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Base 64 encode & decode c/c++ 支持中文

By admin  •  2021-08-03 19:32:15  •  74次点击
永久外链: https://i.otherhill.com/static/740cf7b6f44e11eb9a46809b202ce664.html

这种支持中文的Base64编解码C代码,可是不太好找的哟

#include
<stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

//https://rangsub.tistory.com/8
/*------ Base64 Encoding Table ------*/
static const char MimeBase64[] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/'
};
int base64_encode(char *text, int numBytes, char **encodedText)
{
unsigned char input[3] = { 0,0,0 };
unsigned char output[4] = { 0,0,0,0 };
int index, i, j, size;
char *p, *plen;
plen = text + numBytes - 1;
size = (4 * (numBytes / 3)) + (numBytes % 3 ? 4 : 0) + 1;
(*encodedText) = (char*)malloc(size);
j = 0;
for (i = 0, p = text; p <= plen; i++, p++) {
index = i % 3;
input[index] = *p;
if (index == 2 || p == plen) {
output[0] = ((input[0] & 0xFC) >> 2);
output[1] = ((input[0] & 0x3) << 4) | ((input[1] & 0xF0) >> 4);
output[2] = ((input[1] & 0xF) << 2) | ((input[2] & 0xC0) >> 6);
output[3] = (input[2] & 0x3F);
(*encodedText)[j++] = MimeBase64[output[0]];
(*encodedText)[j++] = MimeBase64[output[1]];
(*encodedText)[j++] = index == 0 ? '=' : MimeBase64[output[2]];
(*encodedText)[j++] = index < 2 ? '=' : MimeBase64[output[3]];
input[0] = input[1] = input[2] = 0;
}
}
(*encodedText)[j] = '\0';
return size;
}
/*------ Base64 Decoding Table ------*/
static int DecodeMimeBase64[256] = {
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* 00-0F */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* 10-1F */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63, /* 20-2F */
52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-1,-1,-1, /* 30-3F */
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14, /* 40-4F */
15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1, /* 50-5F */
-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, /* 60-6F */
41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1, /* 70-7F */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* 80-8F */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* 90-9F */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* A0-AF */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* B0-BF */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* C0-CF */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* D0-DF */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* E0-EF */
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 /* F0-FF */
};


int base64_decode(char * text, unsigned char * dst, int numBytes)
{
const char* cp;
int space_idx = 0, phase;
int d, prev_d = 0;
unsigned char c;
space_idx = 0;
phase = 0;
for (cp = text; *cp != '\0'; ++cp) {
d = DecodeMimeBase64[(int)*cp];
if (d != -1) {
switch (phase) {
case 0:
++phase;
break;
case 1:
c = ((prev_d << 2) | ((d & 0x30) >> 4));
if (space_idx < numBytes)
dst[space_idx++] = c;
++phase;
break;
case 2:
c = (((prev_d & 0xf) << 4) | ((d & 0x3c) >> 2));
if (space_idx < numBytes)
dst[space_idx++] = c;
++phase;
break;
case 3:
c = (((prev_d & 0x03) << 6) | d);
if (space_idx < numBytes)
dst[space_idx++] = c;
phase = 0;
break;
}
prev_d = d;
}
}
return space_idx;
}


int main(){
char * data = "Hello World大!";
size_t input_size = strlen(data);
char * pOut= (char*)malloc(500);
int nSize = base64_encode(data, input_size, &pOut);
printf("Encoded Data is: %s \n",pOut);
char * pPlainText= (char*)malloc(500);
int numBytes = base64_decode(pOut, (unsigned char *)pPlainText, nSize);
printf("Decoded Data is: %s \n", pPlainText);
free(pPlainText);
free(pOut);
return 0;
}





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