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// https://docs.microsoft.com/en-us/typography/opentype/spec/maxp
use core::num::NonZeroU16;
use crate::parser::Stream;
// We care only about `numGlyphs`.
pub fn parse(data: &[u8]) -> Option<NonZeroU16> {
let mut s = Stream::new(data);
let version: u32 = s.read()?;
if !(version == 0x00005000 || version == 0x00010000) {
return None;
}
let n: u16 = s.read()?;
NonZeroU16::new(n)
}
#[cfg(test)]
mod tests {
#[test]
fn version_05() {
let num_glyphs = super::parse(&[
0x00, 0x00, 0x50, 0x00, // version: 0.3125
0x00, 0x01, // number of glyphs: 1
]).map(|n| n.get());
assert_eq!(num_glyphs, Some(1));
}
#[test]
fn version_1_full() {
let num_glyphs = super::parse(&[
0x00, 0x01, 0x00, 0x00, // version: 1
0x00, 0x01, // number of glyphs: 1
0x00, 0x00, // maximum points in a non-composite glyph: 0
0x00, 0x00, // maximum contours in a non-composite glyph: 0
0x00, 0x00, // maximum points in a composite glyph: 0
0x00, 0x00, // maximum contours in a composite glyph: 0
0x00, 0x00, // maximum zones: 0
0x00, 0x00, // maximum twilight points: 0
0x00, 0x00, // number of Storage Area locations: 0
0x00, 0x00, // number of FDEFs: 0
0x00, 0x00, // number of IDEFs: 0
0x00, 0x00, // maximum stack depth: 0
0x00, 0x00, // maximum byte count for glyph instructions: 0
0x00, 0x00, // maximum number of components: 0
0x00, 0x00, // maximum levels of recursion: 0
]).map(|n| n.get());
assert_eq!(num_glyphs, Some(1));
}
#[test]
fn version_1_trimmed() {
// We don't really care about the data after the number of glyphs.
let num_glyphs = super::parse(&[
0x00, 0x01, 0x00, 0x00, // version: 1
0x00, 0x01, // number of glyphs: 1
]).map(|n| n.get());
assert_eq!(num_glyphs, Some(1));
}
#[test]
fn unknown_version() {
let num_glyphs = super::parse(&[
0x00, 0x00, 0x00, 0x00, // version: 0
0x00, 0x01, // number of glyphs: 1
]).map(|n| n.get());
assert_eq!(num_glyphs, None);
}
#[test]
fn zero_glyphs() {
let num_glyphs = super::parse(&[
0x00, 0x00, 0x50, 0x00, // version: 0.3125
0x00, 0x00, // number of glyphs: 0
]).map(|n| n.get());
assert_eq!(num_glyphs, None);
}
// TODO: what to do when the number of glyphs is 0xFFFF?
// we're actually checking this in loca
}