consensus

Documentation

Index

• Constants
• Variables
• func BlockSubsidy(height uint64) uint64
• func IsBech32SegwitPrefix(prefix string, params *Params) bool
• type Checkpoint
• type Params
• type ServiceFlag
  • func (f ServiceFlag) IsEnable(checkFlag ServiceFlag) bool

Constants

const (
	// Max gas that one block contains
	MaxBlockGas      = uint64(10000000)
	VMGasRate        = int64(200)
	StorageGasRate   = int64(1)
	MaxGasAmount     = int64(200000)
	DefaultGasCredit = int64(30000)

	//config parameter for coinbase reward
	CoinbasePendingBlockNumber = uint64(100)

	InitialBlockSubsidy = uint64(140700041250000000)

	// config for pow mining
	BlocksPerRetarget     = uint64(2016)
	TargetSecondsPerBlock = uint64(150)
	SeedPerRetarget       = uint64(256)

	// MaxTimeOffsetSeconds is the maximum number of seconds a block time is allowed to be ahead of the current time
	MaxTimeOffsetSeconds = uint64(60 * 60)
	MedianTimeBlocks     = 11

	PayToWitnessPubKeyHashDataSize = 20
	PayToWitnessScriptHashDataSize = 32
	CoinbaseArbitrarySizeLimit     = 128

	BTMAlias = "BTM"
)

consensus variables

Variables

var ActiveNetParams = MainNetParams

ActiveNetParams is ...

var BTMAssetID = &bc.AssetID{
	V0: binary.BigEndian.Uint64([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}),
	V1: binary.BigEndian.Uint64([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}),
	V2: binary.BigEndian.Uint64([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}),
	V3: binary.BigEndian.Uint64([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}),
}

BTMAssetID is BTM's asset id, the soul asset of Bytom

var BTMDefinitionMap = map[string]interface{}{
	"name":        BTMAlias,
	"symbol":      BTMAlias,
	"decimals":    8,
	"description": `Bytom Official Issue`,
}

BTMDefinitionMap is the ....

var InitialSeed = &bc.Hash{
	V0: uint64(11412844483649490393),
	V1: uint64(4614157290180302959),
	V2: uint64(1780246333311066183),
	V3: uint64(9357197556716379726),
}

InitialSeed is SHA3-256 of Byte[0^32]

