mirror of
https://github.com/coreutils/coreutils.git
synced 2024-11-28 12:35:36 +08:00
*** empty log message ***
This commit is contained in:
Jim Meyering
parent
0374086247
commit
51fd587ca6
416
lib/base64.c
Normal file
416
lib/base64.c
Normal file
@ -0,0 +1,416 @@
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/* base64.c -- Encode binary data using printable characters.
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Copyright (C) 1999, 2000, 2001, 2004, 2005, 2006 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, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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/* Written by Simon Josefsson. Partially adapted from GNU MailUtils
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* (mailbox/filter_trans.c, as of 2004-11-28). Improved by review
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* from Paul Eggert, Bruno Haible, and Stepan Kasal.
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*
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* See also RFC 3548 <http://www.ietf.org/rfc/rfc3548.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 = base64_decode_alloc (in, inlen, &out, &outlen);
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* if (!ok)
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* FAIL: input was not valid base64
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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 = base64_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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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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/* Get prototype. */
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#include "base64.h"
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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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/* C89 compliant way to cast 'char' to 'unsigned char'. */
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static inline 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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/* Base64 encode IN array of size INLEN into OUT array of size OUTLEN.
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If OUTLEN is less than BASE64_LENGTH(INLEN), write as many bytes as
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possible. If OUTLEN is larger than BASE64_LENGTH(INLEN), also zero
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terminate the output buffer. */
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void
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base64_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 b64str[64] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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while (inlen && outlen)
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{
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*out++ = b64str[to_uchar (in[0]) >> 2];
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if (!--outlen)
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break;
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*out++ = b64str[((to_uchar (in[0]) << 4)
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+ (--inlen ? to_uchar (in[1]) >> 4 : 0))
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& 0x3f];
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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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? b64str[((to_uchar (in[1]) << 2)
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+ (--inlen ? to_uchar (in[2]) >> 6 : 0))
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& 0x3f]
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: '=');
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if (!--outlen)
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break;
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*out++ = inlen ? b64str[to_uchar (in[2]) & 0x3f] : '=';
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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 += 3;
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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 base64 encoded data
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from array IN of size INLEN, returning BASE64_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 fail, OUT is set to NULL, and the return value
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indicate length of the requested memory block, i.e.,
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BASE64_LENGTH(inlen) + 1. */
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size_t
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base64_encode_alloc (const char *in, size_t inlen, char **out)
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{
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size_t outlen = 1 + BASE64_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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* If the operation (inlen + 2) overflows then it yields at most +1, so
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* outlen is 0.
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*
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* If the multiplication overflows, we lose at least half of the
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* correct value, so the result is < ((inlen + 2) / 3) * 2, which is
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* less than (inlen + 2) * 0.66667, which is less than inlen as soon as
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* (inlen > 4).
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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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base64_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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Base64 alphabet (A-Za-z0-9+/) 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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#define B64(x) \
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((x) == 'A' ? 0 \
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: (x) == 'B' ? 1 \
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: (x) == 'C' ? 2 \
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: (x) == 'D' ? 3 \
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: (x) == 'E' ? 4 \
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: (x) == 'F' ? 5 \
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: (x) == 'G' ? 6 \
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: (x) == 'H' ? 7 \
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: (x) == 'I' ? 8 \
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: (x) == 'J' ? 9 \
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: (x) == 'K' ? 10 \
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: (x) == 'L' ? 11 \
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: (x) == 'M' ? 12 \
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: (x) == 'N' ? 13 \
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: (x) == 'O' ? 14 \
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: (x) == 'P' ? 15 \
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: (x) == 'Q' ? 16 \
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: (x) == 'R' ? 17 \
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: (x) == 'S' ? 18 \
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: (x) == 'T' ? 19 \
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: (x) == 'U' ? 20 \
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: (x) == 'V' ? 21 \
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: (x) == 'W' ? 22 \
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: (x) == 'X' ? 23 \
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: (x) == 'Y' ? 24 \
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: (x) == 'Z' ? 25 \
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: (x) == 'a' ? 26 \
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: (x) == 'b' ? 27 \
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: (x) == 'c' ? 28 \
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: (x) == 'd' ? 29 \
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: (x) == 'e' ? 30 \
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: (x) == 'f' ? 31 \
