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‎examples/demo.py‎

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from examples import assets_dir
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from sfnttools.font import SfntFont
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def main():
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SfntFont.load(assets_dir.joinpath('source-han-sans', 'SourceHanSansSC-VF.otf'), verify_checksum=True)
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SfntFont.load(assets_dir.joinpath('source-han-sans', 'SourceHanSansSC-VF.otf.woff2'), verify_checksum=True)
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SfntFont.load(assets_dir.joinpath('source-han-sans', 'SourceHanSansSC-VF.ttf'), verify_checksum=True)
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SfntFont.load(assets_dir.joinpath('source-han-sans', 'SourceHanSansSC-VF.ttf.woff2'), verify_checksum=True)
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a = SfntFont.load(assets_dir.joinpath('demo', 'demo.otf'), verify_checksum=True)
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b = SfntFont.load(assets_dir.joinpath('demo', 'demo.otf.woff'), verify_checksum=True)
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c = SfntFont.load(assets_dir.joinpath('demo', 'demo.otf.woff2'), verify_checksum=True)
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d = SfntFont.load(assets_dir.joinpath('demo', 'demo.ttf'), verify_checksum=True)
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e = SfntFont.load(assets_dir.joinpath('demo', 'demo.ttf.woff'), verify_checksum=True)
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f = SfntFont.load(assets_dir.joinpath('demo', 'demo.ttf.woff2'), verify_checksum=True)
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print()
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if __name__ == '__main__':
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main()

‎src/sfnttools/checksum.py‎

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_CHECKSUM_MASK = 0xFFFFFFFF
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_CHECKSUM_MAGIC_NUMBER = 0xB1B0AFBA
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def calculate_checksum(data: bytes) -> int:
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checksum = 0
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for i in range(0, len(data), 4):
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chunk = data[i:i + 4]
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if len(chunk) < 4:
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chunk += b'\x00' * (4 - len(chunk))
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checksum += int.from_bytes(chunk, 'big', signed=False)
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checksum &= _CHECKSUM_MASK
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return checksum
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def calculate_checksum_adjustment(checksums: list[int]) -> int:
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total_checksum = sum(checksums) & _CHECKSUM_MASK
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checksum_adjustment = (_CHECKSUM_MAGIC_NUMBER - total_checksum) & _CHECKSUM_MASK
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return checksum_adjustment

‎src/sfnttools/error.py‎

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class SfntError(Exception):
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pass

