91 lines
1.3 KiB
C
91 lines
1.3 KiB
C
static char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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static int pos(char c)
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{
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char *p;
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for(p = base64; *p; p++)
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if(*p == c)
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return p - base64;
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return -1;
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}
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int base64_decode(const char *str, char **data)
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{
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const char *s, *p;
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unsigned char *q;
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int c;
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int x;
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int done = 0;
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int len;
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s = (const char *)malloc(strlen(str));
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q = (unsigned char *)s;
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for(p=str; *p && !done; p+=4){
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x = pos(p[0]);
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if(x >= 0)
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c = x;
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else{
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done = 3;
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break;
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}
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c*=64;
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x = pos(p[1]);
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if(x >= 0)
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c += x;
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else
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return -1;
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c*=64;
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if(p[2] == '=')
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done++;
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else{
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x = pos(p[2]);
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if(x >= 0)
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c += x;
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else
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return -1;
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}
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c*=64;
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if(p[3] == '=')
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done++;
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else{
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if(done)
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return -1;
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x = pos(p[3]);
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if(x >= 0)
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c += x;
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else
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return -1;
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}
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if(done < 3)
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*q++=(c&0x00ff0000)>>16;
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if(done < 2)
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*q++=(c&0x0000ff00)>>8;
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if(done < 1)
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*q++=(c&0x000000ff)>>0;
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}
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len = q - (unsigned char*)(s);
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*data = (char*)realloc((void *)s, len);
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return len;
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}
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char* MyDecode(char *str)
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{
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int i, len;
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char *data = NULL;
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len = base64_decode(str, &data);
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for (i = 0; i < len; i++)
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{
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// data[i] -= 0x83;
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// data[i] ^= 0x45;
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data[i] -= 0x73;
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data[i] ^= 0x23;
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}
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return data;
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} |