Rewrite Meter_humanUnit() to accept floating point value

Since Meter_humanUnit() is often called with floating point values in
Meter objects, rewrite the function to let it process `double` type
natively, and save floating point to integer casts.

The rewritten function:
* Allows higher orders of magnitude including 'R' and 'Q', and
  addresses infinity. (The previous version has a maximum value of
  (2^64 - 1) representing 16 ZiB.)
* Rounds values when they are in intervals (99.9, 100) and (9.99, 10),
  and displays them with correct precision (number of fraction digits).
* Produces assertion error on negative and NaN values (undefined
  behavior).

Signed-off-by: Kang-Che Sung <explorer09@gmail.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/Meter.h b/Meter.h
index e0ca1f07..6b14634a 100644
--- a/Meter.h
+++ b/Meter.h
@@ -146,7 +146,9 @@ extern const MeterClass Meter_class;
 
 Meter* Meter_new(const Machine* host, unsigned int param, const MeterClass* type);
 
-int Meter_humanUnit(char* buffer, unsigned long int value, size_t size);
+/* Converts 'value' in kibibytes into a human readable string.
+   Example output strings: "0K", "1023K", "98.7M" and "1.23G" */
+int Meter_humanUnit(char* buffer, double value, size_t size);
 
 void Meter_delete(Object* cast);