Random Number Generation

Random Number Generation — Random number generation

Synopsis




#define     oil_rand_s32                    ()
#define     oil_rand_s32_l31                ()
#define     oil_rand_s16                    ()
#define     oil_rand_s16_l15                ()
#define     oil_rand_s16_l9                 ()
#define     oil_rand_s16_l8                 ()
#define     oil_rand_s16_l4                 ()
#define     oil_rand_s8                     ()
#define     oil_rand_u32                    ()
#define     oil_rand_u32_l31                ()
#define     oil_rand_u16                    ()
#define     oil_rand_u8                     ()
#define     oil_rand_f64_0_1                ()
#define     oil_rand_f64_s32                ()
#define     oil_rand_f64_s16                ()
#define     oil_rand_f64_s8                 ()
#define     oil_rand_f64_u32                ()
#define     oil_rand_f64_u16                ()
#define     oil_rand_f64_u8                 ()
#define     oil_rand_f32_0_1                ()
#define     oil_rand_f32_s32                ()
#define     oil_rand_f32_s16                ()
#define     oil_rand_f32_s8                 ()
#define     oil_rand_f32_u32                ()
#define     oil_rand_f32_u16                ()
#define     oil_rand_f32_u8                 ()
#define     oil_rand_s64                    ()
#define     oil_rand_u64                    ()
#define     oil_rand_rgba                   (a)

Description

Details

oil_rand_s32()

#define oil_rand_s32() ((rand()&0xffff)<<16 | (rand()&0xffff))

Evaluates to a random integer in the range [-(1<<31), (1<<31)-1].


oil_rand_s32_l31()

#define oil_rand_s32_l31() (((int32_t)rand())-0x40000000)

Evaluates to a random integer in the range [-(1<<30), (1<<30)-1].


oil_rand_s16()

#define oil_rand_s16() ((int16_t)(rand()&0xffff))

Evaluates to a random integer in the range [-(1<<15), (1<<15)-1].


oil_rand_s16_l15()

#define oil_rand_s16_l15() (oil_rand_s16()>>1)

Evaluates to a random integer in the range [-(1<<14), (1<<14)-1].


oil_rand_s16_l9()

#define oil_rand_s16_l9() (oil_rand_s16()>>7)

Evaluates to a random integer in the range [-(1<<8), (1<<8)-1].


oil_rand_s16_l8()

#define oil_rand_s16_l8() (oil_rand_s16()>>8)

Evaluates to a random integer in the range [-(1<<7), (1<<7)-1].


oil_rand_s16_l4()

#define oil_rand_s16_l4() (oil_rand_s16()>>12)

Evaluates to a random integer in the range [-(1<<3), (1<<3)-1].


oil_rand_s8()

#define oil_rand_s8() ((int8_t)(rand()&0xffff))

Evaluates to a random integer in the range [-(1<<7), (1<<7)-1].


oil_rand_u32()

#define oil_rand_u32() ((uint32_t)((rand()&0xffff)<<16 | (rand()&0xffff)))

Evaluates to a random integer in the range [0, (1<<32)-1].


oil_rand_u32_l31()

#define oil_rand_u32_l31() ((uint32_t)rand())

Evaluates to a random integer in the range [0, (1<<31)-1].


oil_rand_u16()

#define oil_rand_u16() ((uint16_t)(rand()&0xffff))

Evaluates to a random integer in the range [0, (1<<16)-1].


oil_rand_u8()

#define oil_rand_u8() ((uint8_t)(rand()&0xffff))

Evaluates to a random integer in the range [0, (1<<8)-1].


oil_rand_f64_0_1()

#define oil_rand_f64_0_1() (((rand()/(RAND_MAX+1.0))+rand())/(RAND_MAX+1.0))

Evaluates to a random double-precision floating point number in the range [0, 1.0).


oil_rand_f64_s32()

#define oil_rand_f64_s32() (oil_rand_f64_0_1()*4294967296.0-2147483648.0)

