legacy_random.h File Reference

#include "OOFunctionAttributes.h"
#include <math.h>
#include <stdint.h>

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Classes
struct	Random_Seed
struct	RNG_Seed
struct	RANROTSeed
struct	OORandomState

Macros
#define	ranrot_rand()   ((int)Ranrot())

Typedefs
typedef struct Random_Seed	Random_Seed
typedef struct RNG_Seed	RNG_Seed
typedef struct RANROTSeed	RANROTSeed

Functions
void	clear_checksum (void)
int16_t	munge_checksum (long long value)
double	cunningFee (double value, double precision)
void	ranrot_srand (uint32_t seed)
unsigned	Ranrot (void)
float	randf (void)
float	bellf (int n)
RANROTSeed	RANROTGetFullSeed (void)
void	RANROTSetFullSeed (RANROTSeed seed)
RANROTSeed	MakeRanrotSeed (uint32_t seed)
RANROTSeed	RanrotSeedFromRNGSeed (RNG_Seed seed)
RANROTSeed	RanrotSeedFromRandomSeed (Random_Seed seed)
unsigned	RanrotWithSeed (RANROTSeed *ioSeed)
float	randfWithSeed (RANROTSeed *ioSeed)
OOINLINE double	distanceBetweenPlanetPositions (int x1, int y1, int x2, int y2) INLINE_CONST_FUNC
OOINLINE double	accurateDistanceBetweenPlanetPositions (int x1, int y1, int x2, int y2) INLINE_CONST_FUNC
void	seed_for_planet_description (Random_Seed s_seed)
void	seed_RNG_only_for_planet_description (Random_Seed s_seed)
RNG_Seed	currentRandomSeed (void)
void	setRandomSeed (RNG_Seed a_seed)
int	gen_rnd_number (void)
void	make_pseudo_random_seed (Random_Seed *seed_ptr)
OOINLINE int	is_nil_seed (Random_Seed a_seed) INLINE_CONST_FUNC
void	rotate_seed (Random_Seed *seed_ptr)
OOINLINE int	rotate_byte_left (int x) INLINE_CONST_FUNC
OOINLINE int	equal_seeds (Random_Seed seed1, Random_Seed seed2) INLINE_CONST_FUNC
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)
OOINLINE double	travelTimeBetweenPlanetPositions (int x1, int y1, int x2, int y2)

Variables
const Random_Seed	kNilRandomSeed

Macro Definition Documentation

ranrot_rand

#define ranrot_rand

(

)

((int)Ranrot())

Definition at line 78 of file legacy_random.h.

Referenced by PlayerSetEscapePodDestination().

Typedef Documentation

Random_Seed

typedef struct Random_Seed Random_Seed

RANROTSeed

typedef struct RANROTSeed RANROTSeed

RNG_Seed

typedef struct RNG_Seed RNG_Seed

Function Documentation

accurateDistanceBetweenPlanetPositions()

OOINLINE double accurateDistanceBetweenPlanetPositions	(	int	x1,
		int	y1,
		int	x2,
		int	y2 )

Definition at line 178 of file legacy_random.h.

{
    double dx = x1 - x2;
    double dy = (y1 - y2) / 2.0;
    double dist = hypot(dx, dy);
    return 0.4 * dist;
}

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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distanceBetweenPlanetPositions()

OOINLINE double distanceBetweenPlanetPositions	(	int	x1,
		int	y1,
		int	x2,
		int	y2 )

Definition at line 169 of file legacy_random.h.

{
    int dx = x1 - x2;
    int dy = (y1 - y2)/2;
    int dist = sqrt(dx*dx + dy*dy); // N.b. Rounding error due to truncation is desired.
    return 0.4 * dist;
}

Referenced by SystemInfoDistanceToSystem(), and travelTimeBetweenPlanetPositions().

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equal_seeds()

OOINLINE int equal_seeds	(	Random_Seed	seed1,
		Random_Seed	seed2 )

Definition at line 148 of file legacy_random.h.

{
    return ((seed1.a == seed2.a)&&(seed1.b == seed2.b)&&(seed1.c == seed2.c)&&(seed1.d == seed2.d)&&(seed1.e == seed2.e)&&(seed1.f == seed2.f));
}

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

Referenced by is_nil_seed().

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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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is_nil_seed()

OOINLINE int is_nil_seed

(

Random_Seed

a_seed

)

Definition at line 154 of file legacy_random.h.

{
    return equal_seeds(a_seed, kNilRandomSeed);
}

References equal_seeds(), and kNilRandomSeed.

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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 RANROTSeed::low, and 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 OORandomState::ranrot, 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 RNG_Seed::a, 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_byte_left()

OOINLINE int rotate_byte_left

(

int

x

)

Definition at line 160 of file legacy_random.h.

{
    return ((x << 1) | (x >> 7)) & 255;
}

References x.

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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travelTimeBetweenPlanetPositions()

OOINLINE double travelTimeBetweenPlanetPositions	(	int	x1,
		int	y1,
		int	x2,
		int	y2 )

Definition at line 187 of file legacy_random.h.

{
    double distance = distanceBetweenPlanetPositions(x1, y1, x2, y2);
    return distance * distance;
}

References distanceBetweenPlanetPositions().

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Variable Documentation

kNilRandomSeed

const Random_Seed kNilRandomSeed

extern

Definition at line 34 of file legacy_random.c.

{0};

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