golang 将[]byte转成16进制的实现
时间：2021-05-31 08:24:07|栏目：Golang|点击： 次
将[]byte转成16进制
import "crypto/md5"
import "fmt"
sign := md5.Sum([]byte("date string"))
signStr := fmt.Sprintf("%x", sign) //将[]byte转成16进制
补充：golang []byte存储存储的16进制转10进制
项目中有用[]byte存储16进制需要转到10进制，如果用系统自带的函数处理，需要先将[]byte通过hex.EncodeToString转为string，再用strconv.ParseInt转到10进制，过程中由于两次转换导致内存分配过多（每秒执行近100w次），GC出现错误导致进程挂掉。
自己写了一个函数来转，主要是避免出现内存泄漏：
var b2m_map map[byte]uint64 = map[byte]uint64{
0x00: 0,
0x01: 1,
0x02: 2,
0x03: 3,
0x04: 4,
0x05: 5,
0x06: 6,
0x07: 7,
0x08: 8,
0x09: 9,
0x0A: 10,
0x0B: 11,
0x0C: 12,
0x0D: 13,
0x0E: 14,
0x0F: 15,
0x10: 16,
0x11: 17,
0x12: 18,
0x13: 19,
0x14: 20,
0x15: 21,
0x16: 22,
0x17: 23,
0x18: 24,
0x19: 25,
0x1A: 26,
0x1B: 27,
0x1C: 28,
0x1D: 29,
0x1E: 30,
0x1F: 31,
0x20: 32,
0x21: 33,
0x22: 34,
0x23: 35,
0x24: 36,
0x25: 37,
0x26: 38,
0x27: 39,
0x28: 40,
0x29: 41,
0x2A: 42,
0x2B: 43,
0x2C: 44,
0x2D: 45,
0x2E: 46,
0x2F: 47,
0x30: 48,
0x31: 49,
0x32: 50,
0x33: 51,
0x34: 52,
0x35: 53,
0x36: 54,
0x37: 55,
0x38: 56,
0x39: 57,
0x3A: 58,
0x3B: 59,
0x3C: 60,
0x3D: 61,
0x3E: 62,
0x3F: 63,
0x40: 64,
0x41: 65,
0x42: 66,
0x43: 67,
0x44: 68,
0x45: 69,
0x46: 70,
0x47: 71,
0x48: 72,
0x49: 73,
0x4A: 74,
0x4B: 75,
0x4C: 76,
0x4D: 77,
0x4E: 78,
0x4F: 79,
0x50: 80,
0x51: 81,
0x52: 82,
0x53: 83,
0x54: 84,
0x55: 85,
0x56: 86,
0x57: 87,
0x58: 88,
0x59: 89,
0x5A: 90,
0x5B: 91,
0x5C: 92,
0x5D: 93,
0x5E: 94,
0x5F: 95,
0x60: 96,
0x61: 97,
0x62: 98,
0x63: 99,
0x64: 100,
0x65: 101,
0x66: 102,
0x67: 103,
0x68: 104,
0x69: 105,
0x6A: 106,
0x6B: 107,
0x6C: 108,
0x6D: 109,
0x6E: 110,
0x6F: 111,
0x70: 112,
0x71: 113,
0x72: 114,
0x73: 115,
0x74: 116,
0x75: 117,
0x76: 118,
0x77: 119,
0x78: 120,
0x79: 121,
0x7A: 122,
0x7B: 123,
0x7C: 124,
0x7D: 125,
0x7E: 126,
0x7F: 127,
0x80: 128,
0x81: 129,
0x82: 130,
0x83: 131,
0x84: 132,
0x85: 133,
0x86: 134,
0x87: 135,
0x88: 136,
0x89: 137,
0x8A: 138,
0x8B: 139,
0x8C: 140,
0x8D: 141,
0x8E: 142,
0x8F: 143,
0x90: 144,
0x91: 145,
0x92: 146,
0x93: 147,
0x94: 148,
0x95: 149,
0x96: 150,
0x97: 151,
0x98: 152,
0x99: 153,
0x9A: 154,
0x9B: 155,
0x9C: 156,
0x9D: 157,
0x9E: 158,
0x9F: 159,
0xA0: 160,
0xA1: 161,
0xA2: 162,
0xA3: 163,
0xA4: 164,
0xA5: 165,
0xA6: 166,
0xA7: 167,
0xA8: 168,
0xA9: 169,
0xAA: 170,
0xAB: 171,
0xAC: 172,
0xAD: 173,
0xAE: 174,
0xAF: 175,
0xB0: 176,
0xB1: 177,
0xB2: 178,
0xB3: 179,
0xB4: 180,
0xB5: 181,
0xB6: 182,
0xB7: 183,
0xB8: 184,
0xB9: 185,
0xBA: 186,
0xBB: 187,
0xBC: 188,
0xBD: 189,
0xBE: 190,
0xBF: 191,
0xC0: 192,
0xC1: 193,
0xC2: 194,
0xC3: 195,
0xC4: 196,
0xC5: 197,
0xC6: 198,
0xC7: 199,
0xC8: 200,
0xC9: 201,
0xCA: 202,
0xCB: 203,
0xCC: 204,
0xCD: 205,
0xCE: 206,
0xCF: 207,
0xD0: 208,
0xD1: 209,
0xD2: 210,
0xD3: 211,
0xD4: 212,
0xD5: 213,
0xD6: 214,
0xD7: 215,
0xD8: 216,
0xD9: 217,
0xDA: 218,
0xDB: 219,
0xDC: 220,
0xDD: 221,
0xDE: 222,
0xDF: 223,
0xE0: 224,
0xE1: 225,
0xE2: 226,
0xE3: 227,
0xE4: 228,
0xE5: 229,
0xE6: 230,
0xE7: 231,
0xE8: 232,
0xE9: 233,
0xEA: 234,
0xEB: 235,
0xEC: 236,
0xED: 237,
0xEE: 238,
0xEF: 239,
0xF0: 240,
0xF1: 241,
0xF2: 242,
0xF3: 243,
0xF4: 244,
0xF5: 245,
0xF6: 246,
0xF7: 247,
0xF8: 248,
0xF9: 249,
0xFA: 250,
0xFB: 251,
0xFC: 252,
0xFD: 253,
0xFE: 254,
0xFF: 255,
}
func hex2int(hexB *[]byte) uint64 {
var retInt uint64
hexLen := len(*hexB)
for k, v := range *hexB {
retInt += b2m_map[v] * exponent(16, uint64(2*(hexLen-k-1)))
}
return retInt
}
func exponent(a, n uint64) uint64 {
result := uint64(1)
for i := n; i > 0; i >>= 1 {
if i&1 != 0 {
result *= a
}
a *= a
}
return result
}
经过测试，性能和自带的方法接近，略有提升。
goos: windows goarch: amd64 pkg: benchmark Benchmark_General-4 10000000 144 ns/op Benchmark_Better-4 10000000 128 ns/op PASS ok benchmark 3.086s
栏 目：Golang
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