From e0395341f7e38e804646bce23809b407564e84db Mon Sep 17 00:00:00 2001 From: Guanqun Lu Date: Sat, 12 Oct 2019 12:45:28 +0800 Subject: [PATCH] replace the hand-written binary search with the library one --- src/libsyntax/source_map.rs | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) diff --git a/src/libsyntax/source_map.rs b/src/libsyntax/source_map.rs index 7d0d2392945e..07c301f524ea 100644 --- a/src/libsyntax/source_map.rs +++ b/src/libsyntax/source_map.rs @@ -882,21 +882,13 @@ impl SourceMap { let files = &files.source_files; let count = files.len(); - // Binary search for the `SourceFile`. - let mut a = 0; - let mut b = count; - while b - a > 1 { - let m = (a + b) / 2; - if files[m].start_pos > pos { - b = m; - } else { - a = m; - } - } + // (p - 1) below will not underflow, this follows previous implementation's assumption. + assert!(count >= 1); + let ret = files.binary_search_by_key(&pos, |key| key.start_pos).unwrap_or_else(|p| p - 1); - assert!(a < count, "position {} does not resolve to a source location", pos.to_usize()); + assert!(ret < count, "position {} does not resolve to a source location", pos.to_usize()); - return a; + return ret; } pub fn count_lines(&self) -> usize {