diff options
Diffstat (limited to 'base64.c')
| -rw-r--r-- | base64.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/base64.c b/base64.c new file mode 100644 index 0000000..7c9731d --- /dev/null +++ b/base64.c @@ -0,0 +1,172 @@ +/* $KAME: base64.c,v 1.1 2004/06/08 07:26:56 jinmei Exp $ */ + +/* + * Copyright (C) 2004 WIDE Project. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the project nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* + * Copyright (C) 2004 Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 1998-2001, 2003 Internet Software Consortium. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +#include <string.h> + +typedef enum { FALSE = 0, TRUE = 1 } boolean_t; + +static const char base64[] = + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; + +/* + * State of a base64 decoding process in progress. + */ +typedef struct { + int length; /* Desired length of binary data or -1 */ + int digits; /* Number of buffered base64 digits */ + boolean_t seen_end; /* True if "=" end marker seen */ + int val[4]; + + char *dst; /* Head of the available space for resulting + * binary data */ + char *dstend; /* End of the buffer */ +} base64_decode_ctx_t; + +static int +mem_tobuffer(base64_decode_ctx_t *ctx, void *base, unsigned int length) +{ + if (ctx->dst + length >= ctx->dstend) + return (-1); + memcpy(ctx->dst, base, length); + ctx->dst += length; + return (0); +} + +static inline void +base64_decode_init(base64_decode_ctx_t *ctx, int length, + char *result, size_t resultlen) +{ + ctx->digits = 0; + ctx->seen_end = FALSE; + ctx->length = length; + ctx->dst = result; + ctx->dstend = result + resultlen; +} + +static inline int +base64_decode_char(base64_decode_ctx_t *ctx, int c) +{ + char *s; + + if (ctx->seen_end == TRUE) + return (-1); + if ((s = strchr(base64, c)) == NULL) + return (-1); + ctx->val[ctx->digits++] = s - base64; + if (ctx->digits == 4) { + int n; + unsigned char buf[3]; + if (ctx->val[0] == 64 || ctx->val[1] == 64) + return (-1); + if (ctx->val[2] == 64 && ctx->val[3] != 64) + return (-1); + /* + * Check that bits that should be zero are. + */ + if (ctx->val[2] == 64 && (ctx->val[1] & 0xf) != 0) + return (-1); + /* + * We don't need to test for ctx->val[2] != 64 as + * the bottom two bits of 64 are zero. + */ + if (ctx->val[3] == 64 && (ctx->val[2] & 0x3) != 0) + return (-1); + n = (ctx->val[2] == 64) ? 1 : + (ctx->val[3] == 64) ? 2 : 3; + if (n != 3) { + ctx->seen_end = TRUE; + if (ctx->val[2] == 64) + ctx->val[2] = 0; + if (ctx->val[3] == 64) + ctx->val[3] = 0; + } + buf[0] = (ctx->val[0]<<2)|(ctx->val[1]>>4); + buf[1] = (ctx->val[1]<<4)|(ctx->val[2]>>2); + buf[2] = (ctx->val[2]<<6)|(ctx->val[3]); + if (mem_tobuffer(ctx, buf, n)) + return (-1); + if (ctx->length >= 0) { + if (n > ctx->length) + return (-1); + else + ctx->length -= n; + } + ctx->digits = 0; + } + return (0); +} + +static inline int +base64_decode_finish(base64_decode_ctx_t *ctx) +{ + if (ctx->length > 0) + return (-1); + if (ctx->digits != 0) + return (-1); + return (0); +} + +int +base64_decodestring(const char *cstr, char *result, size_t resultlen) +{ + base64_decode_ctx_t ctx; + + base64_decode_init(&ctx, -1, result, resultlen); + for (;;) { + int c = *cstr++; + if (c == '\0') + break; + if (c == ' ' || c == '\t' || c == '\n' || c== '\r') + continue; + if (base64_decode_char(&ctx, c)) + return (-1); + } + if (base64_decode_finish(&ctx)) + return (-1); + return (ctx.dst - result); +} |