--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pgtoolkit/prettysize.py	Tue Aug 16 16:03:46 2011 +0200
@@ -0,0 +1,67 @@
+# -*- coding: utf-8 -*-
+#
+# prettysize - print data sizes in format easily readable by humans
+#
+# Copyright (c) 2011  Radek Brich <radek.brich@devl.cz>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+iec_prefixes = ('Ki', 'Mi', 'Gi', 'Ti', 'Pi', 'Ei', 'Zi', 'Yi')
+si_prefixes = 'kMGTPEZY'
+big_prefixes = 'KMGTPEZY'
+
+
+def prettysize(num, base=1024, prefixes=si_prefixes, unit='B', sep=' '):
+    '''Convert data size in bytes to human readable aproximation.
+
+    Beware that default output is invalid by recent standardization.
+    Still, this form was in use for ages.
+
+    For standardized output, see prettysize_si and prettysize_iec.
+
+    '''
+    prefixes = list(prefixes)
+    prefix = ''
+    num = float(num)
+    while True:
+        if num < base:
+            # format number
+            out = '{:.2f}'.format(num)
+            # cut off trailing zeros
+            out = out.rstrip('0')
+            if out.endswith('.'):
+                out = out[:-1]
+            return out + sep + prefix + unit
+        num /= base
+        prefix = prefixes.pop(0)
+
+    raise OverflowError('Number is too large.')
+
+
+def prettysize_si(num, **kw):
+    return prettysize(num, base=1000, **kw)
+
+
+def prettysize_short(num):
+    return prettysize(num, unit='', sep='', prefixes=big_prefixes)
+
+
+def prettysize_iec(num):
+    return prettysize(num, prefixes=iec_prefixes)
+