prj/cam/src/framewrk/rand.cpp

   1 /*
   2 @Copyright Looking Glass Studios, Inc.
   3 1996,1997,1998,1999,2000 Unpublished Work.
   4 */
   5
   6 ///////////////////////////////////////////////////////////////////////////////
   7 // $Source: r:/t2repos/thief2/src/framewrk/rand.cpp,v $
   8 // $Author: XEMU $
   9 // $Date: 1999/06/05 17:55:16 $
  10 // $Revision: 1.9 $
  11 //
  12
  13 #include <stdlib.h>
  14 #include <lg.h>
  15 #include <appagg.h>
  16 #include <recapi.h>
  17 #include <rnd.h>
  18 #include <rand.h>
  19 #include <hashfns.h>
  20
  21 // Must be last header
  22 #include <dbmem.h>
  23
  24 //#define COUNT_RANDS
  25
  26 ///////////////////////////////////////////////////////////////////////////////
  27
  28 uchar g_R250IncrementTable[250] = { 1,  2,  3,  4,  5,  6,  7,  8,  9, 10,
  29                                     11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
  30                                     21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
  31                                     31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
  32                                     41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
  33                                     51, 52, 53, 54, 55, 56, 57, 58, 59, 60,
  34                                     61, 62, 63, 64, 65, 66, 67, 68, 69, 70,
  35                                     71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
  36                                     81, 82, 83, 84, 85, 86, 87, 88, 89, 90,
  37                                     91, 92, 93, 94, 95, 96, 97, 98, 99,100,
  38                                     101,102,103,104,105,106,107,108,109,110,
  39                                     111,112,113,114,115,116,117,118,119,120,
  40                                     121,122,123,124,125,126,127,128,129,130,
  41                                     131,132,133,134,135,136,137,138,139,140,
  42                                     141,142,143,144,145,146,147,148,149,150,
  43                                     151,152,153,154,155,156,157,158,159,160,
  44                                     161,162,163,164,165,166,167,168,169,170,
  45                                     171,172,173,174,175,176,177,178,179,180,
  46                                     181,182,183,184,185,186,187,188,189,190,
  47                                     191,192,193,194,195,196,197,198,199,200,
  48                                     201,202,203,204,205,206,207,208,209,210,
  49                                     211,212,213,214,215,216,217,218,219,220,
  50                                     221,222,223,224,225,226,227,228,229,230,
  51                                     231,232,233,234,235,236,237,238,239,240,
  52                                     241,242,243,244,245,246,247,248,249,  0 };
  53
  54 unsigned g_R250Index1 = 0;
  55 unsigned g_R250Index2 = 103;
  56 unsigned g_R250Table[250];
  57
  58 ///////////////////////////////////////////////////////////////////////////////
  59
  60 extern "C"
  61 __declspec(dllimport) DWORD __stdcall timeGetTime(void);
  62
  63 static BOOL g_fRandInited;
  64 static RNDSTREAM_STD(g_CoreRandStream);
  65
  66 #ifdef COUNT_RANDS
  67 int RandsBuilt=0;
  68 #define OneMoreRand() do { RandsBuilt++; } while (0)
  69 #else
  70 #define OneMoreRand()
  71 #endif
  72
  73 ///////////////////////////////////////////////////////////////////////////////
  74
  75 long Rand250()
  76 {
  77    int i1, i2;
  78
  79    g_R250Index1 = g_R250IncrementTable[i1 = g_R250Index1];
  80    g_R250Index2 = g_R250IncrementTable[i2 = g_R250Index2];
  81
  82    return g_R250Table[i1] ^= g_R250Table[i2];
  83 }
  84
  85 void Rand250Seed(int seed)
  86 {
  87    seed = seed ^ HashLong(seed);
  88    srand(seed);
  89
  90    int i;
  91    unsigned long lo, hi, ll, lh, hh, hl;
  92    unsigned long msk, bit;
  93
  94 #define IL_RMULT 1103515245
  95
  96    for (i = 0; i < 250; i++)
  97    {
  98       lo = seed & 0xffff;
  99       hi = seed >> 16;
 100       seed = seed * IL_RMULT + 12345;
 101       ll = lo * (IL_RMULT  & 0xffff);
 102       lh = lo * (IL_RMULT >> 16    );
 103       hl = hi * (IL_RMULT  & 0xffff);
 104       hh = hi * (IL_RMULT >> 16    );
 105       g_R250Table[i] = (((ll + 12345) >> 16) + lh + hl + (hh << 16)) ^
 106                        (Rnd(&g_CoreRandStream) | (Rnd(&g_CoreRandStream) >> 16)) ^
 107                        HashLong(seed) ^
 108                        rand();
 109    }
 110
 111    for (i = 3, msk = 0xffffffff, bit = 0x80000000; bit; i += 7)
 112    {
 113       g_R250Table[i] = (g_R250Table[i] & msk) | bit;
 114       msk >>= 1;
 115       bit >>= 1;
 116    }
 117
 118    g_R250Index1 = 0;
 119    g_R250Index2 = 103;
 120
 121    for (i = 0; i < 1000; i++)
 122       Rand250();
 123 }
 124
 125 void AppRandInit()
 126 {
 127    long seed = timeGetTime();
 128
 129    IRecorder * pRecorder = AppGetObj(IRecorder);
 130    RecStreamAddOrExtract(pRecorder, &seed, sizeof(ulong), "DarkRandSeed");
 131    SafeRelease(pRecorder);
 132
 133    RndSeed(&g_CoreRandStream, seed);
 134    Rand250Seed(seed);
 135
 136    g_fRandInited = TRUE;
 137 }
 138
 139 int Rand(void)
 140 {
 141    if (!g_fRandInited)
 142       AppRandInit();
 143
 144    OneMoreRand();
 145
 146 #if 0
 147    return (Rand250() & 0x7fffffff);
 148 #else
 149 // @TBD (toml 10-09-98): track down and kill people relying on 15 bits
 150    return (Rand250() & 0x00007fff);
 151 #endif
 152 }
 153
 154 int RandRange(int low, int high)
 155 {
 156    if (low >= high)
 157       return low;
 158    int randval = Rand();
 159
 160    int range = high - low + 1;
 161    return low + (randval % range);
 162 }
 163
 164 int UnrecordedRand(void)
 165 {
 166    static BOOL fInited;
 167    if (!fInited)
 168    {
 169       srand(timeGetTime());
 170       fInited = TRUE;
 171    }
 172    OneMoreRand();
 173    return rand();
 174 }