revert using regex

Author: donno2048

src/tools/tidy/src/style.rs

@@ -19,6 +19,7 @@
 
 use crate::walk::{filter_dirs, walk};
 use regex::{Regex, RegexSet};
+use std::collections::HashMap;
 use std::{ffi::OsStr, path::Path};
 
 /// Error code markdown is restricted to 80 columns because they can be
@@ -65,8 +66,39 @@ const ANNOTATIONS_TO_IGNORE: &[&str] = &[
     "//@ normalize-stderr-test",
 ];
 
+fn generate_problems<'a>(
+    consts: &'a [u32],
+    letter_digit: &'a HashMap<char, char>,
+) -> impl Iterator<Item = u32> + 'a {
+    consts.into_iter().flat_map(move |const_value| {
+        let mut problem = format!("{:X}", const_value);
+        for (key, value) in letter_digit {
+            problem = problem.replace(&value.to_string(), &key.to_string());
+        }
+        let indexes: Vec<usize> = problem
+            .chars()
+            .enumerate()
+            .filter_map(|(index, c)| if letter_digit.contains_key(&c) { Some(index) } else { None })
+            .collect();
+        (0..1 << indexes.len()).map(move |i| {
+            let result = problem
+                .chars()
+                .enumerate()
+                .map(|(index, c)| {
+                    if let Some(pos) = indexes.iter().position(|&x| x == index) {
+                        if (i >> pos) & 1 == 1 { letter_digit[&c] } else { c }
+                    } else {
+                        c
+                    }
+                })
+                .collect::<String>();
+            u32::from_str_radix(&result, 0x10).unwrap()
+        })
+    })
+}
+
 // Intentionally written in decimal rather than hex
-const PROBLEMATIC_CONSTS: &[u32] = &[
+const ROOT_PROBLEMATIC_CONSTS: &[u32] = &[
     184594741, 2880289470, 2881141438, 2965027518, 2976579765, 3203381950, 3405691582, 3405697037,
     3735927486, 3735932941, 4027431614, 4276992702, 195934910, 252707358, 762133, 179681982,
     173390526,
@@ -268,16 +300,14 @@ pub fn check(path: &Path, bad: &mut bool) {
         // We only check CSS files in rustdoc.
         path.extension().map_or(false, |e| e == "css") && !is_in(path, "src", "librustdoc")
     }
-    let problematic_consts_strings: Vec<String> = (PROBLEMATIC_CONSTS.iter().map(u32::to_string))
-        .chain(PROBLEMATIC_CONSTS.iter().map(|v| {
-            format!("{:x}", v)
-                .replace("a", "[aA4]")
-                .replace("b", "[bB8]")
-                .replace("c", "[cC]")
-                .replace("d", "[dD]")
-                .replace("e", "[eE3]")
-                .replace("f", "[fF]")
-        }))
+    let problematic_consts = generate_problems(
+        ROOT_PROBLEMATIC_CONSTS,
+        &[('A', '4'), ('B', '8'), ('E', '3')].iter().cloned().collect(),
+    )
+    .collect::<Vec<u32>>();
+    let problematic_consts_strings: Vec<String> = (problematic_consts.iter().map(u32::to_string))
+        .chain(problematic_consts.iter().map(|v| format!("{:x}", v)))
+        .chain(problematic_consts.iter().map(|v| format!("{:X}", v)))
         .collect();
     let problematic_regex = RegexSet::new(problematic_consts_strings.as_slice()).unwrap();