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/*
* Copyright (c) 1996, 1998 by 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM 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.
*/
/*
* Portions Copyright (c) 1995 by International Business Machines, Inc.
*
* International Business Machines, Inc. (hereinafter called IBM) grants
* permission under its copyrights to use, copy, modify, and distribute this
* Software with or without fee, provided that the above copyright notice and
* all paragraphs of this notice appear in all copies, and that the name of IBM
* not be used in connection with the marketing of any product incorporating
* the Software or modifications thereof, without specific, written prior
* permission.
*
* To the extent it has a right to do so, IBM grants an immunity from suit
* under its patents, if any, for the use, sale or manufacture of products to
* the extent that such products are used for performing Domain Name System
* dynamic updates in TCP/IP networks by means of the Software. No immunity is
* granted for any product per se or for any other function of any product.
*
* THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
* DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
* IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
*/
#include "bson-compat.h"
#include "bson-macros.h"
#include "bson-types.h"
#define Assert(Cond) if (!(Cond)) abort ()
static const char Base64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char Pad64 = '=';
/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
* The following encoding technique is taken from RFC 1521 by Borenstein
* and Freed. It is reproduced here in a slightly edited form for
* convenience.
*
* A 65-character subset of US-ASCII is used, enabling 6 bits to be
* represented per printable character. (The extra 65th character, "=",
* is used to signify a special processing function.)
*
* The encoding process represents 24-bit groups of input bits as output
* strings of 4 encoded characters. Proceeding from left to right, a
* 24-bit input group is formed by concatenating 3 8-bit input groups.
* These 24 bits are then treated as 4 concatenated 6-bit groups, each
* of which is translated into a single digit in the base64 alphabet.
*
* Each 6-bit group is used as an index into an array of 64 printable
* characters. The character referenced by the index is placed in the
* output string.
*
* Table 1: The Base64 Alphabet
*
* Value Encoding Value Encoding Value Encoding Value Encoding
* 0 A 17 R 34 i 51 z
* 1 B 18 S 35 j 52 0
* 2 C 19 T 36 k 53 1
* 3 D 20 U 37 l 54 2
* 4 E 21 V 38 m 55 3
* 5 F 22 W 39 n 56 4
* 6 G 23 X 40 o 57 5
* 7 H 24 Y 41 p 58 6
* 8 I 25 Z 42 q 59 7
* 9 J 26 a 43 r 60 8
* 10 K 27 b 44 s 61 9
* 11 L 28 c 45 t 62 +
* 12 M 29 d 46 u 63 /
* 13 N 30 e 47 v
* 14 O 31 f 48 w (pad) =
* 15 P 32 g 49 x
* 16 Q 33 h 50 y
*
* Special processing is performed if fewer than 24 bits are available
* at the end of the data being encoded. A full encoding quantum is
* always completed at the end of a quantity. When fewer than 24 input
* bits are available in an input group, zero bits are added (on the
* right) to form an integral number of 6-bit groups. Padding at the
* end of the data is performed using the '=' character.
*
* Since all base64 input is an integral number of octets, only the
* following cases can arise:
*
* (1) the final quantum of encoding input is an integral
* multiple of 24 bits; here, the final unit of encoded
* output will be an integral multiple of 4 characters
* with no "=" padding,
* (2) the final quantum of encoding input is exactly 8 bits;
* here, the final unit of encoded output will be two
* characters followed by two "=" padding characters, or
* (3) the final quantum of encoding input is exactly 16 bits;
* here, the final unit of encoded output will be three
* characters followed by one "=" padding character.
*/
static ssize_t
b64_ntop (uint8_t const *src,
size_t srclength,
char *target,
size_t targsize)
{
size_t datalength = 0;
uint8_t input[3];
uint8_t output[4];
size_t i;
while (2 < srclength) {
input[0] = *src++;
input[1] = *src++;
input[2] = *src++;
srclength -= 3;
output[0] = input[0] >> 2;
output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
output[3] = input[2] & 0x3f;
Assert (output[0] < 64);
Assert (output[1] < 64);
Assert (output[2] < 64);
Assert (output[3] < 64);
if (datalength + 4 > targsize) {
return -1;
}
target[datalength++] = Base64[output[0]];
target[datalength++] = Base64[output[1]];
target[datalength++] = Base64[output[2]];
target[datalength++] = Base64[output[3]];
}
/* Now we worry about padding. */
if (0 != srclength) {
/* Get what's left. */
input[0] = input[1] = input[2] = '\0';
for (i = 0; i < srclength; i++) {
input[i] = *src++;
}
output[0] = input[0] >> 2;
output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
Assert (output[0] < 64);
Assert (output[1] < 64);
Assert (output[2] < 64);
if (datalength + 4 > targsize) {
return -1;
}
target[datalength++] = Base64[output[0]];
target[datalength++] = Base64[output[1]];
if (srclength == 1) {
target[datalength++] = Pad64;
} else{
target[datalength++] = Base64[output[2]];
}
target[datalength++] = Pad64;
}
if (datalength >= targsize) {
return -1;
}
target[datalength] = '\0'; /* Returned value doesn't count \0. */
return datalength;
}
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