legacy_random.c File Reference

#include <stdio.h>
#include <math.h>
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>
#include "legacy_random.h"

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Functions
void	clear_checksum ()
int16_t	munge_checksum (long long value_)
double	cunningFee (double value, double precision)
unsigned	Ranrot (void)
unsigned	RanrotWithSeed (RANROTSeed *ioSeed)
RANROTSeed	MakeRanrotSeed (uint32_t seed)
RANROTSeed	RanrotSeedFromRNGSeed (RNG_Seed seed)
RANROTSeed	RanrotSeedFromRandomSeed (Random_Seed seed)
void	ranrot_srand (uint32_t seed)
float	randf (void)
float	randfWithSeed (RANROTSeed *ioSeed)
float	bellf (int n)
RANROTSeed	RANROTGetFullSeed (void)
void	RANROTSetFullSeed (RANROTSeed seed)
void	seed_RNG_only_for_planet_description (Random_Seed s_seed)
void	seed_for_planet_description (Random_Seed s_seed)
RNG_Seed	currentRandomSeed (void)
void	setRandomSeed (RNG_Seed a_seed)
int	gen_rnd_number (void)
uint32_t	OOReallyRandom (void)
void	OOInitReallyRandom (uint64_t seed)
void	OOSetReallyRandomRANROTSeed (void)
void	OOSetReallyRandomRndSeed (void)
void	OOSetReallyRandomRANROTAndRndSeeds (void)
OORandomState	OOSaveRandomState (void)
void	OORestoreRandomState (OORandomState state)
void	make_pseudo_random_seed (Random_Seed *seed_ptr)
void	rotate_seed (Random_Seed *seed_ptr)

Variables
const Random_Seed	kNilRandomSeed = {0}
static RNG_Seed	rnd_seed
static int32_t	checksum
static RANROTSeed	sRANROT
static bool	sReallyRandomInited = false
static RANROTSeed	sReallyRandomSeed

Function Documentation

bellf()

float bellf

(

int

n

)

Definition at line 168 of file legacy_random.c.

{
    int i = n;
    float total = 0;
    
    if (EXPECT_NOT(i <= 0))
    {
        printf("***** ERROR - attempt to generate bellf(%d)\n", n);
        return 0.0f; // catch possible div-by-zero problem
    }
    
    while (i-- > 0)
        total += (Ranrot() & 1023);
    return total / (1024.0f * n);
}

References EXPECT_NOT, and Ranrot().

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clear_checksum()

void clear_checksum

(

void

)

Definition at line 42 of file legacy_random.c.

{
    checksum = 0;
}

References checksum.

cunningFee()

double cunningFee	(	double	value,
		double	precision )

Definition at line 62 of file legacy_random.c.

{
    double fee = value;
    double superfee = 100000.0;
    double max = 1 + precision;
    double min = 1 - precision;
    unsigned long long rounded_fee = superfee * floor(0.5 + fee / superfee);
    if (rounded_fee == 0)  rounded_fee = 1;
    double ratio = fee / (double)rounded_fee;
    
    while ((ratio < min || ratio > max) && superfee > 1)
    {
        rounded_fee = superfee * floor(0.5 + fee / superfee);
        if (rounded_fee == 0)  rounded_fee = 1;
        ratio = fee / (double)rounded_fee;
        superfee /= 10.0;
    }
    
    if (ratio > min && ratio < max)
        fee = rounded_fee;
    
    return fee;
}

currentRandomSeed()

RNG_Seed currentRandomSeed

(

void

)

Definition at line 213 of file legacy_random.c.

{
    return rnd_seed;
}

References rnd_seed.

Referenced by GlobalRandomName().

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gen_rnd_number()

int gen_rnd_number

(

void

)

Definition at line 225 of file legacy_random.c.

{
    int a,x;
    
    x = (rnd_seed.a * 2) & 0xFF;
    a = x + rnd_seed.c;
    if (rnd_seed.a > 127)
        a++;
    rnd_seed.a = a & 0xFF;
    rnd_seed.c = x;
    
    a = a / 256;    /* a = any carry left from above */
    x = rnd_seed.b;
    a = (a + x + rnd_seed.d) & 0xFF;
    rnd_seed.b = a;
    rnd_seed.d = x;
    return a;
}

References RNG_Seed::a, RNG_Seed::b, RNG_Seed::c, RNG_Seed::d, rnd_seed, and x.

