1// https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-13-many-to-one-range-mappings
2
3use core::convert::TryFrom;
4
5use super::format12::SequentialMapGroup;
6use crate::parser::{LazyArray32, Stream};
7use crate::GlyphId;
8
9/// A [format 13](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-13-segmented-coverage)
10/// subtable.
11#[derive(Clone, Copy)]
12pub struct Subtable13<'a> {
13 groups: LazyArray32<'a, SequentialMapGroup>,
14}
15
16impl<'a> Subtable13<'a> {
17 /// Parses a subtable from raw data.
18 pub fn parse(data: &'a [u8]) -> Option<Self> {
19 let mut s = Stream::new(data);
20 s.skip::<u16>(); // format
21 s.skip::<u16>(); // reserved
22 s.skip::<u32>(); // length
23 s.skip::<u32>(); // language
24 let count = s.read::<u32>()?;
25 let groups = s.read_array32::<super::format12::SequentialMapGroup>(count)?;
26 Some(Self { groups })
27 }
28
29 /// Returns a glyph index for a code point.
30 pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
31 for group in self.groups {
32 let start_char_code = group.start_char_code;
33 if code_point >= start_char_code && code_point <= group.end_char_code {
34 return u16::try_from(group.start_glyph_id).ok().map(GlyphId);
35 }
36 }
37
38 None
39 }
40
41 /// Calls `f` for each codepoint defined in this table.
42 pub fn codepoints(&self, mut f: impl FnMut(u32)) {
43 for group in self.groups {
44 for code_point in group.start_char_code..=group.end_char_code {
45 f(code_point);
46 }
47 }
48 }
49}
50
51impl core::fmt::Debug for Subtable13<'_> {
52 fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
53 write!(f, "Subtable13 {{ ... }}")
54 }
55}
56