src/lib/crypto.c

   1 /************************************************************************
   2 * crypto.c
   3 * voxelands - 3d voxel world sandbox game
   4 * Copyright (C) Lisa 'darkrose' Milne 2016 <lisa@ltmnet.com>
   5 *
   6 * This program is free software: you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation, either version 3 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful, but
  12 * WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  14 * See the GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program.  If not, see <http://www.gnu.org/licenses/>
  18 ************************************************************************/
  19
  20 #include "crypto.h"
  21
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 /* defined in base64.c */
  26 int base64_lencode(char *source, size_t sourcelen, char *target, size_t targetlen);
  27 size_t base64_ldecode(char *source, char *target, size_t targetlen);
  28
  29 /* an XOR hash sum */
  30 uint32_t sum(char* str)
  31 {
  32         uint32_t hash = 0xAAAAAAAA;
  33         uint32_t i;
  34
  35         for (i=0; *str; str++, i++) {
  36                 hash ^= ((i & 1) == 0) ? ((hash <<  7) ^ (*str) * (hash >> 3)) : (~((hash << 11) + ((*str) ^ (hash >> 5))));
  37         }
  38
  39         return hash;
  40 }
  41
  42 /* basic string hash */
  43 uint32_t hash(char* str)
  44 {
  45         uint32_t hash = 5381;
  46         int c;
  47         int i;
  48
  49         for (i=0; str[i]; i++) {
  50                 c = str[i];
  51                 hash = ((hash << 5)+hash)+c;
  52         }
  53
  54         return hash;
  55 }
  56
  57 /* base64 encode a string */
  58 char* base64_encode(char* str)
  59 {
  60         int sl;
  61         int tl;
  62         char* ret;
  63         int el;
  64         if (!str)
  65                 return NULL;
  66
  67         sl = strlen(str);
  68         tl = ((sl+2)/3*4)+5;
  69
  70         ret = malloc(tl);
  71         if (!ret)
  72                 return NULL;
  73
  74         el = base64_lencode(str, sl, ret, tl);
  75         if (!el) {
  76                 free(ret);
  77                 return NULL;
  78         }
  79
  80         return ret;
  81 }
  82
  83 /* decode a base64 string */
  84 char* base64_decode(char* str)
  85 {
  86         int sl;
  87         int tl;
  88         char* ret;
  89         int dl;
  90         if (!str)
  91                 return NULL;
  92
  93         sl = strlen(str);
  94         tl = (sl/4*3)+5;
  95         ret = malloc(tl);
  96         if (!ret)
  97                 return NULL;
  98
  99         dl = base64_ldecode(str, ret, tl);
 100         if (!dl) {
 101                 free(ret);
 102                 return NULL;
 103         }
 104         ret[dl] = 0;
 105
 106         return ret;
 107 }