Vendor things

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/format0.rs

@@ -0,0 +1,47 @@
+use crate::parser::{Stream, NumFrom};
+use crate::GlyphId;
+
+/// A [format 0](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-0-byte-encoding-table)
+/// subtable.
+#[derive(Clone, Copy, Debug)]
+pub struct Subtable0<'a> {
+    /// Just a list of 256 8bit glyph IDs.
+    pub glyph_ids: &'a [u8],
+}
+
+impl<'a> Subtable0<'a> {
+    /// Parses a subtable from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.skip::<u16>(); // format
+        s.skip::<u16>(); // length
+        s.skip::<u16>(); // language
+        let glyph_ids = s.read_bytes(256)?;
+        Some(Self { glyph_ids })
+    }
+
+    /// Returns a glyph index for a code point.
+    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
+        let glyph_id = *self.glyph_ids.get(usize::num_from(code_point))?;
+        // Make sure that the glyph is not zero, the array always has 256 ids,
+        // but some codepoints may be mapped to zero.
+        if glyph_id != 0 {
+            Some(GlyphId(u16::from(glyph_id)))
+        } else {
+            None
+        }
+    }
+
+    /// Calls `f` for each codepoint defined in this table.
+    pub fn codepoints(&self, mut f: impl FnMut(u32)) {
+        for (i, glyph_id) in self.glyph_ids.iter().enumerate() {
+            // In contrast to every other format, here we take a look at the glyph
+            // id and check whether it is zero because otherwise this method would
+            // always simply call `f` for `0..256` which would be kind of pointless
+            // (this array always has length 256 even when the face has fewer glyphs).
+            if *glyph_id != 0 {
+                f(i as u32);
+            }
+        }
+    }
+}

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/format10.rs

@@ -0,0 +1,42 @@
+use crate::parser::{LazyArray32, Stream};
+use crate::GlyphId;
+
+/// A [format 10](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-10-trimmed-array)
+/// subtable.
+#[derive(Clone, Copy, Debug)]
+pub struct Subtable10<'a> {
+    /// First character code covered.
+    pub first_code_point: u32,
+    /// Array of glyph indices for the character codes covered.
+    pub glyphs: LazyArray32<'a, GlyphId>,
+}
+
+impl<'a> Subtable10<'a> {
+    /// Parses a subtable from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.skip::<u16>(); // format
+        s.skip::<u16>(); // reserved
+        s.skip::<u32>(); // length
+        s.skip::<u32>(); // language
+        let first_code_point = s.read::<u32>()?;
+        let count = s.read::<u32>()?;
+        let glyphs = s.read_array32::<GlyphId>(count)?;
+        Some(Self { first_code_point, glyphs })
+    }
+
+    /// Returns a glyph index for a code point.
+    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
+        let idx = code_point.checked_sub(self.first_code_point)?;
+        self.glyphs.get(idx)
+    }
+
+    /// Calls `f` for each codepoint defined in this table.
+    pub fn codepoints(&self, mut f: impl FnMut(u32)) {
+        for i in 0..self.glyphs.len() {
+            if let Some(code_point) = self.first_code_point.checked_add(i) {
+                f(code_point);
+            }
+        }
+    }
+}

