encode.go

package gobbc

import (
	"fmt"
)

const alphabet = "0123456789abcdefghjkmnpqrstvwxyz" //base32 words

// static const uint crc24q_table[256] = {
var crc24qTable = [256]uint{
	0x00000000, 0x01864CFB, 0x028AD50D, 0x030C99F6, 0x0493E6E1, 0x0515AA1A, 0x061933EC, 0x079F7F17,
	0x08A18139, 0x0927CDC2, 0x0A2B5434, 0x0BAD18CF, 0x0C3267D8, 0x0DB42B23, 0x0EB8B2D5, 0x0F3EFE2E,
	0x10C54E89, 0x11430272, 0x124F9B84, 0x13C9D77F, 0x1456A868, 0x15D0E493, 0x16DC7D65, 0x175A319E,
	0x1864CFB0, 0x19E2834B, 0x1AEE1ABD, 0x1B685646, 0x1CF72951, 0x1D7165AA, 0x1E7DFC5C, 0x1FFBB0A7,
	0x200CD1E9, 0x218A9D12, 0x228604E4, 0x2300481F, 0x249F3708, 0x25197BF3, 0x2615E205, 0x2793AEFE,
	0x28AD50D0, 0x292B1C2B, 0x2A2785DD, 0x2BA1C926, 0x2C3EB631, 0x2DB8FACA, 0x2EB4633C, 0x2F322FC7,
	0x30C99F60, 0x314FD39B, 0x32434A6D, 0x33C50696, 0x345A7981, 0x35DC357A, 0x36D0AC8C, 0x3756E077,
	0x38681E59, 0x39EE52A2, 0x3AE2CB54, 0x3B6487AF, 0x3CFBF8B8, 0x3D7DB443, 0x3E712DB5, 0x3FF7614E,
	0x4019A3D2, 0x419FEF29, 0x429376DF, 0x43153A24, 0x448A4533, 0x450C09C8, 0x4600903E, 0x4786DCC5,
	0x48B822EB, 0x493E6E10, 0x4A32F7E6, 0x4BB4BB1D, 0x4C2BC40A, 0x4DAD88F1, 0x4EA11107, 0x4F275DFC,
	0x50DCED5B, 0x515AA1A0, 0x52563856, 0x53D074AD, 0x544F0BBA, 0x55C94741, 0x56C5DEB7, 0x5743924C,
	0x587D6C62, 0x59FB2099, 0x5AF7B96F, 0x5B71F594, 0x5CEE8A83, 0x5D68C678, 0x5E645F8E, 0x5FE21375,
	0x6015723B, 0x61933EC0, 0x629FA736, 0x6319EBCD, 0x648694DA, 0x6500D821, 0x660C41D7, 0x678A0D2C,
	0x68B4F302, 0x6932BFF9, 0x6A3E260F, 0x6BB86AF4, 0x6C2715E3, 0x6DA15918, 0x6EADC0EE, 0x6F2B8C15,
	0x70D03CB2, 0x71567049, 0x725AE9BF, 0x73DCA544, 0x7443DA53, 0x75C596A8, 0x76C90F5E, 0x774F43A5,
	0x7871BD8B, 0x79F7F170, 0x7AFB6886, 0x7B7D247D, 0x7CE25B6A, 0x7D641791, 0x7E688E67, 0x7FEEC29C,
	0x803347A4, 0x81B50B5F, 0x82B992A9, 0x833FDE52, 0x84A0A145, 0x8526EDBE, 0x862A7448, 0x87AC38B3,
	0x8892C69D, 0x89148A66, 0x8A181390, 0x8B9E5F6B, 0x8C01207C, 0x8D876C87, 0x8E8BF571, 0x8F0DB98A,
	0x90F6092D, 0x917045D6, 0x927CDC20, 0x93FA90DB, 0x9465EFCC, 0x95E3A337, 0x96EF3AC1, 0x9769763A,
	0x98578814, 0x99D1C4EF, 0x9ADD5D19, 0x9B5B11E2, 0x9CC46EF5, 0x9D42220E, 0x9E4EBBF8, 0x9FC8F703,
	0xA03F964D, 0xA1B9DAB6, 0xA2B54340, 0xA3330FBB, 0xA4AC70AC, 0xA52A3C57, 0xA626A5A1, 0xA7A0E95A,
	0xA89E1774, 0xA9185B8F, 0xAA14C279, 0xAB928E82, 0xAC0DF195, 0xAD8BBD6E, 0xAE872498, 0xAF016863,
	0xB0FAD8C4, 0xB17C943F, 0xB2700DC9, 0xB3F64132, 0xB4693E25, 0xB5EF72DE, 0xB6E3EB28, 0xB765A7D3,
	0xB85B59FD, 0xB9DD1506, 0xBAD18CF0, 0xBB57C00B, 0xBCC8BF1C, 0xBD4EF3E7, 0xBE426A11, 0xBFC426EA,
	0xC02AE476, 0xC1ACA88D, 0xC2A0317B, 0xC3267D80, 0xC4B90297, 0xC53F4E6C, 0xC633D79A, 0xC7B59B61,
	0xC88B654F, 0xC90D29B4, 0xCA01B042, 0xCB87FCB9, 0xCC1883AE, 0xCD9ECF55, 0xCE9256A3, 0xCF141A58,
	0xD0EFAAFF, 0xD169E604, 0xD2657FF2, 0xD3E33309, 0xD47C4C1E, 0xD5FA00E5, 0xD6F69913, 0xD770D5E8,
	0xD84E2BC6, 0xD9C8673D, 0xDAC4FECB, 0xDB42B230, 0xDCDDCD27, 0xDD5B81DC, 0xDE57182A, 0xDFD154D1,
	0xE026359F, 0xE1A07964, 0xE2ACE092, 0xE32AAC69, 0xE4B5D37E, 0xE5339F85, 0xE63F0673, 0xE7B94A88,
	0xE887B4A6, 0xE901F85D, 0xEA0D61AB, 0xEB8B2D50, 0xEC145247, 0xED921EBC, 0xEE9E874A, 0xEF18CBB1,
	0xF0E37B16, 0xF16537ED, 0xF269AE1B, 0xF3EFE2E0, 0xF4709DF7, 0xF5F6D10C, 0xF6FA48FA, 0xF77C0401,
	0xF842FA2F, 0xF9C4B6D4, 0xFAC82F22, 0xFB4E63D9, 0xFCD11CCE, 0xFD575035, 0xFE5BC9C3, 0xFFDD8538,
}

