big: implemented custom Gob(En/De)coder for Int type
- factored implementation of Int.Bytes, Int.SetBytes
and replaced existing code with much simpler cores
- use the shared bytes, setBytes routines for Gob
(en/de)coding
Fixes #1496.
R=r, eds
CC=golang-dev
https://golang.org/cl/4249063
diff --git a/src/pkg/big/nat.go b/src/pkg/big/nat.go
index a308f69..a04d3b1 100755
--- a/src/pkg/big/nat.go
+++ b/src/pkg/big/nat.go
@@ -1065,3 +1065,50 @@
return true
}
+
+
+// bytes writes the value of z into buf using big-endian encoding.
+// len(buf) must be >= len(z)*_S. The value of z is encoded in the
+// slice buf[i:]. The number i of unused bytes at the beginning of
+// buf is returned as result.
+func (z nat) bytes(buf []byte) (i int) {
+ i = len(buf)
+ for _, d := range z {
+ for j := 0; j < _S; j++ {
+ i--
+ buf[i] = byte(d)
+ d >>= 8
+ }
+ }
+
+ for i < len(buf) && buf[i] == 0 {
+ i++
+ }
+
+ return
+}
+
+
+// setBytes interprets buf as the bytes of a big-endian unsigned
+// integer, sets z to that value, and returns z.
+func (z nat) setBytes(buf []byte) nat {
+ z = z.make((len(buf) + _S - 1) / _S)
+
+ k := 0
+ s := uint(0)
+ var d Word
+ for i := len(buf); i > 0; i-- {
+ d |= Word(buf[i-1]) << s
+ if s += 8; s == _S*8 {
+ z[k] = d
+ k++
+ s = 0
+ d = 0
+ }
+ }
+ if k < len(z) {
+ z[k] = d
+ }
+
+ return z.norm()
+}