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/format12.rs

@@ -0,0 +1,80 @@
+use core::convert::TryFrom;
+
+use crate::parser::{FromData, LazyArray32, Stream};
+use crate::GlyphId;
+
+#[derive(Clone, Copy)]
+pub struct SequentialMapGroup {
+    pub start_char_code: u32,
+    pub end_char_code: u32,
+    pub start_glyph_id: u32,
+}
+
+impl FromData for SequentialMapGroup {
+    const SIZE: usize = 12;
+
+    #[inline]
+    fn parse(data: &[u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        Some(SequentialMapGroup {
+            start_char_code: s.read::<u32>()?,
+            end_char_code: s.read::<u32>()?,
+            start_glyph_id: s.read::<u32>()?,
+        })
+    }
+}
+
+
+/// A [format 12](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-12-segmented-coverage)
+/// subtable.
+#[derive(Clone, Copy)]
+pub struct Subtable12<'a> {
+    groups: LazyArray32<'a, SequentialMapGroup>,
+}
+
+impl<'a> Subtable12<'a> {
+    /// Parses a subtable from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.skip::<u16>(); // format
+        s.skip::<u16>(); // reserved
+        s.skip::<u32>(); // length
+        s.skip::<u32>(); // language
+        let count = s.read::<u32>()?;
+        let groups = s.read_array32::<SequentialMapGroup>(count)?;
+        Some(Self { groups })
+    }
+
+    /// Returns a glyph index for a code point.
+    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
+        let (_, group) = self.groups.binary_search_by(|range| {
+            use core::cmp::Ordering;
+
+            if range.start_char_code > code_point {
+                Ordering::Greater
+            } else if range.end_char_code < code_point {
+                Ordering::Less
+            } else {
+                Ordering::Equal
+            }
+        })?;
+
+        let id = group.start_glyph_id.checked_add(code_point)?.checked_sub(group.start_char_code)?;
+        return u16::try_from(id).ok().map(GlyphId);
+    }
+
+    /// 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);
+            }
+        }
+    }
+}
+
+impl core::fmt::Debug for Subtable12<'_> {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        write!(f, "Subtable12 {{ ... }}")
+    }
+}

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/format13.rs

@@ -0,0 +1,55 @@
+// https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-13-many-to-one-range-mappings
+
+use core::convert::TryFrom;
+
+use crate::parser::{LazyArray32, Stream};
+use super::format12::SequentialMapGroup;
+use crate::GlyphId;
+
+/// A [format 13](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-13-segmented-coverage)
+/// subtable.
+#[derive(Clone, Copy)]
+pub struct Subtable13<'a> {
+    groups: LazyArray32<'a, SequentialMapGroup>,
+}
+
+impl<'a> Subtable13<'a> {
+    /// Parses a subtable from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.skip::<u16>(); // format
+        s.skip::<u16>(); // reserved
+        s.skip::<u32>(); // length
+        s.skip::<u32>(); // language
+        let count = s.read::<u32>()?;
+        let groups = s.read_array32::<super::format12::SequentialMapGroup>(count)?;
+        Some(Self { groups })
+    }
+
+    /// Returns a glyph index for a code point.
+    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
+        for group in self.groups {
+            let start_char_code = group.start_char_code;
+            if code_point >= start_char_code && code_point <= group.end_char_code {
+                return u16::try_from(group.start_glyph_id).ok().map(GlyphId);
+            }
+        }
+
+        None
+    }
+
+    /// 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);
+            }
+        }
+    }
+}
+
+impl core::fmt::Debug for Subtable13<'_> {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        write!(f, "Subtable13 {{ ... }}")
+    }
+}