‎src/sfnttools/font.py‎

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from collections import UserDict, UserList
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from io import BytesIO
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from os import PathLike
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from typing import Any, BinaryIO
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from sfnttools.error import SfntError
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from sfnttools.payload import WoffPayload
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from sfnttools.stream import Stream
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from sfnttools.table import SfntTable
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from sfnttools.tables import TABLE_TYPE_REGISTRY
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from sfnttools.tag import SfntVersion, SfntFileTag
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from sfnttools.woff.reader import WoffReader
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from sfnttools.woff2.reader import Woff2Reader, Woff2CollectionReader
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from sfnttools.xtf.reader import XtfReader, XtfCollectionReader
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class SfntFont(UserDict[str, SfntTable]):
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@staticmethod
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def parse(
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stream: bytes | BinaryIO,
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font_index: int | None = None,
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verify_checksum: bool = False,
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) -> 'SfntFont':
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if isinstance(stream, bytes):
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stream = BytesIO(stream)
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stream = Stream(stream)
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stream.seek(0)
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tag = stream.read_tag()
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if tag == SfntFileTag.TTCF:
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if font_index is None:
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raise SfntError(f'must specify a font index in font collection')
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reader = XtfReader.create_by_ttc(stream, font_index, verify_checksum)
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elif tag == SfntFileTag.WOFF:
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reader = WoffReader.create(stream, verify_checksum)
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elif tag == SfntFileTag.WOFF2:
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stream.seek(4)
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flavor = stream.read_tag()
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if flavor == SfntFileTag.TTCF:
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if font_index is None:
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raise SfntError(f'must specify a font index in font collection')
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reader = Woff2Reader.create_by_ttc(stream, font_index)
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elif flavor in [*SfntVersion]:
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reader = Woff2Reader.create(stream, verify_checksum)
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else:
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raise SfntError('unsupported font')
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elif tag in [*SfntVersion]:
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reader = XtfReader.create(stream, verify_checksum)
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else:
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raise SfntError('unsupported font')
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sfnt_version, tables = reader.parse_font()
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woff_payload = reader.read_woff_payload()
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return SfntFont(sfnt_version, tables, woff_payload)
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@staticmethod
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def load(
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file_path: str | PathLike[str],
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font_index: int | None = None,
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verify_checksum: bool = False,
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) -> 'SfntFont':
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with open(file_path, 'rb') as file:
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return SfntFont.parse(file, font_index, verify_checksum)
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sfnt_version: SfntVersion
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woff_payload: WoffPayload | None
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def __init__(
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self,
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sfnt_version: SfntVersion,
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tables: dict[str, SfntTable] | None = None,
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woff_payload: WoffPayload | None = None,
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):
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super().__init__(tables)
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self.sfnt_version = sfnt_version
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self.woff_payload = woff_payload
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def __setitem__(self, tag: Any, table: Any):
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if not isinstance(tag, str):
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raise KeyError("tag must be a 'str'")
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if len(tag) != 4:
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raise KeyError('tag length must be 4')
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if any(not 0x20 <= ord(c) <= 0x7E for c in tag):
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raise KeyError('tag contains illegal characters')
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if tag.startswith(' '):
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raise KeyError('tag cannot start with a space')
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if ' ' in tag.strip():
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raise KeyError('tag cannot contain spaces in between')
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table_type = TABLE_TYPE_REGISTRY.get(tag, SfntTable)
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if not isinstance(table, table_type):
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raise ValueError(f'bad table type for tag {repr(tag)}')
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super().__setitem__(tag, table)
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def __repr__(self) -> str:
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return object.__repr__(self)
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class SfntFontCollection(UserList[SfntFont]):
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@staticmethod
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def parse(
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stream: bytes | BinaryIO,
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share_tables: bool = True,
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verify_checksum: bool = False,
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) -> 'SfntFontCollection':
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if isinstance(stream, bytes):
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stream = BytesIO(stream)
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stream = Stream(stream)
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stream.seek(0)
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tag = stream.read_tag()
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if tag == SfntFileTag.TTCF:
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collection_reader = XtfCollectionReader.create(stream, share_tables, verify_checksum)
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elif tag == SfntFileTag.WOFF2:
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stream.seek(4)
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flavor = stream.read_tag()
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if flavor != SfntFileTag.TTCF:
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raise SfntError('not a woff2 collection font')
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collection_reader = Woff2CollectionReader.create(stream, share_tables)
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else:
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raise SfntError('unsupported collection font')
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fonts = []
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for font_index in range(collection_reader.get_num_fonts()):
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reader = collection_reader.create_reader(font_index)
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sfnt_version, tables = reader.parse_font()
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fonts.append(SfntFont(sfnt_version, tables))
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woff_payload = collection_reader.read_woff_payload()
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return SfntFontCollection(fonts, woff_payload)
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@staticmethod
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def load(
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file_path: str | PathLike[str],
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share_tables: bool = True,
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verify_checksum: bool = False,
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) -> 'SfntFontCollection':
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with open(file_path, 'rb') as file:
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return SfntFontCollection.parse(file, share_tables, verify_checksum)
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woff_payload: WoffPayload | None
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def __init__(
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self,
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fonts: list[SfntFont] | None = None,
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woff_payload: WoffPayload | None = None,
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):
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super().__init__(fonts)
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self.woff_payload = woff_payload
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def __repr__(self) -> str:
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return object.__repr__(self)

‎src/sfnttools/internal/checksum.py‎

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This file was deleted.

‎src/sfnttools/payload.py‎

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class WoffPayload:
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major_version: int
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minor_version: int
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metadata: bytes | None
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private_data: bytes | None
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def __init__(
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self,
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major_version: int = 0,
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minor_version: int = 0,
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metadata: bytes | None = None,
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private_data: bytes | None = None,
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):
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self.major_version = major_version
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self.minor_version = minor_version
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self.metadata = metadata
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self.private_data = private_data

‎src/sfnttools/internal/stream.py‎ renamed to ‎src/sfnttools/stream.py‎

File renamed without changes.

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