diff --git a/src/libstd/rand/isaac.rs b/src/libstd/rand/isaac.rs new file mode 100644 index 00000000000..d20b05db485 --- /dev/null +++ b/src/libstd/rand/isaac.rs @@ -0,0 +1,198 @@ +// Copyright 2013 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +//! The ISAAC random number generator. + +use rand::{seed, Rng}; +use iter::{Iterator, range, range_step}; +use option::{None, Some}; + +use cast; +use cmp; +use sys; +use vec; + +static RAND_SIZE_LEN: u32 = 8; +static RAND_SIZE: u32 = 1 << RAND_SIZE_LEN; + +/// A random number generator that uses the [ISAAC +/// algorithm](http://en.wikipedia.org/wiki/ISAAC_%28cipher%29). +/// +/// The ISAAC algorithm is suitable for cryptographic purposes. +pub struct IsaacRng { + priv cnt: u32, + priv rsl: [u32, .. RAND_SIZE], + priv mem: [u32, .. RAND_SIZE], + priv a: u32, + priv b: u32, + priv c: u32 +} + +impl IsaacRng { + /// Create an ISAAC random number generator with a random seed. + pub fn new() -> IsaacRng { + IsaacRng::new_seeded(seed(RAND_SIZE as uint * 4)) + } + + /// Create an ISAAC random number generator with a seed. This can be any + /// length, although the maximum number of bytes used is 1024 and any more + /// will be silently ignored. A generator constructed with a given seed + /// will generate the same sequence of values as all other generators + /// constructed with the same seed. + pub fn new_seeded(seed: &[u8]) -> IsaacRng { + let mut rng = IsaacRng { + cnt: 0, + rsl: [0, .. RAND_SIZE], + mem: [0, .. RAND_SIZE], + a: 0, b: 0, c: 0 + }; + + let array_size = sys::size_of_val(&rng.rsl); + let copy_length = cmp::min(array_size, seed.len()); + + // manually create a &mut [u8] slice of randrsl to copy into. + let dest = unsafe { cast::transmute((&mut rng.rsl, array_size)) }; + vec::bytes::copy_memory(dest, seed, copy_length); + rng.init(true); + rng + } + + /// Create an ISAAC random number generator using the default + /// fixed seed. + pub fn new_unseeded() -> IsaacRng { + let mut rng = IsaacRng { + cnt: 0, + rsl: [0, .. RAND_SIZE], + mem: [0, .. RAND_SIZE], + a: 0, b: 0, c: 0 + }; + rng.init(false); + rng + } + + /// Initialises `self`. If `use_rsl` is true, then use the current value + /// of `rsl` as a seed, otherwise construct one algorithmically (not + /// randomly). + fn init(&mut self, use_rsl: bool) { + let mut a = 0x9e3779b9; + let mut b = a; + let mut c = a; + let mut d = a; + let mut e = a; + let mut f = a; + let mut g = a; + let mut h = a; + + macro_rules! mix( + () => {{ + a^=b<<11; d+=a; b+=c; + b^=c>>2; e+=b; c+=d; + c^=d<<8; f+=c; d+=e; + d^=e>>16; g+=d; e+=f; + e^=f<<10; h+=e; f+=g; + f^=g>>4; a+=f; g+=h; + g^=h<<8; b+=g; h+=a; + h^=a>>9; c+=h; a+=b; + }} + ); + + do 4.times { mix!(); } + + if use_rsl { + macro_rules! memloop ( + ($arr:expr) => {{ + for i in range_step(0u32, RAND_SIZE, 8) { + a+=$arr[i ]; b+=$arr[i+1]; + c+=$arr[i+2]; d+=$arr[i+3]; + e+=$arr[i+4]; f+=$arr[i+5]; + g+=$arr[i+6]; h+=$arr[i+7]; + mix!(); + self.mem[i ]=a; self.mem[i+1]=b; + self.mem[i+2]=c; self.mem[i+3]=d; + self.mem[i+4]=e; self.mem[i+5]=f; + self.mem[i+6]=g; self.mem[i+7]=h; + } + }} + ); + + memloop!(self.rsl); + memloop!(self.mem); + } else { + for i in range_step(0u32, RAND_SIZE, 8) { + mix!