refactor: enforce a few minor optimization in code

[POABOB]

---

name: Pull request
about: Propose changes to the code
title: 'make the code cleaner in worker_loop_queue.go and worker_stack.go'
labels: ''
assignees: ''

1. Are you opening this pull request for bug-fixs, optimizations or new feature?

refactor

2. Please describe how these code changes achieve your intention.

I noticed that the original code uses the if statement to determine if the queue is overflowing in worker_loop_queue.go. I think it can use the modulo operator to make it cleaner.
before

wq.head++
if wq.head == wq.size {
    wq.head = 0
}

after

wq.head = (wq.head + 1) % wq.size

And there are two different calculation methods for binary search of the mid variable in worker_loop_queue.go & worker_stack.go.
I think l + ((r - l) >> 1) is a better way.
worker_loop_queue.go

mid = l + ((r - l) >> 1)

worker_stack.go

mid := int(uint(l+r) >> 1) // avoid overflow when computing mid

Last, I think it can reuse the isEmpty() method to evaluate the condition below.

before

if wq.size == 0 {
	return 0
}

if wq.head == wq.tail {
	if wq.isFull {
		return wq.size
	}
	return 0
}

after

if wq.size == 0 || wq.isEmpty() {
	return 0
}

if wq.head == wq.tail && wq.isFull {
	return wq.size
}

3. Please link to the relevant issues (if any).

No

4. Which documentation changes (if any) need to be made/updated because of this PR?

No

4. Checklist

• I have squashed all insignificant commits.
• I have commented my code for explaining package types, values, functions, and non-obvious lines.
• I have written unit tests and verified that all tests passes (if needed).
• I have documented feature info on the README (only when this PR is adding a new feature).
• (optional) I am willing to help maintain this change if there are issues with it later.

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (f0b98c3) 94.08% compared to head (9a26314) 94.43%.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #302      +/-   ##
==========================================
+ Coverage   94.08%   94.43%   +0.35%     
==========================================
  Files           9        9              
  Lines         744      737       -7     
==========================================
- Hits          700      696       -4     
+ Misses         32       30       -2     
+ Partials       12       11       -1     

Flag	Coverage Δ
unittests	94.43% <100.00%> (+0.35%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
worker_loop_queue.go	97.08% <100.00%> (+2.54%)	⬆️
worker_stack.go	100.00% <100.00%> (ø)

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[panjf2000]

LGTM

[panjf2000]

Thanks!