From 621e49bb465f500cc46d47e39e828cf76d6381d7 Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Tue, 24 Jul 2018 14:35:44 +0200 Subject: update vendor --- .../golang.org/x/text/internal/number/decimal.go | 498 +++++++++++++++++++++ 1 file changed, 498 insertions(+) create mode 100644 vendor/golang.org/x/text/internal/number/decimal.go (limited to 'vendor/golang.org/x/text/internal/number/decimal.go') diff --git a/vendor/golang.org/x/text/internal/number/decimal.go b/vendor/golang.org/x/text/internal/number/decimal.go new file mode 100644 index 0000000..9b4035e --- /dev/null +++ b/vendor/golang.org/x/text/internal/number/decimal.go @@ -0,0 +1,498 @@ +// Copyright 2017 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +//go:generate stringer -type RoundingMode + +package number + +import ( + "math" + "strconv" +) + +// RoundingMode determines how a number is rounded to the desired precision. +type RoundingMode byte + +const ( + ToNearestEven RoundingMode = iota // towards the nearest integer, or towards an even number if equidistant. + ToNearestZero // towards the nearest integer, or towards zero if equidistant. + ToNearestAway // towards the nearest integer, or away from zero if equidistant. + ToPositiveInf // towards infinity + ToNegativeInf // towards negative infinity + ToZero // towards zero + AwayFromZero // away from zero + numModes +) + +const maxIntDigits = 20 + +// A Decimal represents a floating point number in decimal format. +// Digits represents a number [0, 1.0), and the absolute value represented by +// Decimal is Digits * 10^Exp. Leading and trailing zeros may be omitted and Exp +// may point outside a valid position in Digits. +// +// Examples: +// Number Decimal +// 12345 Digits: [1, 2, 3, 4, 5], Exp: 5 +// 12.345 Digits: [1, 2, 3, 4, 5], Exp: 2 +// 12000 Digits: [1, 2], Exp: 5 +// 12000.00 Digits: [1, 2], Exp: 5 +// 0.00123 Digits: [1, 2, 3], Exp: -2 +// 0 Digits: [], Exp: 0 +type Decimal struct { + digits + + buf [maxIntDigits]byte +} + +type digits struct { + Digits []byte // mantissa digits, big-endian + Exp int32 // exponent + Neg bool + Inf bool // Takes precedence over Digits and Exp. + NaN bool // Takes precedence over Inf. +} + +// Digits represents a floating point number represented in digits of the +// base in which a number is to be displayed. It is similar to Decimal, but +// keeps track of trailing fraction zeros and the comma placement for +// engineering notation. Digits must have at least one digit. +// +// Examples: +// Number Decimal +// decimal +// 12345 Digits: [1, 2, 3, 4, 5], Exp: 5 End: 5 +// 12.345 Digits: [1, 2, 3, 4, 5], Exp: 2 End: 5 +// 12000 Digits: [1, 2], Exp: 5 End: 5 +// 12000.00 Digits: [1, 2], Exp: 5 End: 7 +// 0.00123 Digits: [1, 2, 3], Exp: -2 End: 3 +// 0 Digits: [], Exp: 0 End: 1 +// scientific (actual exp is Exp - Comma) +// 0e0 Digits: [0], Exp: 1, End: 1, Comma: 1 +// .0e0 Digits: [0], Exp: 0, End: 1, Comma: 0 +// 0.0e0 Digits: [0], Exp: 1, End: 2, Comma: 1 +// 1.23e4 Digits: [1, 2, 3], Exp: 5, End: 3, Comma: 1 +// .123e5 Digits: [1, 2, 3], Exp: 5, End: 3, Comma: 0 +// engineering +// 12.3e3 Digits: [1, 2, 3], Exp: 5, End: 3, Comma: 2 +type Digits struct { + digits + // End indicates the end position of the number. + End int32 // For decimals Exp <= End. For scientific len(Digits) <= End. + // Comma is used for the comma position for scientific (always 0 or 1) and + // engineering notation (always 0, 1, 2, or 3). + Comma uint8 + // IsScientific indicates whether this number is to be rendered as a + // scientific number. + IsScientific bool +} + +func (d *Digits) NumFracDigits() int { + if d.Exp >= d.End { + return 0 + } + return int(d.End - d.Exp) +} + +// normalize returns a new Decimal with leading and trailing zeros removed. +func (d *Decimal) normalize() (n Decimal) { + n = *d + b := n.Digits + // Strip leading zeros. Resulting number of digits is significant digits. + for len(b) > 0 && b[0] == 0 { + b = b[1:] + n.Exp-- + } + // Strip trailing zeros + for len(b) > 0 && b[len(b)-1] == 0 { + b = b[:len(b)-1] + } + if len(b) == 0 { + n.Exp = 0 + } + n.Digits = b + return n +} + +func (d *Decimal) clear() { + b := d.Digits + if b == nil { + b = d.buf[:0] + } + *d = Decimal{} + d.Digits = b[:0] +} + +func (x *Decimal) String() string { + if x.NaN { + return "NaN" + } + var buf []byte + if x.Neg { + buf = append(buf, '-') + } + if x.Inf { + buf = append(buf, "Inf"...) + return string(buf) + } + switch { + case len(x.Digits) == 0: + buf = append(buf, '0') + case x.Exp <= 0: + // 0.00ddd + buf = append(buf, "0."