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@DanielKeep
Created July 22, 2017 13:45
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unroll macro
#!/usr/bin/env python3
import sys
if len(sys.argv) != 2:
print('Usage: gen-code.py LIMIT')
sys.exit(1)
LIMIT = int(sys.argv[1])
print(
r'''#[macro_export]
macro_rules! unroll {
(for $v:ident in 0..0 $c:block) => {};
(for $v:ident in 0..$b:tt {$($c:tt)*}) => {
#[allow(non_upper_case_globals)] { unroll!(@$v, 0, $b, {$($c)*}); }
};''')
for i in range(1, LIMIT + 1):
print(
r''' (@$v:ident, $a:expr, %d, $c:block) => {''' % i)
limit = i
if limit <= 16:
for a in [''] + list(' + %d' % x for x in range(1, limit)):
print(
r''' { const $v: usize = $a%s; $c }''' % a)
else:
half = limit // 2
if 2*half == limit:
for a in ('', ' + %d' % half):
print(
r''' unroll!(@$v, $a%s, %d, $c);''' % (a, half))
else:
if half > 1:
print(
r''' unroll!(@$v, $a, %d, $c);''' % (limit - 1))
print(
r''' { const $v: usize = $a + %d; $c }''' % (limit - 1))
print(
r''' };''')
print(
r'''}''')
print(
r'''
#[test]
fn test() {
{
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..%d {
a.push(i);
}
}
assert_eq!(a, (0..%d).collect::<Vec<usize>>());
}
}
''' % (LIMIT, LIMIT))
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