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</pre><pre class='rust '>
<span class='comment'>// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT</span>
<span class='comment'>// file at the top-level directory of this distribution and at</span>
<span class='comment'>// http://rust-lang.org/COPYRIGHT.</span>
<span class='comment'>//</span>
<span class='comment'>// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span>
<span class='comment'>// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span>
<span class='comment'>// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your</span>
<span class='comment'>// option. This file may not be copied, modified, or distributed</span>
<span class='comment'>// except according to those terms.</span>
<span class='doccomment'>//! The implementations of `Rand` for the built-in types.</span>
<span class='kw'>use</span> <span class='ident'>std</span>::<span class='ident'>char</span>;
<span class='kw'>use</span> <span class='ident'>std</span>::<span class='ident'>mem</span>;
<span class='kw'>use</span> {<span class='ident'>Rand</span>,<span class='ident'>Rng</span>};
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>isize</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>isize</span> {
<span class='kw'>if</span> <span class='ident'>mem</span>::<span class='ident'>size_of</span>::<span class='op'><</span><span class='ident'>isize</span><span class='op'>></span>() <span class='op'>==</span> <span class='number'>4</span> {
<span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>i32</span><span class='op'>></span>() <span class='kw'>as</span> <span class='ident'>isize</span>
} <span class='kw'>else</span> {
<span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>i64</span><span class='op'>></span>() <span class='kw'>as</span> <span class='ident'>isize</span>
}
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>i8</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>i8</span> {
<span class='ident'>rng</span>.<span class='ident'>next_u32</span>() <span class='kw'>as</span> <span class='ident'>i8</span>
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>i16</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>i16</span> {
<span class='ident'>rng</span>.<span class='ident'>next_u32</span>() <span class='kw'>as</span> <span class='ident'>i16</span>
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>i32</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>i32</span> {
<span class='ident'>rng</span>.<span class='ident'>next_u32</span>() <span class='kw'>as</span> <span class='ident'>i32</span>
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>i64</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>i64</span> {
<span class='ident'>rng</span>.<span class='ident'>next_u64</span>() <span class='kw'>as</span> <span class='ident'>i64</span>
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>usize</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>usize</span> {
<span class='kw'>if</span> <span class='ident'>mem</span>::<span class='ident'>size_of</span>::<span class='op'><</span><span class='ident'>usize</span><span class='op'>></span>() <span class='op'>==</span> <span class='number'>4</span> {
<span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>u32</span><span class='op'>></span>() <span class='kw'>as</span> <span class='ident'>usize</span>
} <span class='kw'>else</span> {
<span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>u64</span><span class='op'>></span>() <span class='kw'>as</span> <span class='ident'>usize</span>
}
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>u8</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>u8</span> {
<span class='ident'>rng</span>.<span class='ident'>next_u32</span>() <span class='kw'>as</span> <span class='ident'>u8</span>
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>u16</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>u16</span> {
<span class='ident'>rng</span>.<span class='ident'>next_u32</span>() <span class='kw'>as</span> <span class='ident'>u16</span>
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>u32</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>u32</span> {
<span class='ident'>rng</span>.<span class='ident'>next_u32</span>()
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>u64</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>u64</span> {
<span class='ident'>rng</span>.<span class='ident'>next_u64</span>()
}
}
<span class='macro'>macro_rules</span><span class='macro'>!</span> <span class='ident'>float_impls</span> {
(<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>mod_name</span>:<span class='ident'>ident</span>, <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span>:<span class='ident'>ty</span>, <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>mantissa_bits</span>:<span class='ident'>expr</span>, <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>method_name</span>:<span class='ident'>ident</span>) <span class='op'>=></span> {
<span class='kw'>mod</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>mod_name</span> {
<span class='kw'>use</span> {<span class='ident'>Rand</span>, <span class='ident'>Rng</span>, <span class='ident'>Open01</span>, <span class='ident'>Closed01</span>};
<span class='kw'>const</span> <span class='ident'>SCALE</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span> <span class='op'>=</span> (<span class='number'>1u64</span> <span class='op'><<</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>mantissa_bits</span>) <span class='kw'>as</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span>;
