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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: buf.c,v 1.3 2001/03/03 12:06:48 mdw Exp $ |
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4 | * |
5 | * Buffer handling |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Trivial IP Encryption (TrIPE). |
13 | * |
14 | * TrIPE is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * TrIPE is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with TrIPE; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: buf.c,v $ |
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32 | * Revision 1.3 2001/03/03 12:06:48 mdw |
33 | * Use 16-bit lengths on MPs, since there's a packet limit of 64K anyway. |
34 | * |
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35 | * Revision 1.2 2001/02/16 21:23:20 mdw |
36 | * Various minor changes. Check that MPs are in canonical form when |
37 | * loading. |
38 | * |
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39 | * Revision 1.1 2001/02/03 20:26:37 mdw |
40 | * Initial checkin. |
41 | * |
42 | */ |
43 | |
44 | /*----- Header files ------------------------------------------------------*/ |
45 | |
46 | #include "tripe.h" |
47 | |
48 | /*----- Main code ---------------------------------------------------------*/ |
49 | |
50 | /* --- @buf_init@ --- * |
51 | * |
52 | * Arguments: @buf *b@ = pointer to a buffer block |
53 | * @void *p@ = pointer to a buffer |
54 | * @size_t sz@ = size of the buffer |
55 | * |
56 | * Returns: --- |
57 | * |
58 | * Use: Initializes the buffer block appropriately. |
59 | */ |
60 | |
61 | void buf_init(buf *b, void *p, size_t sz) |
62 | { |
63 | b->base = b->p = p; |
64 | b->limit = b->p + sz; |
65 | b->f = 0; |
66 | } |
67 | |
68 | /* --- @buf_break@ --- * |
69 | * |
70 | * Arguments: @buf *b@ = pointer to a buffer block |
71 | * |
72 | * Returns: Some negative value. |
73 | * |
74 | * Use: Marks a buffer as broken. |
75 | */ |
76 | |
77 | int buf_break(buf *b) { b->f |= BF_BROKEN; return (-1); } |
78 | |
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79 | /* --- @buf_flip@ --- * |
80 | * |
81 | * Arguments: @buf *b@ = pointer to a buffer block |
82 | * |
83 | * Returns: --- |
84 | * |
85 | * Use: Flips a buffer so that if you've just been writing to it, |
86 | * you can now read from the bit you've written. |
87 | */ |
88 | |
89 | void buf_flip(buf *b) |
90 | { |
91 | b->limit = b->p; |
92 | b->p = b->base; |
93 | } |
94 | |
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95 | /* --- @buf_ensure@ --- * |
96 | * |
97 | * Arguments: @buf *b@ = pointer to a buffer block |
98 | * @size_t sz@ = size of data wanted |
99 | * |
100 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
101 | * |
102 | * Use: Ensures that there are @sz@ bytes still in the buffer. |
103 | */ |
104 | |
105 | int buf_ensure(buf *b, size_t sz) { return (BENSURE(b, sz)); } |
106 | |
107 | /* --- @buf_get@ --- * |
108 | * |
109 | * Arguments: @buf *b@ = pointer to a buffer block |
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110 | * @size_t sz@ = size of the buffer |
111 | * |
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112 | * Returns: Pointer to the place in the buffer. |
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113 | * |
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114 | * Use: Reserves a space in the buffer of the requested size, and |
115 | * returns its start address. |
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116 | */ |
117 | |
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118 | void *buf_get(buf *b, size_t sz) |
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119 | { |
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120 | void *p; |
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121 | if (BENSURE(b, sz)) |
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122 | return (0); |
123 | p = BCUR(b); |
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124 | BSTEP(b, sz); |
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125 | return (p); |
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126 | } |
127 | |
128 | /* --- @buf_put@ --- * |
129 | * |
130 | * Arguments: @buf *b@ = pointer to a buffer block |
131 | * @const void *p@ = pointer to a buffer |
132 | * @size_t sz@ = size of the buffer |
133 | * |
134 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
135 | * |
136 | * Use: Fetches data from some place and puts it in the buffer |
137 | */ |
138 | |
139 | int buf_put(buf *b, const void *p, size_t sz) |
140 | { |
141 | if (BENSURE(b, sz)) |
142 | return (-1); |
143 | memcpy(BCUR(b), p, sz); |
144 | BSTEP(b, sz); |
145 | return (0); |
146 | } |
147 | |
148 | /* --- @buf_getbyte@ --- * |
149 | * |
150 | * Arguments: @buf *b@ = pointer to a buffer block |
151 | * |
152 | * Returns: A byte, or less than zero if there wasn't a byte there. |
153 | * |