(); + self.mem[i ]=a; self.mem[i+1]=b; + self.mem[i+2]=c; self.mem[i+3]=d; + self.mem[i+4]=e; self.mem[i+5]=f; + self.mem[i+6]=g; self.mem[i+7]=h; + } + } + + self.isaac(); + } + + /// Refills the output buffer (`self.rsl`) + #[inline] + fn isaac(&mut self) { + self.c += 1; + // abbreviations + let mut a = self.a; + let mut b = self.b + self.c; + + static MIDPOINT: uint = RAND_SIZE as uint / 2; + + macro_rules! ind (($x:expr) => { + self.mem[($x >> 2) & (RAND_SIZE - 1)] + }); + macro_rules! rngstep( + ($j:expr, $shift:expr) => {{ + let base = $j; + let mix = if $shift < 0 { + a >> -$shift as uint + } else { + a << $shift as uint + }; + + let x = self.mem[base + mr_offset]; + a = (a ^ mix) + self.mem[base + m2_offset]; + let y = ind!(x) + a + b; + self.mem[base + mr_offset] = y; + + b = ind!(y >> RAND_SIZE_LEN) + x; + self.rsl[base + mr_offset] = b; + }} + ); + + let r = [(0, MIDPOINT), (MIDPOINT, 0)]; + for &(mr_offset, m2_offset) in r.iter() { + for i in range_step(0u, MIDPOINT, 4) { + rngstep!(i + 0, 13); + rngstep!(i + 1, -6); + rngstep!(i + 2, 2); + rngstep!(i + 3, -16); + } + } + + self.a = a; + self.b = b; + self.cnt = RAND_SIZE; + } +} + +impl Rng for IsaacRng { + #[inline] + fn next(&mut self) -> u32 { + if self.cnt == 0 { + // make some more numbers + self.isaac(); + } + self.cnt -= 1; + self.rsl[self.cnt] + } +} diff --git a/src/libstd/rand/mod.rs b/src/libstd/rand/mod.rs index 70bcb0f7170..3348f5ee7f7 100644 --- a/src/libstd/rand/mod.rs +++ b/src/libstd/rand/mod.rs @@ -58,7 +58,10 @@ use uint; use vec; use libc::size_t; +pub use self::isaac::IsaacRng; + pub mod distributions; +pub mod isaac; /// A type that can be randomly generated using an Rng pub trait Rand { @@ -576,184 +579,6 @@ pub fn weak_rng() -> XorShiftRng { XorShiftRng::new() } -static RAND_SIZE_LEN: u32 = 8; -static RAND_SIZE: u32 = 1 << RAND_SIZE_LEN; - -/// A random number generator that uses the [ISAAC -/// algorithm](http://en.wikipedia.org/wiki/ISAAC_%28cipher%29). -/// -/// The ISAAC algorithm is suitable for cryptographic purposes. -pub struct IsaacRng { - priv cnt: u32, - priv rsl: [u32, .. RAND_SIZE], - priv mem: [u32, .. RAND_SIZE], - priv a: u32, - priv b: u32, - priv c: u32 -} - -impl IsaacRng { - /// Create an ISAAC random number generator with a random seed. - pub fn new() -> IsaacRng { - IsaacRng::new_seeded(seed()) - } - - /// Create an ISAAC random number generator with a seed. This can be any - /// length, although the maximum number of bytes used is 1024 and any more - /// will be silently ignored. A generator constructed with a given seed - /// will generate the same sequence of values as all other generators - /// constructed with the same seed. - pub fn new_seeded(seed: &[u8]) -> IsaacRng { - let mut rng = IsaacRng { - cnt: 0, - rsl: [0, .. RAND_SIZE], - mem: [0, .. RAND_SIZE], - a: 0, b: 0, c: 0 - }; - - let array_size = sys::size_of_val(&rng.rsl); - let copy_length = cmp::min(array_size, seed.len()); - - // manually create a &mut [u8] slice of randrsl to copy into. - let dest = unsafe { cast::transmute((&mut rng.rsl, array_size)) }; - vec::bytes::copy_memory(dest, seed, copy_length); - rng.init(true); - rng - } - - /// Create an ISAAC random number generator using the default - /// fixed seed. - pub fn new_unseeded() -> IsaacRng { - let mut rng = IsaacRng { - cnt: 0, - rsl: [0, .. RAND_SIZE], - mem: [0, .. RAND_SIZE], - a: 0, b: 0, c: 0 - }; - rng.init(false); - rng - } - - /// Initialises `self`. If `use_rsl` is true, then use the current value - /// of `rsl` as a seed, otherwise construct one algorithmically (not - /// randomly). - fn init(&mut self, use_rsl: bool) { - let mut a = 0x9e3779b9; - let mut b = a; - let mut c = a; - let mut d = a; - let mut e = a; - let mut f = a; - let mut g = a; - let mut h = a; - - macro_rules! mix( - () => {{ - a^=b<<11; d+=a; b+=c; - b^=c>>2; e+=b; c+=d; - c^=d<<8; f+=c; d+=e; - d^=e>>16; g+=d; e+=f; - e^=f<<10; h+=e; f+=g; - f^=g>>4; a+=f; g+=h; - g^=h<<8; b+=g; h+=a; - h^=a>>9; c+=h; a+=b; - }} - ); - - do 4.times { mix!