fix: fix some edge case errors

src/elements/block.rs

@@ -6,7 +6,7 @@ use memchr::memchr2;
 pub fn parse(src: &str) -> Option<(&str, Option<&str>, usize, usize, usize)> {
     debug_assert!(src.starts_with("#+"));
 
-    if src[2..8].to_uppercase() != "BEGIN_" {
+    if src.len() <= 8 || src[2..8].to_uppercase() != "BEGIN_" {
         return None;
     }
 

src/elements/dyn_block.rs

@@ -6,7 +6,7 @@ use memchr::memchr2;
 pub fn parse(src: &str) -> Option<(&str, Option<&str>, usize, usize, usize)> {
     debug_assert!(src.starts_with("#+"));
 
-    if !src[2..9].eq_ignore_ascii_case("BEGIN: ") {
+    if src.len() <= 9 || !src[2..9].eq_ignore_ascii_case("BEGIN: ") {
         return None;
     }
 

src/elements/mod.rs

@@ -96,8 +96,8 @@ pub fn parse<'a>(src: &'a str) -> (Option<Element<'a>>, usize, Option<(Element<'
 
         macro_rules! brk {
             ($ele:expr, $off:expr) => {
-                break if line_beg == 0 || pos == start {
-                    (Some($ele), start + $off, None)
+                break if line_beg == start || pos == start {
+                    (Some($ele), pos + $off, None)
                 } else {
                     (
                         Some(Element::Paragraph {
@@ -272,8 +272,7 @@ pub fn parse<'a>(src: &'a str) -> (Option<Element<'a>>, usize, Option<(Element<'
 mod tests {
     #[test]
     fn parse() {
-        use super::parse;
-        use super::Element::*;
+        use super::{Element::*, *};
 
         assert_eq!(parse("\n\n\n"), (None, 3, None));
 
@@ -388,6 +387,17 @@ mod tests {
                 ))
             )
         );
+        assert_eq!(
+            parse("\n  #+ATTR_HTML: :width 200px"),
+            (
+                Some(Keyword {
+                    key: keyword::Key::Attr { backend: "HTML" },
+                    value: ":width 200px"
+                }),
+                "\n  #+ATTR_HTML: :width 200px".len(),
+                None
+            )
+        );
         // TODO: more tests
     }
 }

src/objects/mod.rs

@@ -144,7 +144,7 @@ pub fn parse<'a>(src: &'a str) -> (Object<'a>, usize, Option<(Object<'a>, usize)
         if let Some(off) = bs
             .find(&bytes[pos + 1..])
             .map(|i| i + pos + 1)
-            .filter(|&i| i < src.len() - 2)
+            .filter(|&i| i < src.len() - 3)
         {
             pos = off;
         } else {