/*************************************** *************************
This is a sample routine of base64 algorithm. The goal is
Revoke strate principles, so some details may be ignored.
Author Email: zhangwu2003@163.com
**************************************** *************************/
# Include <stdio. h>
# Include <string. h>
# Include <malloc. h> Char * ch64 = "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789 + /"; Unsigned char * encode (unsigned char * SRC, int srclen)
{
Int N, buflen, I, j;
Int pading = 0;
Unsigned char * Buf;
Static unsigned char * DST; Buf = SRC;
Buflen = n = srclen;
If (N % 3! = 0)/* pad with '=' by using a temp buffer */
{
Pading = 1;
Buflen = N + N % 3;
Buf = malloc (buflen + 1 );
Memset (BUF, 0, buflen + 1 );
Memcpy (BUF, SRC, N );
For (I = 0; I <nitrate % 3; I ++)
Buf [n + I] = ';
}
DST = malloc (buflexn * 4/3 + 1 );
Memset (DST, 0, buflen * 4/3 + 1 );
For (I = 0, j = 0; I <buflen; I + = 3, J + = 4)
{
DST [J] = (BUF [I] & 0xfc)> 2;
DST [J + 1] = (BUF [I] & 0x03) <4) + (BUF [I + 1] & 0xf0)> 4 );
DST [J + 2] = (BUF [I + 1] & 0x0f) <2) + (BUF [I + 2] & 0xc0)> 6 );
DST [J + 3] = Buf [I + 2] & 0x3f;
}
For (I = 0; I <buflen * 4/3; I ++)/* map 6 bit value to base64 ASCII character */
DST [I] = ch64 [DST [I];
If (pading)
Free (BUF );
Return DST;
} Unsigned char * decode (unsigned char * SRC)
{
Int N, I, j;
Unsigned char * P;
Static unsigned char * DST; N = strlen (SRC );
For (I = 0; I <n; I ++)/* map base64 ASCII character to 6 bit value */
{
P = strchr (ch64, Src [I]);
If (! P)
Break;
SRC [I] = p-ch64;
}
DST = malloc (N * 3/4 + 1 );
Memset (DST, 0, N * 3/4 + 1 );
For (I = 0, j = 0; I <n; I + = 4, J + = 3)
{
DST [J] = (SRC [I] <2) + (SRC [I + 1] & 0x30)> 4 );
DST [J + 1] = (SRC [I + 1] & 0x0f) <4) + (SRC [I + 2] & 0x3c)> 2 );
DST [J + 2] = (SRC [I + 2] & 0x03) <6) + SRC [I + 3];
}
Return DST;
} Void main ()
{
// Char * src = "zhangwu ";
Char SRC [] = {'1', '2', '3', 0, 'A', 'B', '*', 0, 'A ', 'B', '$ '};
Unsigned char * dst1;
Unsigned char * dst2;
Unsigned int I; Dst1 = encode (SRC, 11);/* The second parameter must accord with the first one */
Printf ("% s/n", dst1 );
Dst2 = decode (dst1 );
For (I = 0; I <_ msize (dst2); I ++)
Printf ("% C", dst2 [I]); Free (dst1 );
Free (dst2 );
} |
