Add check_ascii_printable function to reduce duplicated code

[waketzheng]

Summary

Add check_ascii_printable function to reduce duplicated code.

Checklist

• [x] I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• [ ] I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• [ ] I've updated the documentation accordingly.