General utilities cleanup. Add signature support to catcrypt. Throw in
[u/mdw/catacomb] / pgen.c
CommitLineData
0f5ec153 1/* -*-c-*-
2 *
b817bfc6 3 * $Id: pgen.c,v 1.10 2004/04/08 01:36:15 mdw Exp $
0f5ec153 4 *
581c854e 5 * Prime generation glue
0f5ec153 6 *
7 * (c) 1999 Straylight/Edgeware
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of Catacomb.
13 *
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
18 *
19 * Catacomb 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 Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
27 * MA 02111-1307, USA.
28 */
29
0f5ec153 30/*----- Header files ------------------------------------------------------*/
31
581c854e 32#include <assert.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36
37#include "fibrand.h"
38#include "grand.h"
0f5ec153 39#include "mp.h"
581c854e 40#include "mprand.h"
0f5ec153 41#include "pgen.h"
581c854e 42#include "pfilt.h"
0f5ec153 43#include "rabin.h"
44
581c854e 45/*----- Standard prime filter ---------------------------------------------*/
0f5ec153 46
581c854e 47/* --- @pgen_filter@ --- */
0f5ec153 48
581c854e 49int pgen_filter(int rq, pgen_event *ev, void *p)
0f5ec153 50{
581c854e 51 pgen_filterctx *f = p;
52 int rc = PGEN_ABORT;
53
54 switch (rq) {
55 case PGEN_BEGIN:
56 rc = pfilt_create(&f->f, ev->m);
57 mp_drop(ev->m);
58 break;
59 case PGEN_TRY:
60 mp_drop(ev->m);
61 if (!((f->step | f->f.m->v[0]) & 1))
62 rc = pfilt_step(&f->f, 1);
0f5ec153 63 else
581c854e 64 rc = pfilt_step(&f->f, f->step);
65 break;
66 case PGEN_DONE:
67 pfilt_destroy(&f->f);
68 return (PGEN_DONE);
0f5ec153 69 }
581c854e 70
71 while (rc == PGEN_FAIL)
72 rc = pfilt_step(&f->f, f->step);
73 ev->m = MP_COPY(f->f.m);
0f5ec153 74 return (rc);
75}
76
581c854e 77/* --- @pgen_jump@ --- *
0f5ec153 78 *
581c854e 79 * Similar to the standard @pgen_filter@, but jumps in large steps rather
80 * than small ones.
0f5ec153 81 */
82
581c854e 83int pgen_jump(int rq, pgen_event *ev, void *p)
0f5ec153 84{
581c854e 85 pgen_jumpctx *f = p;
86 int rc = PGEN_ABORT;
0f5ec153 87
581c854e 88 switch (rq) {
8b021c3f 89 case PGEN_BEGIN: {
90 mp *g = MP_NEW;
91 mp_gcd(&g, 0, 0, ev->m, f->j->m);
92 if (MP_CMP(g, >, MP_ONE)) {
93 mp_drop(g);
94 return (PGEN_ABORT);
95 }
96 mp_drop(g);
581c854e 97 rc = pfilt_create(&f->f, ev->m);
98 mp_drop(ev->m);
8b021c3f 99 } break;
581c854e 100 case PGEN_TRY:
101 mp_drop(ev->m);
102 rc = pfilt_jump(&f->f, f->j);
103 break;
104 case PGEN_DONE:
105 pfilt_destroy(&f->f);
106 return (PGEN_DONE);
107 }
108
109 while (rc == PGEN_FAIL)
110 rc = pfilt_jump(&f->f, f->j);
111 ev->m = MP_COPY(f->f.m);
112 return (rc);
113}
0f5ec153 114
581c854e 115/*----- Standard prime test -----------------------------------------------*/
0f5ec153 116
581c854e 117/* --- @pgen_test@ --- */
0f5ec153 118
581c854e 119int pgen_test(int rq, pgen_event *ev, void *p)
120{
121 rabin *r = p;
122 int rc = PGEN_ABORT;
0f5ec153 123
581c854e 124 switch (rq) {
125 case PGEN_BEGIN:
126 rabin_create(r, ev->m);
127 rc = PGEN_TRY;
128 break;
283b9af0 129 case PGEN_TRY:
130 if (!ev->tests)
131 rc = rabin_rtest(r, MP_TWO);
132 else {
133 mp *a = mprand_range(MP_NEW, ev->m, ev->r, 0);
134 rc = rabin_rtest(r, a);
135 mp_drop(a);
136 }
137 break;
581c854e 138 case PGEN_DONE:
139 rabin_destroy(r);
140 rc = PGEN_DONE;
141 break;
0f5ec153 142 }
143
0f5ec153 144 return (rc);
145}
146
581c854e 147/*----- The main driver ---------------------------------------------------*/
148
149/* --- @pgen@ --- *
bd98b2df 150 *
581c854e 151 * Arguments: @const char *name@ = name of the value being searched for
152 * @mp *d@ = destination for the result integer
153 * @mp *m@ = start value to pass to stepper
154 * @pgen_proc *event@ = event handler function
155 * @void *ectx@ = context argument for event andler
156 * @unsigned steps@ = number of steps to take in search
157 * @pgen_proc *step@ = stepper function to use
158 * @void *sctx@ = context argument for stepper
159 * @unsigned tests@ = number of tests to make
160 * @pgen_proc *test@ = tester function to use
161 * @void *tctx@ = context argument for tester
bd98b2df 162 *
581c854e 163 * Returns: Pointer to final result, or null.
