%s!", decodeStr);
    //释放出从java端接收的字符串
    env->ReleaseStringUTFChars(str, datestring);
    //返回解码的字符串到java端
    return env->NewStringUTF((char *) decodeStr);
}

    public native String base64Encrypt(String str);

    public native String base64Decrypt(String str);

    static {
        System.loadLibrary("生成的库名称");
    }