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: (x) == 'g' ? 32 \
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: (x) == 'h' ? 33 \
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: (x) == 'i' ? 34 \
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: (x) == 'j' ? 35 \
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: (x) == 'k' ? 36 \
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: (x) == 'l' ? 37 \
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: (x) == 'm' ? 38 \
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: (x) == 'n' ? 39 \
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: (x) == 'o' ? 40 \
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: (x) == 'p' ? 41 \
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: (x) == 'q' ? 42 \
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: (x) == 'r' ? 43 \
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: (x) == 's' ? 44 \
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: (x) == 't' ? 45 \
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: (x) == 'u' ? 46 \
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: (x) == 'v' ? 47 \
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: (x) == 'w' ? 48 \
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: (x) == 'x' ? 49 \
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: (x) == 'y' ? 50 \
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: (x) == 'z' ? 51 \
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: (x) == '0' ? 52 \
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: (x) == '1' ? 53 \
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: (x) == '2' ? 54 \
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: (x) == '3' ? 55 \
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: (x) == '4' ? 56 \
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: (x) == '5' ? 57 \
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: (x) == '6' ? 58 \
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: (x) == '7' ? 59 \
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: (x) == '8' ? 60 \
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: (x) == '9' ? 61 \
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: (x) == '+' ? 62 \
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: (x) == '/' ? 63 \
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: -1)
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static const signed char b64[0x100] = {
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B64 (0), B64 (1), B64 (2), B64 (3),
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B64 (4), B64 (5), B64 (6), B64 (7),
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B64 (8), B64 (9), B64 (10), B64 (11),
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B64 (12), B64 (13), B64 (14), B64 (15),
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B64 (16), B64 (17), B64 (18), B64 (19),
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B64 (20), B64 (21), B64 (22), B64 (23),
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B64 (24), B64 (25), B64 (26), B64 (27),
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B64 (28), B64 (29), B64 (30), B64 (31),
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B64 (32), B64 (33), B64 (34), B64 (35),
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B64 (36), B64 (37), B64 (38), B64 (39),
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B64 (40), B64 (41), B64 (42), B64 (43),
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B64 (44), B64 (45), B64 (46), B64 (47),
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B64 (48), B64 (49), B64 (50), B64 (51),
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B64 (52), B64 (53), B64 (54), B64 (55),
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B64 (56), B64 (57), B64 (58), B64 (59),
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B64 (60), B64 (61), B64 (62), B64 (63),
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B64 (64), B64 (65), B64 (66), B64 (67),
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B64 (68), B64 (69), B64 (70), B64 (71),
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B64 (72), B64 (73), B64 (74), B64 (75),
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B64 (76), B64 (77), B64 (78), B64 (79),
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B64 (80), B64 (81), B64 (82), B64 (83),
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B64 (84), B64 (85), B64 (86), B64 (87),
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B64 (88), B64 (89), B64 (90), B64 (91),
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B64 (92), B64 (93), B64 (94), B64 (95),
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B64 (96), B64 (97), B64 (98), B64 (99),
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B64 (100), B64 (101), B64 (102), B64 (103),
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B64 (104), B64 (105), B64 (106), B64 (107),
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B64 (108), B64 (109), B64 (110), B64 (111),
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B64 (112), B64 (113), B64 (114), B64 (115),
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B64 (116), B64 (117), B64 (118), B64 (119),
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B64 (120), B64 (121), B64 (122), B64 (123),
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B64 (124), B64 (125), B64 (126), B64 (127),
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B64 (128), B64 (129), B64 (130), B64 (131),
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B64 (132), B64 (133), B64 (134), B64 (135),
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B64 (136), B64 (137), B64 (138), B64 (139),
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B64 (140), B64 (141), B64 (142), B64 (143),
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B64 (144), B64 (145), B64 (146), B64 (147),
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B64 (148), B64 (149), B64 (150), B64 (151),
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B64 (152), B64 (153), B64 (154), B64 (155),
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B64 (156), B64 (157), B64 (158), B64 (159),
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B64 (160), B64 (161), B64 (162), B64 (163),
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B64 (164), B64 (165), B64 (166), B64 (167),
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B64 (168), B64 (169), B64 (170), B64 (171),
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B64 (172), B64 (173), B64 (174), B64 (175),
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B64 (176), B64 (177), B64 (178), B64 (179),
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B64 (180), B64 (181), B64 (182), B64 (183),
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B64 (184), B64 (185), B64 (186), B64 (187),
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B64 (188), B64 (189), B64 (190), B64 (191),
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B64 (192), B64 (193), B64 (194), B64 (195),
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B64 (196), B64 (197), B64 (198), B64 (199),
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B64 (200), B64 (201), B64 (202), B64 (203),
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B64 (204), B64 (205), B64 (206), B64 (207),
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B64 (208), B64 (209), B64 (210), B64 (211),
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B64 (212), B64 (213), B64 (214), B64 (215),
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B64 (216), B64 (217), B64 (218), B64 (219),
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B64 (220), B64 (221), B64 (222), B64 (223),
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B64 (224), B64 (225), B64 (226), B64 (227),
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B64 (228), B64 (229), B64 (230), B64 (231),
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B64 (232), B64 (233), B64 (234), B64 (235),
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B64 (236), B64 (237), B64 (238), B64 (239),
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B64 (240), B64 (241), B64 (242), B64 (243),
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B64 (244), B64 (245), B64 (246), B64 (247),
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B64 (248), B64 (249), B64 (250), B64 (251),
