refactor: cleanup parse function

src/objects/emphasis.rs

@@ -1,44 +1,59 @@
 use memchr::memchr;
 
-pub struct Emphasis;
+#[inline]
+/// returns offset
+pub fn parse(src: &str, marker: u8) -> Option<usize> {
+    debug_assert!(src.len() >= 3);
 
-impl Emphasis {
-    // TODO: return usize instead of Option<usize>
-    pub fn parse(src: &str, marker: u8) -> Option<usize> {
-        expect!(src, 1, |c: u8| !c.is_ascii_whitespace())?;
+    let bytes = src.as_bytes();
 
-        let bytes = src.as_bytes();
-        let end = memchr(marker, &bytes[1..])
-            .map(|i| i + 1)
-            .filter(|&i| bytes[1..i].iter().filter(|&&c| c == b'\n').count() < 2)?;
+    if bytes[1].is_ascii_whitespace() {
+        return None;
+    }
 
-        expect!(src, end - 1, |c: u8| !c.is_ascii_whitespace())?;
+    let end = memchr(marker, &bytes[1..])
+        .map(|i| i + 1)
+        .filter(|&i| bytes[1..i].iter().filter(|&&c| c == b'\n').count() < 2)?;
 
-        if end < src.len() - 1 {
-            expect!(src, end + 1, |ch| ch == b' '
-                || ch == b'-'
-                || ch == b'.'
-                || ch == b','
-                || ch == b':'
-                || ch == b'!'
-                || ch == b'?'
-                || ch == b'\''
-                || ch == b'\n'
-                || ch == b')'
-                || ch == b'}')?;
+    if bytes[end - 1].is_ascii_whitespace() {
+        return None;
+    }
+
+    if end < src.len() - 1 {
+        let post = bytes[end + 1];
+        if post == b' '
+            || post == b'-'
+            || post == b'.'
+            || post == b','
+            || post == b':'
+            || post == b'!'
+            || post == b'?'
+            || post == b'\''
+            || post == b'\n'
+            || post == b')'
+            || post == b'}'
+        {
+            Some(end)
+        } else {
+            None
         }
-
+    } else {
         Some(end)
     }
 }
 
-#[test]
-fn parse() {
-    assert_eq!(Emphasis::parse("*bold*", b'*').unwrap(), "*bold".len());
-    assert_eq!(Emphasis::parse("*bo\nld*", b'*').unwrap(), "*bo\nld".len());
-    assert!(Emphasis::parse("*bold*a", b'*').is_none());
-    assert!(Emphasis::parse("*bold*", b'/').is_none());
-    assert!(Emphasis::parse("*bold *", b'*').is_none());
-    assert!(Emphasis::parse("* bold*", b'*').is_none());
-    assert!(Emphasis::parse("*b\nol\nd*", b'*').is_none());
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn parse() {
+        use super::parse;
+
+        assert_eq!(parse("*bold*", b'*').unwrap(), "*bold".len());
+        assert_eq!(parse("*bo\nld*", b'*').unwrap(), "*bo\nld".len());
+        assert!(parse("*bold*a", b'*').is_none());
+        assert!(parse("*bold*", b'/').is_none());
+        assert!(parse("*bold *", b'*').is_none());
+        assert!(parse("* bold*", b'*').is_none());
+        assert!(parse("*b\nol\nd*", b'*').is_none());
+    }
 }