var MainNetParams = Params{
	Name:            "main",
	Bech32HRPSegwit: "bm",
	DefaultPort:     "46657",
	DNSSeeds:        []string{"www.mainnetseed.bytom.io"},
	Checkpoints: []Checkpoint{
		{10000, bc.NewHash([32]byte{0x93, 0xe1, 0xeb, 0x78, 0x21, 0xd2, 0xb4, 0xad, 0x0f, 0x5b, 0x1c, 0xea, 0x82, 0xe8, 0x43, 0xad, 0x8c, 0x09, 0x9a, 0xb6, 0x5d, 0x8f, 0x70, 0xc5, 0x84, 0xca, 0xa2, 0xdd, 0xf1, 0x74, 0x65, 0x2c})},
		{20000, bc.NewHash([32]byte{0x7d, 0x38, 0x61, 0xf3, 0x2c, 0xc0, 0x03, 0x81, 0xbb, 0xcd, 0x9a, 0x37, 0x6f, 0x10, 0x5d, 0xfe, 0x6f, 0xfe, 0x2d, 0xa5, 0xea, 0x88, 0xa5, 0xe3, 0x42, 0xed, 0xa1, 0x17, 0x9b, 0xa8, 0x0b, 0x7c})},
		{30000, bc.NewHash([32]byte{0x32, 0x36, 0x06, 0xd4, 0x27, 0x2e, 0x35, 0x24, 0x46, 0x26, 0x7b, 0xe0, 0xfa, 0x48, 0x10, 0xa4, 0x3b, 0xb2, 0x40, 0xf1, 0x09, 0x51, 0x5b, 0x22, 0x9f, 0xf3, 0xc3, 0x83, 0x28, 0xaa, 0x4a, 0x00})},
		{40000, bc.NewHash([32]byte{0x7f, 0xe2, 0xde, 0x11, 0x21, 0xf3, 0xa9, 0xa0, 0xee, 0x60, 0x8d, 0x7d, 0x4b, 0xea, 0xcc, 0x33, 0xfe, 0x41, 0x25, 0xdc, 0x2f, 0x26, 0xc2, 0xf2, 0x9c, 0x07, 0x17, 0xf9, 0xe4, 0x4f, 0x9d, 0x46})},
		{50000, bc.NewHash([32]byte{0x5e, 0xfb, 0xdf, 0xf5, 0x35, 0x38, 0xa6, 0x0b, 0x75, 0x32, 0x02, 0x61, 0x83, 0x54, 0x34, 0xff, 0x3e, 0x82, 0x2e, 0xf8, 0x64, 0xae, 0x2d, 0xc7, 0x6c, 0x9d, 0x5e, 0xbd, 0xa3, 0xd4, 0x50, 0xcf})},
		{62000, bc.NewHash([32]byte{0xd7, 0x39, 0x8f, 0x23, 0x57, 0xf9, 0x4c, 0xa0, 0x28, 0xa7, 0x00, 0x2b, 0x53, 0x9e, 0x51, 0x2d, 0x3e, 0xca, 0xc9, 0x22, 0x59, 0xfc, 0xd0, 0x3f, 0x67, 0x1a, 0x0a, 0xb1, 0x02, 0xbf, 0x2b, 0x03})},
		{72000, bc.NewHash([32]byte{0x66, 0x02, 0x31, 0x19, 0xf1, 0x60, 0x35, 0x61, 0xa4, 0xf1, 0x38, 0x04, 0xcc, 0xe4, 0x59, 0x8f, 0x55, 0x39, 0xba, 0x22, 0xf2, 0x6d, 0x90, 0xbf, 0xc1, 0x87, 0xef, 0x98, 0xcc, 0x70, 0x4d, 0x94})},
		{83700, bc.NewHash([32]byte{0x7f, 0x26, 0xc9, 0x11, 0xe8, 0x46, 0xd0, 0x6e, 0x36, 0xbb, 0xac, 0xce, 0x99, 0xa2, 0x19, 0x89, 0x3f, 0xf7, 0x84, 0x2a, 0xcb, 0x44, 0x7f, 0xbb, 0x0e, 0x3b, 0xa3, 0x68, 0xd6, 0x2b, 0xe8, 0x0d})},
		{93700, bc.NewHash([32]byte{0x70, 0x44, 0x70, 0xe5, 0xb3, 0x9b, 0xd3, 0x67, 0x19, 0x20, 0x08, 0x42, 0x1b, 0x59, 0xe8, 0xdc, 0xb5, 0xbb, 0xb9, 0x2d, 0xd3, 0xdc, 0x28, 0x4e, 0xcb, 0x7b, 0x0b, 0xbf, 0x21, 0x51, 0xe1, 0xba})},
