Improve dedentation performance

Author: WGUNDERWOOD

README.md

@@ -174,7 +174,7 @@ tex-fmt is over a thousand times faster than latexindent.
 
 | **Files** | **Lines** | **Size** | **tex-fmt** | **latexindent** | **latexindent -m** |
 | --- | --- | --- | --- | --- | --- |
-| 49 | 94k | 3.5M | **0.065s** | 99s [x1523] | 132s [x2031] |
+| 49 | 94k | 3.5M | **0.055s** | 99s [x1800] | 132s [x2400] |
 
 ## Contribution
 

src/indent.rs

@@ -68,11 +68,14 @@ fn get_back(line: &str, pattern: &Pattern) -> i8 {
     let mut back: i8 = 0;
     let mut cumul: i8 = 0;
 
-    // delimiters
-    for c in line.chars() {
-        cumul -= i8::from(OPENS.contains(&c));
-        cumul += i8::from(CLOSES.contains(&c));
-        back = max(cumul, back);
+    // Dedent delimiters
+    // Check first whether there are any closing delimiters
+    if CLOSES.iter().any(|c| line.contains(*c)) {
+        for c in line.chars() {
+            cumul -= i8::from(OPENS.contains(&c));
+            cumul += i8::from(CLOSES.contains(&c));
+            back = max(cumul, back);
+        }
     }
 
     // other environments get single indents