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"""Functions for reporting filesizes. Borrowed from https://github.com/PyFilesystem/pyfilesystem2 |
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The functions declared in this module should cover the different |
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use cases needed to generate a string representation of a file size |
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using several different units. Since there are many standards regarding |
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file size units, three different functions have been implemented. |
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See Also: |
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* `Wikipedia: Binary prefix <https://en.wikipedia.org/wiki/Binary_prefix>`_ |
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""" |
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__all__ = ["decimal"] |
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from typing import Iterable, List, Optional, Tuple |
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def _to_str( |
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size: int, |
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suffixes: Iterable[str], |
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base: int, |
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*, |
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precision: Optional[int] = 1, |
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separator: Optional[str] = " ", |
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) -> str: |
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if size == 1: |
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return "1 byte" |
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elif size < base: |
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return f"{size:,} bytes" |
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for i, suffix in enumerate(suffixes, 2): |
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unit = base**i |
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if size < unit: |
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break |
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return "{:,.{precision}f}{separator}{}".format( |
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(base * size / unit), |
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suffix, |
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precision=precision, |
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separator=separator, |
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) |
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def pick_unit_and_suffix(size: int, suffixes: List[str], base: int) -> Tuple[int, str]: |
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"""Pick a suffix and base for the given size.""" |
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for i, suffix in enumerate(suffixes): |
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unit = base**i |
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if size < unit * base: |
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break |
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return unit, suffix |
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def decimal( |
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size: int, |
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*, |
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precision: Optional[int] = 1, |
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separator: Optional[str] = " ", |
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) -> str: |
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"""Convert a filesize in to a string (powers of 1000, SI prefixes). |
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In this convention, ``1000 B = 1 kB``. |
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This is typically the format used to advertise the storage |
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capacity of USB flash drives and the like (*256 MB* meaning |
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actually a storage capacity of more than *256 000 000 B*), |
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or used by **Mac OS X** since v10.6 to report file sizes. |
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Arguments: |
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int (size): A file size. |
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int (precision): The number of decimal places to include (default = 1). |
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str (separator): The string to separate the value from the units (default = " "). |
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Returns: |
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`str`: A string containing a abbreviated file size and units. |
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Example: |
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>>> filesize.decimal(30000) |
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'30.0 kB' |
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>>> filesize.decimal(30000, precision=2, separator="") |
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'30.00kB' |
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""" |
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return _to_str( |
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size, |
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("kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"), |
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1000, |
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precision=precision, |
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separator=separator, |
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) |
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