init

src/ihash/ihash.go

@@ -0,0 +1,63 @@
+package ihash
+
+import (
+	"encoding/binary"
+	"fmt"
+	"image"
+
+	"github.com/corona10/goimagehash"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/bsontype"
+)
+
+type IHash struct {
+	pHash, dHash, aHash *goimagehash.ImageHash
+}
+
+func (h IHash) Compare(other IHash) uint64 {
+	pd, _ := h.pHash.Distance(other.pHash)
+	dd, _ := h.dHash.Distance(other.dHash)
+	ad, _ := h.aHash.Distance(other.aHash)
+	return uint64(pd + dd + ad)
+}
+
+func GenerateIHash(img image.Image) (IHash, error) {
+	hash := IHash{}
+
+	var err error
+	hash.pHash, err = goimagehash.PerceptionHash(img)
+	if err != nil {
+		return hash, fmt.Errorf("perception hash error: %s", err.Error())
+	}
+	hash.dHash, err = goimagehash.DifferenceHash(img)
+	if err != nil {
+		return hash, fmt.Errorf("difference hash error: %s", err.Error())
+	}
+	hash.aHash, err = goimagehash.AverageHash(img)
+	if err != nil {
+		return hash, fmt.Errorf("average hash error: %s", err.Error())
+	}
+
+	return hash, nil
+}
+
+func (h IHash) MarshalBSONValue() (bsontype.Type, []byte, error) {
+	b := make([]byte, 0, 8*3)
+	b = binary.LittleEndian.AppendUint64(b, h.pHash.GetHash())
+	b = binary.LittleEndian.AppendUint64(b, h.dHash.GetHash())
+	b = binary.LittleEndian.AppendUint64(b, h.aHash.GetHash())
+
+	return bson.MarshalValue(b)
+}
+
+// UnmarshalBSONValue implements bson.ValueUnmarshaler interface.
+func (h *IHash) UnmarshalBSONValue(t bsontype.Type, data []byte) error {
+	if h == nil {
+		return bson.ErrDecodeToNil
+	}
+
+	h.pHash = goimagehash.NewImageHash(binary.LittleEndian.Uint64(data[0:8]), goimagehash.PHash)
+	h.dHash = goimagehash.NewImageHash(binary.LittleEndian.Uint64(data[8:16]), goimagehash.DHash)
+	h.aHash = goimagehash.NewImageHash(binary.LittleEndian.Uint64(data[16:24]), goimagehash.PHash)
+	return nil
+}