1 files changed, 87 insertions, 0 deletions
diff --git a/core/types/json.go b/core/types/json.go
new file mode 100644
index 000000000..403e79899
--- /dev/null
+++ b/core/types/json.go
@@ -0,0 +1,87 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package types
+
+import (
+	"encoding/hex"
+	"fmt"
+	"math/big"
+)
+
+// JSON unmarshaling utilities.
+
+type hexBytes []byte
+
+func (b *hexBytes) UnmarshalJSON(input []byte) error {
+	if len(input) < 2 || input[0] != '"' || input[len(input)-1] != '"' {
+		return fmt.Errorf("cannot unmarshal non-string into hexBytes")
+	}
+	input = input[1 : len(input)-1]
+	if len(input) < 2 || input[0] != '0' || input[1] != 'x' {
+		return fmt.Errorf("missing 0x prefix in hexBytes input %q", input)
+	}
+	dec := make(hexBytes, (len(input)-2)/2)
+	if _, err := hex.Decode(dec, input[2:]); err != nil {
+		return err
+	}
+	*b = dec
+	return nil
+}
+
+type hexBig big.Int
+
+func (b *hexBig) UnmarshalJSON(input []byte) error {
+	raw, err := checkHexNumber(input)
+	if err != nil {
+		return err
+	}
+	dec, ok := new(big.Int).SetString(string(raw), 16)
+	if !ok {
+		return fmt.Errorf("invalid hex number")
+	}
+	*b = (hexBig)(*dec)
+	return nil
+}
+
+type hexUint64 uint64
+
+func (b *hexUint64) UnmarshalJSON(input []byte) error {
+	raw, err := checkHexNumber(input)
+	if err != nil {
+		return err
+	}
+	_, err = fmt.Sscanf(string(raw), "%x", b)
+	return err
+}
+
+func checkHexNumber(input []byte) (raw []byte, err error) {
+	if len(input) < 2 || input[0] != '"' || input[len(input)-1] != '"' {
+		return nil, fmt.Errorf("cannot unmarshal non-string into hex number")
+	}
+	input = input[1 : len(input)-1]
+	if len(input) < 2 || input[0] != '0' || input[1] != 'x' {
+		return nil, fmt.Errorf("missing 0x prefix in hex number input %q", input)
+	}
+	if len(input) == 2 {
+		return nil, fmt.Errorf("empty hex number")
+	}
+	raw = input[2:]
+	if len(raw)%2 != 0 {
+		raw = append([]byte{'0'}, raw...)
+	}
+	return raw, nil
+}