...) + buf = appendZeros(buf, -int(x.Exp)) + buf = appendDigits(buf, x.Digits) + + case /* 0 < */ int(x.Exp) < len(x.Digits): + // dd.ddd + buf = appendDigits(buf, x.Digits[:x.Exp]) + buf = append(buf, '.') + buf = appendDigits(buf, x.Digits[x.Exp:]) + + default: // len(x.Digits) <= x.Exp + // ddd00 + buf = appendDigits(buf, x.Digits) + buf = appendZeros(buf, int(x.Exp)-len(x.Digits)) + } + return string(buf) +} + +func appendDigits(buf []byte, digits []byte) []byte { + for _, c := range digits { + buf = append(buf, c+'0') + } + return buf +} + +// appendZeros appends n 0 digits to buf and returns buf. +func appendZeros(buf []byte, n int) []byte { + for ; n > 0; n-- { + buf = append(buf, '0') + } + return buf +} + +func (d *digits) round(mode RoundingMode, n int) { + if n >= len(d.Digits) { + return + } + // Make rounding decision: The result mantissa is truncated ("rounded down") + // by default. Decide if we need to increment, or "round up", the (unsigned) + // mantissa. + inc := false + switch mode { + case ToNegativeInf: + inc = d.Neg + case ToPositiveInf: + inc = !d.Neg + case ToZero: + // nothing to do + case AwayFromZero: + inc = true + case ToNearestEven: + inc = d.Digits[n] > 5 || d.Digits[n] == 5 && + (len(d.Digits) > n+1 || n == 0 || d.Digits[n-1]&1 != 0) + case ToNearestAway: + inc = d.Digits[n] >= 5 + case ToNearestZero: + inc = d.Digits[n] > 5 || d.Digits[n] == 5 && len(d.Digits) > n+1 + default: + panic("unreachable") + } + if inc { + d.roundUp(n) + } else { + d.roundDown(n) + } +} + +// roundFloat rounds a floating point number. +func (r RoundingMode) roundFloat(x float64) float64 { + // Make rounding decision: The result mantissa is truncated ("rounded down") + // by default. Decide if we need to increment, or "round up", the (unsigned) + // mantissa. + abs := x + if x < 0 { + abs = -x + } + i, f := math.Modf(abs) + if f == 0.0 { + return x + } + inc := false + switch r { + case ToNegativeInf: + inc = x < 0 + case ToPositiveInf: + inc = x >= 0 + case ToZero: + // nothing to do + case AwayFromZero: + inc = true + case ToNearestEven: + // TODO: check overflow + inc = f > 0.5 || f == 0.5 && int64(i)&1 != 0 + case ToNearestAway: + inc = f >= 0.5 + case ToNearestZero: + inc = f > 0.5 + default: + panic("unreachable") + } + if inc { + i += 1 + } + if abs != x { + i = -i + } + return i +} + +func (x *digits) roundUp(n int) { + if n < 0 || n >= len(x.Digits) { + return // nothing to do + } + // find first digit < 9 + for n > 0 && x.Digits[n-1] >= 9 { + n-- + } + + if n == 0 { + // all digits are 9s => round up to 1 and update exponent + x.Digits[0] = 1 // ok since len(x.Digits) > n + x.Digits = x.Digits[:1] + x.Exp++ + return + } + x.Digits[n-1]++ + x.Digits = x.Digits[:n] + // x already trimmed +} + +func (x *digits) roundDown(n int) { + if n < 0 || n >= len(x.Digits) { + return // nothing to do + } + x.Digits = x.Digits[:n] + trim(x) +} + +// trim cuts off any trailing zeros from x's mantissa; +// they are meaningless for the value of x. +func trim(x *digits) { + i := len(x.Digits) + for i > 0 && x.Digits[i-1] == 0 { + i-- + } + x.Digits = x.Digits[:i] + if i == 0 { + x.Exp = 0 + } +} + +// A Converter converts a number into decimals according to the given rounding +// criteria. +type Converter interface { + Convert(d *Decimal, r RoundingContext) +} + +const ( + signed = true + unsigned = false +) + +// Convert converts the given number to the decimal representation using the +// supplied RoundingContext. +func (d *Decimal) Convert(r RoundingContext, number interface{}) { + switch f := number.