diff --git a/Cargo.lock b/Cargo.lock
index 73d7b64a..7173ce79 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -164,7 +164,7 @@ dependencies = [
  "emojis",
  "entities",
  "fmt2io",
- "memchr",
+ "jetscii",
  "ntest",
  "percent-encoding-rfc3986",
  "shell-words",
@@ -373,6 +373,12 @@ version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fad582f4b9e86b6caa621cabeb0963332d92eea04729ab12892c2533951e6440"
 
+[[package]]
+name = "jetscii"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47f142fe24a9c9944451e8349de0a56af5f3e7226dc46f3ed4d4ecc0b85af75e"
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
diff --git a/Cargo.toml b/Cargo.toml
index de5caee5..c309ab9f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -38,20 +38,20 @@ doc = false
 typed-arena = "2.0.2"
 entities = "1.0.1"
 unicode_categories = "0.1.1"
-memchr = "2"
 shell-words = { version = "1.0", optional = true }
-slug = "0.1.4"
 emojis = { version = "0.6.2", optional = true }
 arbitrary = { version = "1", optional = true, features = ["derive"] }
 bon = { version = "3", optional = true }
 caseless = "0.2.1"
 fmt2io = { version = "1.0.0", optional = true }
+jetscii = "0.5.3"
 
 [dev-dependencies]
 ntest = "0.9"
 percent-encoding-rfc3986 = "0.1.3"
 strum = { version = "0.26.3", features = ["derive"] }
 toml = "0.7.3"
+slug = "0.1.4"
 
 [features]
 default = ["cli", "syntect", "bon"]
diff --git a/flake.nix b/flake.nix
index 778a6cb9..877beb23 100644
--- a/flake.nix
+++ b/flake.nix
@@ -93,6 +93,7 @@
               "clippy"
               "rustfmt"
               "rust-src"
+              "llvm-tools-preview"
             ])
           ]
           ++ (with pkgs; [
diff --git a/src/html.rs b/src/html.rs
index 1a61a3b7..ef3d207a 100644
--- a/src/html.rs
+++ b/src/html.rs
@@ -688,7 +688,7 @@ fn render_html_block<'a, T>(
         } else if !context.options.render.unsafe_ {
             context.write_str("<!-- raw HTML omitted -->")?;
         } else if context.options.extension.tagfilter {
-            tagfilter_block(literal, context)?;
+            tagfilter_block(context, literal)?;
         } else {
             context.write_str(literal)?;
         }
@@ -1690,34 +1690,21 @@ fn tagfilter(literal: &str) -> bool {
     false
 }
 
-fn tagfilter_block(input: &str, o: &mut dyn Write) -> fmt::Result {
-    let bytes = input.as_bytes();
-    let size = input.len();
-    let mut i = 0;
-
-    while i < size {
-        let org = i;
-        while i < size && bytes[i] != b'<' {
-            i += 1;
-        }
-
-        if i > org {
-            o.write_str(&input[org..i])?;
-        }
-
-        if i >= size {
-            break;
-        }
+fn tagfilter_block(output: &mut dyn Write, buffer: &str) -> fmt::Result {
+    let bytes = buffer.as_bytes();
+    let matcher = jetscii::bytes!(b'<');
 
-        if tagfilter(&input[i..]) {
-            o.write_str("&lt;")?;
+    let mut offset = 0;
+    while let Some(i) = matcher.find(&bytes[offset..]) {
+        output.write_str(&buffer[offset..offset + i])?;
+        if tagfilter(&buffer[offset + i..]) {
+            output.write_str("&lt;")?;
         } else {
-            o.write_str("<")?;
+            output.write_str("<")?;
         }
-
-        i += 1;
+        offset += i + 1;
     }
-
+    output.write_str(&buffer[offset..])?;
     Ok(())
 }
 
@@ -1741,22 +1728,20 @@ pub fn dangerous_url(input: &str) -> bool {
 /// URLs in attributes.  See escape_href.
 pub fn escape(output: &mut dyn Write, buffer: &str) -> fmt::Result {
     let bytes = buffer.as_bytes();
-    const HTML_UNSAFE: [bool; 256] = character_set!(b"&<>\"");
+    let matcher = jetscii::bytes!(b'"', b'&', b'<', b'>');
 
     let mut offset = 0;
-    for (i, &byte) in bytes.iter().enumerate() {
-        if HTML_UNSAFE[byte as usize] {
-            let esc: &str = match byte {
-                b'"' => "&quot;",
-                b'&' => "&amp;",
-                b'<' => "&lt;",
-                b'>' => "&gt;",
-                _ => unreachable!(),
-            };
-            output.write_str(&buffer[offset..i])?;
-            output.write_str(esc)?;
-            offset = i + 1;
-        }
+    while let Some(i) = matcher.find(&bytes[offset..]) {
+        let esc: &str = match bytes[offset + i] {
+            b'"' => "&quot;",
+            b'&' => "&amp;",
+            b'<' => "&lt;",
+            b'>' => "&gt;",
+            _ => unreachable!(),
+        };
+        output.write_str(&buffer[offset..offset + i])?;
+        output.write_str(esc)?;
+        offset += i + 1;
     }
     output.write_str(&buffer[offset..])?;
     Ok(())