Add codepoints_iter() methods for cmap Subtable4/Subtable12

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ttf-parser"
-version = "0.24.1"
+version = "0.25.0"
 authors = ["Yevhenii Reizner <[email protected]>"]
 keywords = ["ttf", "truetype", "opentype"]
 categories = ["parser-implementations"]

src/tables/cmap/format12.rs

@@ -65,13 +65,16 @@ impl<'a> Subtable12<'a> {
         u16::try_from(id).ok().map(GlyphId)
     }
 
+    /// Iterate over each codepoint defined in this table.
+    pub fn codepoints_iter(&'a self) -> impl Iterator<Item = u32> + 'a {
+        self.groups
+            .into_iter()
+            .flat_map(|group| group.start_char_code..=group.end_char_code)
+    }
+
     /// Calls `f` for each codepoint defined in this table.
-    pub fn codepoints(&self, mut f: impl FnMut(u32)) {
-        for group in self.groups {
-            for code_point in group.start_char_code..=group.end_char_code {
-                f(code_point);
-            }
-        }
+    pub fn codepoints(&self, f: impl FnMut(u32)) {
+        self.codepoints_iter().for_each(f)
     }
 }
 

src/tables/cmap/format4.rs

@@ -100,18 +100,19 @@ impl<'a> Subtable4<'a> {
         None
     }
 
-    /// Calls `f` for each codepoint defined in this table.
-    pub fn codepoints(&self, mut f: impl FnMut(u32)) {
-        for (start, end) in self.start_codes.into_iter().zip(self.end_codes) {
-            // OxFFFF value is special and indicates codes end.
-            if start == end && start == 0xFFFF {
-                break;
-            }
+    /// Iterate over each codepoint defined in this table.
+    pub fn codepoints_iter(&'a self) -> impl Iterator<Item = u32> + 'a {
+        self.start_codes
+            .into_iter()
+            .zip(self.end_codes)
+            .take_while(|&(start, end)| !(start == end && start == 0xFFFF))
+            .flat_map(|(start, end)| start..=end)
+            .map(u32::from)
+    }
 
-            for code_point in start..=end {
-                f(u32::from(code_point));
-            }
-        }
+    /// Calls `f` for each codepoint defined in this table.
+    pub fn codepoints(&self, f: impl FnMut(u32)) {
+        self.codepoints_iter().for_each(f)
     }
 }