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"""Functions for reporting filesizes. Borrowed from https://github.com/PyFilesystem/pyfilesystem2
The functions declared in this module should cover the different
use cases needed to generate a string representation of a file size
using several different units. Since there are many standards regarding
file size units, three different functions have been implemented.
See Also:
* `Wikipedia: Binary prefix <https://en.wikipedia.org/wiki/Binary_prefix>`_
"""
__all__ = ["decimal"]
from typing import Iterable, List, Optional, Tuple
def _to_str(
size: int,
suffixes: Iterable[str],
base: int,
*,
precision: Optional[int] = 1,
separator: Optional[str] = " ",
) -> str:
if size == 1:
return "1 byte"
elif size < base:
return f"{size:,} bytes"
for i, suffix in enumerate(suffixes, 2): # noqa: B007
unit = base**i
if size < unit:
break
return "{:,.{precision}f}{separator}{}".format(
(base * size / unit),
suffix,
precision=precision,
separator=separator,
)
def pick_unit_and_suffix(size: int, suffixes: List[str], base: int) -> Tuple[int, str]:
"""Pick a suffix and base for the given size."""
for i, suffix in enumerate(suffixes):
unit = base**i
if size < unit * base:
break
return unit, suffix
def decimal(
size: int,
*,
precision: Optional[int] = 1,
separator: Optional[str] = " ",
) -> str:
"""Convert a filesize in to a string (powers of 1000, SI prefixes).
In this convention, ``1000 B = 1 kB``.
This is typically the format used to advertise the storage
capacity of USB flash drives and the like (*256 MB* meaning
actually a storage capacity of more than *256 000 000 B*),
or used by **Mac OS X** since v10.6 to report file sizes.
Arguments:
int (size): A file size.
int (precision): The number of decimal places to include (default = 1).
str (separator): The string to separate the value from the units (default = " ").
Returns:
`str`: A string containing a abbreviated file size and units.
Example:
>>> filesize.decimal(30000)
'30.0 kB'
>>> filesize.decimal(30000, precision=2, separator="")
'30.00kB'
"""
return _to_str(
size,
("kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"),
1000,
precision=precision,
separator=separator,
)