HashChecker

class torchdata.datapipes.iter.HashChecker(source_datapipe: IterDataPipe[Tuple[str, IOBase]], hash_dict: Dict[str, str], hash_type: str = 'sha256', rewind: bool = True)

计算并检查每个文件的哈希值，来自文件名和数据/流元组的输入 DataPipe（函数名称：check_hash）。如果哈希值与字典中给定的哈希值匹配，则它会生成文件名和数据/流的元组。否则，它将引发错误。

参数：

• source_datapipe – 包含文件名和数据/流元组的 IterDataPipe

• hash_dict – 将文件名映射到其相应哈希值的字典

• hash_type – 要应用的哈希函数类型

• rewind – 使用流计算哈希值后倒带流（这对于不可搜索的流（例如 HTTP）不起作用）

示例

>>> from torchdata.datapipes.iter import IterableWrapper, FileOpener
>>> expected_MD5_hash = "bb9675028dd39d2dd2bf71002b93e66c"
File is from "https://raw.githubusercontent.com/pytorch/data/main/LICENSE"
>>> file_dp = FileOpener(IterableWrapper(["LICENSE.txt"]), mode='rb')
>>> # An exception is only raised when the hash doesn't match, otherwise (path, stream) is returned
>>> check_hash_dp = file_dp.check_hash({"LICENSE.txt": expected_MD5_hash}, "md5", rewind=True)
>>> reader_dp = check_hash_dp.readlines()
>>> it = iter(reader_dp)
>>> path, line = next(it)
>>> path
LICENSE.txt
>>> line
b'BSD 3-Clause License'