Support IEC suffix for sizes

To be consistent with what the "aws s3 ls" command outputs.
As per review feedback.

awscli/customizations/s3/utils.py

@@ -40,6 +40,10 @@
     'mb': 1024 ** 2,
     'gb': 1024 ** 3,
     'tb': 1024 ** 4,
+    'kib': 1024,
+    'mib': 1024 ** 2,
+    'gib': 1024 ** 3,
+    'tib': 1024 ** 4,
 }
 
 
@@ -86,7 +90,12 @@ def human_readable_to_bytes(value):
     :returns: The converted value in bytes as an integer
 
     """
-    suffix = value[-2:].lower()
+    value = value.lower()
+    if value[-2:] == 'ib':
+        # Assume IEC suffix.
+        suffix = value[-3:].lower()
+    else:
+        suffix = value[-2:].lower()
     has_size_identifier = (
         len(value) >= 2 and suffix in SIZE_SUFFIX)
     if not has_size_identifier:
@@ -96,7 +105,7 @@ def human_readable_to_bytes(value):
             raise ValueError("Invalid size value: %s" % value)
     else:
         multiplier = SIZE_SUFFIX[suffix]
-        return int(value[:-2]) * multiplier
+        return int(value[:-len(suffix)]) * multiplier
 
 
 class AppendFilter(argparse.Action):

tests/unit/customizations/s3/test_utils.py

@@ -56,6 +56,14 @@ def test_convert_human_readable_to_bytes():
     yield _test_convert_human_readable_to_bytes, "1GB", 1024 ** 3
     yield _test_convert_human_readable_to_bytes, "1TB", 1024 ** 4
 
+    # Also because of the "ls" output for s3, we support
+    # the IEC "mebibyte" format (MiB).
+    yield _test_convert_human_readable_to_bytes, "1KiB", 1024
+    yield _test_convert_human_readable_to_bytes, "1kib", 1024
+    yield _test_convert_human_readable_to_bytes, "1MiB", 1024 ** 2
+    yield _test_convert_human_readable_to_bytes, "1GiB", 1024 ** 3
+    yield _test_convert_human_readable_to_bytes, "1TiB", 1024 ** 4
+
 
 def _test_convert_human_readable_to_bytes(size_str, expected):
     assert_equal(human_readable_to_bytes(size_str), expected)