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/format14.rs

@@ -0,0 +1,140 @@
+use crate::GlyphId;
+use crate::parser::{FromData, LazyArray32, Offset, Offset32, Stream, U24};
+
+#[derive(Clone, Copy)]
+struct VariationSelectorRecord {
+    var_selector: u32,
+    default_uvs_offset: Option<Offset32>,
+    non_default_uvs_offset: Option<Offset32>,
+}
+
+impl FromData for VariationSelectorRecord {
+    const SIZE: usize = 11;
+
+    #[inline]
+    fn parse(data: &[u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        Some(VariationSelectorRecord {
+            var_selector: s.read::<U24>()?.0,
+            default_uvs_offset: s.read::<Option<Offset32>>()?,
+            non_default_uvs_offset: s.read::<Option<Offset32>>()?,
+        })
+    }
+}
+
+
+#[derive(Clone, Copy)]
+struct UVSMappingRecord {
+    unicode_value: u32,
+    glyph_id: GlyphId,
+}
+
+impl FromData for UVSMappingRecord {
+    const SIZE: usize = 5;
+
+    #[inline]
+    fn parse(data: &[u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        Some(UVSMappingRecord {
+            unicode_value: s.read::<U24>()?.0,
+            glyph_id: s.read::<GlyphId>()?,
+        })
+    }
+}
+
+
+#[derive(Clone, Copy)]
+struct UnicodeRangeRecord {
+    start_unicode_value: u32,
+    additional_count: u8,
+}
+
+impl UnicodeRangeRecord {
+    fn contains(&self, c: u32) -> bool {
+        // Never overflows, since `start_unicode_value` is actually u24.
+        let end = self.start_unicode_value + u32::from(self.additional_count);
+        (self.start_unicode_value..=end).contains(&c)
+    }
+}
+
+impl FromData for UnicodeRangeRecord {
+    const SIZE: usize = 4;
+
+    #[inline]
+    fn parse(data: &[u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        Some(UnicodeRangeRecord {
+            start_unicode_value: s.read::<U24>()?.0,
+            additional_count: s.read::<u8>()?,
+        })
+    }
+}
+
+
+/// A result of a variation glyph mapping.
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub enum GlyphVariationResult {
+    /// Glyph was found in the variation encoding table.
+    Found(GlyphId),
+    /// Glyph should be looked in other, non-variation tables.
+    ///
+    /// Basically, you should use `Encoding::glyph_index` or `Face::glyph_index`
+    /// in this case.
+    UseDefault,
+}
+
+
+/// A [format 14](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-14-unicode-variation-sequences)
+/// subtable.
+#[derive(Clone, Copy)]
+pub struct Subtable14<'a> {
+    records: LazyArray32<'a, VariationSelectorRecord>,
+    // The whole subtable data.
+    data: &'a [u8],
+}
+
+impl<'a> Subtable14<'a> {
+    /// Parses a subtable from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.skip::<u16>(); // format
+        s.skip::<u32>(); // length
+        let count = s.read::<u32>()?;
+        let records = s.read_array32::<VariationSelectorRecord>(count)?;
+        Some(Self { records, data })
+    }
+
+    /// Returns a glyph index for a code point.
+    pub fn glyph_index(&self, code_point: u32, variation: u32) -> Option<GlyphVariationResult> {
+        let (_, record) = self.records.binary_search_by(|v| v.var_selector.cmp(&variation))?;
+
+        if let Some(offset) = record.default_uvs_offset {
+            let data = self.data.get(offset.to_usize()..)?;
+            let mut s = Stream::new(data);
+            let count = s.read::<u32>()?;
+            let ranges = s.read_array32::<UnicodeRangeRecord>(count)?;
+            for range in ranges {
+                if range.contains(code_point) {
+                    return Some(GlyphVariationResult::UseDefault);
+                }
+            }
+        }
+
+        if let Some(offset) = record.non_default_uvs_offset {
+            let data = self.data.get(offset.to_usize()..)?;
+            let mut s = Stream::new(data);
+            let count = s.read::<u32>()?;
+            let uvs_mappings = s.read_array32::<UVSMappingRecord>(count)?;
+            let (_, mapping) = uvs_mappings.binary_search_by(|v| v.unicode_value.cmp(&code_point))?;
+            return Some(GlyphVariationResult::Found(mapping.glyph_id));
+        }
+
+        None
+    }
+}
+
+impl core::fmt::Debug for Subtable14<'_> {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        write!(f, "Subtable14 {{ ... }}")
+    }
+}

