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Diffstat (limited to 'base64.c')
| -rw-r--r-- | base64.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/base64.c b/base64.c new file mode 100644 index 0000000..769a3be --- /dev/null +++ b/base64.c @@ -0,0 +1,167 @@ +/* + * This file is part of libESMTP, a library for submission of RFC 2822 + * formatted electronic mail messages using the SMTP protocol described + * in RFC 2821. + * + * Copyright (C) 2001,2002 Brian Stafford <brian@stafford.uklinux.net> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <assert.h> + +/* Routines to encode and decode base64 text. + */ +#include <ctype.h> +#include <string.h> +#include "base64.h" + +/* RFC 2045 section 6.8 */ + +static const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "0123456789" + "+/"; + +static const char index_64[128] = + { + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, + -1, 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, -1, -1, -1, -1, -1, + -1, 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, -1, -1, -1, -1, -1, + }; + +/* Decode srclen bytes of base64 data contained in src and put the result + in dst. Since the destination buffer may contain arbitrary binary + data and it is not necessarily a string, there is no \0 byte at the + end of the decoded data. */ +int +b64_decode (void *dst, int dstlen, const char *src, int srclen) +{ + const unsigned char *p, *q; + unsigned char *t; + int c1, c2; + + assert (dst != NULL && dstlen > 0); + + if (src == NULL) + return 0; + + if (srclen < 0) + srclen = strlen (src); + + /* Remove leading and trailing white space */ + for (p = (const unsigned char *) src; + srclen > 0 && isspace (*p); + p++, srclen--) + ; + for (q = p + srclen - 1; q >= p && isspace (*q); q--, srclen--) + ; + + /* Length MUST be a multiple of 4 */ + if (srclen % 4 != 0) + return -1; + + /* Destination buffer length must be sufficient */ + if (srclen / 4 * 3 + 1 > dstlen) + return -1; + + t = dst; + while (srclen > 0) + { + srclen -= 4; + if (*p >= 128 || (c1 = index_64[*p++]) == -1) + return -1; + if (*p >= 128 || (c2 = index_64[*p++]) == -1) + return -1; + *t++ = (c1 << 2) | ((c2 & 0x30) >> 4); + + if (p[0] == '=' && p[1] == '=') + break; + if (*p >= 128 || (c1 = index_64[*p++]) == -1) + return -1; + *t++ = ((c2 & 0x0f) << 4) | ((c1 & 0x3c) >> 2); + + if (p[0] == '=') + break; + if (*p >= 128 || (c2 = index_64[*p++]) == -1) + return -1; + *t++ = ((c1 & 0x03) << 6) | c2; + } + + return t - (unsigned char *) dst; +} + +/* Return a pointer to a base 64 encoded string. The input data is + arbitrary binary data, the output is a \0 terminated string. + src and dst may not share the same buffer. */ +int +b64_encode (char *dst, int dstlen, const void *src, int srclen) +{ + char *to = dst; + const unsigned char *from; + unsigned char c1, c2; + int dst_needed; + + assert (dst != NULL && dstlen > 0 && srclen >= 0); + + if (src == NULL) + return 0; + + dst_needed = (srclen + 2) / 3; + dst_needed *= 4; + if (dstlen < dst_needed + 1) + return -1; + + from = src; + while (srclen > 0) + { + c1 = *from++; srclen--; + *to++ = base64[c1 >> 2]; + c1 = (c1 & 0x03) << 4; + if (srclen <= 0) + { + *to++ = base64[c1]; + *to++ = '='; + *to++ = '='; + break; + } + c2 = *from++; srclen--; + c1 |= (c2 >> 4) & 0x0f; + *to++ = base64[c1]; + c1 = (c2 & 0x0f) << 2; + if (srclen <= 0) + { + *to++ = base64[c1]; + *to++ = '='; + break; + } + c2 = *from++; srclen--; + c1 |= (c2 >> 6) & 0x03; + *to++ = base64[c1]; + *to++ = base64[c2 & 0x3f]; + } + *to = '\0'; + return to - dst; +} + |