From: Kevin Ballard Date: Wed, 7 Aug 2013 05:34:22 +0000 (-0700) Subject: Implement DoubleEndedIterator on Range X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=8964fcc5ac9cefcc55ea071142c3c81d623a52be;p=rust.git Implement DoubleEndedIterator on Range Range is now invertable as long as its element type conforms to Integer. Remove int::range_rev() et al in favor of range().invert(). --- diff --git a/src/libstd/iterator.rs b/src/libstd/iterator.rs index 29f54bd10fb..d10a5541e41 100644 --- a/src/libstd/iterator.rs +++ b/src/libstd/iterator.rs @@ -18,9 +18,9 @@ */ use cmp; -use num::{Zero, One, Saturating}; +use num::{Zero, One, Integer, Saturating}; use option::{Option, Some, None}; -use ops::{Add, Mul}; +use ops::{Add, Mul, Sub}; use cmp::Ord; use clone::Clone; use uint; @@ -1531,7 +1531,7 @@ pub fn range + Ord + Clone + One>(start: A, stop: A) -> Range { Range{state: start, stop: stop, one: One::one()} } -impl + Ord + Clone + One> Iterator for Range { +impl + Ord + Clone> Iterator for Range { #[inline] fn next(&mut self) -> Option { if self.state < self.stop { @@ -1544,6 +1544,22 @@ fn next(&mut self) -> Option { } } +impl + Integer + Ord + Clone> DoubleEndedIterator for Range { + #[inline] + fn next_back(&mut self) -> Option { + if self.stop > self.state { + // Integer doesn't technically define this rule, but we're going to assume that every + // Integer is reachable from every other one by adding or subtracting enough Ones. This + // seems like a reasonable-enough rule that every Integer should conform to, even if it + // can't be statically checked. + self.stop = self.stop - self.one; + Some(self.stop.clone()) + } else { + None + } + } +} + impl + Clone> Iterator for Counter { #[inline] fn next(&mut self) -> Option { @@ -2121,4 +2137,17 @@ fn test_random_access_cycle() { check_randacc_iter(xs.iter().cycle().take_(27), 27); check_randacc_iter(empty.iter().cycle(), 0); } + + #[test] + fn test_double_ended_range() { + assert_eq!(range(11i, 14).invert().collect::<~[int]>(), ~[13i, 12, 11]); + for _ in range(10i, 0).invert() { + fail!("unreachable"); + } + + assert_eq!(range(11u, 14).invert().collect::<~[uint]>(), ~[13u, 12, 11]); + for _ in range(10u, 0).invert() { + fail!("unreachable"); + } + } } diff --git a/src/libstd/num/int_macros.rs b/src/libstd/num/int_macros.rs index 9842a570d7e..b692bedebfd 100644 --- a/src/libstd/num/int_macros.rs +++ b/src/libstd/num/int_macros.rs @@ -124,14 +124,6 @@ pub fn range_step_inclusive(start: $T, last: $T, step: $T, it: &fn($T) -> bool) range_step_core(start, last, step, Closed, it) } - -#[inline] -/// Iterate over the range (`hi`..`lo`] -pub fn range_rev(hi: $T, lo: $T, it: &fn($T) -> bool) -> bool { - if hi == min_value { return true; } - range_step_inclusive(hi-1, lo, -1 as $T, it) -} - impl Num for $T {} #[cfg(not(test))] @@ -889,10 +881,6 @@ fn test_int_from_str_overflow() { fn test_ranges() { let mut l = ~[]; - do range_rev(14,11) |i| { - l.push(i); - true - }; do range_step(20,26,2) |i| { l.push(i); true @@ -917,8 +905,7 @@ fn test_ranges() { l.push(i); true }; - assert_eq!(l, ~[13,12,11, - 20,22,24, + assert_eq!(l, ~[20,22,24, 36,34,32, max_value-2, max_value-3,max_value-1, @@ -926,9 +913,6 @@ fn test_ranges() { min_value+3,min_value+1]); // None of the `fail`s should execute. - do range_rev(0,10) |_i| { - fail!(~"unreachable"); - }; do range_step(10,0,1) |_i| { fail!(~"unreachable"); }; diff --git a/src/libstd/num/uint_macros.rs b/src/libstd/num/uint_macros.rs index a2874c96703..29b8f29d87d 100644 --- a/src/libstd/num/uint_macros.rs +++ b/src/libstd/num/uint_macros.rs @@ -125,13 +125,6 @@ pub fn range_step_inclusive(start: $T, last: $T, step: $T_SIGNED, it: &fn($T) -> range_step_core(start, last, step, Closed, it) } -#[inline] -/// Iterate over the range (`hi`..`lo`] -pub fn range_rev(hi: $T, lo: $T, it: &fn($T) -> bool) -> bool { - if hi == min_value { return true; } - range_step_inclusive(hi-1, lo, -1 as $T_SIGNED, it) -} - impl Num for $T {} #[cfg(not(test))] @@ -654,10 +647,6 @@ pub fn to_str_radix37() { pub fn test_ranges() { let mut l = ~[]; - do range_rev(14,11) |i| { - l.push(i); - true - }; do range_step(20,26,2) |i| { l.push(i); true @@ -683,8 +672,7 @@ pub fn test_ranges() { true }; - assert_eq!