bd98b2df 164 *
581c854e 165 * Use: A generalized prime-number search skeleton. Yes, that's a
166 * scary number of arguments.
bd98b2df 167 */
168
581c854e 169mp *pgen(const char *name, mp *d, mp *m, pgen_proc *event, void *ectx,
170 unsigned steps, pgen_proc *step, void *sctx,
171 unsigned tests, pgen_proc *test, void *tctx)
bd98b2df 172{
581c854e 173 pgen_event ev;
174 int rq, rc;
175 pgen_proc *proc;
176 void *ctx;
bd98b2df 177
581c854e 178 /* --- Set up the initial event block --- */
bd98b2df 179
581c854e 180 ev.name = name;
181 if (m)
182 ev.m = MP_COPY(m);
183 else
184 ev.m = 0;
283b9af0 185 ev.steps = 0;
186 ev.tests = 0;
581c854e 187 ev.r = fibrand_create(0);
bd98b2df 188
581c854e 189 /* --- Tell the event handler we're under way --- */
bd98b2df 190
581c854e 191 if (event && event(PGEN_BEGIN, &ev, ectx) == PGEN_ABORT)
192 return (0);
bd98b2df 193
581c854e 194 /* --- Set up for the initial call --- */
bd98b2df 195
581c854e 196 proc = step; ctx = sctx; rq = PGEN_BEGIN;
0f5ec153 197
581c854e 198 /* --- Enter the great maelstrom of state transitions --- */
0f5ec153 199
581c854e 200 for (;;) {
201 unsigned act = 0;
202
203 enum {
204 A_STEP = 1u,
205 A_TEST = 2u,
206 A_EVENT = 4u,
207 A_ENDTEST = 8u,
208 A_ENDSTEP = 16u,
209 A_DONE = 32u
210 };
211
212 /* --- Call the procedure and decide what to do next --- */
213
214 rc = proc(rq, &ev, ctx);
215 switch (rc) {
216 case PGEN_TRY:
217 if (proc == test)
218 rq = PGEN_TRY;
219 else {
220 act |= A_EVENT;
221 proc = test; ctx = tctx;
222 rq = PGEN_BEGIN;
223 }
224 break;
225 case PGEN_PASS:
226 act |= A_TEST | A_EVENT;
227 if (proc == test)
228 rq = PGEN_TRY;
229 else {
230 proc = test; ctx = tctx;
231 rq = PGEN_BEGIN;
232 }
233 break;
234 case PGEN_FAIL:
235 act |= A_STEP;
236 if (proc == test) {
237 act |= A_ENDTEST | A_EVENT;
238 proc = step; ctx = sctx;
239 }
240 rq = PGEN_TRY;
241 break;
242 case PGEN_DONE:
243 act |= A_EVENT | A_DONE | A_ENDSTEP;
244 if (proc == test)
245 act |= A_ENDTEST;
246 break;
247 case PGEN_ABORT:
248 act |= A_EVENT | A_DONE;
249 if (proc == test || rq == PGEN_TRY)
250 act |= A_ENDSTEP;
251 if (proc == test && rq == PGEN_BEGIN)
252 act |= A_ENDTEST;
253 break;
254 default:
255 assert(((void)"Invalid response from function", 0));
256 break;
257 }
0f5ec153 258
581c854e 259 /* --- If decrementing counters is requested, do that --- */
0f5ec153 260
581c854e 261 if ((act & A_STEP) && steps) {
283b9af0 262 ev.steps++;
263 if (ev.steps == steps) {
581c854e 264 act |= A_EVENT | A_ENDSTEP | A_DONE;
265 rc = PGEN_ABORT;
266 }
283b9af0 267 ev.tests = 0;
581c854e 268 }
0f5ec153 269
581c854e 270 if ((act & A_TEST) && tests) {
283b9af0 271 ev.tests++;
272 if (ev.tests == tests) {
581c854e 273 act |= A_ENDTEST | A_ENDSTEP | A_DONE;
274 rc = PGEN_DONE;
275 }
0f5ec153 276 }
0f5ec153 277
