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Properly terminate in subroutines with an endchar operator #22

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Merged
laurmaedje merged 3 commits into from
May 4, 2026
Merged

Properly terminate in subroutines with an endchar operator #22

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ccb489b
Add test
LaurenzV May 1, 2026
6aa0bfe
Properly handle subroutines with `endchar`
LaurenzV May 1, 2026
78e96d9
Make font smaller
LaurenzV May 1, 2026
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1 change: 1 addition & 0 deletions NOTICE
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Original file line number Diff line number Diff line change
Expand Up @@ -264,6 +264,7 @@ from Tavmjong Bah. For further information, contact: tavmjong @ free

The GUST font license applies to the following fonts:
- fonts/LatinModernRoman-Regular.otf
- fonts/EndcharInSubroutine_1.otf (derived from LatinModernRoman-Regular.otf)
- fonts/NewCMMath-Regular.otf

% This is version 1.0, dated 22 June 2009, of the GUST Font License.
Expand Down
Binary file added fonts/EndcharInSubroutine.otf
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29 changes: 22 additions & 7 deletions src/cff/charstring.rs
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Expand Up @@ -21,6 +21,11 @@ pub struct Decompiler<'a> {
hint_mask_bytes: u16,
}

enum CharStringEnd {
Return,
EndChar,
}

impl<'a> Decompiler<'a> {
/// Create a new charstring decompiler.
pub fn new(
Expand Down Expand Up @@ -48,7 +53,7 @@ impl<'a> Decompiler<'a> {
charstring: CharString<'a>,
program: &mut Program<'a>,
depth: u8,
) -> Result<()> {
) -> Result<CharStringEnd> {
if depth > 64 {
return Err(CFFError);
}
Expand Down Expand Up @@ -94,9 +99,7 @@ impl<'a> Decompiler<'a> {
self.stack.pop_all();
program.push(Instruction::Operator(operator));
}
RETURN => {
// Don't do anything for return, since we desubroutinize.
}
RETURN => return Ok(CharStringEnd::Return),
CALL_GLOBAL_SUBROUTINE => {
// Pop the subroutine index from the program.
program.0.pop();
Expand All @@ -107,7 +110,12 @@ impl<'a> Decompiler<'a> {
.gsubr_handler
.get_with_biased(biased_index)
.ok_or(CFFError)?;
self.decompile_inner(gsubr, program, depth + 1)?;
if matches!(
self.decompile_inner(gsubr, program, depth + 1)?,
CharStringEnd::EndChar
) {
return Ok(CharStringEnd::EndChar);
}
}
CALL_LOCAL_SUBROUTINE => {
// Pop the subroutine index from the program.
Expand All @@ -119,7 +127,12 @@ impl<'a> Decompiler<'a> {
.lsubr_handler
.get_with_biased(biased_index)
.ok_or(CFFError)?;
self.decompile_inner(lsubr, program, depth + 1)?;
if matches!(
self.decompile_inner(lsubr, program, depth + 1)?,
CharStringEnd::EndChar
) {
return Ok(CharStringEnd::EndChar);
}
}
HINT_MASK | COUNTER_MASK => {
program.push(Instruction::Operator(operator));
Expand All @@ -141,14 +154,16 @@ impl<'a> Decompiler<'a> {
}

program.push(Instruction::Operator(operator));