Referenced by make_pseudo_random_seed(), and OldRandomDigrams().

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make_pseudo_random_seed()

void make_pseudo_random_seed

(

Random_Seed *

seed_ptr

)

Definition at line 309 of file legacy_random.c.

{
    seed_ptr->a = gen_rnd_number();
    seed_ptr->b = gen_rnd_number();
    seed_ptr->c = gen_rnd_number();
    seed_ptr->d = gen_rnd_number();
    seed_ptr->e = gen_rnd_number();
    seed_ptr->f = gen_rnd_number();
}

References Random_Seed::a, Random_Seed::b, Random_Seed::c, Random_Seed::d, Random_Seed::e, Random_Seed::f, and gen_rnd_number().

Referenced by GlobalRandomInhabitantsDescription().

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MakeRanrotSeed()

RANROTSeed MakeRanrotSeed

(

uint32_t

seed

)

Definition at line 113 of file legacy_random.c.

{
    RANROTSeed result =
    {
        .low = seed,
        .high = ~seed
    };
    
    // Mix it up a bit.
    RanrotWithSeed(&result);
    RanrotWithSeed(&result);
    RanrotWithSeed(&result);
 
    return result;
}

References RanrotWithSeed().

Referenced by ranrot_srand(), and RanrotSeedFromRNGSeed().

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munge_checksum()

int16_t munge_checksum

(

long long

value_

)

Definition at line 48 of file legacy_random.c.

{
    uint32_t value = (uint32_t)value_;
    int32_t mult1 = (value & 15) + 8;
    checksum += value;
    checksum *= mult1;
    checksum += mult1;
    checksum &= 0xffff;
    return checksum;
}

References checksum.

OOInitReallyRandom()

void OOInitReallyRandom

(

uint64_t

seed

)

Definition at line 256 of file legacy_random.c.

{
    assert(!sReallyRandomInited);
    seed ^= 0xA471D52AEF3B6322ULL;
    sReallyRandomSeed.high = (seed >> 32) & 0xFFFFFFFF;
    sReallyRandomSeed.low = seed  & 0xFFFFFFFF;
    sReallyRandomInited = true;
    OOReallyRandom();
}

References RANROTSeed::high, RANROTSeed::low, OOReallyRandom(), sReallyRandomInited, and sReallyRandomSeed.

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OOReallyRandom()

uint32_t OOReallyRandom

(

void

)

Definition at line 249 of file legacy_random.c.

{
    assert(sReallyRandomInited);
    return RanrotWithSeed(&sReallyRandomSeed);
}

References RanrotWithSeed(), sReallyRandomInited, and sReallyRandomSeed.

Referenced by OOInitReallyRandom(), OOSetReallyRandomRANROTSeed(), and OOSetReallyRandomRndSeed().

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OORestoreRandomState()

void OORestoreRandomState

(

OORandomState

state

)

Definition at line 302 of file legacy_random.c.

{
    sRANROT = state.ranrot;
    rnd_seed = state.rnd;
}

References OORandomState::ranrot, OORandomState::rnd, rnd_seed, and sRANROT.

Referenced by OOExpandDescriptionString().

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OOSaveRandomState()

OORandomState OOSaveRandomState

(

void

)

Definition at line 292 of file legacy_random.c.

{
    return (OORandomState)
    {
        .ranrot = sRANROT,
        .rnd = rnd_seed
    };
}

References rnd_seed, and sRANROT.

Referenced by OOExpandDescriptionString().

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OOSetReallyRandomRANROTAndRndSeeds()

void OOSetReallyRandomRANROTAndRndSeeds

(

void

)

Definition at line 285 of file legacy_random.c.

{
    OOSetReallyRandomRANROTSeed();
    OOSetReallyRandomRndSeed();
}

References OOSetReallyRandomRANROTSeed(), and OOSetReallyRandomRndSeed().

Referenced by OOExpandDescriptionString().

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OOSetReallyRandomRANROTSeed()

void OOSetReallyRandomRANROTSeed

(

void

)

Definition at line 267 of file legacy_random.c.

{
    assert(sReallyRandomInited);
    sRANROT = sReallyRandomSeed;
    OOReallyRandom();   // Don't go reusing it.
}

References OOReallyRandom(), sRANROT, sReallyRandomInited, and sReallyRandomSeed.

Referenced by OOSetReallyRandomRANROTAndRndSeeds().