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/format2.rs

@@ -0,0 +1,157 @@
+// This table has a pretty complex parsing algorithm.
+// A detailed explanation can be found here:
+// https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-2-high-byte-mapping-through-table
+// https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6cmap.html
+// https://github.com/fonttools/fonttools/blob/a360252709a3d65f899915db0a5bd753007fdbb7/Lib/fontTools/ttLib/tables/_c_m_a_p.py#L360
+
+use core::convert::TryFrom;
+
+use crate::parser::{FromData, LazyArray16, Stream};
+use crate::GlyphId;
+
+#[derive(Clone, Copy)]
+struct SubHeaderRecord {
+    first_code: u16,
+    entry_count: u16,
+    id_delta: i16,
+    id_range_offset: u16,
+}
+
+impl FromData for SubHeaderRecord {
+    const SIZE: usize = 8;
+
+    #[inline]
+    fn parse(data: &[u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        Some(SubHeaderRecord {
+            first_code: s.read::<u16>()?,
+            entry_count: s.read::<u16>()?,
+            id_delta: s.read::<i16>()?,
+            id_range_offset: s.read::<u16>()?,
+        })
+    }
+}
+
+/// A [format 2](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-2-high-byte-mapping-through-table)
+/// subtable.
+#[derive(Clone, Copy)]
+pub struct Subtable2<'a> {
+    sub_header_keys: LazyArray16<'a, u16>,
+    sub_headers_offset: usize,
+    sub_headers: LazyArray16<'a, SubHeaderRecord>,
+    // The whole subtable data.
+    data: &'a [u8],
+}
+
+impl<'a> Subtable2<'a> {
+    /// Parses a subtable from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.skip::<u16>(); // format
+        s.skip::<u16>(); // length
+        s.skip::<u16>(); // language
+        let sub_header_keys = s.read_array16::<u16>(256)?;
+        // The maximum index in a sub_header_keys is a sub_headers count.
+        let sub_headers_count = sub_header_keys.into_iter().map(|n| n / 8).max()? + 1;
+
+        // Remember sub_headers offset before reading. Will be used later.
+        let sub_headers_offset = s.offset();
+        let sub_headers = s.read_array16::<SubHeaderRecord>(sub_headers_count)?;
+
+        Some(Self {
+            sub_header_keys,
+            sub_headers_offset,
+            sub_headers,
+            data,
+        })
+    }
+
+    /// Returns a glyph index for a code point.
+    ///
+    /// Returns `None` when `code_point` is larger than `u16`.
+    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
+        // This subtable supports code points only in a u16 range.
+        let code_point = u16::try_from(code_point).ok()?;
+
+        let code_point = code_point;
+        let high_byte = code_point >> 8;
+        let low_byte = code_point & 0x00FF;
+
+        let i = if code_point < 0xff {
+            // 'SubHeader 0 is special: it is used for single-byte character codes.'
+            0
+        } else {
+            // 'Array that maps high bytes to subHeaders: value is subHeader index × 8.'
+            self.sub_header_keys.get(high_byte)? / 8
+        };
+
+        let sub_header = self.sub_headers.get(i)?;
+
+        let first_code = sub_header.first_code;
+        let range_end = first_code.checked_add(sub_header.entry_count)?;
+        if low_byte < first_code || low_byte >= range_end {
+            return None;
+        }
+
+        // SubHeaderRecord::id_range_offset points to SubHeaderRecord::first_code
+        // in the glyphIndexArray. So we have to advance to our code point.
+        let index_offset = usize::from(low_byte.checked_sub(first_code)?) * u16::SIZE;
+
+        // 'The value of the idRangeOffset is the number of bytes
+        // past the actual location of the idRangeOffset'.
+        let offset =
+            self.sub_headers_offset
+                // Advance to required subheader.
+                + SubHeaderRecord::SIZE * usize::from(i + 1)
+                // Move back to idRangeOffset start.
+                - u16::SIZE
+                // Use defined offset.
+                + usize::from(sub_header.id_range_offset)
+                // Advance to required index in the glyphIndexArray.
+                + index_offset;
+
+        let glyph: u16 = Stream::read_at(self.data, offset)?;
+        if glyph == 0 {
+            return None;
+        }
+
+        u16::try_from((i32::from(glyph) + i32::from(sub_header.id_delta)) % 65536).ok().map(GlyphId)
+    }
+
+    /// Calls `f` for each codepoint defined in this table.
+    pub fn codepoints(&self, f: impl FnMut(u32)) {
+        let _ = self.codepoints_inner(f);
+    }
+
+    #[inline]
+    fn codepoints_inner(&self, mut f: impl FnMut(u32)) -> Option<()> {
+        for first_byte in 0u16..256 {
+            let i = self.sub_header_keys.get(first_byte)? / 8;
+            let sub_header = self.sub_headers.get(i)?;
+            let first_code = sub_header.first_code;
+
+            if i == 0 {
+                // This is a single byte code.
+                let range_end = first_code.checked_add(sub_header.entry_count)?;
+                if first_byte >= first_code && first_byte < range_end {
+                    f(u32::from(first_byte));
+                }
+            } else {
+                // This is a two byte code.
+                let base = first_code.checked_add(first_byte << 8)?;
+                for k in 0..sub_header.entry_count {
+                    let code_point = base.checked_add(k)?;
+                    f(u32::from(code_point));
+                }
+            }
+        }
+
+        Some(())
+    }
+}
+
+impl core::fmt::Debug for Subtable2<'_> {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        write!(f, "Subtable2 {{ ... }}")
+    }
+}

