689 lines
22 KiB
C
689 lines
22 KiB
C
/* base32.c -- Encode binary data using printable characters.
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Copyright (C) 1999-2001, 2004-2006, 2009-2012 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <http://www.gnu.org/licenses/>. */
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/* Adapted from Simon Josefsson's base64 code by Gijs van Tulder.
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*
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* See also RFC 4648 <http://www.ietf.org/rfc/rfc4648.txt>.
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*
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* Be careful with error checking. Here is how you would typically
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* use these functions:
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*
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* bool ok = base32_decode_alloc (in, inlen, &out, &outlen);
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* if (!ok)
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* FAIL: input was not valid base32
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* if (out == NULL)
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* FAIL: memory allocation error
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* OK: data in OUT/OUTLEN
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*
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* size_t outlen = base32_encode_alloc (in, inlen, &out);
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* if (out == NULL && outlen == 0 && inlen != 0)
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* FAIL: input too long
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* if (out == NULL)
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* FAIL: memory allocation error
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* OK: data in OUT/OUTLEN.
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*
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*/
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/* Get prototype. */
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/* Get size_t. */
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# include <stddef.h>
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/* Get bool. */
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# include <stdbool.h>
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/* This uses that the expression (n+(k-1))/k means the smallest
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integer >= n/k, i.e., the ceiling of n/k. */
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# define BASE32_LENGTH(inlen) ((((inlen) + 4) / 5) * 8)
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struct base32_decode_context
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{
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unsigned int i;
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char buf[8];
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};
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extern bool isbase32 (char ch);
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extern void base32_encode (const char *restrict in, size_t inlen,
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char *restrict out, size_t outlen);
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extern size_t base32_encode_alloc (const char *in, size_t inlen, char **out);
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extern void base32_decode_ctx_init (struct base32_decode_context *ctx);
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extern bool base32_decode_ctx (struct base32_decode_context *ctx,
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const char *restrict in, size_t inlen,
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char *restrict out, size_t *outlen);
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extern bool base32_decode_alloc_ctx (struct base32_decode_context *ctx,
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const char *in, size_t inlen,
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char **out, size_t *outlen);
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#define base32_decode(in, inlen, out, outlen) \
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base32_decode_ctx (NULL, in, inlen, out, outlen)
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#define base32_decode_alloc(in, inlen, out, outlen) \
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base32_decode_alloc_ctx (NULL, in, inlen, out, outlen)
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/* Get malloc. */
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#include <stdlib.h>
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/* Get UCHAR_MAX. */
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#include <limits.h>
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#include <string.h>
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/* C89 compliant way to cast 'char' to 'unsigned char'. */
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static unsigned char
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to_uchar (char ch)
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{
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return ch;
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}
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/* Base32 encode IN array of size INLEN into OUT array of size OUTLEN.
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If OUTLEN is less than BASE32_LENGTH(INLEN), write as many bytes as
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possible. If OUTLEN is larger than BASE32_LENGTH(INLEN), also zero
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terminate the output buffer. */
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void
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base32_encode (const char *restrict in, size_t inlen,
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char *restrict out, size_t outlen)
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{
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static const char b32str[32] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
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while (inlen && outlen)
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{
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*out++ = b32str[(to_uchar (in[0]) >> 3) & 0x1f];
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if (!--outlen)
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break;
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*out++ = b32str[((to_uchar (in[0]) << 2)
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+ (--inlen ? to_uchar (in[1]) >> 6 : 0))
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& 0x1f];
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if (!--outlen)
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break;
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*out++ =
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(inlen
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? b32str[(to_uchar (in[1]) >> 1) & 0x1f]
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: '=');
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if (!--outlen)
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break;
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*out++ =
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(inlen
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? b32str[((to_uchar (in[1]) << 4)
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+ (--inlen ? to_uchar (in[2]) >> 4 : 0))
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& 0x1f]
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: '=');
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if (!--outlen)
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break;
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*out++ =
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(inlen
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? b32str[((to_uchar (in[2]) << 1)
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+ (--inlen ? to_uchar (in[3]) >> 7 : 0))
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& 0x1f]
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: '=');
