Why this base64 function stop working when increasing max length?
- by flyout
I am using this class to encode/decode text to base64.
It works fine with MAX_LEN up to 512 but if I increase it to 1024 the decode function returns and empty var.
This is the function:
char* Base64::encode(char *src)
{
char* ptr = dst+0;
unsigned triad;
unsigned int d_len = MAX_LEN;
memset(dst,'\0', MAX_LEN);
unsigned s_len = strlen(src);
for (triad = 0; triad < s_len; triad += 3)
{
unsigned long int sr = 0;
unsigned byte;
for (byte = 0; (byte<3)&&(triad+byte<s_len); ++byte)
{
sr <<= 8;
sr |= (*(src+triad+byte) & 0xff);
}
sr <<= (6-((8*byte)%6))%6; // shift left to next 6bit alignment
if (d_len < 4) return NULL; // error - dest too short
*(ptr+0) = *(ptr+1) = *(ptr+2) = *(ptr+3) = '=';
switch(byte)
{
case 3:
*(ptr+3) = base64[sr&0x3f];
sr >>= 6;
case 2:
*(ptr+2) = base64[sr&0x3f];
sr >>= 6;
case 1:
*(ptr+1) = base64[sr&0x3f];
sr >>= 6;
*(ptr+0) = base64[sr&0x3f];
}
ptr += 4;
d_len -= 4;
}
return dst;
}
Why could be causing this?
