mirror of
https://github.com/yarrick/iodine.git
synced 2024-05-06 20:19:20 +03:00
262 lines
7.3 KiB
C
262 lines
7.3 KiB
C
/*
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* Copyright (C) 2009 J.A.Bezemer@opensourcepartners.nl
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* raw 76543210 76543210 76543210 76543210 76543210 76543210 76543210
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* enc 65432106 54321065 43210654 32106543 21065432 10654321 06543210
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* ^ ^ ^ ^ ^ ^ ^ ^
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*
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* 0001 1 0001 1
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* 0011 3 0011 3
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* 0111 7 0111 7
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* 1111 f 0110 6
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* 1110 e 0100 4
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* 1100 c
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* 1000 8
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "encoding.h"
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#define BASE128_BLKSIZE_RAW 7
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#define BASE128_BLKSIZE_ENC 8
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/* Don't use '-' (restricted to middle of labels), prefer iso_8859-1
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* accent chars since they might readily be entered in normal use,
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* don't use 254-255 because of possible function overloading in DNS systems.
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*/
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static const unsigned char cb128[] =
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"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
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"\274\275\276\277"
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"\300\301\302\303\304\305\306\307\310\311\312\313\314\315\316\317"
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"\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336\337"
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"\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357"
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"\360\361\362\363\364\365\366\367\370\371\372\373\374\375";
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static unsigned char rev128[256];
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static int reverse_init = 0;
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inline static void base128_reverse_init(void)
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{
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int i;
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unsigned char c;
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if (!reverse_init) {
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memset(rev128, 0, 256);
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for (i = 0; i < 128; i++) {
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c = cb128[i];
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rev128[(int) c] = i;
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}
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reverse_init = 1;
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}
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}
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/*
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* Fills *buf with max. *buflen characters, encoding size bytes of *data.
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*
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* NOTE: *buf space should be at least 1 byte _more_ than *buflen
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* to hold the trailing '\0'.
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*
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* return value : #bytes filled in buf (excluding \0)
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* sets *buflen to : #bytes encoded from data
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*/
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static int base128_encode(char *buf, size_t *buflen, const void *data,
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size_t size)
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{
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unsigned char *ubuf = (unsigned char *) buf;
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unsigned char *udata = (unsigned char *) data;
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int iout = 0; /* to-be-filled output char */
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int iin = 0; /* one more than last input byte that can be
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successfully decoded */
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/* Note: Don't bother to optimize manually. GCC optimizes
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better(!) when using simplistic array indexing. */
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while (1) {
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if (iout >= *buflen || iin >= size)
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break;
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ubuf[iout] = cb128[((udata[iin] & 0xfe) >> 1)];
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iout++;
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if (iout >= *buflen || iin >= size) {
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iout--; /* previous char is useless */
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break;
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}
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ubuf[iout] = cb128[((udata[iin] & 0x01) << 6) |
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((iin + 1 < size) ?
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((udata[iin + 1] & 0xfc) >> 2) : 0)];
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iin++; /* 0 complete, iin=1 */
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iout++;
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if (iout >= *buflen || iin >= size)
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break;
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ubuf[iout] = cb128[((udata[iin] & 0x03) << 5) |
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((iin + 1 < size) ?
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((udata[iin + 1] & 0xf8) >> 3) : 0)];
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iin++; /* 1 complete, iin=2 */
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iout++;
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if (iout >= *buflen || iin >= size)
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break;
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ubuf[iout] = cb128[((udata[iin] & 0x07) << 4) |
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((iin + 1 < size) ?
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((udata[iin + 1] & 0xf0) >> 4) : 0)];
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iin++; /* 2 complete, iin=3 */
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iout++;
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if (iout >= *buflen || iin >= size)
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break;
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ubuf[iout] = cb128[((udata[iin] & 0x0f) << 3) |
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((iin + 1 < size) ?
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((udata[iin + 1] & 0xe0) >> 5) : 0)];
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iin++; /* 3 complete, iin=4 */
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iout++;
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if (iout >= *buflen || iin >= size)
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break;
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ubuf[iout] = cb128[((udata[iin] & 0x1f) << 2) |
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((iin + 1 < size) ?
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((udata[iin + 1] & 0xc0) >> 6) : 0)];
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iin++; /* 4 complete, iin=5 */
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iout++;
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if (iout >= *buflen || iin >= size)
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break;
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ubuf[iout] = cb128[((udata[iin] & 0x3f) << 1) |
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((iin + 1 < size) ?
