convert to more flexible size formatters

those can now support both file sizes (in SI/decimal format, powers of 10) and memory sizes (in binary format, powers of 2)

tests still fail because the result is always displayed as floats

borg/helpers.py

@@ -460,16 +460,20 @@ def format_file_mode(mod):
 def format_file_size(v):
     """Format file size into a human friendly format
     """
-    if abs(v) > 10**12:
-        return '%.2f TB' % (v / 10**12)
-    elif abs(v) > 10**9:
-        return '%.2f GB' % (v / 10**9)
-    elif abs(v) > 10**6:
-        return '%.2f MB' % (v / 10**6)
-    elif abs(v) > 10**3:
-        return '%.2f kB' % (v / 10**3)
-    else:
-        return '%d B' % v
+    return sizeof_fmt_decimal(v, suffix='B', sep=' ')
+
+def sizeof_fmt(num, suffix='B', units=None, power=None, sep=''):
+    for unit in units[:-1]:
+        if abs(round(num, 2)) < power:
+            return "%3.2f%s%s%s" % (num, sep, unit, suffix)
+        num /= float(power)
+    return "%.2f%s%s%s" % (num, sep, units[-1], suffix)
+
+def sizeof_fmt_iec(num, suffix='B', sep=''):
+   return sizeof_fmt(num, suffix=suffix, sep=sep, units=['','Ki','Mi','Gi','Ti','Pi','Ei','Zi', 'Yi'], power=1024)
+
+def sizeof_fmt_decimal(num, suffix='B', sep=''):
+   return sizeof_fmt(num, suffix=suffix, sep=sep, units=['','k','M','G','T','P','E','Z', 'Y'], power=1000)
 
 
 def format_archive(archive):

borg/testsuite/helpers.py

@@ -450,7 +450,7 @@ def test_size():
                     1: '1 B',
                     142: '142 B',
                     999: '999 B',
-                    1000: '1000 B', # XXX: fail
+                    1000: '1.00 kB',
                     1001: '1.00 kB',
                     1234: '1.23 kB',
                     10**6: '1.00 MB',
@@ -459,7 +459,7 @@ def test_size():
                     10**9+1: '1.00 GB',
                     10**9-1: '1.00 GB',
                     10**9-10*10**3: '999.99 MB',
-                    10**9-10*10**3+1: '1.00 GB',
+                    10**9-10*10**3+5*10**3: '1.00 GB',
                     10**12+1: '1.00 TB',
                     10**15+1: '1.00 PB',
                     10**18+1: '1.00 EB',