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span> {
<span class='doccomment'>/// Generate a floating point number in the half-open</span>
<span class='doccomment'>/// interval `[0,1)`.</span>
<span class='doccomment'>///</span>
<span class='doccomment'>/// See `Closed01` for the closed interval `[0,1]`,</span>
<span class='doccomment'>/// and `Open01` for the open interval `(0,1)`.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span> {
<span class='ident'>rng</span>.<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>method_name</span>()
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>Open01</span><span class='op'><</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span><span class='op'>></span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>Open01</span><span class='op'><</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span><span class='op'>></span> {
<span class='comment'>// add a small amount (specifically 2 bits below</span>
<span class='comment'>// the precision of f64/f32 at 1.0), so that small</span>
<span class='comment'>// numbers are larger than 0, but large numbers</span>
<span class='comment'>// aren't pushed to/above 1.</span>
<span class='ident'>Open01</span>(<span class='ident'>rng</span>.<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>method_name</span>() <span class='op'>+</span> <span class='number'>0.25</span> <span class='op'>/</span> <span class='ident'>SCALE</span>)
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>Closed01</span><span class='op'><</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span><span class='op'>></span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>Closed01</span><span class='op'><</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ty</span><span class='op'>></span> {
<span class='comment'>// rescale so that 1.0 - epsilon becomes 1.0</span>
<span class='comment'>// precisely.</span>
<span class='ident'>Closed01</span>(<span class='ident'>rng</span>.<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>method_name</span>() <span class='op'>*</span> <span class='ident'>SCALE</span> <span class='op'>/</span> (<span class='ident'>SCALE</span> <span class='op'>-</span> <span class='number'>1.0</span>))
}
}
}
}
}
<span class='macro'>float_impls</span><span class='macro'>!</span> { <span class='ident'>f64_rand_impls</span>, <span class='ident'>f64</span>, <span class='number'>53</span>, <span class='ident'>next_f64</span> }
<span class='macro'>float_impls</span><span class='macro'>!</span> { <span class='ident'>f32_rand_impls</span>, <span class='ident'>f32</span>, <span class='number'>24</span>, <span class='ident'>next_f32</span> }
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>char</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>char</span> {
<span class='comment'>// a char is 21 bits</span>
<span class='kw'>const</span> <span class='ident'>CHAR_MASK</span>: <span class='ident'>u32</span> <span class='op'>=</span> <span class='number'>0x001f_ffff</span>;
<span class='kw'>loop</span> {
<span class='comment'>// Rejection sampling. About 0.2% of numbers with at most</span>
<span class='comment'>// 21-bits are invalid codepoints (surrogates), so this</span>
<span class='comment'>// will succeed first go almost every time.</span>
<span class='kw'>match</span> <span class='ident'>char</span>::<span class='ident'>from_u32</span>(<span class='ident'>rng</span>.<span class='ident'>next_u32</span>() <span class='op'>&</span> <span class='ident'>CHAR_MASK</span>) {
<span class='prelude-val'>Some</span>(<span class='ident'>c</span>) <span class='op'>=></span> <span class='kw'>return</span> <span class='ident'>c</span>,
<span class='prelude-val'>None</span> <span class='op'>=></span> {}
}
}
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='ident'>bool</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='ident'>bool</span> {
<span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>u8</span><span class='op'>></span>() <span class='op'>&</span> <span class='number'>1</span> <span class='op'>==</span> <span class='number'>1</span>
}
}
<span class='macro'>macro_rules</span><span class='macro'>!</span> <span class='ident'>tuple_impl</span> {
<span class='comment'>// use variables to indicate the arity of the tuple</span>
($(<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>tyvar</span>:<span class='ident'>ident</span>),<span class='op'>*</span> ) <span class='op'>=></span> {
<span class='comment'>// the trailing commas are for the 1 tuple</span>
<span class='kw'>impl</span><span class='op'><</span>
$( <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>tyvar</span> : <span class='ident'>Rand</span> ),<span class='op'>*</span>
<span class='op'>></span> <span class='ident'>Rand</span> <span class='kw'>for</span> ( $( <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>tyvar</span> ),<span class='op'>*</span> , ) {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>_rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> ( $( <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>tyvar</span> ),<span class='op'>*</span> , ) {
(
<span class='comment'>// use the $tyvar's to get the appropriate number of</span>
<span class='comment'>// repeats (they're not actually needed)</span>
$(
