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# This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT.
# See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details.
# Author(s): Hind Montassif
#
# Copyright (C) 2021 Inria
#
# Modification(s):
# - YYYY/MM Author: Description of the modification
import hashlib
from os.path import join, exists
from os import makedirs
from urllib.request import urlretrieve
def _checksum_sha256(file_path):
"""
Compute the file checksum using sha256
Parameters
----------
file_path: string
Full path of the created file.
Returns
-------
The hex digest of file_path
"""
sha256_hash = hashlib.sha256()
chunk_size = 4096
with open(file_path,"rb") as f:
# Read and update hash string value in blocks of 4K
while True:
buffer = f.read(chunk_size)
if not buffer:
break
sha256_hash.update(buffer)
return sha256_hash.hexdigest()
def fetch(url, filename, dirname = "remote_datasets", file_checksum = None):
"""
Fetch the wanted dataset from the given url and save it in file_path
Parameters
----------
url : string
The url to fetch the dataset from.
filename : string
The name to give to downloaded file.
dirname : string
The directory to save the file to. Default is "remote_datasets".
file_checksum : string
The file checksum using sha256 to check against the one computed on the downloaded file.
Default is 'None'.
Returns
-------
file_path: string
Full path of the created file.
"""
file_path = join(dirname, filename)
# Check that an existing file does not already exist at file_path
if not exists(file_path):
# Create directory if not existing
if not exists(dirname):
makedirs(dirname)
urlretrieve(url, file_path)
if file_checksum is not None:
checksum = _checksum_sha256(file_path)
if file_checksum != checksum:
raise IOError("{} has a SHA256 checksum : {}, "
"different from expected : {}."
"The file may be corrupted or the given url may be wrong !".format(file_path, checksum,
file_checksum))
return file_path
def fetch_spiral_2d(filename = "spiral_2d.csv", dirname = "remote_datasets"):
"""
Fetch spiral_2d.csv remotely
Parameters
----------
filename : string
The name to give to downloaded file. Default is "spiral_2d.csv"
dirname : string
The directory to save the file to. Default is "remote_datasets".
Returns
-------
file_path: string
Full path of the created file.
"""
return fetch("https://raw.githubusercontent.com/GUDHI/gudhi-data/main/points/spiral_2d.csv", filename, dirname,
'37530355d980d957c4ec06b18c775f90a91e446107d06c6201c9b4000b077f38')
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