address: make Prefix overridable

As it should be, it's specified in the configuration file (and it should be
treated as byte in the config)

cli/server/server.go

@@ -9,6 +9,7 @@ import (
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
+	"github.com/CityOfZion/neo-go/pkg/encoding/address"
 	"github.com/CityOfZion/neo-go/pkg/io"
 	"github.com/CityOfZion/neo-go/pkg/network"
 	"github.com/CityOfZion/neo-go/pkg/network/metrics"
@@ -361,6 +362,9 @@ func initBlockChain(cfg config.Config) (*core.Blockchain, error) {
 	if err != nil {
 		return nil, cli.NewExitError(fmt.Errorf("could not initialize blockchain: %s", err), 1)
 	}
+	if cfg.ProtocolConfiguration.AddressVersion != 0 {
+		address.Prefix = cfg.ProtocolConfiguration.AddressVersion
+	}
 	return chain, nil
 }
 

config/config.go

@@ -43,7 +43,7 @@ type (
 	// ProtocolConfiguration represents the protocol config.
 	ProtocolConfiguration struct {
 		Magic                   NetMode   `yaml:"Magic"`
-		AddressVersion          int64     `yaml:"AddressVersion"`
+		AddressVersion          byte      `yaml:"AddressVersion"`
 		SecondsPerBlock         int       `yaml:"SecondsPerBlock"`
 		LowPriorityThreshold    float64   `yaml:"LowPriorityThreshold"`
 		MaxTransactionsPerBlock int64     `yaml:"MaxTransactionsPerBlock"`

pkg/encoding/address/address.go

@@ -5,10 +5,14 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
+// Prefix is the byte used to prepend to addresses when encoding them, it can
+// be changed and defaults to 23 (0x17), the standard NEO prefix.
+var Prefix = byte(0x17)
+
 // EncodeUint160 returns the "NEO address" from the given Uint160.
 func EncodeUint160(u util.Uint160) string {
 	// Dont forget to prepend the Address version 0x17 (23) A
-	b := append([]byte{0x17}, u.BytesBE()...)
+	b := append([]byte{Prefix}, u.BytesBE()...)
 	return base58.CheckEncode(b)
 }