1 files changed, 112 insertions, 0 deletions
diff --git a/src/utils/regex_replacement.rs b/src/utils/regex_replacement.rs
new file mode 100644
index 00000000..5f07902e
--- /dev/null
+++ b/src/utils/regex_replacement.rs
@@ -0,0 +1,112 @@
+use std::borrow::Cow;
+
+use regex::{Regex, RegexBuilder};
+
+#[derive(Clone, Debug)]
+pub struct RegexReplacement {
+    regex: Regex,
+    replacement: String,
+    replace_all: bool,
+}
+
+impl RegexReplacement {
+    pub fn from_sed_command(sed_command: &str) -> Option<Self> {
+        let sep = sed_command.chars().nth(1)?;
+        let mut parts = sed_command[2..].split(sep);
+        let regex = parts.next()?;
+        let replacement = parts.next()?.to_string();
+        let flags = parts.next()?;
+        let mut re_builder = RegexBuilder::new(regex);
+        let mut replace_all = false;
+        for flag in flags.chars() {
+            match flag {
+                'g' => {
+                    replace_all = true;
+                }
+                'i' => {
+                    re_builder.case_insensitive(true);
+                }
+                'm' => {
+                    re_builder.multi_line(true);
+                }
+                's' => {
+                    re_builder.dot_matches_new_line(true);
+                }
+                'U' => {
+                    re_builder.swap_greed(true);
+                }
+                'x' => {
+                    re_builder.ignore_whitespace(true);
+                }
+                _ => {}
+            }
+        }
+        let regex = re_builder.build().ok()?;
+        Some(RegexReplacement {
+            regex,
+            replacement,
+            replace_all,
+        })
+    }
+
+    pub fn execute<'t>(&self, s: &'t str) -> Cow<'t, str> {
+        if self.replace_all {
+            self.regex.replace_all(s, &self.replacement)
+        } else {
+            self.regex.replace(s, &self.replacement)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_sed_command() {
+        let command = "s,foo,bar,";
+        let rr = RegexReplacement::from_sed_command(command).unwrap();
+        assert_eq!(rr.regex.as_str(), "foo");
+        assert_eq!(rr.replacement, "bar");
+        assert_eq!(rr.replace_all, false);
+        assert_eq!(rr.execute("foo"), "bar");
+    }
+
+    #[test]
+    fn test_sed_command_i_flag() {
+        let command = "s,FOO,bar,";
+        let rr = RegexReplacement::from_sed_command(command).unwrap();
+        assert_eq!(rr.execute("foo"), "foo");
+        let command = "s,FOO,bar,i";
+        let rr = RegexReplacement::from_sed_command(command).unwrap();
+        assert_eq!(rr.execute("foo"), "bar");
+    }
+
+    #[test]
+    fn test_sed_command_g_flag() {
+        let command = "s,foo,bar,";
+        let rr = RegexReplacement::from_sed_command(command).unwrap();
+        assert_eq!(rr.execute("foofoo"), "barfoo");
+        let command = "s,foo,bar,g";
+        let rr = RegexReplacement::from_sed_command(command).unwrap();
+        assert_eq!(rr.execute("foofoo"), "barbar");
+    }
+
+    #[test]
+    fn test_sed_command_with_named_captures() {
+        let command = r"s/(?P<last>[^,\s]+),\s+(?P<first>\S+)/$first $last/";
+        let rr = RegexReplacement::from_sed_command(command).unwrap();
+        assert_eq!(rr.execute("Springsteen, Bruce"), "Bruce Springsteen");
+    }
+
+    #[test]
+    fn test_sed_command_invalid() {
+        assert!(RegexReplacement::from_sed_command("").is_none());
+        assert!(RegexReplacement::from_sed_command("s").is_none());
+        assert!(RegexReplacement::from_sed_command("s,").is_none());
+        assert!(RegexReplacement::from_sed_command("s,,").is_none());
+        assert!(RegexReplacement::from_sed_command("s,,i").is_none());
+        assert!(RegexReplacement::from_sed_command("s,,,").is_some());
+        assert!(RegexReplacement::from_sed_command("s,,,i").is_some());
+    }
+}