release/src/router/minidlna/tivo_utils.c

   1 /* MiniDLNA media server
   2  * Copyright (C) 2009  Justin Maggard
   3  *
   4  * This file is part of MiniDLNA.
   5  *
   6  * MiniDLNA is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * MiniDLNA is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with MiniDLNA. If not, see <http://www.gnu.org/licenses/>.
  17  */
  18 #include "config.h"
  19 #ifdef TIVO_SUPPORT
  20 #include <stdlib.h>
  21 #include <stdint.h>
  22 #include <string.h>
  23 #include <ctype.h>
  24 #include <sqlite3.h>
  25 #include "tivo_utils.h"
  26
  27 /* This function based on byRequest */
  28 char *
  29 decodeString(char * string, int inplace)
  30 {
  31         if( !string )
  32                 return NULL;
  33         int alloc = (int)strlen(string)+1;
  34         char * ns = NULL;
  35         unsigned char in;
  36         int strindex=0;
  37         long hex;
  38
  39         if( !inplace )
  40         {
  41                 if( !(ns = malloc(alloc)) )
  42                         return NULL;
  43         }
  44
  45         while(--alloc > 0)
  46         {
  47                 in = *string;
  48                 if((in == '%') && isxdigit(string[1]) && isxdigit(string[2]))
  49                 {
  50                         /* this is two hexadecimal digits following a '%' */
  51                         char hexstr[3];
  52                         char *ptr;
  53                         hexstr[0] = string[1];
  54                         hexstr[1] = string[2];
  55                         hexstr[2] = 0;
  56
  57                         hex = strtol(hexstr, &ptr, 16);
  58
  59                         in = (unsigned char)hex; /* this long is never bigger than 255 anyway */
  60                         if( inplace )
  61                         {
  62                                 *string = in;
  63                                 memmove(string+1, string+3, alloc-2);
  64                         }
  65                         else
  66                         {
  67                                 string+=2;
  68                         }
  69                         alloc-=2;
  70                 }
  71                 if( !inplace )
  72                         ns[strindex++] = in;
  73                 string++;
  74         }
  75         if( inplace )
  76         {
  77                 if( ns )
  78                         free(ns);
  79                 return string;
  80         }
  81         else
  82         {
  83                 ns[strindex] = '\0'; /* terminate it */
  84                 return ns;
  85         }
  86 }
  87
  88 /* These next functions implement a repeatable random function with a user-provided seed */
  89 static int
  90 seedRandomByte(uint32_t seed)
  91 {
  92         unsigned char t;
  93
  94         if( !sqlite3Prng.isInit )
  95         {
  96                 int i;
  97                 char k[256];
  98                 sqlite3Prng.j = 0;
  99                 sqlite3Prng.i = 0;
 100                 memset(&k, '\0', sizeof(k));
 101                 memcpy(&k, &seed, 4);
 102                 for(i=0; i<256; i++)
 103                         sqlite3Prng.s[i] = i;
 104                 for(i=0; i<256; i++)
 105                 {
 106                         sqlite3Prng.j += sqlite3Prng.s[i] + k[i];
 107                         t = sqlite3Prng.s[sqlite3Prng.j];
 108                         sqlite3Prng.s[sqlite3Prng.j] = sqlite3Prng.s[i];
 109                         sqlite3Prng.s[i] = t;
 110                 }
 111                 sqlite3Prng.isInit = 1;
 112         }
 113         /* Generate and return single random byte */
 114         sqlite3Prng.i++;
 115         t = sqlite3Prng.s[sqlite3Prng.i];
 116         sqlite3Prng.j += t;
 117         sqlite3Prng.s[sqlite3Prng.i] = sqlite3Prng.s[sqlite3Prng.j];
 118         sqlite3Prng.s[sqlite3Prng.j] = t;
 119         t += sqlite3Prng.s[sqlite3Prng.i];
 120
 121         return sqlite3Prng.s[t];
 122 }
 123
 124 void
 125 seedRandomness(int n, void *pbuf, uint32_t seed)
 126 {
 127         unsigned char *zbuf = pbuf;
 128
 129         while( n-- )
 130                 *(zbuf++) = seedRandomByte(seed);
 131 }
 132
 133 void
 134 TiVoRandomSeedFunc(sqlite3_context *context, int argc, sqlite3_value **argv)
 135 {
 136         sqlite_int64 r, seed;
 137
 138         if( argc != 1 || sqlite3_value_type(argv[0]) != SQLITE_INTEGER )
 139                 return;
 140         seed = sqlite3_value_int64(argv[0]);
 141         seedRandomness(sizeof(r), &r, seed);
 142         sqlite3_result_int64(context, r);
 143 }
 144 #endif