make unicode normalization optional

it's not always necessary or desired, and adds quite a lot to the binary
size (for instance, the problem it solves is pretty much non-existent in
web browsers, and wasm builds are also very sensitive to code size)

4 files changed, 26 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 71a9d35..b4edf50 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## Unreleased
+
+### Added
+
+* New (default-on) cargo feature `unicode-normalization` which can be disabled
+  to disable normalizing cell contents to NFC - it's a pretty small edge case,
+  and the data tables required to support it are quite large, which affects
+  size-sensitive targets like wasm
+
 ## [0.6.3] - 2019-11-20
 
 ### Fixed
diff --git a/Cargo.toml b/Cargo.toml
index 7ec13a4..3b79b41 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,10 +12,13 @@ keywords = ["terminal", "vt100"]
 categories = ["command-line-interface", "encoding"]
 license = "MIT"
 
+[features]
+default = ["unicode-normalization"]
+
 [dependencies]
 itoa = "0.4"
 enumset = "0.4"
 log = "0.4"
-unicode-normalization = "0.1"
+unicode-normalization = { version = "0.1", optional = true }
 unicode-width = "0.1"
 vte = "0.3"
diff --git a/src/cell.rs b/src/cell.rs
index 05d93be..ecc44b2 100644
--- a/src/cell.rs
+++ b/src/cell.rs
@@ -1,4 +1,3 @@
-use unicode_normalization::UnicodeNormalization as _;
 use unicode_width::UnicodeWidthChar as _;
 
 const CODEPOINTS_IN_CELL: usize = 6;
@@ -49,6 +48,18 @@ impl Cell {
         self.contents[self.len()] = c;
         self.len += 1;
 
+        self.normalize();
+    }
+
+    #[cfg(not(feature = "unicode-normalization"))]
+    #[inline]
+    fn normalize(&mut self) {}
+
+    #[cfg(feature = "unicode-normalization")]
+    #[inline]
+    fn normalize(&mut self) {
+        use unicode_normalization::UnicodeNormalization as _;
+
         // some fonts have combined characters but can't render combining
         // characters correctly, so try to prefer precombined characters when
         // possible
diff --git a/tests/text.rs b/tests/text.rs
index 81201a1..1ad16ae 100644
--- a/tests/text.rs
+++ b/tests/text.rs
@@ -130,6 +130,7 @@ fn wide() {
     );
 }
 
+#[cfg(feature = "unicode-normalization")]
 #[test]
 fn combining() {
     let mut parser = vt100::Parser::default();