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/* $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);
}
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