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/format4.rs

@@ -0,0 +1,121 @@
+use core::convert::TryFrom;
+
+use crate::parser::{LazyArray16, Stream};
+use crate::GlyphId;
+
+/// A [format 4](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-4-segment-mapping-to-delta-values)
+/// subtable.
+#[derive(Clone, Copy)]
+pub struct Subtable4<'a> {
+    start_codes: LazyArray16<'a, u16>,
+    end_codes: LazyArray16<'a, u16>,
+    id_deltas: LazyArray16<'a, i16>,
+    id_range_offsets: LazyArray16<'a, u16>,
+    id_range_offset_pos: usize,
+    // The whole subtable data.
+    data: &'a [u8],
+}
+
+impl<'a> Subtable4<'a> {
+    /// Parses a subtable from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.advance(6); // format + length + language
+        let seg_count_x2 = s.read::<u16>()?;
+        if seg_count_x2 < 2 {
+            return None;
+        }
+
+        let seg_count = seg_count_x2 / 2;
+        s.advance(6); // searchRange + entrySelector + rangeShift
+
+        let end_codes = s.read_array16::<u16>(seg_count)?;
+        s.skip::<u16>(); // reservedPad
+        let start_codes = s.read_array16::<u16>(seg_count)?;
+        let id_deltas = s.read_array16::<i16>(seg_count)?;
+        let id_range_offset_pos = s.offset();
+        let id_range_offsets = s.read_array16::<u16>(seg_count)?;
+
+        Some(Self {
+            start_codes,
+            end_codes,
+            id_deltas,
+            id_range_offsets,
+            id_range_offset_pos,
+            data,
+        })
+    }
+
+    /// Returns a glyph index for a code point.
+    ///
+    /// Returns `None` when `code_point` is larger than `u16`.
+    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
+        // This subtable supports code points only in a u16 range.
+        let code_point = u16::try_from(code_point).ok()?;
+
+        // A custom binary search.
+        let mut start = 0;
+        let mut end = self.start_codes.len();
+        while end > start {
+            let index = (start + end) / 2;
+            let end_value = self.end_codes.get(index)?;
+            if end_value >= code_point {
+                let start_value = self.start_codes.get(index)?;
+                if start_value > code_point {
+                    end = index;
+                } else {
+                    let id_range_offset = self.id_range_offsets.get(index)?;
+                    let id_delta = self.id_deltas.get(index)?;
+                    if id_range_offset == 0 {
+                        return Some(GlyphId(code_point.wrapping_add(id_delta as u16)));
+                    } else if id_range_offset == 0xFFFF {
+                        // Some malformed fonts have 0xFFFF as the last offset,
+                        // which is invalid and should be ignored.
+                        return None;
+                    }
+
+                    let delta = (u32::from(code_point) - u32::from(start_value)) * 2;
+                    let delta = u16::try_from(delta).ok()?;
+
+                    let id_range_offset_pos = (self.id_range_offset_pos + usize::from(index) * 2) as u16;
+                    let pos = id_range_offset_pos.wrapping_add(delta);
+                    let pos = pos.wrapping_add(id_range_offset);
+
+                    let glyph_array_value: u16 = Stream::read_at(self.data, usize::from(pos))?;
+
+                    // 0 indicates missing glyph.
+                    if glyph_array_value == 0 {
+                        return None;
+                    }
+
+                    let glyph_id = (glyph_array_value as i16).wrapping_add(id_delta);
+                    return u16::try_from(glyph_id).ok().map(GlyphId);
+                }
+            } else {
+                start = index + 1;
+            }
+        }
+
+        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;
+            }
+
+            for code_point in start..=end {
+                f(u32::from(code_point));
+            }
+        }
+    }
+}
+
+impl core::fmt::Debug for Subtable4<'_> {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        write!(f, "Subtable4 {{ ... }}")
+    }
+}

