1 files changed, 80 insertions, 0 deletions
diff --git a/common/math/dist.go b/common/math/dist.go
new file mode 100644
index 000000000..0a0731971
--- /dev/null
+++ b/common/math/dist.go
@@ -0,0 +1,80 @@
+package math
+
+import (
+	"math/big"
+	"sort"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+type Summer interface {
+	Sum(i int) *big.Int
+	Len() int
+}
+
+func Sum(slice Summer) (sum *big.Int) {
+	sum = new(big.Int)
+
+	for i := 0; i < slice.Len(); i++ {
+		sum.Add(sum, slice.Sum(i))
+	}
+	return
+}
+
+type Vector struct {
+	Gas, Price *big.Int
+}
+
+type VectorsBy func(v1, v2 Vector) bool
+
+func (self VectorsBy) Sort(vectors []Vector) {
+	bs := vectorSorter{
+		vectors: vectors,
+		by:      self,
+	}
+	sort.Sort(bs)
+}
+
+type vectorSorter struct {
+	vectors []Vector
+	by      func(v1, v2 Vector) bool
+}
+
+func (v vectorSorter) Len() int           { return len(v.vectors) }
+func (v vectorSorter) Less(i, j int) bool { return v.by(v.vectors[i], v.vectors[j]) }
+func (v vectorSorter) Swap(i, j int)      { v.vectors[i], v.vectors[j] = v.vectors[j], v.vectors[i] }
+
+func PriceSort(v1, v2 Vector) bool { return v1.Price.Cmp(v2.Price) < 0 }
+func GasSort(v1, v2 Vector) bool   { return v1.Gas.Cmp(v2.Gas) < 0 }
+
+type vectorSummer struct {
+	vectors []Vector
+	by      func(v Vector) *big.Int
+}
+
+type VectorSum func(v Vector) *big.Int
+
+func (v VectorSum) Sum(vectors []Vector) *big.Int {
+	vs := vectorSummer{
+		vectors: vectors,
+		by:      v,
+	}
+	return Sum(vs)
+}
+
+func (v vectorSummer) Len() int           { return len(v.vectors) }
+func (v vectorSummer) Sum(i int) *big.Int { return v.by(v.vectors[i]) }
+
+func GasSum(v Vector) *big.Int { return v.Gas }
+
+var etherInWei = new(big.Rat).SetInt(common.String2Big("1000000000000000000"))
+
+func GasPrice(bp, gl, ep *big.Int) *big.Int {
+	BP := new(big.Rat).SetInt(bp)
+	GL := new(big.Rat).SetInt(gl)
+	EP := new(big.Rat).SetInt(ep)
+	GP := new(big.Rat).Quo(BP, GL)
+	GP = GP.Quo(GP, EP)
+
+	return GP.Mul(GP, etherInWei).Num()
+}