		{106600, bc.NewHash([32]byte{0x31, 0x15, 0x2b, 0x00, 0xd4, 0x07, 0xe1, 0xa7, 0x06, 0xe1, 0xae, 0x2e, 0x98, 0x69, 0x8f, 0x47, 0xff, 0x44, 0x97, 0x01, 0xa7, 0x9e, 0x08, 0xdb, 0xeb, 0x0f, 0x1f, 0x5a, 0xdd, 0xf5, 0x26, 0xb9})},
		{116600, bc.NewHash([32]byte{0x08, 0xeb, 0xf7, 0x6c, 0x27, 0xed, 0x81, 0xe7, 0xe7, 0xfe, 0x13, 0xca, 0x80, 0x71, 0x29, 0x26, 0x28, 0x72, 0x25, 0xa5, 0x2a, 0xa0, 0x36, 0x30, 0x58, 0xaa, 0x58, 0xc6, 0xdd, 0xf2, 0xa0, 0xe7})},
		{126600, bc.NewHash([32]byte{0xac, 0x10, 0x41, 0x08, 0x24, 0x80, 0xe9, 0x5a, 0x9f, 0x32, 0x0a, 0x5e, 0x17, 0x7b, 0x01, 0x8d, 0x0d, 0x0d, 0x3d, 0xfc, 0xa7, 0x1d, 0x81, 0x5f, 0x13, 0xb4, 0xad, 0x0f, 0xc6, 0xde, 0x7a, 0x10})},
		{131260, bc.NewHash([32]byte{0xdf, 0x18, 0xb5, 0xb1, 0x6f, 0x5f, 0xd2, 0x77, 0x7c, 0xab, 0xb8, 0x59, 0xcb, 0x13, 0x64, 0xce, 0x06, 0x06, 0x51, 0x39, 0x89, 0x30, 0x1b, 0x69, 0xd6, 0x00, 0xec, 0xd8, 0xfa, 0xd2, 0x09, 0x93})},
		{157000, bc.NewHash([32]byte{0xb7, 0x70, 0x38, 0x4c, 0x81, 0x32, 0xaf, 0x12, 0x8d, 0xfa, 0xb4, 0xeb, 0x46, 0x4e, 0xb7, 0xeb, 0x66, 0x14, 0xd9, 0x24, 0xc2, 0xd1, 0x0c, 0x9c, 0x14, 0x20, 0xc9, 0xea, 0x0e, 0x85, 0xc8, 0xc3})},
		{180000, bc.NewHash([32]byte{0x3c, 0x2a, 0x91, 0x55, 0xf3, 0x36, 0x6a, 0x5a, 0x60, 0xcf, 0x84, 0x42, 0xec, 0x4d, 0x0c, 0x63, 0xbc, 0x34, 0xe9, 0x1d, 0x1c, 0x6b, 0xb0, 0xf0, 0x50, 0xf3, 0xfb, 0x2d, 0xf6, 0xa1, 0xd9, 0x5c})},
		{191000, bc.NewHash([32]byte{0x09, 0x4f, 0xe3, 0x23, 0x91, 0xb5, 0x11, 0x18, 0x68, 0xcc, 0x99, 0x9f, 0xeb, 0x95, 0xf9, 0xcc, 0xa5, 0x27, 0x6a, 0xf9, 0x0e, 0xda, 0x1b, 0xc6, 0x2e, 0x03, 0x29, 0xfe, 0x08, 0xdd, 0x2b, 0x01})},
		{205000, bc.NewHash([32]byte{0x6f, 0xdd, 0x87, 0x26, 0x73, 0x3f, 0x0b, 0xc7, 0x58, 0x64, 0xa4, 0xdf, 0x45, 0xe4, 0x50, 0x27, 0x68, 0x38, 0x18, 0xb9, 0xa9, 0x44, 0x56, 0x20, 0x34, 0x68, 0xd8, 0x68, 0x72, 0xdb, 0x65, 0x6f})},
		{219700, bc.NewHash([32]byte{0x98, 0x49, 0x8d, 0x4b, 0x7e, 0xe9, 0x44, 0x55, 0xc1, 0x07, 0xdd, 0x9a, 0xba, 0x6b, 0x49, 0x92, 0x61, 0x15, 0x03, 0x4f, 0x59, 0x42, 0x35, 0x74, 0xea, 0x3b, 0xdb, 0x2c, 0x53, 0x11, 0x75, 0x74})},