<span class='ident'>_rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>tyvar</span><span class='op'>></span>()
),<span class='op'>*</span>
,
)
}
}
}
}
<span class='kw'>impl</span> <span class='ident'>Rand</span> <span class='kw'>for</span> () {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(_: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> () { () }
}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>, <span class='ident'>E</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>, <span class='ident'>E</span>, <span class='ident'>F</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>, <span class='ident'>E</span>, <span class='ident'>F</span>, <span class='ident'>G</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>, <span class='ident'>E</span>, <span class='ident'>F</span>, <span class='ident'>G</span>, <span class='ident'>H</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>, <span class='ident'>E</span>, <span class='ident'>F</span>, <span class='ident'>G</span>, <span class='ident'>H</span>, <span class='ident'>I</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>, <span class='ident'>E</span>, <span class='ident'>F</span>, <span class='ident'>G</span>, <span class='ident'>H</span>, <span class='ident'>I</span>, <span class='ident'>J</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>, <span class='ident'>E</span>, <span class='ident'>F</span>, <span class='ident'>G</span>, <span class='ident'>H</span>, <span class='ident'>I</span>, <span class='ident'>J</span>, <span class='ident'>K</span>}
<span class='macro'>tuple_impl</span><span class='macro'>!</span>{<span class='ident'>A</span>, <span class='ident'>B</span>, <span class='ident'>C</span>, <span class='ident'>D</span>, <span class='ident'>E</span>, <span class='ident'>F</span>, <span class='ident'>G</span>, <span class='ident'>H</span>, <span class='ident'>I</span>, <span class='ident'>J</span>, <span class='ident'>K</span>, <span class='ident'>L</span>}
<span class='macro'>macro_rules</span><span class='macro'>!</span> <span class='ident'>array_impl</span> {
{<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>n</span>:<span class='ident'>expr</span>, <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>t</span>:<span class='ident'>ident</span>, $(<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ts</span>:<span class='ident'>ident</span>,)<span class='kw-2'>*</span>} <span class='op'>=></span> {
<span class='macro'>array_impl</span><span class='macro'>!</span>{(<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>n</span> <span class='op'>-</span> <span class='number'>1</span>), $(<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ts</span>,)<span class='kw-2'>*</span>}
<span class='kw'>impl</span><span class='op'><</span><span class='ident'>T</span><span class='op'>></span> <span class='ident'>Rand</span> <span class='kw'>for</span> [<span class='ident'>T</span>; <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>n</span>] <span class='kw'>where</span> <span class='ident'>T</span>: <span class='ident'>Rand</span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>_rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> [<span class='ident'>T</span>; <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>n</span>] {
[<span class='ident'>_rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>t</span><span class='op'>></span>(), $(<span class='ident'>_rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>ts</span><span class='op'>></span>()),<span class='kw-2'>*</span>]
}
}
};
{<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>n</span>:<span class='ident'>expr</span>,} <span class='op'>=></span> {
<span class='kw'>impl</span><span class='op'><</span><span class='ident'>T</span><span class='op'>></span> <span class='ident'>Rand</span> <span class='kw'>for</span> [<span class='ident'>T</span>; <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>n</span>] {
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>_rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> [<span class='ident'>T</span>; <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>n</span>] { [] }
}
};
}
<span class='macro'>array_impl</span><span class='macro'>!</span>{<span class='number'>32</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>, <span class='ident'>T</span>,}
<span class='kw'>impl</span><span class='op'><</span><span class='ident'>T</span>:<span class='ident'>Rand</span><span class='op'>></span> <span class='ident'>Rand</span> <span class='kw'>for</span> <span class='prelude-ty'>Option</span><span class='op'><</span><span class='ident'>T</span><span class='op'>></span> {
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand</span><span class='op'><</span><span class='ident'>R</span>: <span class='ident'>Rng</span><span class='op'>></span>(<span class='ident'>rng</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>R</span>) <span class='op'>-></span> <span class='prelude-ty'>Option</span><span class='op'><</span><span class='ident'>T</span><span class='op'>></span> {
<span class='kw'>if</span> <span class='ident'>rng</span>.<span class='ident'>gen</span>() {
<span class='prelude-val'>Some</span>(<span class='ident'>rng</span>.<span class='ident'>gen</span>())
} <span class='kw'>else</span> {
<span class='prelude-val'>None</span>
}
}
}
<span class='attribute'>#[<span class='ident'>cfg</span>(<span class='ident'>test</span>)]</span>
<span class='kw'>mod</span> <span class='ident'>tests</span> {