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OOSetReallyRandomRndSeed()

void OOSetReallyRandomRndSeed

(

void

)

Definition at line 275 of file legacy_random.c.

{
    uint32_t val = OOReallyRandom();
    rnd_seed.a = (val >> 24) & 0xFF;
    rnd_seed.b = (val >> 16) & 0xFF;
    rnd_seed.c = (val >> 8) & 0xFF;
    rnd_seed.d = val & 0xFF;
}

References RNG_Seed::a, RNG_Seed::b, RNG_Seed::c, RNG_Seed::d, OOReallyRandom(), and rnd_seed.

Referenced by OOSetReallyRandomRANROTAndRndSeeds().

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randf()

float randf

(

void

)

Definition at line 156 of file legacy_random.c.

{
    return (Ranrot() & 0xffff) * (1.0f / 65536.0f);
}

References Ranrot().

Referenced by WormholeEntity::DrawWormholeCorona, fillRanNoiseBuffer(), OOFuzzyBooleanFromObject(), OOHPRandomPositionInBoundingBox(), OOHPVectorRandomRadial(), OOHPVectorRandomSpatial(), OORandomPositionInBoundingBox(), OORandomPositionInCylinder(), OORandomUnitHPVector(), OORandomUnitVector(), OOVectorRandomRadial(), and OOVectorRandomSpatial().

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randfWithSeed()

float randfWithSeed

(

RANROTSeed *

ioSeed

)

Definition at line 162 of file legacy_random.c.

{
    return (RanrotWithSeed(ioSeed) & 0xffff) * (1.0f / 65536.0f);
}

References RanrotWithSeed().

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Ranrot()

unsigned Ranrot

(

void

)

Definition at line 93 of file legacy_random.c.

{
    sRANROT.high = (sRANROT.high << 16) + (sRANROT.high >> 16);
    sRANROT.high += sRANROT.low;
    sRANROT.low += sRANROT.high;
    return sRANROT.high & 0x7FFFFFFF;
}

References RANROTSeed::high, RANROTSeed::low, and sRANROT.

Referenced by bellf(), GlobalRandomName(), quaternion_set_random(), randf(), Octree::randomFullNodeFrom, StationAddShipToShipyard(), and SVGDumpBeginPrimitive().

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ranrot_srand()

void ranrot_srand

(

uint32_t

seed

)

Definition at line 150 of file legacy_random.c.

{
    sRANROT = MakeRanrotSeed(seed);
}

References MakeRanrotSeed(), and sRANROT.

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RANROTGetFullSeed()

RANROTSeed RANROTGetFullSeed

(

void

)

Definition at line 185 of file legacy_random.c.

{
    return sRANROT;
}

References sRANROT.

Referenced by fillRanNoiseBuffer().

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RanrotSeedFromRandomSeed()

RANROTSeed RanrotSeedFromRandomSeed

(

Random_Seed

seed

)

Definition at line 136 of file legacy_random.c.

{
    // Same pattern as seed_for_planet_description().
    RNG_Seed s =
    {
        .a = seed.c,
        .b = seed.d,
        .c = seed.e,
        .d = seed.f
    };
    return RanrotSeedFromRNGSeed(s);
}

References Random_Seed::c, Random_Seed::d, Random_Seed::e, Random_Seed::f, and RanrotSeedFromRNGSeed().

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RanrotSeedFromRNGSeed()

RANROTSeed RanrotSeedFromRNGSeed

(

RNG_Seed

seed

)

Definition at line 130 of file legacy_random.c.

{
    return MakeRanrotSeed(seed.a * 0x1000000 + seed.b * 0x10000 + seed.c * 0x100 + seed.d);
}

References RNG_Seed::a, RNG_Seed::b, RNG_Seed::c, RNG_Seed::d, and MakeRanrotSeed().

Referenced by RanrotSeedFromRandomSeed(), and seed_for_planet_description().

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RANROTSetFullSeed()

void RANROTSetFullSeed

(

RANROTSeed

seed

)

Definition at line 191 of file legacy_random.c.

{
    sRANROT = seed;
}

References sRANROT.

RanrotWithSeed()

unsigned RanrotWithSeed

(

RANROTSeed *

ioSeed

)

Definition at line 102 of file legacy_random.c.

