/* This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) any * later version. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more * details. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc., 59 Temple * Place - Suite 330, Boston, MA 02111-1307, USA. * * Adapted from code written by Eric S. Raymond * */ /* Pair of functions to convert to/from base64. * Also can be used to build a standalone utility and a loopback test. * see http://www.faqs.org/rfcs/rfc3548.html */ #include static const char base64digits[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; #define BAD (-1) static const char base64val[] = { BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD, 62, BAD,BAD,BAD, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,BAD,BAD, BAD,BAD,BAD,BAD, BAD, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,BAD, BAD,BAD,BAD,BAD, BAD, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,BAD, BAD,BAD,BAD,BAD }; #define DECODE64(c) (isascii(c) ? base64val[c] : BAD) /* convert inlen raw bytes at in to base64 string (NUL-terminated) at out. * out size should be at least 4*inlen/3 + 4. * return length of out (sans trailing NUL). */ int to64frombits(unsigned char *out, const unsigned char *in, int inlen) { unsigned char *out0 = out; for (; inlen >= 3; inlen -= 3) { *out++ = base64digits[in[0] >> 2]; *out++ = base64digits[((in[0] << 4) & 0x30) | (in[1] >> 4)]; *out++ = base64digits[((in[1] << 2) & 0x3c) | (in[2] >> 6)]; *out++ = base64digits[in[2] & 0x3f]; in += 3; } if (inlen > 0) { unsigned char fragment; *out++ = base64digits[in[0] >> 2]; fragment = (in[0] << 4) & 0x30; if (inlen > 1) fragment |= in[1] >> 4; *out++ = base64digits[fragment]; *out++ = (inlen < 2) ? '=' : base64digits[(in[1] << 2) & 0x3c]; *out++ = '='; } *out = '\0'; return (out-out0); } /* convert base64 at in to raw bytes out, returning count or <0 on error. * base64 may contain any embedded whitespace. * out should be at least 3/4 the length of in. */ int from64tobits(char *out, const char *in) { int len = 0; register unsigned char digit1, digit2, digit3, digit4; do { do {digit1 = *in++;} while (isspace(digit1)); if (DECODE64(digit1) == BAD) return(-1); do {digit2 = *in++;} while (isspace(digit2)); if (DECODE64(digit2) == BAD) return(-2); do {digit3 = *in++;} while (isspace(digit3)); if (digit3 != '=' && DECODE64(digit3) == BAD) return(-3); do {digit4 = *in++;} while (isspace(digit4)); if (digit4 != '=' && DECODE64(digit4) == BAD) return(-4); *out++ = (DECODE64(digit1) << 2) | (DECODE64(digit2) >> 4); ++len; if (digit3 != '=') { *out++ = ((DECODE64(digit2) << 4) & 0xf0) | (DECODE64(digit3) >> 2); ++len; if (digit4 != '=') { *out++ = ((DECODE64(digit3) << 6) & 0xc0) | DECODE64(digit4); ++len; } } while (isspace(*in)) in++; } while (*in && digit4 != '='); return (len); } #ifdef BASE64_PROGRAM /* standalone program that converts to/from base64. * cc -o base64 -DBASE64_PROGRAM base64.c */ #include #include #include static void usage (char *me) { fprintf (stderr, "Purpose: convert stdin to/from base64 on stdout\n"); fprintf (stderr, "Usage: %s {-t,-f}\n", me); exit (1); } int main (int ac, char *av[]) { int to64 = 1; /* decide whether to or from base64 */ if (ac == 2 && strcmp (av[1], "-f") == 0) to64 = 0; else if (ac != 1 && (ac != 2 || strcmp (av[1], "-t"))) usage (av[0]); if (to64) { unsigned char *rawin, *b64; int i, n, nrawin, nb64; /* read raw on stdin until EOF */ rawin = malloc(4096); nrawin = 0; while ((n = fread (rawin+nrawin, 1, 4096, stdin)) > 0) rawin = realloc (rawin, (nrawin+=n)+4096); /* convert to base64 */ b64 = malloc (4*nrawin/3+4); nb64 = to64frombits(b64, rawin, nrawin); /* pretty print */ for (i = 0; i < nb64; i += 72) printf ("%.*s\n", 72, b64+i); } else { unsigned char *raw, *b64; int n, nraw, nb64; /* read base64 on stdin until EOF */ b64 = malloc(4096); nb64 = 0; while ((n = fread (b64+nb64, 1, 4096, stdin)) > 0) b64 = realloc (b64, (nb64+=n)+4096); b64[nb64] = '\0'; /* convert to raw */ raw = malloc (3*nb64/4); nraw = from64tobits(raw, b64); if (nraw < 0) { fprintf (stderr, "base64 conversion error: %d\n", nraw); return (1); } /* write */ fwrite (raw, 1, nraw, stdout); } return (0); } #endif #ifdef LOOPBACK_TEST /* standalone test that reads binary on stdin, converts to base64 and back, * then compares. exit 0 if compares the same else 1 */ #include #include #include int main (int ac, char *av[]) { unsigned char *rawin, *b64, *rawback; int n, nrawin, nrawback, nb64; /* read raw on stdin until EOF */ rawin = malloc(4096); nrawin = 0; while ((n = fread (rawin+nrawin, 1, 4096, stdin)) > 0) rawin = realloc (rawin, (nrawin+=n)+4096); /* convert to base64 */ b64 = malloc (4*nrawin*3 + 4); nb64 = to64frombits(b64, rawin, nrawin); /* convert back to raw */ rawback = malloc (3*nb64/4); nrawback = from64tobits(rawback, b64); if (nrawback < 0) { fprintf (stderr, "base64 error: %d\n", nrawback); return(1); } if (nrawback != nrawin) { fprintf (stderr, "base64 back length %d != %d\n", nrawback, nrawin); return(1); } /* compare */ if (memcmp (rawback, rawin, nrawin)) { fprintf (stderr, "compare error\n"); return (1); } /* success */ return (0); } #endif /* For RCS Only -- Do Not Edit */ static char *rcsid[2] = {(char *)rcsid, "@(#) $RCSfile: base64.c,v $ $Date: 2005/03/14 20:25:43 $ $Revision: 1.2 $ $Name: $"};