Merge pull request #9 from dylanlott/v5

v5 concurrent read and write ops

pkg/v4/v4.go

@@ -0,0 +1,56 @@
+package v4
+
+import (
+	"fmt"
+	"sync"
+)
+
+type books struct {
+	buy  *sync.Map
+	sell *sync.Map
+}
+
+type order struct {
+	ID    string
+	Price uint64
+	Side  bool
+}
+
+func newBooks() *books {
+	b := &books{
+		buy:  &sync.Map{},
+		sell: &sync.Map{},
+	}
+	return b
+}
+
+// Push pushes order [ord] into the books.
+func (b *books) Push(ord *order) error {
+	if ord.Side {
+		// push buy side
+		loaded, ok := b.buy.Load(ord.Price)
+		if !ok {
+			// nothing exists at this price, push it into map
+			b.buy.Store(ord.Price, []*order{ord})
+			return nil
+		}
+		if val, ok := loaded.([]*order); ok {
+			val = append(val, ord)
+		} else {
+			return fmt.Errorf("ErrNotImpl for type %T", loaded)
+		}
+	}
+	// push sell side
+	loaded, ok := b.sell.Load(ord.Price)
+	if !ok {
+		// nothing exists at this price, push it into the map at the price
+		b.sell.Store(ord.Price, []*order{ord})
+		return nil
+	}
+	if val, ok := loaded.([]*order); ok {
+		val = append(val, ord)
+	} else {
+		return fmt.Errorf("ErrNotImpl for type %T", loaded)
+	}
+	return nil
+}

pkg/v4/v4_test.go

@@ -0,0 +1,36 @@
+package v4
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/matryer/is"
+)
+
+func TestV4(t *testing.T) {
+	is := is.New(t)
+
+	b := &books{
+		buy:  &sync.Map{},
+		sell: &sync.Map{},
+	}
+
+	err := b.Push(&order{
+		ID:    "foo",
+		Price: 1000,
+		Side:  true,
+	})
+	is.NoErr(err)
+	err = b.Push(&order{
+		ID:    "bar",
+		Price: 1000,
+		Side:  false,
+	})
+	is.NoErr(err)
+	err = b.Push(&order{
+		ID:    "buz",
+		Price: 1000,
+		Side:  true,
+	})
+	is.NoErr(err)
+}