Hein
337af294f3
Fixes GO-2026-6629 (golang.org/x/text precis panic). Bumps bun and bun/dialect/pgdialect together to v1.3.0; go directive now 1.26.0.
115 lines
5.3 KiB
Go
115 lines
5.3 KiB
Go
package decimal
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import (
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"math/big"
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"strings"
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)
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const (
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strLn10 = "2.302585092994045684017991454684364207601101488628772976033327900967572609677352480235997205089598298341967784042286248633409525465082806756666287369098781689482907208325554680843799894826233198528393505308965377732628846163366222287698219886746543667474404243274365155048934314939391479619404400222105101714174800368808401264708068556774321622835522011480466371565912137345074785694768346361679210180644507064800027750268491674655058685693567342067058113642922455440575892572420824131469568901675894025677631135691929203337658714166023010570308963457207544037084746994016826928280848118428931484852494864487192780967627127577539702766860595249671667418348570442250719796500471495105049221477656763693866297697952211071826454973477266242570942932258279850258550978526538320760672631716430950599508780752371033310119785754733154142180842754386359177811705430982748238504564801909561029929182431823752535770975053956518769751037497088869218020518933950723853920514463419726528728696511086257149219884997874887377134568620916705849807828059751193854445009978131146915934666241071846692310107598438319191292230792503747298650929009880391941702654416816335727555703151596113564846546190897042819763365836983716328982174407366009162177850541779276367731145041782137660111010731042397832521894898817597921798666394319523936855916447118246753245630912528778330963604262982153040874560927760726641354787576616262926568298704957954913954918049209069438580790032763017941503117866862092408537949861264933479354871737451675809537088281067452440105892444976479686075120275724181874989395971643105518848195288330746699317814634930000321200327765654130472621883970596794457943468343218395304414844803701305753674262153675579814770458031413637793236291560128185336498466942261465206459942072917119370602444929358037007718981097362533224548366988505528285966192805098447175198503666680874970496982273220244823343097169111136813588418696549323714996941979687803008850408979618598756579894836445212043698216415292987811742973332588607915912510967187510929248475023930572665446276200923068791518135803477701295593646298412366497023355174586195564772461857717369368404676577047874319780573853271810933883496338813069945569399346101090745616033312247949360455361849123333063704751724871276379140924398331810164737823379692265637682071706935846394531616949411701841938119405416449466111274712819705817783293841742231409930022911502362192186723337268385688273533371925103412930705632544426611429765388301822384091026198582888433587455960453004548370789052578473166283701953392231047527564998119228742789713715713228319641003422124210082180679525276689858180956119208391760721080919923461516952599099473782780648128058792731993893453415320185969711021407542282796298237068941764740642225757212455392526179373652434440560595336591539160312524480149313234572453879524389036839236450507881731359711238145323701508413491122324390927681724749607955799151363982881058285740538000653371655553014196332241918087621018204919492651483892"
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)
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var (
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ln10 = newConstApproximation(strLn10)
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)
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type constApproximation struct {
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exact Decimal
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approximations []Decimal
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}
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func newConstApproximation(value string) constApproximation {
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parts := strings.Split(value, ".")
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coeff, fractional := parts[0], parts[1]
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coeffLen := len(coeff)
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maxPrecision := len(fractional)
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var approximations []Decimal
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for p := 1; p < maxPrecision; p *= 2 {
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r := RequireFromString(value[:coeffLen+p])
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approximations = append(approximations, r)
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}
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return constApproximation{
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RequireFromString(value),
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approximations,
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}
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}
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// Returns the smallest approximation available that's at least as precise
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// as the passed precision (places after decimal point), i.e. Floor[ log2(precision) ] + 1
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func (c constApproximation) withPrecision(precision int32) Decimal {
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i := 0
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if precision >= 1 {
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i++
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}
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for precision >= 16 {
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precision /= 16
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i += 4
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}
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for precision >= 2 {
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precision /= 2
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i++
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}
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if i >= len(c.approximations) {
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return c.exact
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}
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return c.approximations[i]
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}
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var zeroInt = big.NewInt(0)
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var oneInt = big.NewInt(1)
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var twoInt = big.NewInt(2)
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var fourInt = big.NewInt(4)
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var fiveInt = big.NewInt(5)
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var tenInt = big.NewInt(10)
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var twentyInt = big.NewInt(20)
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// pow10Table holds 10^0 ... 10^127, its values must not be modified.
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var pow10Table = func() []*big.Int {
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t := make([]*big.Int, 128)
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t[0] = big.NewInt(1)
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for i := 1; i < len(t); i++ {
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t[i] = new(big.Int).Mul(t[i-1], tenInt)
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}
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return t
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}()
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// pow10Uint64 holds 10^0 ... 10^19.
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var pow10Uint64 = func() (t [20]uint64) {
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t[0] = 1
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for i := 1; i < len(t); i++ {
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t[i] = t[i-1] * 10
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}
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return t
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}()
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// float64Pow10 holds 10^0 ... 10^22, the powers of ten that float64 represents exactly.
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var float64Pow10 = [...]float64{1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 1e10,
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1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, 1e20, 1e21, 1e22}
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// pow5Int64 holds 5^0 ... 5^22.
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var pow5Int64 = func() (t [23]int64) {
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t[0] = 1
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for i := 1; i < len(t); i++ {
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t[i] = t[i-1] * 5
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}
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return t
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}()
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// pow10 returns 10^n for n >= 0, the result must not be modified.
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func pow10(n int64) *big.Int {
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if n < int64(len(pow10Table)) {
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return pow10Table[n]
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}
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return new(big.Int).Exp(tenInt, big.NewInt(n), nil)
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}
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const zeros = "0000000000000000000000000000000000000000000000000000000000000000"
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