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if (!--outlen)
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break;
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*out++ =
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(inlen
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? b32str[(to_uchar (in[3]) >> 2) & 0x1f]
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: '=');
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if (!--outlen)
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break;
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*out++ =
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(inlen
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? b32str[((to_uchar (in[3]) << 3)
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+ (--inlen ? to_uchar (in[4]) >> 5 : 0))
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& 0x1f]
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: '=');
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if (!--outlen)
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break;
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*out++ = inlen ? b32str[to_uchar (in[4]) & 0x1f] : '=';
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if (!--outlen)
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break;
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if (inlen)
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inlen--;
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if (inlen)
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in += 5;
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}
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if (outlen)
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*out = '\0';
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}
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/* Allocate a buffer and store zero terminated base32 encoded data
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from array IN of size INLEN, returning BASE32_LENGTH(INLEN), i.e.,
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the length of the encoded data, excluding the terminating zero. On
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return, the OUT variable will hold a pointer to newly allocated
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memory that must be deallocated by the caller. If output string
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length would overflow, 0 is returned and OUT is set to NULL. If
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memory allocation failed, OUT is set to NULL, and the return value
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indicates length of the requested memory block, i.e.,
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BASE32_LENGTH(inlen) + 1. */
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size_t
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base32_encode_alloc (const char *in, size_t inlen, char **out)
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{
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size_t outlen = 1 + BASE32_LENGTH (inlen);
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/* Check for overflow in outlen computation.
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*
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* If there is no overflow, outlen >= inlen.
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*
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* TODO Is this a sufficient check? (See the notes in base64.c.)
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*/
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if (inlen > outlen)
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{
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*out = NULL;
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return 0;
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}
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*out = malloc (outlen);
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if (!*out)
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return outlen;
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base32_encode (in, inlen, *out, outlen);
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return outlen - 1;
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}
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/* With this approach this file works independent of the charset used
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(think EBCDIC). However, it does assume that the characters in the
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Base32 alphabet (A-Z2-7) are encoded in 0..255. POSIX
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1003.1-2001 require that char and unsigned char are 8-bit
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quantities, though, taking care of that problem. But this may be a
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potential problem on non-POSIX C99 platforms.
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IBM C V6 for AIX mishandles "#define B32(x) ...'x'...", so use "_"
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as the formal parameter rather than "x". */
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#define B32(_) \
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((_) == 'A' ? 0 \
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: (_) == 'B' ? 1 \
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: (_) == 'C' ? 2 \
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: (_) == 'D' ? 3 \
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: (_) == 'E' ? 4 \
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: (_) == 'F' ? 5 \
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: (_) == 'G' ? 6 \
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: (_) == 'H' ? 7 \
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: (_) == 'I' ? 8 \
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: (_) == 'J' ? 9 \
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: (_) == 'K' ? 10 \
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: (_) == 'L' ? 11 \
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: (_) == 'M' ? 12 \
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: (_) == 'N' ? 13 \
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: (_) == 'O' ? 14 \
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: (_) == 'P' ? 15 \
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: (_) == 'Q' ? 16 \
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: (_) == 'R' ? 17 \
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: (_) == 'S' ? 18 \
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: (_) == 'T' ? 19 \
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: (_) == 'U' ? 20 \
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: (_) == 'V' ? 21 \
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: (_) == 'W' ? 22 \
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: (_) == 'X' ? 23 \
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: (_) == 'Y' ? 24 \
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: (_) == 'Z' ? 25 \
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: (_) == '2' ? 26 \
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: (_) == '3' ? 27 \
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: (_) == '4' ? 28 \
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: (_) == '5' ? 29 \
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: (_) == '6' ? 30 \
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: (_) == '7' ? 31 \
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: -1)
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static const signed char b32[0x100] = {
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B32 (0), B32 (1), B32 (2), B32 (3),
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B32 (4), B32 (5), B32 (6), B32 (7),
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B32 (8), B32 (9), B32 (10), B32 (11),
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B32 (12), B32 (13), B32 (14), B32 (15),
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B32 (16), B32 (17), B32 (18), B32 (19),
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B32 (20), B32 (21), B32 (22), B32 (23),
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B32 (24), B32 (25), B32 (26), B32 (27),
