rcl_difference_times() function 32 bit overflow

[kenny-y]

rcl_difference_times() function can't process time diff > 2^31

Bug report

Required Info:

• Operating System:
  • Ubuntu 16.04
• Installation type:
  • Ardent Apalone
• Version or commit hash:
  • NA
• DDS implementation:
  • Default
• Client library (if applicable):
  • rcl

Steps to reproduce issue

This test case would pass

Start: sec = 1514423496, nanosec = 0
Finish: sec = 1514423498, nanosec = 147483647
64 bit .nanoseconds: (1514423496000000000 - 1514423498147483647)
rcl_difference_times: delta.nanoseconds = 2147483647
Human readable result: { sec: 2, nanosec: 147483647 }

This test case would fail

Start: sec = 1514423496, nanosec = 0
Finish: sec = 1514423498, nanosec = 147483648
64 bit .nanoseconds: (1514423496000000000 - 1514423498147483648)
rcl_difference_times: delta.nanoseconds = -2147483648  // This is the issue
Human readable result: { sec: -2, nanosec: -147483648 }

Expected behavior

that rcl_difference_times() function can process diff > 2 ^ 31 (e.g. 3 seconds or greater)

Actual behavior

32 bit signed integer overflow

Additional information

I found this when I'm writing Node.js bindings to rcl

[wjwwood]

Thanks for pointing it out @kenny-y. A pr with a test for this and a fix would be greatly appreciated. Otherwise we'll get to it as soon as we have time.

[kenny-y]

I'll see what I can do after the new year vacation.