Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8d582a2e authored by Henri Chataing's avatar Henri Chataing
Browse files

pdl: Use correct semantic for padding field 

Padding field completes an array field by padding the size
to a fixed value using 0x00 fill

Test: atest --host --no-bazel pdl_python_generator_tes
Change-Id: Iee0271c7ea1b9ba9b8073585450edf6916d53adf
parent 910e2b1a

tools/pdl/doc/reference.md

+5 −3
Original line number Diff line number Diff line
@@ -563,11 +563,13 @@ packet CRCedBrew { 
> padding_field:\

>    `_padding_` `[` [INTEGER](#integer) `]`



A *\_padding\_* field adds a number of **octet** of padding.

A *\_padding\_* field immediately following an array field pads the array field with `0`s to the

specified number of **octets**.



```

packet Padded {

  _padding_[1] // 1 octet/8bit of padding

packet PaddedCoffee {

  additions: CoffeeAddition[],

  _padding_[100]

}

```

tools/pdl/scripts/generate_python_backend.py

+19 −1
Original line number Diff line number Diff line
@@ -177,6 +177,8 @@ class FieldParser: 
        """Parse the selected array field."""

        array_size = core.get_array_field_size(field)

        element_width = core.get_array_element_size(field)

        padded_size = field.padded_size



        if element_width:

            if element_width % 8 != 0:

                raise Exception('Array element size is not a multiple of 8')
@@ -202,6 +204,12 @@ class FieldParser: 
        if field.size_modifier and size:

            self.append_(f"{size} = {size} - {field.size_modifier}")



        # Parse from the padded array if padding is present.

        if padded_size:

            self.check_size_(padded_size)

            self.append_(f"remaining_span = span[{padded_size}:]")

            self.append_(f"span = span[:{padded_size}]")



        # The element width is not known, but the array full octet size

        # is known by size field. Parse elements item by item as a vector.

        if element_width is None and size is not None:
@@ -263,6 +271,10 @@ class FieldParser: 
            if size is not None:

                self.append_(f"span = span[{size}:]")



        # Drop the padding

        if padded_size:

            self.append_(f"span = remaining_span")



    def parse_bit_field_(self, field: ast.Field):

        """Parse the selected field as a bit field.

        The field is added to the current chunk. When a byte boundary
@@ -346,7 +358,7 @@ class FieldParser: 


        if self.shift != 0:

            raise Exception('Padding field does not start on an octet boundary')

        self.offset += field.width

        self.offset += field.size



    def parse_payload_field_(self, field: Union[ast.BodyField, ast.PayloadField]):

        """Parse body and payload fields."""
@@ -535,6 +547,9 @@ class FieldSerializer: 


    def serialize_array_field_(self, field: ast.ArrayField):

        """Serialize the selected array field."""

        if field.padded_size:

            self.append_(f"_{field.id}_start = len(_span)")



        if field.width == 8:

            self.append_(f"_span.extend(self.{field.id})")

        else:
@@ -543,6 +558,9 @@ class FieldSerializer: 
            self.serialize_array_element_(field)

            self.unindent_()



        if field.padded_size:

            self.append_(f"_span.extend([0] * ({field.padded_size} - len(_span) + _{field.id}_start))")



    def serialize_bit_field_(self, field: ast.Field):

        """Serialize the selected field as a bit field.

        The field is added to the current chunk. When a byte boundary

tools/pdl/scripts/pdl/ast.py

+2 −1
Original line number Diff line number Diff line
@@ -59,7 +59,7 @@ class ChecksumField(Field): 


@node('padding_field')

class PaddingField(Field):

    width: int

    size: int





@node('size_field')
@@ -109,6 +109,7 @@ class ArrayField(Field): 
    type_id: Optional[str]

    size_modifier: Optional[str]

    size: Optional[int]

    padded_size: Optional[int] = field(init=False, default=None)



    @property

    def type(self) -> Optional['Declaration']:

tools/pdl/scripts/pdl/core.py

+8 −3
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ from typing import Optional, List, Dict, Union, Tuple 
from .ast import *





def desugar_field_(field: Field, constraints: Dict[str, Constraint]) -> List[Field]:

def desugar_field_(field: Field, previous: Field, constraints: Dict[str, Constraint]) -> List[Field]:

    """Inline group and constrained fields.

    Constrained fields are transformed into fixed fields.

    Group fields are inlined and recursively desugared."""
@@ -13,6 +13,10 @@ def desugar_field_(field: Field, constraints: Dict[str, Constraint]) -> List[Fie 
        fixed.parent = field.parent

        return [fixed]



    elif isinstance(field, PaddingField):

        previous.padded_size = field.size

        return []



    elif isinstance(field, TypedefField) and field.id in constraints:

        tag_id = constraints[field.id].tag_id

        fixed = FixedField(kind='fixed_field', loc=field.loc, enum_id=field.type_id, tag_id=tag_id)
@@ -24,7 +28,8 @@ def desugar_field_(field: Field, constraints: Dict[str, Constraint]) -> List[Fie 
        constraints = dict([(c.id, c) for c in field.constraints])

        fields = []

        for f in group.fields:

            fields.extend(desugar_field_(f, constraints))

            fields.extend(desugar_field_(f, previous, constraints))

            previous = f

        return fields



    else:
@@ -45,7 +50,7 @@ def desugar(file: File): 
        if isinstance(d, (PacketDeclaration, StructDeclaration)):

            fields = []

            for f in d.fields:

                fields.extend(desugar_field_(f, {}))

                fields.extend(desugar_field_(f, fields[-1] if len(fields) > 0 else None, {}))

            d.fields = fields



        declarations.append(d)

tools/pdl/src/ast.rs

+1 −1
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ pub enum Field { 
    #[serde(rename = "checksum_field")]

    Checksum { loc: SourceRange, field_id: String },

    #[serde(rename = "padding_field")]

    Padding { loc: SourceRange, width: usize },

    Padding { loc: SourceRange, size: usize },

    #[serde(rename = "size_field")]

    Size { loc: SourceRange, field_id: String, width: usize },

    #[serde(rename = "count_field")]