currency: Adds matching lookup table built from available pairs.

[shazbert]

PR Description

@gloriousCode brought up an issue with the old matching system with respective benchmarks here sometimes when using this super fast function can result in incorrect return pair if there is no delimiter. These benchmarks can be run again.

• Adds matching lookup table that is built from available pairs list for a faster return that doesn't impact currency package NewPairFromString and derivatives which call currency.NewCode() * 2
• Adds optimisation to NewPairFromString for even speedier usage 💨
• Adds new exchange base function for the matching of symbols to stored pairs MatchSymbolWithAvailablePairs
• If type currency.Pair is used for a json field this has become more strict and requires now a delimiter as we have to make sure that we are correctly formatting to match with our stored list.

Note: Keeping this as non-invasive as possible, separate PR's can be opened when needed if MatchSymbolWithAvailablePairs is found to be a better use case for speed considerations (mainly websocket throughput).

Type of change

Please delete options that are not relevant and add an x in [] as item is complete.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How has this been tested

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration and
also consider improving test coverage whilst working on a certain feature or package.

• go test ./... -race
• golangci-lint run
• Test X

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation and regenerated documentation via the documentation tool
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally and on Github Actions/AppVeyor with my changes
• Any dependent changes have been merged and published in downstream modules

[gloriousCode]

This is nice 🍐💨

[gloriousCode]

So utilising the same benchmarking as last time for comparison:

func BenchmarkNewPairFromString(b *testing.B) {
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		_, _ = currency.NewPairFromString("ZTG_USDT")
	}
}

func BenchmarkDeriveFrom(b *testing.B) {
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		avail, _ := g.GetAvailablePairs(asset.Spot)
		_, _ = avail.DeriveFrom(strings.Replace("ZTG_USDT", "_", "", 1))
	}
}

func BenchmarkDeriveFromCheating(b *testing.B) {
	b.ReportAllocs()
	avail, _ := g.GetAvailablePairs(asset.Spot)
	for i := 0; i < b.N; i++ {
		_, _ = avail.DeriveFrom(strings.Replace("ZTG_USDT", "_", "", 1))
	}
}

func BenchmarkMatchSymbolWithAvailablePairs(b *testing.B) {
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		_, _ = g.MatchSymbolWithAvailablePairs("ZTG_USDT", asset.Spot, true)
	}
}

Benchmark	times tested	time taken	Bytes per op	Allocations
BenchmarkNewPairFromString-10	20982969	57.07 ns/op	4 B/op	1 allocs/op
BenchmarkDeriveFrom-10	17596	67605 ns/op	294928 B/op	4 allocs/op
BenchmarkDeriveFromCheating-10	156580	7163 ns/op	17 B/op	2 allocs/op
BenchmarkMatchSymbolWithAvailablePairs-10	15378223	76.50 ns/op	16 B/op	2 allocs/op

Does show a lovely improvement. Would you be considering the removal of Derivefrom? Because your new feature seems underutilised in this PR

Plus very nice work on the PairFromString improvements!

[gloriousCode]

Nice. Just need to update Bybit to be filtering on enabled pairs to not change behaviour

[gloriousCode]

I'm happy with this. I'm already wanting to use it
Please update tests:

--- FAIL: TestUpdateTicker (1.85s)
    bitmex_test.go:1103: pair not found for xrpusd perpetualcontract
--- FAIL: TestUpdateTickers (6.73s)
    bitfinex_test.go:504: pair not found for xautf0btcf0 spot
--- FAIL: TestUpdateTicker (0.32s)
    bitfinex_test.go:477: pair not found for btcf0eutf0 spot
--- FAIL: TestGetFundingRates (0.00s)
    rpcserver_test.go:3031: received: 'pair matcher is nil' but expected: '<nil>'
  --- FAIL: TestAllExchangeWrappers/coinut_wrapper_tests (0.43s)
        --- FAIL: TestAllExchangeWrappers/coinut_wrapper_tests/MatchSymbolWithAvailablePairs-- (0.00s)
            exchange_wrapper_standards_test.go:214: COINUT Func 'MatchSymbolWithAvailablePairs' Error: 'pair not found for 1337 '. Inputs: [1337  false].

And any others. Which now fail due from this update

[gloriousCode]

Thanks for that, just finishing up I think. I know this is annoying 😭

[gloriousCode]

Just one thing I noticed, plus please rebase/merge and check that tests are good 🤙

[gloriousCode]

tACK! Nice work Shazbert

[gloriousCode]

I think this is why we try not to use Atoi, thanks for the fix!

[thrasher-]

Nice work @shazbert !