base64的C++實現

最後更新：2018-12-03 來源：互聯網

上載者：User

創建阿里雲帳戶，並獲得超過 40 款產品的免費試用版；而企業帳戶則可以享有總值 $1200 的免費試用版。立即註冊！

概述
base64可以將不可顯示的編碼轉換成可顯示的編碼，以便於儲存。
比如http一般傳輸的是文字格式設定的報文，如果要傳輸圖片，那麼就要先將圖片編碼成base64的報文傳輸，然後在客用戶端顯示的時候，將base64的報文解密，轉換成二進位的圖片資料顯示。
下面給出原始碼，可以直接在linux,msvc環境下進行編譯。
代碼
Base64.h代碼如下：
/** * (C) Copyright 2009, asiainfo * @version v1.0 * @author chenli * @brief base64編碼和解碼 * * history: * chenli 2009-02-17 1.0 build this moudle */#ifndef ___BASE64_H___ #define ___BASE64_H___#include <string>using namespace std;class CBase64 { public: CBase64(); ~CBase64();/********************************************************* * 函數說明：將輸入資料進行base64編碼 * 參數說明：[in]pIn需要進行編碼的資料 [in]uInLen 輸入參數的位元組數 [out]strOut 輸出的進行base64編碼之後的字串 * 傳回值：true處理成功,false失敗 * 作者：ChenLi * 編寫時間：2009-02-17 **********************************************************/ bool static Encode(const unsigned char *pIn, unsigned long uInLen, string& strOut);/********************************************************* * 函數說明：將輸入資料進行base64編碼 * 參數說明：[in]pIn需要進行編碼的資料 [in]uInLen輸入參數的位元組數 [out]pOut輸出的進行base64編碼之後的字串 [out]uOutLen輸出的進行base64編碼之後的字串長度 * 傳回值：true處理成功,false失敗 * 作者：ChenLi * 編寫時間：2009-02-17 **********************************************************/ bool static Encode(const unsigned char *pIn, unsigned long uInLen, unsigned char *pOut, unsigned long *uOutLen);/********************************************************* * 函數說明：將輸入資料進行base64解碼 * 參數說明：[in]strIn需要進行解碼的資料 [out]pOut輸出解碼之後的節數資料 [out]uOutLen輸出的解碼之後的位元組數長度 * 傳回值：true處理成功,false失敗 * 作者：ChenLi * 編寫時間：2009-02-17 **********************************************************/ bool static Decode(const string& strIn, unsigned char *pOut, unsigned long *uOutLen) ;/********************************************************* * 函數說明：將輸入資料進行base64解碼 * 參數說明：[in]strIn需要進行解碼的資料 [out]pOut輸出解碼之後的節數資料 [out]uOutLen輸出的解碼之後的位元組數長度 * 傳回值：true處理成功,false失敗 * 作者：ChenLi * 編寫時間：2009-02-17 **********************************************************/ bool static Decode(const unsigned char *pIn, unsigned long uInLen, unsigned char *pOut, unsigned long *uOutLen) ; };#endif // ___BASE64_H___ 
Base64.cpp代碼如下：
/* * *Base64? * * * */#include "Base64.h"static const char *g_pCodes = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";static const unsigned char g_pMap[256] = { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255, 254, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255, 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 };CBase64::CBase64() { }CBase64::~CBase64() { }bool CBase64::Encode(const unsigned char *pIn, unsigned long uInLen, unsigned char *pOut, unsigned long *uOutLen) { unsigned long i, len2, leven; unsigned char *p;if(pOut == NULL || *uOutLen == 0) return false;//ASSERT((pIn != NULL) && (uInLen != 0) && (pOut != NULL) && (uOutLen != NULL));len2 = ((uInLen + 2) / 3) << 2; if((*uOutLen) < (len2 + 1)) return false;p = pOut; leven = 3 * (uInLen / 3); for(i = 0; i < leven; i += 3) { *p++ = g_pCodes[pIn[0] >> 2]; *p++ = g_pCodes[((pIn[0] & 3) << 4) + (pIn[1] >> 4)]; *p++ = g_pCodes[((pIn[1] & 