type uint256 [32]byte

var hexDigits = [256]uint8{
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0-27
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, // 28..48(0).49(1)...55(7)
	8, 9, 0, 0, 0, 0, 0, 0, 0, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 56(8)...65(0xa)...70(0xf)...83
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 84...97(0xa)...102(0xf)...111
}

func uint256SetHex(t *uint256, hexed string) int {
	for i, j := 0, len(hexed)-1; i < 32; i++ {
		t[i] = hexDigits[hexed[j]]
		j--
		t[i] = t[i] | hexDigits[hexed[j]]<<4
		j--
	}
	return 0
}

func uint256GetHex(data []byte) string {
	s := ""

	for i := len(data) - 1; i >= 0; i-- {
		x := data[i]
		// for _, x := range data {
		s += fmt.Sprintf("%02x", uint8(x))
		fmt.Printf("%d => %02x\n", uint8(x), uint8(x))
	}
	return s
}

func crc24q(data []uint8, size int) uint {
	var crc uint = 0
	for i := 0; i < size; i++ {
		x := uint(data[i])
		crc = (crc << 8) ^ crc24qTable[x^(0xFF&(crc>>16))]
	}
	return crc & 0x00ffffff
}

func base32Encode5Bytes(md5 []uint8) string {
	// fmt.Println("base325bytes in:", md5)
	ret := ""
	ret = ret + string(alphabet[(md5[0]>>3)&0x1F])
	ret = ret + string(alphabet[((md5[0]<<2)&0x1C)|((md5[1]>>6)&0x03)])
	ret = ret + string(alphabet[(md5[1]>>1)&0x1F])
	ret = ret + string(alphabet[((md5[1]<<4)&0x10)|((md5[2]>>4)&0x0F)])
	ret = ret + string(alphabet[((md5[2]<<1)&0x1E)|((md5[3]>>7)&0x01)])
	ret = ret + string(alphabet[(md5[3]>>2)&0x1F])
	ret = ret + string(alphabet[((md5[3]<<3)&0x18)|((md5[4]>>5)&0x07)])
	ret = ret + string(alphabet[(md5[4]&0x1F)])
	return ret
}

// Base32Encode copied from c++
func Base32Encode(md32 []uint8) string {
	// fmt.Println("base32encode in: ", md32)
	var crc uint = crc24q(md32, 32)
	// fmt.Printf("crc24q result: %d\n", crc)
	s := ""
	for i := 0; i < 30; i = i + 5 {
		s += base32Encode5Bytes(md32[i : i+5])
	}

	tail := [5]uint8{md32[30], md32[31], (uint8)(crc >> 16), (uint8)(crc >> 8), (uint8)(crc)}
	s += base32Encode5Bytes(tail[:])
	return s
}