		{240000, bc.NewHash([32]byte{0x35, 0x16, 0x65, 0x58, 0xf4, 0xef, 0x24, 0x82, 0x43, 0xbb, 0x15, 0x79, 0xd4, 0xfe, 0x1b, 0x14, 0x9f, 0xe9, 0xf0, 0xe0, 0x48, 0x72, 0x86, 0x68, 0xa7, 0xb9, 0xda, 0x58, 0x66, 0x3b, 0x1c, 0xcb})},
		{270000, bc.NewHash([32]byte{0x9d, 0x6f, 0xcc, 0xd8, 0xb8, 0xe4, 0x8c, 0x17, 0x52, 0x9a, 0xe6, 0x1b, 0x40, 0x60, 0xe0, 0xe3, 0x6d, 0x1e, 0x89, 0xc0, 0x26, 0xdf, 0x1c, 0x28, 0x18, 0x0d, 0x29, 0x0c, 0x9b, 0x15, 0xcc, 0x97})},
		{300000, bc.NewHash([32]byte{0xa2, 0x85, 0x84, 0x6c, 0xe0, 0x3e, 0x1d, 0x68, 0x98, 0x7d, 0x93, 0x21, 0xea, 0xcc, 0x1d, 0x07, 0x88, 0xd1, 0x4c, 0x77, 0xa3, 0xd7, 0x55, 0x8a, 0x2b, 0x4a, 0xf7, 0x4d, 0x50, 0x14, 0x53, 0x5d})},
		{320000, bc.NewHash([32]byte{0xc6, 0xe7, 0x91, 0x6f, 0xcb, 0x7a, 0x42, 0x5d, 0xd6, 0x22, 0xef, 0x5d, 0x6a, 0x5c, 0xc1, 0x91, 0xa9, 0xd9, 0x06, 0x44, 0xcf, 0x36, 0x43, 0x55, 0xfe, 0x45, 0xaf, 0x24, 0x07, 0x31, 0x23, 0xc6})},
		{350000, bc.NewHash([32]byte{0xf4, 0x88, 0x6f, 0x9a, 0x17, 0x9a, 0x1c, 0x2a, 0x43, 0x9f, 0xc5, 0xae, 0x2f, 0xe4, 0xa6, 0x33, 0x71, 0xb4, 0xcd, 0x83, 0xc5, 0x23, 0xc1, 0x14, 0xb2, 0xb0, 0xa8, 0x43, 0xf2, 0xa1, 0x4b, 0x5c})},
		{380000, bc.NewHash([32]byte{0xf1, 0x00, 0x41, 0xcc, 0xea, 0xf0, 0x67, 0x98, 0x49, 0x89, 0x5f, 0xa6, 0xa0, 0x8d, 0x33, 0x04, 0x93, 0x1b, 0xf8, 0x49, 0x76, 0xe1, 0x22, 0xe3, 0xce, 0xc2, 0x6f, 0x19, 0xff, 0x4f, 0x80, 0xf1})},
		{420000, bc.NewHash([32]byte{0xdc, 0x99, 0xc7, 0x2d, 0x52, 0xa9, 0xc7, 0x2f, 0xdb, 0xcc, 0xf2, 0xb0, 0x51, 0xa2, 0x31, 0xde, 0x01, 0x06, 0x3d, 0x5d, 0x5e, 0x1a, 0x35, 0xd7, 0x1f, 0xf0, 0x5c, 0x2b, 0x59, 0x5c, 0x06, 0x32})},
		{460000, bc.NewHash([32]byte{0xf7, 0xfa, 0x12, 0xc9, 0xab, 0x6c, 0xcd, 0x32, 0x4e, 0xb0, 0x4a, 0x57, 0x6a, 0xe0, 0x9e, 0xd4, 0xa3, 0x59, 0x2d, 0x83, 0x5a, 0x27, 0xbb, 0x1b, 0xc0, 0xcd, 0x12, 0x94, 0x9e, 0xaf, 0x03, 0x7d})},
		{500000, bc.NewHash([32]byte{0x35, 0xc7, 0x54, 0x9a, 0x4b, 0x7b, 0x61, 0x2a, 0xe9, 0x4e, 0x16, 0xd6, 0x29, 0x8b, 0x97, 0x18, 0x0c, 0xa5, 0x73, 0x6a, 0xcb, 0x79, 0xfb, 0x2a, 0xc6, 0x4a, 0xf2, 0xc8, 0x2a, 0x18, 0x35, 0xe6})},
		{570000, bc.NewHash([32]byte{0x46, 0xd2, 0x28, 0xb4, 0xf3, 0xa2, 0x92, 0xde, 0x9d, 0xb3, 0x1c, 0x86, 0x4b, 0xb9, 0x94, 0x65, 0xad, 0x31, 0xa4, 0xa7, 0x28, 0x94, 0x30, 0x8c, 0xea, 0xa0, 0xaa, 0xf1, 0x9a, 0xe0, 0xbd, 0x9c})},
	},
}