154 | * Use: Gets a single byte from a buffer. |
155 | */ |
156 | |
157 | int buf_getbyte(buf *b) |
158 | { |
159 | if (BENSURE(b, 1)) |
160 | return (-1); |
161 | return (*b->p++); |
162 | } |
163 | |
164 | /* --- @buf_putbyte@ --- * |
165 | * |
166 | * Arguments: @buf *b@ = pointer to a buffer block |
167 | * @int ch@ = byte to write |
168 | * |
169 | * Returns: Zero if OK, nonzero if there wasn't enough space. |
170 | * |
171 | * Use: Puts a single byte in a buffer. |
172 | */ |
173 | |
174 | int buf_putbyte(buf *b, int ch) |
175 | { |
176 | if (BENSURE(b, 1)) |
177 | return (-1); |
178 | *b->p++ = ch; |
179 | return (0); |
180 | } |
181 | |
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182 | /* --- @buf_getu16@ --- * |
183 | * |
184 | * Arguments: @buf *b@ = pointer to a buffer block |
185 | * @uint16 *w@ = where to put the word |
186 | * |
187 | * Returns: Zero if OK, or nonzero if there wasn't a word there. |
188 | * |
189 | * Use: Gets a 16-bit word from a buffer. |
190 | */ |
191 | |
192 | int buf_getu16(buf *b, uint16 *w) |
193 | { |
194 | if (BENSURE(b, 2)) |
195 | return (-1); |
196 | *w = LOAD16(b->p); |
197 | BSTEP(b, 2); |
198 | return (0); |
199 | } |
200 | |
201 | /* --- @buf_putu16@ --- * |
202 | * |
203 | * Arguments: @buf *b@ = pointer to a buffer block |
204 | * @uint16 w@ = word to write |
205 | * |
206 | * Returns: Zero if OK, nonzero if there wasn't enough space. |
207 | * |
208 | * Use: Puts a 16-but word in a buffer. |
209 | */ |
210 | |
211 | int buf_putu16(buf *b, uint16 w) |
212 | { |
213 | if (BENSURE(b, 2)) |
214 | return (-1); |
215 | STORE16(b->p, w); |
216 | BSTEP(b, 2); |
217 | return (0); |
218 | } |
219 | |
220 | /* --- @buf_getu32@ --- * |
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221 | * |
222 | * Arguments: @buf *b@ = pointer to a buffer block |
223 | * @uint32 *w@ = where to put the word |
224 | * |
225 | * Returns: Zero if OK, or nonzero if there wasn't a word there. |
226 | * |
227 | * Use: Gets a 32-bit word from a buffer. |
228 | */ |
229 | |
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230 | int buf_getu32(buf *b, uint32 *w) |
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231 | { |
232 | if (BENSURE(b, 4)) |
233 | return (-1); |
234 | *w = LOAD32(b->p); |
235 | BSTEP(b, 4); |
236 | return (0); |
237 | } |
238 | |
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239 | /* --- @buf_putu32@ --- * |
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240 | * |
241 | * Arguments: @buf *b@ = pointer to a buffer block |
242 | * @uint32 w@ = word to write |
243 | * |
244 | * Returns: Zero if OK, nonzero if there wasn't enough space. |
245 | * |
246 | * Use: Puts a 32-but word in a buffer. |
247 | */ |
248 | |
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249 | int buf_putu32(buf *b, uint32 w) |
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250 | { |
251 | if (BENSURE(b, 4)) |
252 | return (-1); |
253 | STORE32(b->p, w); |
254 | BSTEP(b, 4); |
255 | return (0); |
256 | } |
257 | |
258 | /* --- @buf_getmp@ --- * |
259 | * |
260 | * Arguments: @buf *b@ = pointer to a buffer block |
261 | * |
262 | * Returns: A multiprecision integer, or null if there wasn't one there. |
263 | * |
264 | * Use: Gets a multiprecision integer from a buffer. |
265 | */ |
266 | |
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267 | mp *buf_getmp(buf *b) |
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268 | { |
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269 | uint16 sz; |
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270 | mp *m; |
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271 | if (buf_getu16(b, &sz) || buf_ensure(b, sz)) |
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272 | return (0); |
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273 | m = mp_loadb(MP_NEW, BCUR(b), sz); |
274 | if (mp_octets(m) != sz) { |
275 | mp_drop(m); |
276 | return (0); |
277 | } |
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278 | BSTEP(b, sz); |
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279 | return (m); |
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280 | } |
281 | |
282 | /* --- @buf_putmp@ --- * |
283 | * |
284 | * Arguments: @buf *b@ = pointer to a buffer block |
285 | * @mp *m@ = a multiprecision integer |
286 | * |
287 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
288 | * |
289 | * Use: Puts a multiprecision integer to a buffer. |
290 | */ |
291 | |
292 | int buf_putmp(buf *b, mp *m) |
293 | { |
294 | size_t sz = mp_octets(m); |
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295 | assert(sz < MASK16); |
296 | if (buf_putu16(b, sz) || buf_ensure(b, sz)) |
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297 | return (-1); |
298 | mp_storeb(m, BCUR(b), sz); |
299 | BSTEP(b, sz); |
300 | return (0); |
301 | } |
302 | |
303 | /*----- That's all, folks -------------------------------------------------*/ |