(); } - - if use_rsl { - macro_rules! memloop ( - ($arr:expr) => {{ - for i in range_step(0u32, RAND_SIZE, 8) { - a+=$arr[i ]; b+=$arr[i+1]; - c+=$arr[i+2]; d+=$arr[i+3]; - e+=$arr[i+4]; f+=$arr[i+5]; - g+=$arr[i+6]; h+=$arr[i+7]; - mix!(); - self.mem[i ]=a; self.mem[i+1]=b; - self.mem[i+2]=c; self.mem[i+3]=d; - self.mem[i+4]=e; self.mem[i+5]=f; - self.mem[i+6]=g; self.mem[i+7]=h; - } - }} - ); - - memloop!(self.rsl); - memloop!(self.mem); - } else { - for i in range_step(0u32, RAND_SIZE, 8) { - mix!(); - self.mem[i ]=a; self.mem[i+1]=b; - self.mem[i+2]=c; self.mem[i+3]=d; - self.mem[i+4]=e; self.mem[i+5]=f; - self.mem[i+6]=g; self.mem[i+7]=h; - } - } - - self.isaac(); - } - - /// Refills the output buffer (`self.rsl`) - #[inline] - fn isaac(&mut self) { - self.c += 1; - // abbreviations - let mut a = self.a; - let mut b = self.b + self.c; - - static MIDPOINT: uint = RAND_SIZE as uint / 2; - - macro_rules! ind (($x:expr) => { - self.mem[($x >> 2) & (RAND_SIZE - 1)] - }); - macro_rules! rngstep( - ($j:expr, $shift:expr) => {{ - let base = $j; - let mix = if $shift < 0 { - a >> -$shift as uint - } else { - a << $shift as uint - }; - - let x = self.mem[base + mr_offset]; - a = (a ^ mix) + self.mem[base + m2_offset]; - let y = ind!(x) + a + b; - self.mem[base + mr_offset] = y; - - b = ind!(y >> RAND_SIZE_LEN) + x; - self.rsl[base + mr_offset] = b; - }} - ); - - let r = [(0, MIDPOINT), (MIDPOINT, 0)]; - for &(mr_offset, m2_offset) in r.iter() { - for i in range_step(0u, MIDPOINT, 4) { - rngstep!(i + 0, 13); - rngstep!(i + 1, -6); - rngstep!(i + 2, 2); - rngstep!(i + 3, -16); - } - } - - self.a = a; - self.b = b; - self.cnt = RAND_SIZE; - } -} - -impl Rng for IsaacRng { - #[inline] - fn next(&mut self) -> u32 { - if self.cnt == 0 { - // make some more numbers - self.isaac(); - } - self.cnt -= 1; - self.rsl[self.cnt] - } -} - /// An [Xorshift random number /// generator](http://en.wikipedia.org/wiki/Xorshift). /// @@ -786,7 +611,8 @@ impl XorShiftRng { pub fn new() -> XorShiftRng { #[fixed_stack_segment]; #[inline(never)]; - // generate seeds the same way as seed(), except we have a spceific size + // generate seeds the same way as seed(), except we have a + // specific size, so we can just use a fixed buffer. let mut s = [0u8, ..16]; loop { do s.as_mut_buf |p, sz| { @@ -817,12 +643,11 @@ impl XorShiftRng { } } -/// Create a new random seed. -pub fn seed() -> ~[u8] { +/// Create a new random seed of length `n`. +pub fn seed(n: uint) -> ~[u8] { #[fixed_stack_segment]; #[inline(never)]; unsafe { - let n = RAND_SIZE * 4; let mut s = vec::from_elem(n as uint, 0_u8); do s.as_mut_buf |p, sz| { rustrt::rand_gen_seed(p, sz as size_t) @@ -844,7 +669,7 @@ pub fn task_rng() -> @mut IsaacRng { let r = local_data::get(tls_rng_state, |k| k.map(|&k| *k)); match r { None => { - let rng = @@mut IsaacRng::new_seeded(seed()); + let rng = @@mut IsaacRng::new(); local_data::set(tls_rng_state, rng); *rng } @@ -877,7 +702,7 @@ mod test { #[test] fn test_rng_seeded() { - let seed = seed(); + let seed = seed(400); let mut ra = IsaacRng::new_seeded(seed); let mut rb = IsaacRng::new_seeded(seed); assert_eq!(ra.gen_ascii_str(100u), rb.gen_ascii_str(100u));