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/format6.rs

@@ -0,0 +1,47 @@
+use core::convert::TryFrom;
+
+use crate::parser::{LazyArray16, Stream};
+use crate::GlyphId;
+
+/// A [format 6](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-6-trimmed-table-mapping)
+/// subtable.
+#[derive(Clone, Copy, Debug)]
+pub struct Subtable6<'a> {
+    /// First character code of subrange.
+    pub first_code_point: u16,
+    /// Array of glyph indexes for character codes in the range.
+    pub glyphs: LazyArray16<'a, GlyphId>,
+}
+
+impl<'a> Subtable6<'a> {
+    /// Parses a subtable from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.skip::<u16>(); // format
+        s.skip::<u16>(); // length
+        s.skip::<u16>(); // language
+        let first_code_point = s.read::<u16>()?;
+        let count = s.read::<u16>()?;
+        let glyphs = s.read_array16::<GlyphId>(count)?;
+        Some(Self { first_code_point, glyphs })
+    }
+
+    /// Returns a glyph index for a code point.
+    ///
+    /// Returns `None` when `code_point` is larger than `u16`.
+    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
+        // This subtable supports code points only in a u16 range.
+        let code_point = u16::try_from(code_point).ok()?;
+        let idx = code_point.checked_sub(self.first_code_point)?;
+        self.glyphs.get(idx)
+    }
+
+    /// Calls `f` for each codepoint defined in this table.
+    pub fn codepoints(&self, mut f: impl FnMut(u32)) {
+        for i in 0..self.glyphs.len() {
+            if let Some(code_point) = self.first_code_point.checked_add(i) {
+                f(u32::from(code_point));
+            }
+        }
+    }
+}

