| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Buffer handling |
| 4 | * |
| 5 | * (c) 2001 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of Catacomb. |
| 11 | * |
| 12 | * Catacomb is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * Catacomb is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with Catacomb; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | */ |
| 27 | |
| 28 | /*----- Header files ------------------------------------------------------*/ |
| 29 | |
| 30 | #include <string.h> |
| 31 | |
| 32 | #include "mp.h" |
| 33 | #include "ec.h" |
| 34 | #include "buf.h" |
| 35 | |
| 36 | /*----- Main code ---------------------------------------------------------*/ |
| 37 | |
| 38 | /* --- @buf_getmp@ --- * |
| 39 | * |
| 40 | * Arguments: @buf *b@ = pointer to a buffer block |
| 41 | * |
| 42 | * Returns: A multiprecision integer, or null if there wasn't one there. |
| 43 | * |
| 44 | * Use: Gets a multiprecision integer from a buffer. |
| 45 | */ |
| 46 | |
| 47 | mp *buf_getmp(buf *b) |
| 48 | { |
| 49 | uint16 sz; |
| 50 | size_t n; |
| 51 | mp *m; |
| 52 | if (buf_getu16(b, &sz) || buf_ensure(b, sz)) |
| 53 | return (0); |
| 54 | m = mp_loadb(MP_NEW, BCUR(b), sz); |
| 55 | n = mp_octets(m); |
| 56 | if (n != sz && n != 0 && sz != 1) { |
| 57 | mp_drop(m); |
| 58 | return (0); |
| 59 | } |
| 60 | BSTEP(b, sz); |
| 61 | return (m); |
| 62 | } |
| 63 | |
| 64 | /* --- @buf_putmp@ --- * |
| 65 | * |
| 66 | * Arguments: @buf *b@ = pointer to a buffer block |
| 67 | * @mp *m@ = a multiprecision integer |
| 68 | * |
| 69 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 70 | * |
| 71 | * Use: Puts a multiprecision integer to a buffer. |
| 72 | */ |
| 73 | |
| 74 | int buf_putmp(buf *b, mp *m) |
| 75 | { |
| 76 | size_t sz = mp_octets(m); |
| 77 | assert(sz < MASK16); |
| 78 | if (!sz) sz = 1; |
| 79 | if (buf_putu16(b, sz) || buf_ensure(b, sz)) |
| 80 | return (-1); |
| 81 | mp_storeb(m, BCUR(b), sz); |
| 82 | BSTEP(b, sz); |
| 83 | return (0); |
| 84 | } |
| 85 | |
| 86 | /* --- @buf_getec@ --- * |
| 87 | * |
| 88 | * Arguments: @buf *b@ = pointer to a buffer block |
| 89 | * @ec *p@ = where to put the point |
| 90 | * |
| 91 | * Returns: Zero if it worked, nonzero if it failed. |
| 92 | * |
| 93 | * Use: Gets a multiprecision integer from a buffer. The point must |
| 94 | * be initialized. |
| 95 | */ |
| 96 | |
| 97 | int buf_getec(buf *b, ec *p) |
| 98 | { |
| 99 | mp *x = 0, *y = 0; |
| 100 | uint16 n; |
| 101 | if (buf_ensure(b, 2)) return (-1); |
| 102 | n = LOAD16(BCUR(b)); if (!n) { BSTEP(b, 2); EC_SETINF(p); return (0); } |
| 103 | if ((x = buf_getmp(b)) == 0 || (y = buf_getmp(b)) == 0) { |
| 104 | mp_drop(x); mp_drop(y); return (-1); |
| 105 | } |
| 106 | EC_DESTROY(p); p->x = x; p->y = y; p->z = 0; |
| 107 | return (0); |
| 108 | } |
| 109 | |
| 110 | /* --- @buf_putec@ --- * |
| 111 | * |
| 112 | * Arguments: @buf *b@ = pointer to a buffer block |
| 113 | * @ec *p@ = an elliptic curve point |
| 114 | * |
| 115 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 116 | * |
| 117 | * Use: Puts an elliptic curve point to a buffer. |
| 118 | */ |
| 119 | |
| 120 | int buf_putec(buf *b, ec *p) |
| 121 | { |
| 122 | if (EC_ATINF(p)) return (buf_putu16(b, 0)); |
| 123 | if (buf_putmp(b, p->x) || buf_putmp(b, p->y)) return (-1); |
| 124 | return (0); |
| 125 | } |
| 126 | |
| 127 | /*----- That's all, folks -------------------------------------------------*/ |