"""Utilities to convert to and from bytes.
Used by nengo.rc in order to present file sizes to users in
human-readable formats.
This code adapted from https://goo.gl/zeJZl under the MIT License.
"""
[docs]def bytes2human(n, fmt="%(value).1f %(symbol)s"):
"""Convert from a size in bytes to a human readable string.
Examples
--------
.. testcode::
from nengo.utils.cache import bytes2human
print(bytes2human(10000))
print(bytes2human(100001221))
.. testoutput::
9.8 KB
95.4 MB
"""
symbols = ("B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB")
prefix = {}
for i, s in enumerate(symbols[1:]):
prefix[s] = 1 << (i + 1) * 10
for symbol in reversed(symbols[1:]):
if n >= prefix[symbol]:
value = float(n) / prefix[symbol]
return fmt % {"value": value, "symbol": symbol}
return fmt % {"value": n, "symbol": symbols[0]}
[docs]def human2bytes(s):
"""Convert from a human readable string to a size in bytes.
Examples
--------
.. testcode::
from nengo.utils.cache import human2bytes
print(human2bytes('1 MB'))
print(human2bytes('1 GB'))
.. testoutput::
1048576
1073741824
"""
symbols = ("B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB")
ix = -1 if s[-2].isdigit() else -2
letter = s[ix:].strip().upper()
num = s[:ix].strip()
assert letter in symbols
num = float(num)
prefix = {symbols[0]: 1}
for i, s in enumerate(symbols[1:]):
prefix[s] = 1 << (i + 1) * 10
return int(num * prefix[letter])
[docs]def byte_align(size, alignment):
"""Returns the int larger than ``size`` aligned to ``alginment`` bytes."""
mask = alignment - 1
if size & mask == 0:
return size
else:
return (size | mask) + 1
