Silence the following warnings:
```
/mruby/mrbgems/mruby-time/src/time.c:260:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if ((MRB_INT_MAX > MRB_TIME_MAX && i > 0 && i > MRB_TIME_MAX) ||
^
```
Silence the following warnings:
```
/mruby/mrbgems/mruby-time/src/time.c:871:15: warning: result of comparison of constant 9223372036854775807 with expression of type 'time_t' (aka 'long') is always false [-Wtautological-constant-out-of-range-compare]
if (tm->sec > MRB_INT_MAX || tm->sec < MRB_INT_MIN) {
~~~~~~~ ^ ~~~~~~~~~~~
/mruby/mrbgems/mruby-time/src/time.c:871:40: warning: result of comparison of constant -9223372036854775808 with expression of type 'time_t' (aka 'long') is always false [-Wtautological-constant-out-of-range-compare]
if (tm->sec > MRB_INT_MAX || tm->sec < MRB_INT_MIN) {
~~~~~~~ ^ ~~~~~~~~~~~
/mruby/mrbgems/mruby-time/src/time.c:887:16: warning: result of comparison of constant 9223372036854775807 with expression of type 'time_t' (aka 'long') is always false [-Wtautological-constant-out-of-range-compare]
if (tm->usec > MRB_INT_MAX || tm->usec < MRB_INT_MIN) {
~~~~~~~~ ^ ~~~~~~~~~~~
/mruby/mrbgems/mruby-time/src/time.c:887:42: warning: result of comparison of constant -9223372036854775808 with expression of type 'time_t' (aka 'long') is always false [-Wtautological-constant-out-of-range-compare]
if (tm->usec > MRB_INT_MAX || tm->usec < MRB_INT_MIN) {
~~~~~~~~ ^ ~~~~~~~~~~~
```
Silence the following warning:
```
/mruby/mrbgems/mruby-time/src/time.c:258:60: warning: result of comparison of constant -9223372036854775808 with expression of type 'mrb_int' (aka 'int') is always false [-Wtautological-constant-out-of-range-compare]
if ((mrb_time_int)i > MRB_TIME_MAX || MRB_TIME_MIN > i) {
~~~~~~~~~~~~ ^ ~
```
The binary sizes (gems are only `mruby-bin-mruby`) are reduced slightly in
my environment than before the introduction of new specifiers/modifiers
(5116789a) with this change.
------------+-------------------+-------------------+--------
BINARY | BEFORE (5116789a) | AFTER (This PR) | RATIO
------------+-------------------+-------------------+--------
mruby | 593416 bytes | 593208 bytes | -0.04%
libmruby.a | 769048 bytes | 767264 bytes | -0.23%
------------+-------------------+-------------------+--------
BTW, I accidentally changed `tasks/toolchains/visualcpp.rake` at #4613,
so I put it back.
Warnings:
- If `MRB_TIME_T_UINT` is defined, the compiler issues a warning with an
integer comparison of different signs.
- It is mentioned that the `usec` variable passed to the
`mrb_to_time_t()` function may not be initialized
Use own implementation to calculate UTC offset on Visual Studio 2015 or
earlier or MinGW because `strftime("%z")` on these environments does not
conform C99.
- `Time.local` and `Time.utc` are able to use with `MRB_INT16 + MRB_WITHOUT_FLOAT`.
- `time_t` is converted directly from the Ruby object.
- `time + sec` and` time - sec` are not affected by the precision of `mrb_float`.
Similarly, calculations are possible with `MRB_INT16 + MRB_WITHOUT_FLOAT`.
For the following reasons:
- Ruby compatibility.
- Add UTC offset (time zone informations was not included by #4433).
- More readable.
Example:
Before this patch:
p Time.gm(2003,4,5,6,7,8,9) #=> Sat Apr 5 06:07:08 2003
p Time.local(2013,10,28,16,27,48) #=> Mon Oct 28 16:27:48 2013
After this patch:
p Time.gm(2003,4,5,6,7,8,9) #=> 2003-04-05 06:07:08 UTC
p Time.local(2013,10,28,16,27,48) #=> 2013-10-28 16:27:48 +0900
Implementation:
I use `strftime(3)` because UTC offset can be added and program size become
smaller than the other implementations (using `sprintf(3)`, self conversion
etc) in my environment.
- A leading charactor for day is space.
- Time zone does not included.
Before this patch:
Time.gm(1982,3,4,5,6,7).asctime #=> "Thu Mar 04 05:06:07 UTC 1982"
After this patch:
Time.gm(1982,3,4,5,6,7).asctime #=> "Thu Mar 4 05:06:07 1982"
dearblue