Skip to content

[PoC] Speed up reading #1709

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
behdad wants to merge 4 commits into
base: main
Choose a base branch
from
Open

[PoC] Speed up reading #1709

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
3180fb0
[codegen/read-fonts] Part 1 of remove bounds-checking from constructors
behdad Dec 30, 2025
e1f32b4
[codegen/read-fonts] Part 2 of remove bounds checking from constructors
behdad Dec 30, 2025
0dd615b
Remove unused shape from TableRef
behdad Dec 30, 2025
b71a265
[code-gen/read-fonts] Use unsafe unchecked access across all reads
behdad Dec 31, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
31 changes: 21 additions & 10 deletions font-codegen/src/fields.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -315,14 +315,26 @@ fn if_expression(xform: &IfTransform, add_self: bool) -> TokenStream {
}

impl Condition {
fn condition_tokens_for_read(&self) -> TokenStream {
pub(crate) fn condition_tokens_for_read(&self) -> TokenStream {
match self {
Condition::SinceVersion(version) => quote!(version.compatible(#version)),
Condition::IfFlag { field, flag } => quote!(#field.contains(#flag)),
Condition::IfCond { xform } => if_expression(xform, false),
}
}

pub(crate) fn condition_tokens_for_access(&self) -> TokenStream {
match self {
Condition::SinceVersion(version) => quote!(self.version().compatible(#version)),
Condition::IfFlag { field, flag } => quote!(self.#field().contains(#flag)),
Condition::IfCond { xform } => match xform {
IfTransform::AnyFlag(field, flags) => {
quote!(self.#field().intersects(#(#flags)|*))
}
},
}
}

fn condition_tokens_for_write(&self) -> TokenStream {
match self {
Condition::SinceVersion(version) => quote!(version.compatible(#version)),
Expand Down Expand Up @@ -690,7 +702,7 @@ impl Field {
self.attrs.skip_getter.is_none()
}

pub(crate) fn shape_len_expr(&self) -> TokenStream {
pub(crate) fn shape_len_expr(&self, start_expr: TokenStream) -> TokenStream {
// is this a scalar/offset? then it's just 'RAW_BYTE_LEN'
// is this computed? then it is stored
match &self.typ {
Expand All @@ -702,8 +714,7 @@ impl Field {
| FieldType::ComputedArray { .. }
| FieldType::VarLenArray(_) => {
let len_field = self.shape_byte_len_field_name();
let try_op = self.is_conditional().then(|| quote!(?));
quote!(self.#len_field #try_op)
quote!(self.#len_field(#start_expr))
}
FieldType::PendingResolution { .. } => panic!("Should have resolved {self:?}"),
}
Expand All @@ -717,7 +728,7 @@ impl Field {
result.extend(
count
.iter_referenced_fields()
.map(|fld| (fld.clone(), NeededWhen::Parse)),
.map(|fld| (fld.clone(), NeededWhen::Both)),
);
}
if let Some(flds) = self.attrs.conditional.as_ref().map(|c| c.input_field()) {
Expand Down Expand Up @@ -814,13 +825,13 @@ impl Field {
let range_stmt = self.getter_range_stmt();
let mut read_stmt = if let Some(args) = &self.attrs.read_with_args {
let get_args = args.to_tokens_for_table_getter();
quote!( self.data.read_with_args(range, &#get_args).unwrap() )
quote!(unchecked::read_with_args(self.data, range, &#get_args))
} else if is_var_array {
quote!(VarLenArray::read(self.data.split_off(range.start).unwrap()).unwrap())
quote!(VarLenArray::read(unchecked::split_off(self.data, range.start)).unwrap())
} else if is_array {
quote!(self.data.read_array(range).unwrap())
quote!(unchecked::read_array(self.data, range))
} else {
quote!(self.data.read_at(range.start).unwrap())
quote!(unchecked::read_at(self.data, range.start))
};
if is_versioned {
read_stmt = quote!(Some(#read_stmt));
Expand Down Expand Up @@ -887,7 +898,7 @@ impl Field {
fn getter_range_stmt(&self) -> TokenStream {
let shape_range_fn_name = self.shape_byte_range_fn_name();
let try_op = self.is_conditional().then(|| quote!(?));
quote!( self.shape.#shape_range_fn_name() #try_op )
quote!( self.#shape_range_fn_name() #try_op )
}

fn typed_offset_getter_docs(&self, has_data_arg: bool) -> TokenStream {
Expand Down
Loading
Loading