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Annotation of embedaddon/quagga/tests/prng.c, revision 1.1.1.1

1.1       misho       1: /*
                      2:  * Very simple prng to allow for randomized tests with reproducable
                      3:  * results.
                      4:  *
                      5:  * Copyright (C) 2012 by Open Source Routing.
                      6:  * Copyright (C) 2012 by Internet Systems Consortium, Inc. ("ISC")
                      7:  *
                      8:  * This file is part of Quagga
                      9:  *
                     10:  * Quagga is free software; you can redistribute it and/or modify it
                     11:  * under the terms of the GNU General Public License as published by the
                     12:  * Free Software Foundation; either version 2, or (at your option) any
                     13:  * later version.
                     14:  *
                     15:  * Quagga is distributed in the hope that it will be useful, but
                     16:  * WITHOUT ANY WARRANTY; without even the implied warranty of
                     17:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
                     18:  * General Public License for more details.
                     19:  *
                     20:  * You should have received a copy of the GNU General Public License
                     21:  * along with Quagga; see the file COPYING.  If not, write to the Free
                     22:  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
                     23:  * 02111-1307, USA.
                     24:  */
                     25: 
                     26: #include <zebra.h>
                     27: 
                     28: #include <assert.h>
                     29: #include <stdlib.h>
                     30: #include <string.h>
                     31: 
                     32: #include "prng.h"
                     33: 
                     34: struct prng
                     35: {
                     36:   unsigned long long state1;
                     37:   unsigned long long state2;
                     38: };
                     39: 
                     40: static char
                     41: prng_bit(struct prng *prng)
                     42: {
                     43:   prng->state1 *= 2416;
                     44:   prng->state1 += 374441;
                     45:   prng->state1 %= 1771875;
                     46: 
                     47:   if (prng->state1 % 2)
                     48:     {
                     49:       prng->state2 *= 84589;
                     50:       prng->state2 += 45989;
                     51:       prng->state2 %= 217728;
                     52:     }
                     53: 
                     54:   return prng->state2 % 2;
                     55: }
                     56: 
                     57: struct prng*
                     58: prng_new(unsigned long long seed)
                     59: {
                     60:   struct prng *rv = calloc(sizeof(*rv), 1);
                     61:   assert(rv);
                     62: 
                     63:   rv->state1 = rv->state2 = seed;
                     64: 
                     65:   return rv;
                     66: }
                     67: 
                     68: unsigned int
                     69: prng_rand(struct prng *prng)
                     70: {
                     71:   unsigned int i, rv = 0;
                     72: 
                     73:   for (i = 0; i < 32; i++)
                     74:     {
                     75:       rv |= prng_bit(prng);
                     76:       rv <<= 1;
                     77:     }
                     78:   return rv;
                     79: }
                     80: 
                     81: const char *
                     82: prng_fuzz(struct prng *prng,
                     83:           const char *string,
                     84:           const char *charset,
                     85:           unsigned int operations)
                     86: {
                     87:   static char buf[256];
                     88:   unsigned int charset_len;
                     89:   unsigned int i;
                     90:   unsigned int offset;
                     91:   unsigned int op;
                     92:   unsigned int character;
                     93: 
                     94:   assert(strlen(string) < sizeof(buf));
                     95: 
                     96:   strncpy(buf, string, sizeof(buf));
                     97:   charset_len = strlen(charset);
                     98: 
                     99:   for (i = 0; i < operations; i++)
                    100:     {
                    101:       offset = prng_rand(prng) % strlen(buf);
                    102:       op = prng_rand(prng) % 3;
                    103: 
                    104:       switch (op)
                    105:         {
                    106:         case 0:
                    107:           /* replace */
                    108:           character = prng_rand(prng) % charset_len;
                    109:           buf[offset] = charset[character];
                    110:           break;
                    111:         case 1:
                    112:           /* remove */
                    113:           memmove(buf + offset, buf + offset + 1, strlen(buf) - offset);
                    114:           break;
                    115:         case 2:
                    116:           /* insert */
                    117:           assert(strlen(buf) + 1 < sizeof(buf));
                    118: 
                    119:           memmove(buf + offset + 1, buf + offset, strlen(buf) + 1 - offset);
                    120:           character = prng_rand(prng) % charset_len;
                    121:           buf[offset] = charset[character];
                    122:           break;
                    123:         }
                    124:     }
                    125:   return buf;
                    126: }
                    127: 
                    128: void
                    129: prng_free(struct prng *prng)
                    130: {
                    131:   free(prng);
                    132: }