131 lines
2.5 KiB
Go
131 lines
2.5 KiB
Go
package postgres
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import (
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"fmt"
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"math/big"
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"github.com/jackc/pgtype"
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)
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type Numeric struct {
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pgtype.Numeric
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}
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func NewZeroNumeric() Numeric {
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return Numeric{pgtype.Numeric{Exp: 0, Int: big.NewInt(0), Status: pgtype.Present, NaN: false}}
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}
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func (n Numeric) GetFloat64() float64 {
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if n.Status != pgtype.Present {
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return 0
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}
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var balance float64
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err := n.AssignTo(&balance)
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if err != nil {
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panic(err)
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}
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return balance
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}
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func (n Numeric) IsPositive() bool {
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if n.Status != pgtype.Present {
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return true
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}
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float := n.GetFloat64()
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return float >= 0
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}
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func (n Numeric) IsZero() bool {
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if n.Status != pgtype.Present {
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return true
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}
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float := n.GetFloat64()
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return float == 0
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}
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func (n Numeric) MatchExp(exp int32) Numeric {
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diffExp := n.Exp - exp
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factor := big.NewInt(0).Exp(big.NewInt(10), big.NewInt(int64(diffExp)), nil) //nolint:gomnd
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return Numeric{pgtype.Numeric{
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Exp: exp,
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Int: big.NewInt(0).Mul(n.Int, factor),
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Status: n.Status,
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NaN: n.NaN,
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}}
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}
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func (n Numeric) Sub(other Numeric) Numeric {
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left := n
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right := other
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if n.Exp < other.Exp {
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right = other.MatchExp(n.Exp)
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} else if n.Exp > other.Exp {
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left = n.MatchExp(other.Exp)
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}
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if left.Exp == right.Exp {
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return Numeric{pgtype.Numeric{
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Exp: left.Exp,
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Int: big.NewInt(0).Sub(left.Int, right.Int),
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}}
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}
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panic("Cannot subtract with different exponents")
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}
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func (n Numeric) Add(other Numeric) Numeric {
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left := n
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right := other
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if n.Exp < other.Exp {
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right = other.MatchExp(n.Exp)
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} else if n.Exp > other.Exp {
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left = n.MatchExp(other.Exp)
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}
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if left.Exp == right.Exp {
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return Numeric{pgtype.Numeric{
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Exp: left.Exp,
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Int: big.NewInt(0).Add(left.Int, right.Int),
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}}
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}
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panic("Cannot add with different exponents")
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}
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func (n Numeric) MarshalJSON() ([]byte, error) {
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if n.Int.Int64() == 0 {
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return []byte("0"), nil
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}
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s := fmt.Sprintf("%d", n.Int)
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bytes := []byte(s)
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exp := n.Exp
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for exp > 0 {
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bytes = append(bytes, byte('0'))
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exp--
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}
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if exp == 0 {
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return bytes, nil
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}
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length := int32(len(bytes))
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var bytesWithSeparator []byte
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exp = -exp
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for length <= exp {
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bytes = append(bytes, byte('0'))
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length++
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}
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split := length - exp
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bytesWithSeparator = append(bytesWithSeparator, bytes[:split]...)
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if split == 1 && n.Int.Int64() < 0 {
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bytesWithSeparator = append(bytesWithSeparator, byte('0'))
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}
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bytesWithSeparator = append(bytesWithSeparator, byte('.'))
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bytesWithSeparator = append(bytesWithSeparator, bytes[split:]...)
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return bytesWithSeparator, nil
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}
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