kediaco / decimal

decimal package (go)

Package provides Decimal type which is used in various parts of finex.

Overview

Decimal type:

• stores value in single uint64;
• is unsigned;
• has minimum value of 0.00000000;
• has maximum value of 99999999999.99999999;
• is equivalent to MySQL type DECIMAL(19, 8) UNSIGNED;
• can be added (+), subtracted (-) and compared (>, <, ==) directly;
• can be multiplied using Multiply() method;
• can store 1 satoshi (BTC) or 10 Gwei (ETH) without losing precision: 0.00000001

Design

Max uint64 value is 18446744073709551615, which has string length of 20 characters, so we can reliably represent decimal number with 19 decimal points in total:

18446744073709551615
_9999999999999999999
99999999999.99999999
||||||||||| 100000000 = 1e8
100000000000          = 1e11

Benchmarks

BenchmarkDecimal_Scan-4                 10000000             156    ns/op
BenchmarkDecimal_String-4               20000000              76.4  ns/op
BenchmarkDecimal_Split-4              2000000000               0.58 ns/op
BenchmarkDecimal_Multiplication-4        5000000             253    ns/op

PASS
ok      github.com/openware/decimal     6.212s