MainNetParams is the config for production

var NetParams = map[string]Params{
	"mainnet": MainNetParams,
	"wisdom":  TestNetParams,
	"solonet": SoloNetParams,
}

NetParams is the correspondence between chain_id and Params

var SoloNetParams = Params{
	Name:            "solo",
	Bech32HRPSegwit: "sm",
	Checkpoints:     []Checkpoint{},
}

SoloNetParams is the config for test-net

var TestNetParams = Params{
	Name:            "test",
	Bech32HRPSegwit: "tm",
	DefaultPort:     "46656",
	DNSSeeds:        []string{"www.testnetseed.bytom.io"},
	Checkpoints: []Checkpoint{
		{10303, bc.NewHash([32]byte{0x3e, 0x94, 0x5d, 0x35, 0x70, 0x30, 0xd4, 0x3b, 0x3d, 0xe3, 0xdd, 0x80, 0x67, 0x29, 0x9a, 0x5e, 0x09, 0xf9, 0xfb, 0x2b, 0xad, 0x5f, 0x92, 0xc8, 0x69, 0xd1, 0x42, 0x39, 0x74, 0x9a, 0xd1, 0x1c})},
		{40000, bc.NewHash([32]byte{0x6b, 0x13, 0x9a, 0x5b, 0x76, 0x77, 0x9b, 0xd4, 0x1c, 0xec, 0x53, 0x68, 0x44, 0xbf, 0xf4, 0x48, 0x94, 0x3d, 0x16, 0xe3, 0x9b, 0x2e, 0xe8, 0xa1, 0x0f, 0xa0, 0xbc, 0x7d, 0x2b, 0x17, 0x55, 0xfc})},
		{78000, bc.NewHash([32]byte{0xa9, 0x03, 0xc0, 0x0c, 0x62, 0x1a, 0x3d, 0x00, 0x7f, 0xd8, 0x5d, 0x51, 0xba, 0x43, 0xe4, 0xd0, 0xe3, 0xc5, 0xd4, 0x8f, 0x30, 0xb5, 0x5f, 0xa5, 0x77, 0x62, 0xd8, 0x8b, 0x11, 0x81, 0x5f, 0xb4})},
		{82000, bc.NewHash([32]byte{0x56, 0xb1, 0xba, 0x23, 0x69, 0x5c, 0x8f, 0x51, 0x4e, 0x23, 0xc0, 0xae, 0xaa, 0x25, 0x08, 0xc5, 0x85, 0xf3, 0x7c, 0xd1, 0xc6, 0x15, 0xa2, 0x51, 0xda, 0x79, 0x4f, 0x08, 0x13, 0x66, 0xc9, 0x85})},
		{83200, bc.NewHash([32]byte{0xb4, 0x6f, 0xc5, 0xcf, 0xa3, 0x3d, 0xe1, 0x11, 0x71, 0x68, 0x40, 0x68, 0x0c, 0xe7, 0x4c, 0xaf, 0x5a, 0x11, 0xfe, 0x82, 0xbc, 0x36, 0x88, 0x0f, 0xbd, 0x04, 0xf0, 0xc4, 0x86, 0xd4, 0xd6, 0xd5})},
		{93000, bc.NewHash([32]byte{0x6f, 0x4f, 0x37, 0x5f, 0xe9, 0xfb, 0xdf, 0x66, 0x60, 0x0e, 0xf0, 0x39, 0xb7, 0x18, 0x26, 0x75, 0xa0, 0x9a, 0xa5, 0x9b, 0x83, 0xc9, 0x9a, 0x25, 0x45, 0xb8, 0x7d, 0xd4, 0x99, 0x24, 0xa2, 0x8a})},
		{113300, bc.NewHash([32]byte{0x7a, 0x69, 0x75, 0xa5, 0xf6, 0xb6, 0x94, 0xf3, 0x94, 0xa2, 0x63, 0x91, 0x28, 0xb6, 0xab, 0x7e, 0xf9, 0x71, 0x27, 0x5a, 0xe2, 0x59, 0xd3, 0xff, 0x70, 0x6e, 0xcb, 0xd8, 0xd8, 0x30, 0x9c, 0xc4})},
		{235157, bc.NewHash([32]byte{0xfa, 0x76, 0x36, 0x3e, 0x9e, 0x58, 0xea, 0xe4, 0x7d, 0x26, 0x70, 0x7e, 0xf3, 0x8b, 0xfd, 0xad, 0x1a, 0x99, 0xf7, 0x4c, 0xac, 0xc6, 0x80, 0x99, 0x58, 0x10, 0x13, 0x66, 0x4b, 0x8c, 0x39, 0x4f})},
		{252383, bc.NewHash([32]byte{0xa1, 0xaa, 0xe6, 0xd9, 0x42, 0x94, 0x99, 0x7b, 0x9b, 0x71, 0x5b, 0xf5, 0x23, 0x9a, 0xee, 0x92, 0x27, 0x84, 0x4c, 0x32, 0x47, 0xf2, 0xf2, 0xd9, 0xe3, 0xd7, 0x6a, 0x2b, 0xbe, 0xc3, 0x1f, 0x50})},
		{320000, bc.NewHash([32]byte{0xb5, 0x9f, 0xeb, 0x44, 0x4a, 0xfd, 0x67, 0x2a, 0x1c, 0x99, 0x8e, 0xc8, 0x48, 0xac, 0xeb, 0xfe, 0x80, 0xf6, 0x58, 0x7a, 0xf1, 0x7d, 0xea, 0xd6, 0xc7, 0xe5, 0x93, 0x3f, 0xae, 0x65, 0x88, 0xe6})},
		{360000, bc.NewHash([32]byte{0xad, 0x30, 0x55, 0x89, 0xf6, 0xd3, 0x7c, 0x13, 0x81, 0x8d, 0xeb, 0x09, 0xce, 0xea, 0x08, 0x64, 0xc4, 0x39, 0xd5, 0x80, 0x61, 0x88, 0xe2, 0xa5, 0xc8, 0x8f, 0xd7, 0x64, 0x4b, 0x0b, 0x5a, 0x6b})},
		{400000, bc.NewHash([32]byte{0xc2, 0xa5, 0xa3, 0x64, 0x51, 0x01, 0xe3, 0x1e, 0x57, 0xfb, 0x48, 0x15, 0x41, 0xcf, 0xaa, 0x67, 0x66, 0xd1, 0xb3, 0x2d, 0x91, 0xd2, 0x3d, 0xef, 0x53, 0xcd, 0x59, 0x97, 0x55, 0x04, 0xab, 0xc8})},
		{440000, bc.NewHash([32]byte{0xca, 0x56, 0xff, 0xf7, 0x94, 0x3c, 0x1b, 0xc7, 0x00, 0x52, 0x50, 0xa3, 0x3f, 0x75, 0xa3, 0x4b, 0xeb, 0x06, 0xc8, 0xba, 0xe3, 0x45, 0x9f, 0x93, 0x2a, 0x8c, 0x6c, 0xa3, 0x85, 0x33, 0x2b, 0x82})},
	},
}

