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[Python] Implement TLV List type (#25238)
* [python] Implement TLV List type * Update * Revert "Update" This reverts commit 448c46f. * Fix * Update
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,175 @@ | ||
| #!/usr/bin/env python3 | ||
| # coding=utf-8 | ||
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| # | ||
| # Copyright (c) 2023 Project CHIP Authors | ||
| # All rights reserved. | ||
| # | ||
| # Licensed under the Apache License, Version 2.0 (the "License"); | ||
| # you may not use this file except in compliance with the License. | ||
| # You may obtain a copy of the License at | ||
| # | ||
| # http://www.apache.org/licenses/LICENSE-2.0 | ||
| # | ||
| # Unless required by applicable law or agreed to in writing, software | ||
| # distributed under the License is distributed on an "AS IS" BASIS, | ||
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| # See the License for the specific language governing permissions and | ||
| # limitations under the License. | ||
| # | ||
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| import dataclasses | ||
| import enum | ||
| from typing import Any, Iterator, List, Tuple, Union | ||
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| class TLVList: | ||
| """Represents a list in CHIP TLV. | ||
| A TLVList can be constructed from a `list` of tuples of tag and value. `None` stands for "anonymous tag". | ||
| e.g. | ||
| ``` | ||
| l = TLVList([(1, 'a'), (2, 'b'), (None, 'c')]) | ||
| ``` | ||
| Constructs a list of three items, tag 1 is 'a', tag 2 is 'b' and with an anonymous item 'c'. | ||
| Since TLVLists are ordered, it is meanful to iterate over an list: | ||
| e.g. | ||
| ``` | ||
| for tag, val in l: | ||
| print(f"tag={tag}, val={val}") | ||
| ``` | ||
| Outputs: | ||
| ``` | ||
| tag=1, val=a | ||
| tag=2, val=b | ||
| tag=None, val=c | ||
| ``` | ||
| One can also append items into an list: | ||
| e.g. | ||
| ``` | ||
| l.append(3, 'd') | ||
| ``` | ||
| The content of `l` will be `[(1, 'a'), (2, 'b'), (None, 'c'), (3, 'd')]` | ||
| One can access an item in the list via the tag. | ||
| e.g. | ||
| ``` | ||
| val = l[1] | ||
| # val is 'a' | ||
| ``` | ||
| It is also possible to get an item via the index since it is ordered: | ||
| e.g. | ||
| ``` | ||
| tag, val = l[TLVList.IndexMethod.Tag:2] | ||
| # tag is None, val is 'c' | ||
| ``` | ||
| """ | ||
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| @dataclasses.dataclass | ||
| class TLVListItem: | ||
| tag: Union[None, int] | ||
| value: Any | ||
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| def as_tuple(self): | ||
| return (self.tag, self.value) | ||
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| def as_rich_repr_tuple(self): | ||
| if self.tag is None: | ||
| return "Anonymous", repr(self.value) | ||
| else: | ||
| return str(self.tag), repr(self.value) | ||
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| def __repr__(self): | ||
| if self.tag is None: | ||
| return "Anonymous: " + repr(self.value) | ||
| else: | ||
| return str(self.tag) + ": " + repr(self.value) | ||
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| def __rich_repr__(self): | ||
| yield self.as_rich_repr_tuple() | ||
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| class IndexMethod(enum.Enum): | ||
| Index = 0 | ||
| Tag = 1 | ||
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| class Iterator: | ||
| def __init__(self, iter: Iterator): | ||
| self._iterator = iter | ||
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| def __iter__(self): | ||
| return self | ||
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| def __next__(self): | ||
| res = next(self._iterator) | ||
| return res.tag, res.value | ||
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| def __init__(self, items: List[Tuple[Union[int, None], Any]] = []): | ||
| """Constructs a TLVList. | ||
| items: A list of tuples for the tag and value for the items in the TLVList. | ||
| """ | ||
| self._data: List[TLVList.TLVListItem] = [] | ||
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| for tag, val in items: | ||
| self.append(tag, val) | ||
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| def _get_item_by_tag(self, tag) -> Any: | ||
| if not isinstance(tag, int): | ||
| raise ValueError("Tag should be a integer for non-anonymous fields.") | ||
| for data in self._data: | ||
| if data.tag == tag: | ||
| return data.value | ||
| raise KeyError(f"Tag {tag} not found in the list.") | ||
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| def __getitem__(self, access) -> Any: | ||
| """Gets a item in the list by the tag or the index. | ||
| Examples: | ||
| ``` | ||
| tlv_list[1] # returns the item in the list with tag `1` | ||
| tlv_list[TLVList.IndexMethod.Tag:2] # returns the item in the list with tag `2` | ||
| tlv_list[TLVList.IndexMethod.Index:0] # returns the tag and value of the first item in the list | ||
| ``` | ||
| """ | ||
| if isinstance(access, slice): | ||
| tag, index = access.start, access.stop | ||
| if tag == TLVList.IndexMethod.Tag: | ||
| return self._get_item_by_tag(index) | ||
| elif tag == TLVList.IndexMethod.Index: | ||
| return self._data[index].as_tuple() | ||
| raise ValueError("Method should be TLVList.IndexMethod.Tag or TLVList.IndexMethod.Index") | ||
| elif isinstance(access, int): | ||
| return self._get_item_by_tag(access) | ||
| raise ValueError("Invalid access method") | ||
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| def append(self, tag: Union[None, int], value: Any) -> None: | ||
| """Appends an item to the list.""" | ||
| if (tag is not None) and (not isinstance(tag, int)): | ||
| raise KeyError(f"Tag should be a integer or none for anonymous tag, {type(tag)} got") | ||
| self._data.append(TLVList.TLVListItem(tag, value)) | ||
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| def __repr__(self): | ||
| return "TLVList" + repr(self._data) | ||
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| def __rich_repr__(self): | ||
| for items in self._data: | ||
| yield items.as_rich_repr_tuple() | ||
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| def __iter__(self) -> """TLVList.Iterator""": | ||
| return TLVList.Iterator(iter(self._data)) | ||
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| def __eq__(self, rhs: "TLVList") -> bool: | ||
| if not isinstance(rhs, TLVList): | ||
| return False | ||
| return self._data == rhs._data |
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