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B64 (252), B64 (253), B64 (254), B64 (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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bool
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isbase64 (char ch)
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{
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return uchar_in_range (to_uchar (ch)) && 0 <= b64[to_uchar (ch)];
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}
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/* Decode base64 encoded input array IN of length INLEN to output
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array OUT that can hold *OUTLEN bytes. Return true if decoding was
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successful, i.e. if the input was valid base64 data, false
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otherwise. If *OUTLEN is too small, as many bytes as possible will
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be written to OUT. On return, *OUTLEN holds the length of decoded
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bytes in OUT. Note that as soon as any non-alphabet characters are
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encountered, decoding is stopped and false is returned. */
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bool
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base64_decode (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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size_t outleft = *outlen;
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while (inlen >= 2)
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{
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if (!isbase64 (in[0]) || !isbase64 (in[1]))
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break;
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if (outleft)
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{
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*out++ = ((b64[to_uchar (in[0])] << 2)
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| (b64[to_uchar (in[1])] >> 4));
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outleft--;
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}
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if (inlen == 2)
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break;
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if (in[2] == '=')
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{
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if (inlen != 4)
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break;
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if (in[3] != '=')
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break;
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}
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else
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{
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if (!isbase64 (in[2]))
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break;
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if (outleft)
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{
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*out++ = (((b64[to_uchar (in[1])] << 4) & 0xf0)
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| (b64[to_uchar (in[2])] >> 2));
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outleft--;
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}
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if (inlen == 3)
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break;
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if (in[3] == '=')
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{
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if (inlen != 4)
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break;
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}
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else
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{
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if (!isbase64 (in[3]))
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break;
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if (outleft)
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{
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*out++ = (((b64[to_uchar (in[2])] << 6) & 0xc0)
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| b64[to_uchar (in[3])]);
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outleft--;
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}
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}
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}
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in += 4;
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inlen -= 4;
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}
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*outlen -= outleft;
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if (inlen != 0)
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return false;
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return true;
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}
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/* Allocate an output buffer in *OUT, and decode the base64 encoded
|
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data stored in IN of size INLEN to the *OUT buffer. On return, the
|
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size of the decoded data is stored in *OUTLEN. OUTLEN may be NULL,
|
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if the caller is not interested in the decoded length. *OUT may be
|
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NULL to indicate an out of memory error, in which case *OUTLEN
|
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contain the size of the memory block needed. The function return
|
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true on successful decoding and memory allocation errors. (Use the
|
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*OUT and *OUTLEN parameters to differentiate between successful
|
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decoding and memory error.) The function return false if the input
|
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was invalid, in which case *OUT is NULL and *OUTLEN is
|
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undefined. */
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bool
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base64_decode_alloc (const char *in, size_t inlen, char **out,
|
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size_t *outlen)
|
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{
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/* This may allocate a few bytes too much, depending on input,
|
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but it's not worth the extra CPU time to compute the exact amount.
|
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The exact amount is 3 * inlen / 4, minus 1 if the input ends
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with "=" and minus another 1 if the input ends with "==".
|
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Dividing before multiplying avoids the possibility of overflow. */
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size_t needlen = 3 * (inlen / 4) + 2;
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*out = malloc (needlen);
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if (!*out)
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return true;
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if (!base64_decode (in, inlen, *out, &needlen))
|
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{
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free (*out);
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*out = NULL;
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return false;
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}
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if (outlen)
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*outlen = needlen;
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|
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return true;
|
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}
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||||
Loading…
Reference in New Issue
Block a user