diff options
Diffstat (limited to 'vendor/crunchy/build.rs')
| -rw-r--r-- | vendor/crunchy/build.rs | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/vendor/crunchy/build.rs b/vendor/crunchy/build.rs new file mode 100644 index 0000000..b9c69ae --- /dev/null +++ b/vendor/crunchy/build.rs @@ -0,0 +1,253 @@ +use std::env; +use std::fs::File; +use std::io::Write; +use std::path::Path; + +const LOWER_LIMIT: usize = 16; + +fn main() { + let limit = if cfg!(feature="limit_2048") { + 2048 + } else if cfg!(feature="limit_1024") { + 1024 + } else if cfg!(feature="limit_512") { + 512 + } else if cfg!(feature="limit_256") { + 256 + } else if cfg!(feature="limit_128") { + 128 + } else { + 64 + }; + + let out_dir = env::var("OUT_DIR").unwrap(); + let dest_path = Path::new(&out_dir).join("lib.rs"); + let mut f = File::create(&dest_path).unwrap(); + + let mut output = String::new(); + + output.push_str(r#" +/// Unroll the given for loop +/// +/// Example: +/// +/// ```ignore +/// unroll! { +/// for i in 0..5 { +/// println!("Iteration {}", i); +/// } +/// } +/// ``` +/// +/// will expand into: +/// +/// ```ignore +/// { println!("Iteration {}", 0); } +/// { println!("Iteration {}", 1); } +/// { println!("Iteration {}", 2); } +/// { println!("Iteration {}", 3); } +/// { println!("Iteration {}", 4); } +/// ``` +#[macro_export] +macro_rules! unroll { + (for $v:ident in 0..0 $c:block) => {}; + + (for $v:ident < $max:tt in ($start:tt..$end:tt).step_by($val:expr) {$($c:tt)*}) => { + { + let step = $val; + let start = $start; + let end = start + ($end - start) / step; + unroll! { + for val < $max in start..end { + let $v: usize = ((val - start) * step) + start; + + $($c)* + } + } + } + }; + + (for $v:ident in ($start:tt..$end:tt).step_by($val:expr) {$($c:tt)*}) => { + unroll! { + for $v < $end in ($start..$end).step_by($val) {$($c)*} + } + }; + + (for $v:ident in ($start:tt..$end:tt) {$($c:tt)*}) => { + unroll!{ + for $v in $start..$end {$($c)*} + } + }; + + (for $v:ident in $start:tt..$end:tt {$($c:tt)*}) => { + #[allow(non_upper_case_globals)] + #[allow(unused_comparisons)] + { + unroll!(@$v, 0, $end, { + if $v >= $start {$($c)*} + } + ); + } + }; + + (for $v:ident < $max:tt in $start:tt..$end:tt $c:block) => { + #[allow(non_upper_case_globals)] + { + let range = $start..$end; + assert!( + $max >= range.end, + "`{}` out of range `{:?}`", + stringify!($max), + range, + ); + unroll!( + @$v, + 0, + $max, + { + if $v >= range.start && $v < range.end { + $c + } + } + ); + } + }; + + (for $v:ident in 0..$end:tt {$($statement:tt)*}) => { + #[allow(non_upper_case_globals)] + { unroll!(@$v, 0, $end, {$($statement)*}); } + }; + +"#); + + for i in 0..limit + 1 { + output.push_str(format!(" (@$v:ident, $a:expr, {}, $c:block) => {{\n", i).as_str()); + + if i <= LOWER_LIMIT { + output.push_str(format!(" {{ const $v: usize = $a; $c }}\n").as_str()); + + for a in 1..i { + output.push_str(format!(" {{ const $v: usize = $a + {}; $c }}\n", a).as_str()); + } + } else { + let half = i / 2; + + if i % 2 == 0 { + output.push_str(format!(" unroll!(@$v, $a, {0}, $c);\n", half).as_str()); + output.push_str(format!(" unroll!(@$v, $a + {0}, {0}, $c);\n", half).as_str()); + } else { + if half > 1 { + output.push_str(format!(" unroll!(@$v, $a, {}, $c);\n", i - 1).as_str()) + } + + output.push_str(format!(" {{ const $v: usize = $a + {}; $c }}\n", i - 1).as_str()); + } + } + + output.push_str(" };\n\n"); + } + + output.push_str("}\n\n"); + + output.push_str(format!(r#" +#[cfg(all(test, feature = "std"))] +mod tests {{ + #[test] + fn invalid_range() {{ + let mut a: Vec<usize> = vec![]; + unroll! {{ + for i in (5..4) {{ + a.push(i); + }} + }} + assert_eq!(a, vec![]); + }} + + #[test] + fn start_at_one_with_step() {{ + let mut a: Vec<usize> = vec![]; + unroll! {{ + for i in (2..4).step_by(1) {{ + a.push(i); + }} + }} + assert_eq!(a, vec![2, 3]); + }} + + #[test] + fn start_at_one() {{ + let mut a: Vec<usize> = vec![]; + unroll! {{ + for i in 1..4 {{ + a.push(i); + }} + }} + assert_eq!(a, vec![1, 2, 3]); + }} + + #[test] + fn test_all() {{ + {{ + let a: Vec<usize> = vec![]; + unroll! {{ + for i in 0..0 {{ + a.push(i); + }} + }} + assert_eq!(a, (0..0).collect::<Vec<usize>>()); + }} + {{ + let mut a: Vec<usize> = vec![]; + unroll! {{ + for i in 0..1 {{ + a.push(i); + }} + }} + assert_eq!(a, (0..1).collect::<Vec<usize>>()); + }} + {{ + let mut a: Vec<usize> = vec![]; + unroll! {{ + for i in 0..{0} {{ + a.push(i); + }} + }} + assert_eq!(a, (0..{0}).collect::<Vec<usize>>()); + }} + {{ + let mut a: Vec<usize> = vec![]; + let start = {0} / 4; + let end = start * 3; + unroll! {{ + for i < {0} in start..end {{ + a.push(i); + }} + }} + assert_eq!(a, (start..end).collect::<Vec<usize>>()); + }} + {{ + let mut a: Vec<usize> = vec![]; + unroll! {{ + for i in (0..{0}).step_by(2) {{ + a.push(i); + }} + }} + assert_eq!(a, (0..{0} / 2).map(|x| x * 2).collect::<Vec<usize>>()); + }} + {{ + let mut a: Vec<usize> = vec![]; + let start = {0} / 4; + let end = start * 3; + unroll! {{ + for i < {0} in (start..end).step_by(2) {{ + a.push(i); + }} + }} + assert_eq!(a, (start..end).filter(|x| x % 2 == 0).collect::<Vec<usize>>()); + }} + }} +}} +"#, limit).as_str()); + + f.write_all(output.as_bytes()).unwrap(); +} |