[feature] add bytes2human conversion

1 files changed, 122 insertions, 0 deletions

diff --git a/src/leap/bitmask/vpn/_human.py b/src/leap/bitmask/vpn/_human.py
new file mode 100644
index 00000000..1b2ba64c
--- /dev/null
+++ b/src/leap/bitmask/vpn/_human.py
@@ -0,0 +1,122 @@
+## {{{ http://code.activestate.com/recipes/578019/ (r15)
+#!/usr/bin/env python
+
+"""
+Bytes-to-human / human-to-bytes converter.
+Based on: http://goo.gl/kTQMs
+Working with Python 2.x and 3.x.
+
+Author: Giampaolo Rodola' <g.rodola [AT] gmail [DOT] com>
+License: MIT
+"""
+
+# see: http://goo.gl/kTQMs
+SYMBOLS = {
+    'customary'     : ('B', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'),
+    'customary_ext' : ('byte', 'kilo', 'mega', 'giga', 'tera', 'peta', 'exa',
+                       'zetta', 'iotta'),
+    'iec'           : ('Bi', 'Ki', 'Mi', 'Gi', 'Ti', 'Pi', 'Ei', 'Zi', 'Yi'),
+    'iec_ext'       : ('byte', 'kibi', 'mebi', 'gibi', 'tebi', 'pebi', 'exbi',
+                       'zebi', 'yobi'),
+}
+
+def bytes2human(n, format='%(value).1f %(symbol)s', symbols='customary'):
+    """
+    Convert n bytes into a human readable string based on format.
+    symbols can be either "customary", "customary_ext", "iec" or "iec_ext",
+    see: http://goo.gl/kTQMs
+
+      >>> bytes2human(0)
+      '0.0 B'
+      >>> bytes2human(0.9)
+      '0.0 B'
+      >>> bytes2human(1)
+      '1.0 B'
+      >>> bytes2human(1.9)
+      '1.0 B'
+      >>> bytes2human(1024)
+      '1.0 K'
+      >>> bytes2human(1048576)
+      '1.0 M'
+      >>> bytes2human(1099511627776127398123789121)
+      '909.5 Y'
+
+      >>> bytes2human(9856, symbols="customary")
+      '9.6 K'
+      >>> bytes2human(9856, symbols="customary_ext")
+      '9.6 kilo'
+      >>> bytes2human(9856, symbols="iec")
+      '9.6 Ki'
+      >>> bytes2human(9856, symbols="iec_ext")
+      '9.6 kibi'
+
+      >>> bytes2human(10000, "%(value).1f %(symbol)s/sec")
+      '9.8 K/sec'
+
+      >>> # precision can be adjusted by playing with %f operator
+      >>> bytes2human(10000, format="%(value).5f %(symbol)s")
+      '9.76562 K'
+    """
+    n = int(n)
+    if n < 0:
+        raise ValueError("n < 0")
+    symbols = SYMBOLS[symbols]
+    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 format % locals()
+    return format % dict(symbol=symbols[0], value=n)
+
+def human2bytes(s):
+    """
+    Attempts to guess the string format based on default symbols
+    set and return the corresponding bytes as an integer.
+    When unable to recognize the format ValueError is raised.
+
+      >>> human2bytes('0 B')
+      0
+      >>> human2bytes('1 K')
+      1024
+      >>> human2bytes('1 M')
+      1048576
+      >>> human2bytes('1 Gi')
+      1073741824
+      >>> human2bytes('1 tera')
+      1099511627776
+
+      >>> human2bytes('0.5kilo')
+      512
+      >>> human2bytes('0.1  byte')
+      0
+      >>> human2bytes('1 k')  # k is an alias for K
+      1024
+      >>> human2bytes('12 foo')
+      Traceback (most recent call last):
+          ...
+      ValueError: can't interpret '12 foo'
+    """
+    init = s
+    num = ""
+    while s and s[0:1].isdigit() or s[0:1] == '.':
+        num += s[0]
+        s = s[1:]
+    num = float(num)
+    letter = s.strip()
+    for name, sset in SYMBOLS.items():
+        if letter in sset:
+            break
+    else:
+        if letter == 'k':
+            # treat 'k' as an alias for 'K' as per: http://goo.gl/kTQMs
+            sset = SYMBOLS['customary']
+            letter = letter.upper()
+        else:
+            raise ValueError("can't interpret %r" % init)
+    prefix = {sset[0]:1}
+    for i, s in enumerate(sset[1:]):
+        prefix[s] = 1 << (i+1)*10
+    return int(num * prefix[letter])
+