Base64:字串轉換

#include<string.h>#define AVal(x) Base64ValTab[x]int EncodeBase64(unsigned char * pInput,int inbufLen, unsigned char * pOutput){const unsigned char Base64ValTab[65] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";int i = 0;int loop = 0;int remain = 0;int iDstLen = 0;loop = inbufLen/3;remain = inbufLen%3;for (i=0; i < loop; i++){unsigned char a1 = (pInput[i*3] >> 2);unsigned char a2 = ( ((pInput[i*3] & 0x03) << 4) | (pInput[i*3+1] >> 4) );unsigned char a3 = ( ((pInput[i*3+1] & 0x0F) << 2) | ((pInput[i*3+2] & 0xC0) >> 6) );unsigned char a4 = (pInput[i*3+2] & 0x3F);pOutput[i*4] = AVal(a1);pOutput[i*4+1] = AVal(a2);pOutput[i*4+2] = AVal(a3);pOutput[i*4+3] = AVal(a4);}iDstLen = i*4;if (remain == 1){// should pad two equal signi = inbufLen-1;unsigned char a1 = (pInput[i] >> 2);unsigned char a2 = ((pInput[i] & 0x03) << 4);pOutput[iDstLen++] = AVal(a1);pOutput[iDstLen++] = AVal(a2);pOutput[iDstLen++] = '=';pOutput[iDstLen] = '=';}else if (remain == 2){// should pad one equal signi = inbufLen-2;unsigned char a1 = (pInput[i] >> 2);unsigned char a2 = ( ((pInput[i] & 0x03) << 4) | (pInput[i+1] >> 4));unsigned char a3 = ( (pInput[i+1] & 0x0F) << 2);pOutput[iDstLen++] = AVal(a1);pOutput[iDstLen++] = AVal(a2);pOutput[iDstLen++] = AVal(a3);pOutput[iDstLen] = '=';}return iDstLen;}int main(){unsigned char a[30] = "admin:123";char *a_ptr = (char *)a;unsigned char b[30] = {0};EncodeBase64(a,strlen(a_ptr),b);return 0;}