(type) { + case Converter: + d.clear() + f.Convert(d, r) + case float32: + d.ConvertFloat(r, float64(f), 32) + case float64: + d.ConvertFloat(r, f, 64) + case int: + d.ConvertInt(r, signed, uint64(f)) + case int8: + d.ConvertInt(r, signed, uint64(f)) + case int16: + d.ConvertInt(r, signed, uint64(f)) + case int32: + d.ConvertInt(r, signed, uint64(f)) + case int64: + d.ConvertInt(r, signed, uint64(f)) + case uint: + d.ConvertInt(r, unsigned, uint64(f)) + case uint8: + d.ConvertInt(r, unsigned, uint64(f)) + case uint16: + d.ConvertInt(r, unsigned, uint64(f)) + case uint32: + d.ConvertInt(r, unsigned, uint64(f)) + case uint64: + d.ConvertInt(r, unsigned, f) + + default: + d.NaN = true + // TODO: + // case string: if produced by strconv, allows for easy arbitrary pos. + // case reflect.Value: + // case big.Float + // case big.Int + // case big.Rat? + // catch underlyings using reflect or will this already be done by the + // message package? + } +} + +// ConvertInt converts an integer to decimals. +func (d *Decimal) ConvertInt(r RoundingContext, signed bool, x uint64) { + if r.Increment > 0 { + // TODO: if uint64 is too large, fall back to float64 + if signed { + d.ConvertFloat(r, float64(int64(x)), 64) + } else { + d.ConvertFloat(r, float64(x), 64) + } + return + } + d.clear() + if signed && int64(x) < 0 { + x = uint64(-int64(x)) + d.Neg = true + } + d.fillIntDigits(x) + d.Exp = int32(len(d.Digits)) +} + +// ConvertFloat converts a floating point number to decimals. +func (d *Decimal) ConvertFloat(r RoundingContext, x float64, size int) { + d.clear() + if math.IsNaN(x) { + d.NaN = true + return + } + // Simple case: decimal notation + if r.Increment > 0 { + scale := int(r.IncrementScale) + mult := 1.0 + if scale > len(scales) { + mult = math.Pow(10, float64(scale)) + } else { + mult = scales[scale] + } + // We multiply x instead of dividing inc as it gives less rounding + // issues. + x *= mult + x /= float64(r.Increment) + x = r.Mode.roundFloat(x) + x *= float64(r.Increment) + x /= mult + } + + abs := x + if x < 0 { + d.Neg = true + abs = -x + } + if math.IsInf(abs, 1) { + d.Inf = true + return + } + + // By default we get the exact decimal representation. + verb := byte('g') + prec := -1 + // As the strconv API does not return the rounding accuracy, we can only + // round using ToNearestEven. + if r.Mode == ToNearestEven { + if n := r.RoundSignificantDigits(); n >= 0 { + prec = n + } else if n = r.RoundFractionDigits(); n >= 0 { + prec = n + verb = 'f' + } + } else { + // TODO: At this point strconv's rounding is imprecise to the point that + // it is not useable for this purpose. + // See https://github.com/golang/go/issues/21714 + // If rounding is requested, we ask for a large number of digits and + // round from there to simulate rounding only once. + // Ideally we would have strconv export an AppendDigits that would take + // a rounding mode and/or return an accuracy. Something like this would + // work: + // AppendDigits(dst []byte, x float64, base, size, prec int) (digits []byte, exp, accuracy int) + hasPrec := r.RoundSignificantDigits() >= 0 + hasScale := r.RoundFractionDigits() >= 0 + if hasPrec || hasScale { + // prec is the number of mantissa bits plus some extra for safety. + // We need at least the number of mantissa bits as decimals to + // accurately represent the floating point without rounding, as each + // bit requires one more decimal to represent: 0.5, 0.25, 0.125, ... + prec = 60 + } + } + + b := strconv.AppendFloat(d.Digits[:0], abs, verb, prec, size) + i := 0 + k := 0 + beforeDot := 1 + for i < len(b) { + if c := b[i]; '0' <= c && c <= '9' { + b[k] = c - '0' + k++ + d.Exp += int32(beforeDot) + } else if c == '.' { + beforeDot = 0 + d.Exp = int32(k) + } else { + break + } + i++ + } + d.Digits = b[:k] + if i != len(b) { + i += len("e") + pSign := i + exp := 0 + for i++; i < len(b); i++ { + exp *= 10 + exp += int(b[i] - '0') + } + if b[pSign] == '-' { + exp = -exp + } + d.Exp = int32(exp) + 1 + } +} + +func (d *Decimal) fillIntDigits(x uint64) { + if cap(d.Digits) < maxIntDigits { + d.Digits = d.buf[:] + } else { + d.Digits = d.buf[:maxIntDigits] + } + i := 0 + for ; x > 0; x /= 10 { + d.Digits[i] = byte(x % 10) + i++ + } + d.Digits = d.Digits[:i] + for p := 0; p < i; p++ { + i-- + d.Digits[p], d.Digits[i] = d.Digits[i], d.Digits[p] + } +} + +var scales [70]float64 + +func init() { + x := 1.0 + for i := range scales { + scales[i] = x + x *= 10 + } +} -- cgit v1.2.3