<span class='kw'>use</span> {<span class='ident'>Rng</span>, <span class='ident'>thread_rng</span>, <span class='ident'>Open01</span>, <span class='ident'>Closed01</span>};
<span class='kw'>struct</span> <span class='ident'>ConstantRng</span>(<span class='ident'>u64</span>);
<span class='kw'>impl</span> <span class='ident'>Rng</span> <span class='kw'>for</span> <span class='ident'>ConstantRng</span> {
<span class='kw'>fn</span> <span class='ident'>next_u32</span>(<span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='self'>self</span>) <span class='op'>-></span> <span class='ident'>u32</span> {
<span class='kw'>let</span> <span class='ident'>ConstantRng</span>(<span class='ident'>v</span>) <span class='op'>=</span> <span class='kw-2'>*</span><span class='self'>self</span>;
<span class='ident'>v</span> <span class='kw'>as</span> <span class='ident'>u32</span>
}
<span class='kw'>fn</span> <span class='ident'>next_u64</span>(<span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='self'>self</span>) <span class='op'>-></span> <span class='ident'>u64</span> {
<span class='kw'>let</span> <span class='ident'>ConstantRng</span>(<span class='ident'>v</span>) <span class='op'>=</span> <span class='kw-2'>*</span><span class='self'>self</span>;
<span class='ident'>v</span>
}
}
<span class='attribute'>#[<span class='ident'>test</span>]</span>
<span class='kw'>fn</span> <span class='ident'>floating_point_edge_cases</span>() {
<span class='comment'>// the test for exact equality is correct here.</span>
<span class='macro'>assert</span><span class='macro'>!</span>(<span class='ident'>ConstantRng</span>(<span class='number'>0xffff_ffff</span>).<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>f32</span><span class='op'>></span>() <span class='op'>!=</span> <span class='number'>1.0</span>);
<span class='macro'>assert</span><span class='macro'>!</span>(<span class='ident'>ConstantRng</span>(<span class='number'>0xffff_ffff_ffff_ffff</span>).<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>f64</span><span class='op'>></span>() <span class='op'>!=</span> <span class='number'>1.0</span>);
}
<span class='attribute'>#[<span class='ident'>test</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand_open</span>() {
<span class='comment'>// this is unlikely to catch an incorrect implementation that</span>
<span class='comment'>// generates exactly 0 or 1, but it keeps it sane.</span>
<span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>rng</span> <span class='op'>=</span> <span class='ident'>thread_rng</span>();
<span class='kw'>for</span> _ <span class='kw'>in</span> <span class='number'>0</span>..<span class='number'>1_000</span> {
<span class='comment'>// strict inequalities</span>
<span class='kw'>let</span> <span class='ident'>Open01</span>(<span class='ident'>f</span>) <span class='op'>=</span> <span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>Open01</span><span class='op'><</span><span class='ident'>f64</span><span class='op'>>></span>();
<span class='macro'>assert</span><span class='macro'>!</span>(<span class='number'>0.0</span> <span class='op'><</span> <span class='ident'>f</span> <span class='op'>&&</span> <span class='ident'>f</span> <span class='op'><</span> <span class='number'>1.0</span>);
<span class='kw'>let</span> <span class='ident'>Open01</span>(<span class='ident'>f</span>) <span class='op'>=</span> <span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>Open01</span><span class='op'><</span><span class='ident'>f32</span><span class='op'>>></span>();
<span class='macro'>assert</span><span class='macro'>!</span>(<span class='number'>0.0</span> <span class='op'><</span> <span class='ident'>f</span> <span class='op'>&&</span> <span class='ident'>f</span> <span class='op'><</span> <span class='number'>1.0</span>);
}
}
<span class='attribute'>#[<span class='ident'>test</span>]</span>
<span class='kw'>fn</span> <span class='ident'>rand_closed</span>() {
<span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>rng</span> <span class='op'>=</span> <span class='ident'>thread_rng</span>();
<span class='kw'>for</span> _ <span class='kw'>in</span> <span class='number'>0</span>..<span class='number'>1_000</span> {
<span class='comment'>// strict inequalities</span>
<span class='kw'>let</span> <span class='ident'>Closed01</span>(<span class='ident'>f</span>) <span class='op'>=</span> <span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>Closed01</span><span class='op'><</span><span class='ident'>f64</span><span class='op'>>></span>();
<span class='macro'>assert</span><span class='macro'>!</span>(<span class='number'>0.0</span> <span class='op'><=</span> <span class='ident'>f</span> <span class='op'>&&</span> <span class='ident'>f</span> <span class='op'><=</span> <span class='number'>1.0</span>);
<span class='kw'>let</span> <span class='ident'>Closed01</span>(<span class='ident'>f</span>) <span class='op'>=</span> <span class='ident'>rng</span>.<span class='ident'>gen</span>::<span class='op'><</span><span class='ident'>Closed01</span><span class='op'><</span><span class='ident'>f32</span><span class='op'>>></span>();
<span class='macro'>assert</span><span class='macro'>!</span>(<span class='number'>0.0</span> <span class='op'><=</span> <span class='ident'>f</span> <span class='op'>&&</span> <span class='ident'>f</span> <span class='op'><=</span> <span class='number'>1.0</span>);
}
}
}
</pre>
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