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Diffstat (limited to 'base91.c')
| -rw-r--r-- | base91.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/base91.c b/base91.c new file mode 100644 index 0000000..3d9d7ea --- /dev/null +++ b/base91.c @@ -0,0 +1,159 @@ +/* + * basE91 encoding/decoding routines + * + * Copyright (c) 2000-2006 Joachim Henke + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * - Neither the name of Joachim Henke nor the names of his contributors may + * be used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include "base91.h" + +const unsigned char enctab[91] = { + 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', + 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', + 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '!', '#', '$', + '%', '&', '(', ')', '*', '+', ',', '.', '/', ':', ';', '<', '=', + '>', '?', '@', '[', ']', '^', '_', '`', '{', '|', '}', '~', '"' +}; +const unsigned char dectab[256] = { + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 62, 90, 63, 64, 65, 66, 91, 67, 68, 69, 70, 71, 91, 72, 73, + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 74, 75, 76, 77, 78, 79, + 80, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, + 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 81, 91, 82, 83, 84, + 85, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 86, 87, 88, 89, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, + 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91 +}; + +void basE91_init(struct basE91 *b) +{ + b->queue = 0; + b->nbits = 0; + b->val = -1; +} + +size_t basE91_encode(struct basE91 *b, const void *i, size_t len, void *o) +{ + const unsigned char *ib = i; + unsigned char *ob = o; + size_t n = 0; + + while (len--) { + b->queue |= *ib++ << b->nbits; + b->nbits += 8; + if (b->nbits > 13) { /* enough bits in queue */ + unsigned int val = b->queue & 8191; + + if (val > 88) { + b->queue >>= 13; + b->nbits -= 13; + } else { /* we can take 14 bits */ + val = b->queue & 16383; + b->queue >>= 14; + b->nbits -= 14; + } + ob[n++] = enctab[val % 91]; + ob[n++] = enctab[val / 91]; + } + } + + return n; +} + +/* process remaining bits from bit queue; write up to 2 bytes */ + +size_t basE91_encode_end(struct basE91 *b, void *o) +{ + unsigned char *ob = o; + size_t n = 0; + + if (b->nbits) { + ob[n++] = enctab[b->queue % 91]; + if (b->nbits > 7 || b->queue > 90) + ob[n++] = enctab[b->queue / 91]; + } + b->queue = 0; + b->nbits = 0; + b->val = -1; + + return n; +} + +size_t basE91_decode(struct basE91 *b, const void *i, size_t len, void *o) +{ + const unsigned char *ib = i; + unsigned char *ob = o; + size_t n = 0; + unsigned int d; + + while (len--) { + d = dectab[*ib++]; + if (d == 91) + continue; /* ignore non-alphabet chars */ + if (b->val == -1) + b->val = d; /* start next value */ + else { + b->val += d * 91; + b->queue |= b->val << b->nbits; + b->nbits += (b->val & 8191) > 88 ? 13 : 14; + do { + ob[n++] = b->queue; + b->queue >>= 8; + b->nbits -= 8; + } while (b->nbits > 7); + b->val = -1; /* mark value complete */ + } + } + + return n; +} + +/* process remaining bits; write at most 1 byte */ + +size_t basE91_decode_end(struct basE91 *b, void *o) +{ + unsigned char *ob = o; + size_t n = 0; + + if (b->val != -1) + ob[n++] = b->queue | b->val << b->nbits; + b->queue = 0; + b->nbits = 0; + b->val = -1; + + return n; +} |