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B32 (28), B32 (29), B32 (30), B32 (31),
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B32 (32), B32 (33), B32 (34), B32 (35),
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B32 (36), B32 (37), B32 (38), B32 (39),
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B32 (40), B32 (41), B32 (42), B32 (43),
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B32 (44), B32 (45), B32 (46), B32 (47),
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B32 (48), B32 (49), B32 (50), B32 (51),
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B32 (52), B32 (53), B32 (54), B32 (55),
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B32 (56), B32 (57), B32 (58), B32 (59),
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B32 (60), B32 (61), B32 (62), B32 (63),
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B32 (32), B32 (65), B32 (66), B32 (67),
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B32 (68), B32 (69), B32 (70), B32 (71),
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B32 (72), B32 (73), B32 (74), B32 (75),
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B32 (76), B32 (77), B32 (78), B32 (79),
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B32 (80), B32 (81), B32 (82), B32 (83),
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B32 (84), B32 (85), B32 (86), B32 (87),
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B32 (88), B32 (89), B32 (90), B32 (91),
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B32 (92), B32 (93), B32 (94), B32 (95),
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B32 (96), B32 (97), B32 (98), B32 (99),
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B32 (100), B32 (101), B32 (102), B32 (103),
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B32 (104), B32 (105), B32 (106), B32 (107),
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B32 (108), B32 (109), B32 (110), B32 (111),
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B32 (112), B32 (113), B32 (114), B32 (115),
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B32 (116), B32 (117), B32 (118), B32 (119),
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B32 (120), B32 (121), B32 (122), B32 (123),
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B32 (124), B32 (125), B32 (126), B32 (127),
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B32 (128), B32 (129), B32 (130), B32 (131),
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B32 (132), B32 (133), B32 (134), B32 (135),
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B32 (136), B32 (137), B32 (138), B32 (139),
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B32 (140), B32 (141), B32 (142), B32 (143),
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B32 (144), B32 (145), B32 (146), B32 (147),
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B32 (148), B32 (149), B32 (150), B32 (151),
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B32 (152), B32 (153), B32 (154), B32 (155),
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B32 (156), B32 (157), B32 (158), B32 (159),
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B32 (160), B32 (161), B32 (162), B32 (163),
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B32 (132), B32 (165), B32 (166), B32 (167),
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B32 (168), B32 (169), B32 (170), B32 (171),
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B32 (172), B32 (173), B32 (174), B32 (175),
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B32 (176), B32 (177), B32 (178), B32 (179),
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B32 (180), B32 (181), B32 (182), B32 (183),
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B32 (184), B32 (185), B32 (186), B32 (187),
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B32 (188), B32 (189), B32 (190), B32 (191),
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B32 (192), B32 (193), B32 (194), B32 (195),
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B32 (196), B32 (197), B32 (198), B32 (199),
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B32 (200), B32 (201), B32 (202), B32 (203),
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B32 (204), B32 (205), B32 (206), B32 (207),
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B32 (208), B32 (209), B32 (210), B32 (211),
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B32 (212), B32 (213), B32 (214), B32 (215),
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B32 (216), B32 (217), B32 (218), B32 (219),
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B32 (220), B32 (221), B32 (222), B32 (223),
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B32 (224), B32 (225), B32 (226), B32 (227),
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B32 (228), B32 (229), B32 (230), B32 (231),
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B32 (232), B32 (233), B32 (234), B32 (235),
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B32 (236), B32 (237), B32 (238), B32 (239),
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B32 (240), B32 (241), B32 (242), B32 (243),
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B32 (244), B32 (245), B32 (246), B32 (247),
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B32 (248), B32 (249), B32 (250), B32 (251),
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B32 (252), B32 (253), B32 (254), B32 (255)
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};
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#if UCHAR_MAX == 255
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# define uchar_in_range(c) true
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#else
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# define uchar_in_range(c) ((c) <= 255)
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#endif
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/* Return true if CH is a character from the Base32 alphabet, and
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false otherwise. Note that '=' is padding and not considered to be
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part of the alphabet. */
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bool
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isbase32 (char ch)
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{
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return uchar_in_range (to_uchar (ch)) && 0 <= b32[to_uchar (ch)];
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}
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/* Initialize decode-context buffer, CTX. */
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void
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base32_decode_ctx_init (struct base32_decode_context *ctx)
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{
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ctx->i = 0;
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}
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/* If CTX->i is 0 or 8, there are eight or more bytes in [*IN..IN_END), and
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none of those eight is a newline, then return *IN. Otherwise, copy up to
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4 - CTX->i non-newline bytes from that range into CTX->buf, starting at
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index CTX->i and setting CTX->i to reflect the number of bytes copied,
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and return CTX->buf. In either case, advance *IN to point to the byte
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after the last one processed, and set *N_NON_NEWLINE to the number of
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verified non-newline bytes accessible through the returned pointer. */
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static char *
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get_8 (struct base32_decode_context *ctx,
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char const *restrict *in, char const *restrict in_end,
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size_t *n_non_newline)
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{
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if (ctx->i == 8)
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ctx->i = 0;
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if (ctx->i == 0)
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{