third-party/vendor/ttf-parser-0.15.2/src/tables/cmap/mod.rs

@@ -0,0 +1,275 @@
+/*!
+A [Character to Glyph Index Mapping Table](
+https://docs.microsoft.com/en-us/typography/opentype/spec/cmap) implementation.
+
+This module provides a low-level alternative to
+[`Face::glyph_index`](../struct.Face.html#method.glyph_index) and
+[`Face::glyph_variation_index`](../struct.Face.html#method.glyph_variation_index)
+methods.
+*/
+
+use crate::{GlyphId, name::PlatformId};
+use crate::parser::{FromData, LazyArray16, Offset, Offset32, Stream};
+
+mod format0;
+mod format2;
+mod format4;
+mod format6;
+mod format10;
+mod format12;
+mod format13;
+mod format14;
+
+pub use format0::Subtable0;
+pub use format2::Subtable2;
+pub use format4::Subtable4;
+pub use format6::Subtable6;
+pub use format10::Subtable10;
+pub use format12::Subtable12;
+pub use format13::Subtable13;
+pub use format14::{Subtable14, GlyphVariationResult};
+
+/// A character encoding subtable variant.
+#[allow(missing_docs)]
+#[derive(Clone, Copy, Debug)]
+pub enum Format<'a> {
+    ByteEncodingTable(Subtable0<'a>),
+    HighByteMappingThroughTable(Subtable2<'a>),
+    SegmentMappingToDeltaValues(Subtable4<'a>),
+    TrimmedTableMapping(Subtable6<'a>),
+    MixedCoverage, // unsupported
+    TrimmedArray(Subtable10<'a>),
+    SegmentedCoverage(Subtable12<'a>),
+    ManyToOneRangeMappings(Subtable13<'a>),
+    UnicodeVariationSequences(Subtable14<'a>),
+}
+
+
+/// A character encoding subtable.
+#[derive(Clone, Copy, Debug)]
+pub struct Subtable<'a> {
+    /// Subtable platform.
+    pub platform_id: PlatformId,
+    /// Subtable encoding.
+    pub encoding_id: u16,
+    /// A subtable format.
+    pub format: Format<'a>,
+}
+
+impl<'a> Subtable<'a> {
+    /// Checks that the current encoding is Unicode compatible.
+    #[inline]
+    pub fn is_unicode(&self) -> bool {
+        // https://docs.microsoft.com/en-us/typography/opentype/spec/name#windows-encoding-ids
+        const WINDOWS_UNICODE_BMP_ENCODING_ID: u16 = 1;
+        const WINDOWS_UNICODE_FULL_REPERTOIRE_ENCODING_ID: u16 = 10;
+
+        match self.platform_id {
+            PlatformId::Unicode => true,
+            PlatformId::Windows if self.encoding_id == WINDOWS_UNICODE_BMP_ENCODING_ID => true,
+            PlatformId::Windows => {
+                // "Note: Subtable format 13 has the same structure as format 12; it differs only
+                // in the interpretation of the startGlyphID/glyphID fields".
+                let is_format_12_compatible =
+                    matches!(self.format, Format::SegmentedCoverage(..) | Format::ManyToOneRangeMappings(..));
+
+                // "Fonts that support Unicode supplementary-plane characters (U+10000 to U+10FFFF)
+                // on the Windows platform must have a format 12 subtable for platform ID 3,
+                // encoding ID 10."
+                self.encoding_id == WINDOWS_UNICODE_FULL_REPERTOIRE_ENCODING_ID
+                && is_format_12_compatible
+            }
+            _ => false,
+        }
+    }
+
+    /// Maps a character to a glyph ID.
+    ///
+    /// This is a low-level method and unlike `Face::glyph_index` it doesn't
+    /// check that the current encoding is Unicode.
+    /// It simply maps a `u32` codepoint number to a glyph ID.
+    ///
+    /// Returns `None`:
+    /// - when glyph ID is `0`.
+    /// - when format is `MixedCoverage`, since it's not supported.
+    /// - when format is `UnicodeVariationSequences`. Use `glyph_variation_index` instead.
+    #[inline]
+    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
+        match self.format {
+            Format::ByteEncodingTable(ref subtable) => subtable.glyph_index(code_point),
+            Format::HighByteMappingThroughTable(ref subtable) => subtable.glyph_index(code_point),
+            Format::SegmentMappingToDeltaValues(ref subtable) => subtable.glyph_index(code_point),
+            Format::TrimmedTableMapping(ref subtable) => subtable.glyph_index(code_point),
+            Format::MixedCoverage => None,
+            Format::TrimmedArray(ref subtable) => subtable.glyph_index(code_point),
+            Format::SegmentedCoverage(ref subtable) => subtable.glyph_index(code_point),
+            Format::ManyToOneRangeMappings(ref subtable) => subtable.glyph_index(code_point),
+            // This subtable should be accessed via glyph_variation_index().
+            Format::UnicodeVariationSequences(_) => None,
+        }
+    }
+
+    /// Resolves a variation of a glyph ID from two code points.
+    ///
+    /// Returns `None`:
+    /// - when glyph ID is `0`.
+    /// - when format is not `UnicodeVariationSequences`.
+    #[inline]
+    pub fn glyph_variation_index(&self, code_point: u32, variation: u32) -> Option<GlyphVariationResult> {
+        match self.format {
+            Format::UnicodeVariationSequences(ref subtable) => {
+                subtable.glyph_index(code_point, variation)
+            }
