voussoirkit/voussoirkit/bytestring.py

133 lines
3.7 KiB
Python

import re
import sys
from voussoirkit import pipeable
BYTE = 1
KIBIBYTE = 1024 * BYTE
MIBIBYTE = 1024 * KIBIBYTE
GIBIBYTE = 1024 * MIBIBYTE
TEBIBYTE = 1024 * GIBIBYTE
PEBIBYTE = 1024 * TEBIBYTE
EXIBYTE = 1024 * PEBIBYTE
ZEBIBYTE = 1024 * EXIBYTE
YOBIBYTE = 1024 * ZEBIBYTE
BYTE_STRING = 'b'
KIBIBYTE_STRING = 'KiB'
MIBIBYTE_STRING = 'MiB'
GIBIBYTE_STRING = 'GiB'
TEBIBYTE_STRING = 'TiB'
PEBIBYTE_STRING = 'PiB'
EXIBYTE_STRING = 'EiB'
ZEBIBYTE_STRING = 'ZiB'
YOBIBYTE_STRING = 'YiB'
UNIT_STRINGS = {
BYTE: BYTE_STRING,
KIBIBYTE: KIBIBYTE_STRING,
MIBIBYTE: MIBIBYTE_STRING,
GIBIBYTE: GIBIBYTE_STRING,
TEBIBYTE: TEBIBYTE_STRING,
PEBIBYTE: PEBIBYTE_STRING,
EXIBYTE: EXIBYTE_STRING,
ZEBIBYTE: ZEBIBYTE_STRING,
YOBIBYTE: YOBIBYTE_STRING,
}
REVERSED_UNIT_STRINGS = {value: key for (key, value) in UNIT_STRINGS.items()}
UNIT_SIZES = sorted(UNIT_STRINGS.keys(), reverse=True)
def bytestring(size, decimal_places=3, force_unit=None):
'''
Convert a number into string.
force_unit:
If None, an appropriate size unit is chosen automatically.
Otherwise, you can provide one of the size constants to force that divisor.
'''
if force_unit is None:
divisor = get_appropriate_divisor(size)
else:
if isinstance(force_unit, str):
force_unit = normalize_unit_string(force_unit)
force_unit = REVERSED_UNIT_STRINGS[force_unit]
divisor = force_unit
size_unit_string = UNIT_STRINGS[divisor]
if divisor == BYTE:
decimal_places = 0
size_string = '{number:.0{decimal_places}f} {unit}'
size_string = size_string.format(
decimal_places=decimal_places,
number=size/divisor,
unit=size_unit_string,
)
return size_string
def get_appropriate_divisor(size):
'''
Return the divisor that would be appropriate for displaying this byte size.
For example:
1000 => 1 to display 1,000 b
1024 => 1024 to display 1 KiB
123456789 => 1048576 to display 117.738 MiB
'''
size = abs(size)
for unit in UNIT_SIZES:
if size >= unit:
appropriate_unit = unit
break
else:
appropriate_unit = 1
return appropriate_unit
def normalize_unit_string(string):
'''
Given a string "k" or "kb" or "kib" in any case, return "KiB", etc.
'''
string = string.lower()
for (size, unit_string) in UNIT_STRINGS.items():
unit_string_l = unit_string.lower()
if string in (unit_string_l, unit_string_l[0], unit_string_l.replace('i', '')):
return unit_string
raise ValueError(f'Unrecognized unit string "{string}".')
def parsebytes(string):
'''
Given a string like "100 kib", return the appropriate integer value.
Accepts "k", "kb", "kib" in any casing.
'''
string = string.lower().strip()
string = string.replace(' ', '').replace(',', '')
matches = re.findall(r'[\d\.-]+', string)
if len(matches) == 0:
raise ValueError('No numbers found.')
if len(matches) > 1:
raise ValueError('Too many numbers found.')
number = matches[0]
if not string.startswith(number):
raise ValueError('Number is not at start of string.')
# if the string has no text besides the number, return that int of bytes.
unit_string = string.replace(number, '')
if unit_string == '':
return int(float(number))
number = float(number)
unit_string = normalize_unit_string(unit_string)
multiplier = REVERSED_UNIT_STRINGS[unit_string]
return int(number * multiplier)
def main(args=None):
for line in pipeable.go(args, strip=True, skip_blank=True):
n = int(line)
pipeable.output(bytestring(n))
if __name__ == '__main__':
raise SystemExit(main(sys.argv[1:]))