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char const *t = *in;
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if (8 <= in_end - *in && memchr (t, '\n', 8) == NULL)
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{
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/* This is the common case: no newline. */
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*in += 8;
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*n_non_newline = 8;
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return (char *) t;
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}
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}
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{
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/* Copy non-newline bytes into BUF. */
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char const *p = *in;
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while (p < in_end)
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{
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char c = *p++;
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if (c != '\n')
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{
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ctx->buf[ctx->i++] = c;
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if (ctx->i == 8)
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break;
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}
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}
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*in = p;
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*n_non_newline = ctx->i;
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return ctx->buf;
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}
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}
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#define return_false \
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do \
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{ \
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*outp = out; \
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return false; \
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} \
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while (false)
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/* Decode eight bytes of base32-encoded data, IN, of length INLEN
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into the output buffer, *OUT, of size *OUTLEN bytes. Return true if
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decoding is successful, false otherwise. If *OUTLEN is too small,
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as many bytes as possible are written to *OUT. On return, advance
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*OUT to point to the byte after the last one written, and decrement
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*OUTLEN to reflect the number of bytes remaining in *OUT. */
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static bool
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decode_8 (char const *restrict in, size_t inlen,
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char *restrict *outp, size_t *outleft)
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{
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char *out = *outp;
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if (inlen < 8)
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return false;
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if (!isbase32 (in[0]) || !isbase32 (in[1]) )
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return false;
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if (*outleft)
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{
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*out++ = ((b32[to_uchar (in[0])] << 3)
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| (b32[to_uchar (in[1])] >> 2));
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--*outleft;
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}
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if (in[2] == '=')
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{
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if (in[3] != '=' || in[4] != '=' || in[5] != '='
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|| in[6] != '=' || in[7] != '=')
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return_false;
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}
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else
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{
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if (!isbase32 (in[2]) || !isbase32 (in[3]))
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return_false;
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if (*outleft)
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{
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*out++ = ((b32[to_uchar (in[1])] << 6)
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| (b32[to_uchar (in[2])] << 1)
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| (b32[to_uchar (in[3])] >> 4));
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--*outleft;
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}
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if (in[4] == '=')
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{
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if (in[5] != '=' || in[6] != '=' || in[7] != '=')
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return_false;
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}
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else
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{
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if (!isbase32 (in[4]))
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return_false;
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if (*outleft)
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{
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*out++ = ((b32[to_uchar (in[3])] << 4)
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| (b32[to_uchar (in[4])] >> 1));
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--*outleft;
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}
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if (in[5] == '=')
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{
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if (in[6] != '=' || in[7] != '=')
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return_false;
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}
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else
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{
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if (!isbase32 (in[5]) || !isbase32 (in[6]))
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return_false;
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if (*outleft)
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{
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*out++ = ((b32[to_uchar (in[4])] << 7)
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| (b32[to_uchar (in[5])] << 2)
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| (b32[to_uchar (in[6])] >> 3));
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--*outleft;
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}
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if (in[7] != '=')
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{
|
|
if (!isbase32 (in[7]))
|
|
return_false;
|
|
|
|
if (*outleft)
|
|
{
|
|
*out++ = ((b32[to_uchar (in[6])] << 5)
|
|
| (b32[to_uchar (in[7])]));
|
|
--*outleft;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
*outp = out;
|
|
return true;
|
|
}
|
|
|
|
/* Decode base32-encoded input array IN of length INLEN to output array
|
|
OUT that can hold *OUTLEN bytes. The input data may be interspersed
|
|
with newlines. Return true if decoding was successful, i.e. if the
|
|
input was valid base32 data, false otherwise. If *OUTLEN is too
|
|
small, as many bytes as possible will be written to OUT. On return,
|
|
*OUTLEN holds the length of decoded bytes in OUT. Note that as soon
|
|
as any non-alphabet, non-newline character is encountered, decoding
|
|
is stopped and false is returned. If INLEN is zero, then process
|
|
only whatever data is stored in CTX.