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((udata[iin + 1] & 0x80) >> 7) : 0)];
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iin++; /* 5 complete, iin=6 */
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iout++;
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if (iout >= *buflen || iin >= size)
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break;
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ubuf[iout] = cb128[(udata[iin] & 0x7f)];
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iin++; /* 6 complete, iin=7 */
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iout++;
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}
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ubuf[iout] = '\0';
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/* store number of bytes from data that was used */
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*buflen = iin;
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return iout;
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}
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#define REV128(x) rev128[(int) (x)]
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/*
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* Fills *buf with max. *buflen bytes, decoded from slen chars in *str.
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* Decoding stops early when *str contains \0.
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* Illegal encoded chars are assumed to decode to zero.
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*
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* NOTE: *buf space should be at least 1 byte _more_ than *buflen
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* to hold a trailing '\0' that is added (though *buf will usually
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* contain full-binary data).
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*
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* return value : #bytes filled in buf (excluding \0)
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*/
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static int base128_decode(void *buf, size_t *buflen, const char *str,
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size_t slen)
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{
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unsigned char *ustr = (unsigned char *) str;
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unsigned char *ubuf = (unsigned char *) buf;
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int iout = 0; /* to-be-filled output byte */
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int iin = 0; /* next input char to use in decoding */
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base128_reverse_init();
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/* Note: Don't bother to optimize manually. GCC optimizes
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better(!) when using simplistic array indexing. */
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while (1) {
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if (iout >= *buflen || iin + 1 >= slen ||
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str[iin] == '\0' || str[iin + 1] == '\0')
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break;
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ubuf[iout] = ((REV128(ustr[iin]) & 0x7f) << 1) |
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((REV128(ustr[iin + 1]) & 0x40) >> 6);
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iin++; /* 0 used up, iin=1 */
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iout++;
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if (iout >= *buflen || iin + 1 >= slen ||
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str[iin] == '\0' || str[iin + 1] == '\0')
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break;
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ubuf[iout] = ((REV128(ustr[iin]) & 0x3f) << 2) |
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((REV128(ustr[iin + 1]) & 0x60) >> 5);
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iin++; /* 1 used up, iin=2 */
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iout++;
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if (iout >= *buflen || iin + 1 >= slen ||
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str[iin] == '\0' || str[iin + 1] == '\0')
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break;
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ubuf[iout] = ((REV128(ustr[iin]) & 0x1f) << 3) |
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((REV128(ustr[iin + 1]) & 0x70) >> 4);
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iin++; /* 2 used up, iin=3 */
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iout++;
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if (iout >= *buflen || iin + 1 >= slen ||
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str[iin] == '\0' || str[iin + 1] == '\0')
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break;
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ubuf[iout] = ((REV128(ustr[iin]) & 0x0f) << 4) |
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((REV128(ustr[iin + 1]) & 0x78) >> 3);
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iin++; /* 3 used up, iin=4 */
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iout++;
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if (iout >= *buflen || iin + 1 >= slen ||
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str[iin] == '\0' || str[iin + 1] == '\0')
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break;
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ubuf[iout] = ((REV128(ustr[iin]) & 0x07) << 5) |
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((REV128(ustr[iin + 1]) & 0x7c) >> 2);
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iin++; /* 4 used up, iin=5 */
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iout++;
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if (iout >= *buflen || iin + 1 >= slen ||
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str[iin] == '\0' || str[iin + 1] == '\0')
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break;
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ubuf[iout] = ((REV128(ustr[iin]) & 0x03) << 6) |
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((REV128(ustr[iin + 1]) & 0x7e) >> 1);
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iin++; /* 5 used up, iin=6 */
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iout++;
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if (iout >= *buflen || iin + 1 >= slen ||
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str[iin] == '\0' || str[iin + 1] == '\0')
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break;
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ubuf[iout] = ((REV128(ustr[iin]) & 0x01) << 7) |
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((REV128(ustr[iin + 1]) & 0x7f));
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iin += 2; /* 6,7 used up, iin=8 */
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iout++;
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}
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ubuf[iout] = '\0';
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return iout;
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}
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const struct encoder base128_ops = {
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.name = "Base128",
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.encode = base128_encode,
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.decode = base128_decode,
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.places_dots = false,
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.eats_dots = false,
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.blocksize_raw = BASE128_BLKSIZE_RAW,
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.blocksize_encoded = BASE128_BLKSIZE_ENC,
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};
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