Annotation of embedaddon/quagga/tests/prng.c, revision 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: }

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