0xf) << 2) + (pIn[2] >> 6)]; *p++ = g_pCodes[pIn[2] & 0x3f]; pIn += 3; }if (i < uInLen) { unsigned char a = pIn[0]; unsigned char b = ((i + 1) < uInLen) ? pIn[1] : 0; unsigned char c = 0;*p++ = g_pCodes[a >> 2]; *p++ = g_pCodes[((a & 3) << 4) + (b >> 4)]; *p++ = ((i + 1) < uInLen) ? g_pCodes[((b & 0xf) << 2) + (c >> 6)] : '='; *p++ = '='; }*p = 0; // Append NULL byte *uOutLen = p - pOut; return true; }bool CBase64::Encode(const unsigned char *pIn, unsigned long uInLen, string& strOut) { unsigned long i, len2, leven; strOut = "";//ASSERT((pIn != NULL) && (uInLen != 0) && (pOut != NULL) && (uOutLen != NULL));len2 = ((uInLen + 2) / 3) << 2; //if((*uOutLen) < (len2 + 1)) return false;//p = pOut; leven = 3 * (uInLen / 3); for(i = 0; i < leven; i += 3) { strOut += g_pCodes[pIn[0] >> 2]; strOut += g_pCodes[((pIn[0] & 3) << 4) + (pIn[1] >> 4)]; strOut += g_pCodes[((pIn[1] & 0xf) << 2) + (pIn[2] >> 6)]; strOut += g_pCodes[pIn[2] & 0x3f]; pIn += 3; }if (i < uInLen) { unsigned char a = pIn[0]; unsigned char b = ((i + 1) < uInLen) ? pIn[1] : 0; unsigned char c = 0;strOut += g_pCodes[a >> 2]; strOut += g_pCodes[((a & 3) << 4) + (b >> 4)]; strOut += ((i + 1) < uInLen) ? g_pCodes[((b & 0xf) << 2) + (c >> 6)] : '='; strOut += '='; }//*p = 0; // Append NULL byte //*uOutLen = p - pOut; return true; }bool CBase64::Decode(const string& strIn, unsigned char *pOut, unsigned long *uOutLen) { unsigned long t, x, y, z; unsigned char c; unsigned long g = 3;//ASSERT((pIn != NULL) && (uInLen != 0) && (pOut != NULL) && (uOutLen != NULL));for(x = y = z = t = 0; x < strIn.length(); x++) { c = g_pMap[strIn[x]]; if(c == 255) continue; if(c == 254) { c = 0; g--; }t = (t << 6) | c;if(++y == 4) { if((z + g) > *uOutLen) { return false; } // Buffer overflow pOut[z++] = (unsigned char)((t>>16)&255); if(g > 1) pOut[z++] = (unsigned char)((t>>8)&255); if(g > 2) pOut[z++] = (unsigned char)(t&255); y = t = 0; } }*uOutLen = z; return true; } 
上面有了base64的演算法，下面寫個程式進行測試。
main.cpp檔案內容如下：
#include "Base64.h"#include <iostream>using namespace std;int main() { unsigned long len = 10;unsigned char pIn[100]; unsigned char pOut[100];memcpy(pIn,"你好",5);string strout;cout<<(char*)pIn<<endl; if(CBase64::Encode(pIn, 4, strout)) cout<<strout<<endl; else cout<<"加密失敗"<<endl;string stroIn = strout; cout<<stroIn<<endl;memset(pOut,0,sizeof(pOut));if(CBase64::Decode(stroIn, pOut, &len)) { cout<<(char *)pOut<<endl; cout<<"len="<<strlen((char *)pOut)<<endl; } else cout<<"解密失敗"<<endl;cout<<len<<endl;return 0; }
上面的代碼直接編譯就可以運行了。

本文章原先以中文撰寫並發佈於 aliyun.com，亦設英文版本，僅作資訊用途。本網站不對文章的準確性，完整性或可靠性或其任何翻譯作出任何明示或暗示的陳述或保證。如對該文章有任何疑慮或投訴，請傳送電郵至 info-contact@alibabacloud.com 並提供相關疑慮或投訴的詳細說明。職員會於 5 個工作天內與您聯絡，一經驗證之後，即會刪除該侵權內容。

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

Sales Support

1 on 1 presale consultation

Chat Contact Sales
After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

Open a Ticket
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

Learn More

base64的C++實現

聯繫我們

A Free Trial That Lets You Build Big!

Sales Support

After-Sales Support