|
|
|
|
Initially, CTX must have been initialized via base32_decode_ctx_init.
|
|
Subsequent calls to this function must reuse whatever state is recorded
|
|
in that buffer. It is necessary for when a octuple of base32 input
|
|
bytes spans two input buffers.
|
|
|
|
If CTX is NULL then newlines are treated as garbage and the input
|
|
buffer is processed as a unit. */
|
|
|
|
bool
|
|
base32_decode_ctx (struct base32_decode_context *ctx,
|
|
const char *restrict in, size_t inlen,
|
|
char *restrict out, size_t *outlen)
|
|
{
|
|
size_t outleft = *outlen;
|
|
bool ignore_newlines = ctx != NULL;
|
|
bool flush_ctx = false;
|
|
unsigned int ctx_i = 0;
|
|
|
|
if (ignore_newlines)
|
|
{
|
|
ctx_i = ctx->i;
|
|
flush_ctx = inlen == 0;
|
|
}
|
|
|
|
|
|
while (true)
|
|
{
|
|
size_t outleft_save = outleft;
|
|
if (ctx_i == 0 && !flush_ctx)
|
|
{
|
|
while (true)
|
|
{
|
|
/* Save a copy of outleft, in case we need to re-parse this
|
|
block of four bytes. */
|
|
outleft_save = outleft;
|
|
if (!decode_8 (in, inlen, &out, &outleft))
|
|
break;
|
|
|
|
in += 8;
|
|
inlen -= 8;
|
|
}
|
|
}
|
|
|
|
if (inlen == 0 && !flush_ctx)
|
|
break;
|
|
|
|
/* Handle the common case of 72-byte wrapped lines.
|
|
This also handles any other multiple-of-8-byte wrapping. */
|
|
if (inlen && *in == '\n' && ignore_newlines)
|
|
{
|
|
++in;
|
|
--inlen;
|
|
continue;
|
|
}
|
|
|
|
/* Restore OUT and OUTLEFT. */
|
|
out -= outleft_save - outleft;
|
|
outleft = outleft_save;
|
|
|
|
{
|
|
char const *in_end = in + inlen;
|
|
char const *non_nl;
|
|
|
|
if (ignore_newlines)
|
|
non_nl = get_8 (ctx, &in, in_end, &inlen);
|
|
else
|
|
non_nl = in; /* Might have nl in this case. */
|
|
|
|
/* If the input is empty or consists solely of newlines (0 non-newlines),
|
|
then we're done. Likewise if there are fewer than 8 bytes when not
|
|
flushing context and not treating newlines as garbage. */
|
|
if (inlen == 0 || (inlen < 8 && !flush_ctx && ignore_newlines))
|
|
{
|
|
inlen = 0;
|
|
break;
|
|
}
|
|
if (!decode_8 (non_nl, inlen, &out, &outleft))
|
|
break;
|
|
|
|
inlen = in_end - in;
|
|
}
|
|
}
|
|
|
|
*outlen -= outleft;
|
|
|
|
return inlen == 0;
|
|
}
|
|
|
|
/* Allocate an output buffer in *OUT, and decode the base32 encoded
|
|
data stored in IN of size INLEN to the *OUT buffer. On return, the
|
|
size of the decoded data is stored in *OUTLEN. OUTLEN may be NULL,
|
|
if the caller is not interested in the decoded length. *OUT may be
|
|
NULL to indicate an out of memory error, in which case *OUTLEN
|
|
contains the size of the memory block needed. The function returns
|
|
true on successful decoding and memory allocation errors. (Use the
|
|
*OUT and *OUTLEN parameters to differentiate between successful
|
|
decoding and memory error.) The function returns false if the
|
|
input was invalid, in which case *OUT is NULL and *OUTLEN is
|
|
undefined. */
|
|
bool
|
|
base32_decode_alloc_ctx (struct base32_decode_context *ctx,
|
|
const char *in, size_t inlen, char **out,
|
|
size_t *outlen)
|
|
{
|
|
/* This may allocate a few bytes too many, depending on input,
|
|
but it's not worth the extra CPU time to compute the exact size.