TestNetParams is the config for test-net

Functions

func BlockSubsidy

func BlockSubsidy(height uint64) uint64

BlockSubsidy calculate the coinbase rewards on given block height

func IsBech32SegwitPrefix

func IsBech32SegwitPrefix(prefix string, params *Params) bool

IsBech32SegwitPrefix returns whether the prefix is a known prefix for segwit addresses on any default or registered network. This is used when decoding an address string into a specific address type.

Types

type Checkpoint

type Checkpoint struct {
	Height uint64
	Hash   bc.Hash
}

Checkpoint identifies a known good point in the block chain. Using checkpoints allows a few optimizations for old blocks during initial download and also prevents forks from old blocks.

type Params

type Params struct {
	// Name defines a human-readable identifier for the network.
	Name            string
	Bech32HRPSegwit string
	// DefaultPort defines the default peer-to-peer port for the network.
	DefaultPort string

	// DNSSeeds defines a list of DNS seeds for the network that are used
	// as one method to discover peers.
	DNSSeeds    []string
	Checkpoints []Checkpoint
}

Params store the config for different network

type ServiceFlag

type ServiceFlag uint64

ServiceFlag use uint64 to indicate what kind of server this node can provide. one uint64 can represent 64 type of service flag

const (
	// SFFullNode is a flag used to indicate a peer is a full node.
	SFFullNode ServiceFlag = 1 << iota
	// SFFastSync indicate peer support header first mode
	SFFastSync
	// SFSPV indicate peer support spv mode
	SFSPV
	// DefaultServices is the server that this node support
	DefaultServices = SFFullNode | SFFastSync | SFSPV
)

func (ServiceFlag) IsEnable

func (f ServiceFlag) IsEnable(checkFlag ServiceFlag) bool

IsEnable check does the flag support the input flag function