Evaluates to a random double-precision floating point number in the range [-(1<<31), (1<<31)). Note that when rounded to the nearest integer, this exceeds the range of int32_t.


oil_rand_f64_s16()

#define oil_rand_f64_s16() (oil_rand_f64_0_1()*65536.0-32768.0)

Evaluates to a random double-precision floating point number in the range [-(1<<15), (1<<15)). Note that when rounded to the nearest integer, this exceeds the range of int16_t.


oil_rand_f64_s8()

#define oil_rand_f64_s8() (oil_rand_f64_0_1()*256.0-128.0)

Evaluates to a random double-precision floating point number in the range [-(1<<7), (1<<7)). Note that when rounded to the nearest integer, this exceeds the range of int8_t.


oil_rand_f64_u32()

#define oil_rand_f64_u32() (oil_rand_f64_0_1()*4294967296.0)

Evaluates to a random double-precision floating point number in the range [0, (1<<32)). Note that when rounded to the nearest integer, this exceeds the range of uint32_t.


oil_rand_f64_u16()

#define oil_rand_f64_u16() (oil_rand_f64_0_1()*65536.0)

Evaluates to a random double-precision floating point number in the range [0, (1<<16)). Note that when rounded to the nearest integer, this exceeds the range of uint16_t.


oil_rand_f64_u8()

#define oil_rand_f64_u8() (oil_rand_f64_0_1()*256.0)

Evaluates to a random double-precision floating point number in the range [0, (1<<8)). Note that when rounded to the nearest integer, this exceeds the range of uint8_t.


oil_rand_f32_0_1()

#define oil_rand_f32_0_1() (rand()/(RAND_MAX+1.0))

Evaluates to a random single-precision floating point number in the range [0, 1.0).


oil_rand_f32_s32()

#define oil_rand_f32_s32() (oil_rand_f64_0_1()*4294967296.0-2147483648.0)

Evaluates to a random double-precision floating point number in the range [-(1<<31), (1<<31)). Note that when rounded to the nearest integer, this exceeds the range of int32_t.


oil_rand_f32_s16()

#define oil_rand_f32_s16() (oil_rand_f64_0_1()*65536.0-32768.0)

Evaluates to a random double-precision floating point number in the range [-(1<<15), (1<<15)). Note that when rounded to the nearest integer, this exceeds the range of int16_t.


oil_rand_f32_s8()

#define oil_rand_f32_s8() (oil_rand_f64_0_1()*256.0-128.0)

Evaluates to a random double-precision floating point number in the range [-(1<<7), (1<<7)). Note that when rounded to the nearest integer, this exceeds the range of int8_t.


oil_rand_f32_u32()

#define oil_rand_f32_u32() (oil_rand_f64_0_1()*4294967296.0)

Evaluates to a random double-precision floating point number in the range [0, (1<<32)). Note that when rounded to the nearest integer, this exceeds the range of uint32_t.


oil_rand_f32_u16()

#define oil_rand_f32_u16() (oil_rand_f64_0_1()*65536.0)

Evaluates to a random double-precision floating point number in the range [0, (1<<16)). Note that when rounded to the nearest integer, this exceeds the range of uint16_t.


oil_rand_f32_u8()

#define oil_rand_f32_u8() (oil_rand_f64_0_1()*256.0)

Evaluates to a random double-precision floating point number in the range [0, (1<<8)). Note that when rounded to the nearest integer, this exceeds the range of uint8_t.


oil_rand_s64()

#define oil_rand_s64() ((int64_t)(oil_rand_s32())<<32 | oil_rand_s32())

Evaluates to a random integer in the range [-(1<<63), (1<<63)-1].


oil_rand_u64()

#define oil_rand_u64() ((uint64_t)(oil_rand_u32())<<32 | oil_rand_u32())

Evaluates to a random integer in the range [0, (1<<64)-1].


oil_rand_rgba()

#define     oil_rand_rgba(a)

Creates a valid random RGBA value with the alpha value a. Valid input values for a are [0,255].

Evaluates to the result.

a : an alpha value