{
    assert(ioSeed != NULL);
    
    ioSeed->high = (ioSeed->high << 16) + (ioSeed->high >> 16);
    ioSeed->high += ioSeed->low;
    ioSeed->low += ioSeed->high;
    return ioSeed->high & 0x7FFFFFFF;
}

References RANROTSeed::high, and RANROTSeed::low.

Referenced by MakeRanrotSeed(), OOReallyRandom(), and randfWithSeed().

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rotate_seed()

void rotate_seed

(

Random_Seed *

seed_ptr

)

Definition at line 320 of file legacy_random.c.

{
    uint_fast16_t x;
    uint_fast16_t y;
    
    /*  Note: this is equivalent to adding three (little-endian) 16-bit values
        together, rotating the three numbers and replacing one of them with
        the sum. The byte-oriented approach is presumably because it was
        reverse-engineered from eight-bit machine code. Switching to a plain
        sixteen-bit representation is more trouble than it's worth since so
        much code uses byte values from the seed struct directly.
    */
    x = seed_ptr->a + seed_ptr->c + seed_ptr->e;
    y = seed_ptr->b + seed_ptr->d + seed_ptr->f;
    
    seed_ptr->a = seed_ptr->c;
    seed_ptr->b = seed_ptr->d;
    
    seed_ptr->c = seed_ptr->e;
    seed_ptr->d = seed_ptr->f;
    
    seed_ptr->e = x;
    seed_ptr->f = y + (x >> 8);
}

References Random_Seed::a, Random_Seed::b, Random_Seed::c, Random_Seed::d, Random_Seed::e, Random_Seed::f, x, and y.

seed_for_planet_description()

void seed_for_planet_description

(

Random_Seed

s_seed

)

Definition at line 206 of file legacy_random.c.

{
    seed_RNG_only_for_planet_description(s_seed);
    sRANROT = RanrotSeedFromRNGSeed(rnd_seed);
}

References RanrotSeedFromRNGSeed(), rnd_seed, seed_RNG_only_for_planet_description(), and sRANROT.

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seed_RNG_only_for_planet_description()

void seed_RNG_only_for_planet_description

(

Random_Seed

s_seed

)

Definition at line 197 of file legacy_random.c.

{
    rnd_seed.a = s_seed.c;
    rnd_seed.b = s_seed.d;
    rnd_seed.c = s_seed.e;
    rnd_seed.d = s_seed.f;
}

References RNG_Seed::a, RNG_Seed::b, Random_Seed::c, RNG_Seed::c, Random_Seed::d, RNG_Seed::d, Random_Seed::e, Random_Seed::f, and rnd_seed.

Referenced by OOGenerateSystemDescription(), and seed_for_planet_description().

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setRandomSeed()

void setRandomSeed

(

RNG_Seed

a_seed

)

Definition at line 219 of file legacy_random.c.

{
    rnd_seed = a_seed;
}

References rnd_seed.

Referenced by GlobalRandomName().

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Variable Documentation

checksum

int32_t checksum

static

Definition at line 41 of file legacy_random.c.

Referenced by clear_checksum(), and munge_checksum().

kNilRandomSeed

const Random_Seed kNilRandomSeed = {0}

Definition at line 34 of file legacy_random.c.

{0};

Referenced by GlobalExpandDescription(), GlobalExpandMissionText(), is_nil_seed(), and RandomSeedFromString().

rnd_seed

RNG_Seed rnd_seed

static

Definition at line 37 of file legacy_random.c.

Referenced by currentRandomSeed(), gen_rnd_number(), OORestoreRandomState(), OOSaveRandomState(), OOSetReallyRandomRndSeed(), seed_for_planet_description(), seed_RNG_only_for_planet_description(), and setRandomSeed().

sRANROT

RANROTSeed sRANROT

static

Definition at line 90 of file legacy_random.c.

Referenced by OORestoreRandomState(), OOSaveRandomState(), OOSetReallyRandomRANROTSeed(), Ranrot(), ranrot_srand(), RANROTGetFullSeed(), RANROTSetFullSeed(), and seed_for_planet_description().

sReallyRandomInited

bool sReallyRandomInited = false

static

Definition at line 245 of file legacy_random.c.

Referenced by OOInitReallyRandom(), OOReallyRandom(), and OOSetReallyRandomRANROTSeed().

sReallyRandomSeed

RANROTSeed sReallyRandomSeed

static

Definition at line 246 of file legacy_random.c.

Referenced by OOInitReallyRandom(), OOReallyRandom(), and OOSetReallyRandomRANROTSeed().