|
|
The exact size is 5 * inlen / 8, minus one or more bytes if the
|
|
input is padded with one or more "=".
|
|
Dividing before multiplying avoids the possibility of overflow. */
|
|
size_t needlen = 5 * (inlen / 8) + 5;
|
|
|
|
*out = malloc (needlen);
|
|
if (!*out)
|
|
return true;
|
|
|
|
if (!base32_decode_ctx (ctx, in, inlen, *out, &needlen))
|
|
{
|
|
free (*out);
|
|
*out = NULL;
|
|
return false;
|
|
}
|
|
|
|
if (outlen)
|
|
*outlen = needlen;
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Public functions
|
|
*/
|
|
|
|
/**
|
|
* Encode in Base32 format
|
|
* @param incoming the incoming bytes
|
|
* @param incoming_length the length of the incoming bytes
|
|
* @param results where to put the results
|
|
* @param results_length the size of the buffer, and returns the actual length used
|
|
* @returns true(1) on success
|
|
*/
|
|
int libp2p_crypto_encoding_base32_encode(const unsigned char* incoming, size_t incoming_length,
|
|
unsigned char* results, size_t* results_length) {
|
|
memset(results, 0, *results_length);
|
|
base32_encode((char*)incoming, incoming_length, (char*)results, *results_length);
|
|
if (results[ (*results_length) -1] == 0)
|
|
*results_length = strlen((char*)results);
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* Calculate the size of the buffer necessary to encode
|
|
* @param incoming_length the length of the incoming value
|
|
* @returns the size of the buffer necessary to hold the encoded bytes
|
|
*/
|
|
size_t libp2p_crypto_encoding_base32_encode_size(size_t incoming_length) {
|
|
incoming_length -= 5;
|
|
incoming_length /= 5;
|
|
return incoming_length * 8 + 1;
|
|
}
|
|
|
|
/**
|
|
* Decode from Base16 format
|
|
* @param incoming the incoming base16 encoded string
|
|
* @param incoming_length the length of the incoming string (no need to include null)
|
|
* @param results where to put the results
|
|
* @param results_length the size of the buffer, and returns the actual length used
|
|
* @returns true(1) on success
|
|
*/
|
|
int libp2p_crypto_encoding_base32_decode(const unsigned char* incoming, size_t incoming_length,
|
|
unsigned char* results, size_t* results_length) {
|
|
int retVal = base32_decode_ctx(NULL, (char*)incoming, incoming_length, (char*)results, results_length);
|
|
|
|
// unknown error
|
|
if (results == NULL)
|
|
return 0;
|
|
|
|
// Input was not valid base32
|
|
if (retVal == 0)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* Calculate the size of the buffer necessary to decode
|
|
* @param incoming_length the length of the incoming value
|
|
* @returns the size of the buffer necessary to hold the decoded bytes
|
|
*/
|
|
size_t libp2p_crypto_encoding_base32_decode_size(size_t incoming_length) {
|
|
return 5 * (incoming_length / 8) + 5;
|
|
}
|
|
|