return Ok(CharStringEnd::EndChar);
}
_ => {
return Err(CFFError);
}
}
}

Ok(())
Ok(CharStringEnd::Return)
}

fn count_hints(&mut self) {
Expand Down
1 change: 1 addition & 0 deletions tests/data/fonttools.tests
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Expand Up @@ -10,6 +10,7 @@ NotoSans-Regular.ttf;567-570,2345-2350
Roboto-Regular.ttf;456,460-463
NewCMMath-Regular.otf;803-806,950-952,5600-5602
NotoSansCJKsc-Bold-subset1.otf;1
EndcharInSubroutine.otf;1
NotoSans-Regular_var.ttf;10,40,58,201-205;wght=400
NotoSans-Regular_var.ttf;10,40,58,201-205;wght=900
NotoSans-Regular_var.ttf;10,40,58,201-205;wght=800,wdth=70.0
Expand Down
1 change: 1 addition & 0 deletions tests/src/font_tools.rs
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Expand Up @@ -13,6 +13,7 @@ use crate::*;
#[test] fn roboto_regular_1() {test_font_tools("Roboto-Regular.ttf", "456,460-463", "", 1)}
#[test] fn new_c_m_math_regular_1() {test_font_tools("NewCMMath-Regular.otf", "803-806,950-952,5600-5602", "", 1)}
#[test] fn noto_sans_c_j_ksc_boldsubset1_1() {test_font_tools("NotoSansCJKsc-Bold-subset1.otf", "1", "", 1)}
#[test] fn endchar_in_subroutine_1() {test_font_tools("EndcharInSubroutine.otf", "1", "", 1)}
#[test] #[cfg(feature = "variable-fonts")] fn noto_sans_regular_var_1() {test_font_tools("NotoSans-Regular_var.ttf", "10,40,58,201-205", "wght=400", 1)}
#[test] #[cfg(feature = "variable-fonts")] fn noto_sans_regular_var_2() {test_font_tools("NotoSans-Regular_var.ttf", "10,40,58,201-205", "wght=900", 2)}
#[test] #[cfg(feature = "variable-fonts")] fn noto_sans_regular_var_3() {test_font_tools("NotoSans-Regular_var.ttf", "10,40,58,201-205", "wght=800,wdth=70.0", 3)}
Expand Down
154 changes: 154 additions & 0 deletions tests/ttx/EndcharInSubroutine_1.ttx
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@@ -0,0 +1,154 @@
<?xml version="1.0" encoding="UTF-8"?>
<ttFont sfntVersion="OTTO" ttLibVersion="4.62">

<GlyphOrder>
<!-- The 'id' attribute is only for humans; it is ignored when parsed. -->
<GlyphID id="0" name=".notdef"/>
<GlyphID id="1" name="cid00001"/>
</GlyphOrder>

<head>
<!-- Most of this table will be recalculated by the compiler -->
<tableVersion value="1.0"/>
<fontRevision value="2.004"/>
<checkSumAdjustment value="0x59e8be78"/>
<magicNumber value="0x5f0f3cf5"/>
<flags value="00000000 00000011"/>
<unitsPerEm value="1000"/>
<created value="Thu Oct 8 09:58:12 2009"/>
<modified value="Fri May 1 12:01:06 2026"/>
<xMin value="-430"/>
<yMin value="-290"/>
<xMax value="1417"/>
<yMax value="1127"/>
<macStyle value="00000000 00000000"/>
<lowestRecPPEM value="3"/>
<fontDirectionHint value="2"/>
<indexToLocFormat value="0"/>
<glyphDataFormat value="0"/>
</head>

<hhea>
<tableVersion value="0x00010000"/>
<ascent value="1127"/>
<descent value="-290"/>
<lineGap value="0"/>
<advanceWidthMax value="1457"/>
<minLeftSideBearing value="-430"/>
<minRightSideBearing value="-260"/>
<xMaxExtent value="1417"/>
<caretSlopeRise value="1"/>
<caretSlopeRun value="0"/>
<caretOffset value="0"/>
<reserved0 value="0"/>
<reserved1 value="0"/>
<reserved2 value="0"/>
<reserved3 value="0"/>
<metricDataFormat value="0"/>
<numberOfHMetrics value="2"/>
</hhea>