+            _ => None,
+        }
+    }
+
+    /// Calls `f` for all codepoints contained in this subtable.
+    ///
+    /// This is a low-level method and it doesn't check that the current
+    /// encoding is Unicode. It simply calls the function `f` for all `u32`
+    /// codepoints that are present in this subtable.
+    ///
+    /// Note that this may list codepoints for which `glyph_index` still returns
+    /// `None` because this method finds all codepoints which were _defined_ in
+    /// this subtable. The subtable may still map them to glyph ID `0`.
+    ///
+    /// Returns without doing anything:
+    /// - when format is `MixedCoverage`, since it's not supported.
+    /// - when format is `UnicodeVariationSequences`, since it's not supported.
+    pub fn codepoints<F: FnMut(u32)>(&self, f: F) {
+        match self.format {
+            Format::ByteEncodingTable(ref subtable) => subtable.codepoints(f),
+            Format::HighByteMappingThroughTable(ref subtable) => subtable.codepoints(f),
+            Format::SegmentMappingToDeltaValues(ref subtable) => subtable.codepoints(f),
+            Format::TrimmedTableMapping(ref subtable) => subtable.codepoints(f),
+            Format::MixedCoverage => {} // unsupported
+            Format::TrimmedArray(ref subtable) => subtable.codepoints(f),
+            Format::SegmentedCoverage(ref subtable) => subtable.codepoints(f),
+            Format::ManyToOneRangeMappings(ref subtable) => subtable.codepoints(f),
+            Format::UnicodeVariationSequences(_) => {} // unsupported
+        };
+    }
+}
+
+
+#[derive(Clone, Copy)]
+struct EncodingRecord {
+    platform_id: PlatformId,
+    encoding_id: u16,
+    offset: Offset32,
+}
+
+impl FromData for EncodingRecord {
+    const SIZE: usize = 8;
+
+    #[inline]
+    fn parse(data: &[u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        Some(EncodingRecord {
+            platform_id: s.read::<PlatformId>()?,
+            encoding_id: s.read::<u16>()?,
+            offset: s.read::<Offset32>()?,
+        })
+    }
+}
+
+
+/// A list of subtables.
+#[derive(Clone, Copy, Default)]
+pub struct Subtables<'a> {
+    data: &'a [u8],
+    records: LazyArray16<'a, EncodingRecord>,
+}
+
+impl core::fmt::Debug for Subtables<'_> {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        write!(f, "Subtables {{ ... }}")
+    }
+}
+
+impl<'a> Subtables<'a> {
+    /// Returns a subtable at an index.
+    pub fn get(&self, index: u16) -> Option<Subtable<'a>> {
+        let record = self.records.get(index)?;
+        let data = self.data.get(record.offset.to_usize()..)?;
+        let format = match Stream::read_at::<u16>(data, 0)? {
+            0  => Format::ByteEncodingTable(Subtable0::parse(data)?),
+            2  => Format::HighByteMappingThroughTable(Subtable2::parse(data)?),
+            4  => Format::SegmentMappingToDeltaValues(Subtable4::parse(data)?),
+            6  => Format::TrimmedTableMapping(Subtable6::parse(data)?),
+            8  => Format::MixedCoverage, // unsupported
+            10 => Format::TrimmedArray(Subtable10::parse(data)?),
+            12 => Format::SegmentedCoverage(Subtable12::parse(data)?),
+            13 => Format::ManyToOneRangeMappings(Subtable13::parse(data)?),
+            14 => Format::UnicodeVariationSequences(Subtable14::parse(data)?),
+            _ => return None,
+        };
+
+        Some(Subtable {
+            platform_id: record.platform_id,
+            encoding_id: record.encoding_id,
+            format,
+        })
+    }
+
+    /// Returns the number
+    #[inline]
+    pub fn len(&self) -> u16 {
+        self.records.len()
+    }
+}
+
+impl<'a> IntoIterator for Subtables<'a> {
+    type Item = Subtable<'a>;
+    type IntoIter = SubtablesIter<'a>;
+
+    #[inline]
+    fn into_iter(self) -> Self::IntoIter {
+        SubtablesIter {
+            subtables: self,
+            index: 0,
+        }
+    }
+}
+
+/// An iterator over [`Subtables`].
+#[allow(missing_debug_implementations)]
+pub struct SubtablesIter<'a> {
+    subtables: Subtables<'a>,
+    index: u16,
+}
+
+impl<'a> Iterator for SubtablesIter<'a> {
+    type Item = Subtable<'a>;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.index < self.subtables.len() {
+            self.index += 1;
+            self.subtables.get(self.index - 1)
+        } else {
+            None
+        }
+    }
+}
+
+
+/// A [Character to Glyph Index Mapping Table](
+/// https://docs.microsoft.com/en-us/typography/opentype/spec/cmap).
+#[derive(Clone, Copy, Debug)]
+pub struct Table<'a> {
+    /// A list of subtables.
+    pub subtables: Subtables<'a>,
+}
+
+impl<'a> Table<'a> {
+    /// Parses a table from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        s.skip::<u16>(); // version
+        let count = s.read::<u16>()?;
+        let records = s.read_array16::<EncodingRecord>(count)?;
+        Some(Table { subtables: Subtables { data, records }})
+    }
+}