581c854e 278 /* --- Report an event if so directed --- */
bd98b2df 279
581c854e 280 if ((act & A_EVENT) && event && event(rc, &ev, ectx) == PGEN_ABORT) {
281 rc = PGEN_ABORT;
282 if (!(act & A_DONE)) {
283 act |= A_ENDSTEP | A_DONE;
284 if (proc == test)
285 act |= A_ENDTEST;
286 }
287 }
bd98b2df 288
581c854e 289 /* --- Close down tester and stepper functions --- */
0f5ec153 290
581c854e 291 if (act & A_ENDTEST)
292 test(PGEN_DONE, &ev, tctx);
293 if (act & A_ENDSTEP)
294 step(PGEN_DONE, &ev, sctx);
295
296 /* --- Stop the entire test if necessary --- */
297
298 if (act & A_DONE)
299 break;
300 }
301
302 /* --- Tidy up and return --- */
303
304 if (rc == PGEN_ABORT) {
305 mp_drop(ev.m);
306 ev.m = 0;
307 }
308 ev.r->ops->destroy(ev.r);
eab06f16 309 mp_drop(d);
581c854e 310
311 return (ev.m);
0f5ec153 312}
313
34e4f738 314/* --- @pgen_primep@ --- *
315 *
316 * Arguments: @mp *p@ = a number to check
317 * @grand *gr@ = a random number source
318 *
319 * Returns: Nonzero if @p@ is really prime.
320 */
321
322int pgen_primep(mp *p, grand *gr)
323{
324 int i = rabin_iters(mp_bits(p));
325 rabin r;
326 mp *x = MP_NEW;
327
328 if (MP_ISNEG(p)) return (0);
329 switch (pfilt_smallfactor(p)) {
330 case PGEN_DONE: return (1);
331 case PGEN_FAIL: return (0);
332 }
333 rabin_create(&r, p);
334 while (i) {
335 x = mprand_range(x, p, gr, 0);
336 if (rabin_rtest(&r, x) == PGEN_FAIL)
337 break;
338 i--;
339 }
340 MP_DROP(x);
341 rabin_destroy(&r);
342 return (!i);
343}
344
581c854e 345/*----- Test rig ----------------------------------------------------------*/
0f5ec153 346
347#ifdef TEST_RIG
348
349#include <mLib/testrig.h>
350
351static int verify(dstr *v)
352{
353 mp *m = *(mp **)v[0].buf;
581c854e 354 mp *q = *(mp **)v[1].buf;
355 mp *p;
0f5ec153 356 int ok = 1;
357
581c854e 358 pgen_filterctx pf;
359 rabin r;
0f5ec153 360
581c854e 361 pf.step = 2;
362 p = pgen("p", MP_NEW, m, pgen_evspin, 0, 0, pgen_filter, &pf,
363 rabin_iters(mp_bits(m)), pgen_test, &r);
22bab86c 364 if (!p || !MP_EQ(p, q)) {
581c854e 365 fputs("\n*** pgen failed", stderr);
0f5ec153 366 fputs("\nm = ", stderr); mp_writefile(m, stderr, 10);
581c854e 367 fputs("\np = ", stderr); mp_writefile(p, stderr, 10);
368 fputs("\nq = ", stderr); mp_writefile(q, stderr, 10);
0f5ec153 369 fputc('\n', stderr);
370 ok = 0;
371 }
372
373 mp_drop(m);
581c854e 374 mp_drop(q);
eab06f16 375 mp_drop(p);
d94f85ac 376 assert(mparena_count(MPARENA_GLOBAL) == 0);
0f5ec153 377 return (ok);
378}
379
380static test_chunk tests[] = {
381 { "pgen", verify, { &type_mp, &type_mp, 0 } },
382 { 0, 0, { 0 } }
383};
384
385int main(int argc, char *argv[])
386{
387 sub_init();
388 test_run(argc, argv, tests, SRCDIR "/tests/pgen");
389 return (0);
390}
0f5ec153 391#endif
392
393/*----- That's all, folks -------------------------------------------------*/