<maxp>
<tableVersion value="0x5000"/>
<numGlyphs value="2"/>
</maxp>

<name>
<namerecord nameID="0" platformID="3" platEncID="1" langID="0x409">
Copyright 2003, 2009 B. Jackowski and J. M. Nowacki (on behalf of TeX users groups). This work is released under the GUST Font License -- see http://tug.org/fonts/licenses/GUST-FONT-LICENSE.txt for details.
</namerecord>
<namerecord nameID="1" platformID="3" platEncID="1" langID="0x409">
LM Roman 10
</namerecord>
<namerecord nameID="2" platformID="3" platEncID="1" langID="0x409">
Regular
</namerecord>
<namerecord nameID="3" platformID="3" platEncID="1" langID="0x409">
2.004;UKWN;LMRoman10-Regular
</namerecord>
<namerecord nameID="4" platformID="3" platEncID="1" langID="0x409">
LMRoman10-Regular
</namerecord>
<namerecord nameID="5" platformID="3" platEncID="1" langID="0x409">
Version 2.004;PS 2.004;hotconv 1.0.49;makeotf.lib2.0.14853
</namerecord>
<namerecord nameID="6" platformID="3" platEncID="1" langID="0x409">
LMRoman10-Regular
</namerecord>
</name>

<post>
<formatType value="3.0"/>
<italicAngle value="0.0"/>
<underlinePosition value="-126"/>
<underlineThickness value="40"/>
<isFixedPitch value="0"/>
<minMemType42 value="0"/>
<maxMemType42 value="0"/>
<minMemType1 value="0"/>
<maxMemType1 value="0"/>
</post>

<CFF>
<major value="1"/>
<minor value="0"/>
<CFFFont name="LMRoman10-Regular">
<ROS Registry="Adobe" Order="Identity" Supplement="0"/>
<Notice value="Copyright 2003, 2009 B. Jackowski and J. M. Nowacki (on behalf of TeX users groups). This work is released under the GUST Font License -- see http://tug.org/fonts/licenses/GUST-FONT-LICENSE.txt for details."/>
<isFixedPitch value="0"/>
<ItalicAngle value="0"/>
<UnderlinePosition value="-100"/>
<UnderlineThickness value="50"/>
<PaintType value="0"/>
<CharstringType value="2"/>
<FontMatrix value="0.001 0 0 0.001 0 0"/>
<FontBBox value="-430 -290 1417 1127"/>
<StrokeWidth value="0"/>
<CIDFontVersion value="0"/>
<CIDFontRevision value="0"/>
<CIDFontType value="0"/>
<CIDCount value="65535"/>
<!-- charset is dumped separately as the 'GlyphOrder' element -->
<FDSelect format="3"/>
<FDArray>
<FontDict index="0">
<FontMatrix value="1 0 0 1 0 0"/>
<Private>
<BlueValues value="-22 0 431 448 666 677 683 705"/>
<BlueScale value="0.04546"/>
<BlueShift value="7"/>
<BlueFuzz value="0"/>
<StdHW value="31"/>
<StdVW value="69"/>
<StemSnapH value="22 23 25 26 28 30 31 38 40 42 45 106"/>
<StemSnapV value="25 66 69 75 77 83 86 89 92 97 103 107"/>
<ForceBold value="0"/>
<LanguageGroup value="0"/>
<ExpansionFactor value="0.06"/>
<initialRandomSeed value="0"/>
<defaultWidthX value="0"/>
<nominalWidthX value="0"/>
</Private>
</FontDict>
</FDArray>
<CharStrings>
<CharString name=".notdef" fdSelectIndex="0">
280 endchar
</CharString>
<CharString name="cid00001" fdSelectIndex="0">
333 endchar
</CharString>
</CharStrings>
</CFFFont>

<GlobalSubrs>
<!-- The 'index' attribute is only for humans; it is ignored when parsed. -->
</GlobalSubrs>
</CFF>

<hmtx>
<mtx name=".notdef" width="280" lsb="0"/>
<mtx name="cid00001" width="333" lsb="0"/>
</hmtx>

</ttFont>
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