(l, ~[13,12,11, - 20,22,24, + assert_eq!(l, ~[20,22,24, 36,34,32, max_value-2, max_value-3,max_value-1, @@ -692,9 +680,6 @@ pub fn test_ranges() { min_value+3,min_value+1]); // None of the `fail`s should execute. - do range_rev(0,0) |_i| { - fail!("unreachable"); - }; do range_step(10,0,1) |_i| { fail!("unreachable"); }; diff --git a/src/libstd/run.rs b/src/libstd/run.rs index ef3d881c5fe..694aa672af7 100644 --- a/src/libstd/run.rs +++ b/src/libstd/run.rs @@ -632,7 +632,6 @@ fn spawn_process_os(prog: &str, args: &[~str], use libc::funcs::posix88::unistd::{fork, dup2, close, chdir, execvp}; use libc::funcs::bsd44::getdtablesize; - use int; mod rustrt { use libc::c_void; @@ -665,10 +664,9 @@ mod rustrt { fail!("failure in dup3(err_fd, 2): %s", os::last_os_error()); } // close all other fds - do int::range_rev(getdtablesize() as int, 3) |fd| { + for fd in range(3, getdtablesize()).invert() { close(fd as c_int); - true - }; + } do with_dirp(dir) |dirp| { if !dirp.is_null() && chdir(dirp) == -1 { diff --git a/src/libstd/trie.rs b/src/libstd/trie.rs index a5efae542a1..5ef5526e516 100644 --- a/src/libstd/trie.rs +++ b/src/libstd/trie.rs @@ -282,13 +282,14 @@ fn each<'a>(&'a self, f: &fn(&uint, &'a T) -> bool) -> bool { } fn each_reverse<'a>(&'a self, f: &fn(&uint, &'a T) -> bool) -> bool { - do uint::range_rev(self.children.len(), 0) |idx| { - match self.children[idx] { - Internal(ref x) => x.each_reverse(|i,t| f(i,t)), - External(k, ref v) => f(&k, v), - Nothing => true + for elt in self.children.rev_iter() { + match *elt { + Internal(ref x) => if !x.each_reverse(|i,t| f(i,t)) { return false }, + External(k, ref v) => if !f(&k, v) { return false }, + Nothing => () } } + true } fn mutate_values<'a>(&'a mut self, f: &fn(&uint, &mut T) -> bool) -> bool { @@ -539,10 +540,9 @@ fn test_each() { fn test_each_break() { let mut m = TrieMap::new(); - do uint::range_rev(uint::max_value, uint::max_value - 10000) |x| { + for x in range(uint::max_value - 10000, uint::max_value).invert() { m.insert(x, x / 2); - true - }; + } let mut n = uint::max_value - 10000; do m.each |k, v| { @@ -580,10 +580,9 @@ fn test_each_reverse() { fn test_each_reverse_break() { let mut m = TrieMap::new(); - do uint::range_rev(uint::max_value, uint::max_value - 10000) |x| { + for x in range(uint::max_value - 10000, uint::max_value).invert() { m.insert(x, x / 2); - true - }; + } let mut n = uint::max_value - 1; do m.each_reverse |k, v| { @@ -634,10 +633,9 @@ fn test_iteration() { let last = uint::max_value; let mut map = TrieMap::new(); - do uint::range_rev(last, first) |x| { + for x in range(first, last).invert() { map.insert(x, x / 2); - true - }; + } let mut i = 0; for (k, &v) in map.iter() { diff --git a/src/test/bench/core-map.rs b/src/test/bench/core-map.rs index cf160ca31c6..6475012e009 100644 --- a/src/test/bench/core-map.rs +++ b/src/test/bench/core-map.rs @@ -53,24 +53,21 @@ fn descending>(map: &mut M, n_keys: uint) { io::println(" Descending integers:"); do timed("insert") { - do uint::range_rev(n_keys, 0) |i| { + for i in range(0, n_keys).invert() { map.insert(i, i + 1); - true - }; + } } do timed("search") { - do uint::range_rev(n_keys, 0) |i| { + for i in range(0, n_keys).invert() { assert_eq!(map.find(&i).unwrap(), &(i + 1)); - true - }; + } } do timed("remove") { - do uint::range_rev(n_keys, 0) |i| { + for i in range(0, n_keys) { assert!(map.remove(&i)); - true - }; + } } } diff --git a/src/test/run-fail/assert-eq-macro-fail b/src/test/run-fail/assert-eq-macro-fail new file mode 100755 index 00000000000..2841756d4a0 Binary files /dev/null and b/src/test/run-fail/assert-eq-macro-fail differ diff --git a/src/test/run-pass/num-range-rev.rs b/src/test/run-pass/num-range-rev.rs index 5eecbe7e03a..ea7d4a651f7 100644 --- a/src/test/run-pass/num-range-rev.rs +++ b/src/test/run-pass/num-range-rev.rs @@ -20,11 +20,11 @@ fn int_range(lo: int, hi: int, it: &fn(int) -> bool) -> bool { } fn uint_range_rev(hi: uint, lo: uint, it: &fn(uint) -> bool) -> bool { - uint::range_rev(hi, lo, it) + range(lo, hi).invert().advance(it) } fn int_range_rev(hi: int, lo: int, it: &fn(int) -> bool) -> bool { - int::range_rev(hi, lo, it) + range(lo, hi).invert().advance(it) } fn int_range_step(a: int, b: int, step: int, it: &fn(int) -> bool) -> bool {