Checking in vendor folder for ease of using go get.

vendor/golang.org/x/text/feature/plural/message.go

@@ -0,0 +1,244 @@
+// 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.
+
+package plural
+
+import (
+	"fmt"
+	"io/ioutil"
+	"reflect"
+	"strconv"
+
+	"golang.org/x/text/internal/catmsg"
+	"golang.org/x/text/internal/number"
+	"golang.org/x/text/language"
+	"golang.org/x/text/message/catalog"
+)
+
+// TODO: consider deleting this interface. Maybe VisibleDigits is always
+// sufficient and practical.
+
+// Interface is used for types that can determine their own plural form.
+type Interface interface {
+	// PluralForm reports the plural form for the given language of the
+	// underlying value. It also returns the integer value. If the integer value
+	// is larger than fits in n, PluralForm may return a value modulo
+	// 10,000,000.
+	PluralForm(t language.Tag, scale int) (f Form, n int)
+}
+
+// Selectf returns the first case for which its selector is a match for the
+// arg-th substitution argument to a formatting call, formatting it as indicated
+// by format.
+//
+// The cases argument are pairs of selectors and messages. Selectors are of type
+// string or Form. Messages are of type string or catalog.Message. A selector
+// matches an argument if:
+//    - it is "other" or Other
+//    - it matches the plural form of the argument: "zero", "one", "two", "few",
+//      or "many", or the equivalent Form
+//    - it is of the form "=x" where x is an integer that matches the value of
+//      the argument.
+//    - it is of the form "<x" where x is an integer that is larger than the
+//      argument.
+//
+// The format argument determines the formatting parameters for which to
+// determine the plural form. This is especially relevant for non-integer
+// values.
+//
+// The format string may be "", in which case a best-effort attempt is made to
+// find a reasonable representation on which to base the plural form. Examples
+// of format strings are:
+//   - %.2f   decimal with scale 2
+//   - %.2e   scientific notation with precision 3 (scale + 1)
+//   - %d     integer
+func Selectf(arg int, format string, cases ...interface{}) catalog.Message {
+	var p parser
+	// Intercept the formatting parameters of format by doing a dummy print.
+	fmt.Fprintf(ioutil.Discard, format, &p)
+	m := &message{arg, kindDefault, 0, cases}
+	switch p.verb {
+	case 'g':
+		m.kind = kindPrecision
+		m.scale = p.scale
+	case 'f':
+		m.kind = kindScale
+		m.scale = p.scale
+	case 'e':
+		m.kind = kindScientific
+		m.scale = p.scale
+	case 'd':
+		m.kind = kindScale
+		m.scale = 0
+	default:
+		// TODO: do we need to handle errors?
+	}
+	return m
+}
+
+type parser struct {
+	verb  rune
+	scale int
+}
+
+func (p *parser) Format(s fmt.State, verb rune) {
+	p.verb = verb
+	p.scale = -1
+	if prec, ok := s.Precision(); ok {
+		p.scale = prec
+	}
+}
+
+type message struct {
+	arg   int
+	kind  int
+	scale int
+	cases []interface{}
+}
+
+const (
+	// Start with non-ASCII to allow skipping values.
+	kindDefault    = 0x80 + iota
+	kindScale      // verb f, number of fraction digits follows
+	kindScientific // verb e, number of fraction digits follows
+	kindPrecision  // verb g, number of significant digits follows
+)
+
+var handle = catmsg.Register("golang.org/x/text/feature/plural:plural", execute)
+
+func (m *message) Compile(e *catmsg.Encoder) error {
+	e.EncodeMessageType(handle)
+
+	e.EncodeUint(uint64(m.arg))
+
+	e.EncodeUint(uint64(m.kind))
+	if m.kind > kindDefault {
+		e.EncodeUint(uint64(m.scale))
+	}
+
+	forms := validForms(cardinal, e.Language())
+
+	for i := 0; i < len(m.cases); {
+		if err := compileSelector(e, forms, m.cases[i]); err != nil {
+			return err
+		}
+		if i++; i >= len(m.cases) {
+			return fmt.Errorf("plural: no message defined for selector %v", m.cases[i-1])
+		}
+		var msg catalog.Message
+		switch x := m.cases[i].(type) {
+		case string:
+			msg = catalog.String(x)
+		case catalog.Message:
+			msg = x
+		default:
+			return fmt.Errorf("plural: message of type %T; must be string or catalog.Message", x)
+		}
+		if err := e.EncodeMessage(msg); err != nil {
+			return err
+		}
+		i++
+	}
+	return nil
+}
+
+func compileSelector(e *catmsg.Encoder, valid []Form, selector interface{}) error {
+	form := Other
+	switch x := selector.(type) {
+	case string:
+		if x == "" {
+			return fmt.Errorf("plural: empty selector")
+		}
+		if c := x[0]; c == '=' || c == '<' {
+			val, err := strconv.ParseUint(x[1:], 10, 16)
+			if err != nil {
+				return fmt.Errorf("plural: invalid number in selector %q: %v", selector, err)
+			}
+			e.EncodeUint(uint64(c))
+			e.EncodeUint(val)
+			return nil
+		}
+		var ok bool
+		form, ok = countMap[x]
+		if !ok {
+			return fmt.Errorf("plural: invalid plural form %q", selector)
+		}
+	case Form:
+		form = x
+	default:
+		return fmt.Errorf("plural: selector of type %T; want string or Form", selector)
+	}
+
+	ok := false
+	for _, f := range valid {
+		if f == form {
+			ok = true
+			break
+		}
+	}
+	if !ok {
+		return fmt.Errorf("plural: form %q not supported for language %q", selector, e.Language())
+	}
+	e.EncodeUint(uint64(form))
+	return nil
+}
+
+func execute(d *catmsg.Decoder) bool {
+	lang := d.Language()
+	argN := int(d.DecodeUint())
+	kind := int(d.DecodeUint())
+	scale := -1 // default
+	if kind > kindDefault {
+		scale = int(d.DecodeUint())
+	}
+	form := Other
+	n := -1
+	if arg := d.Arg(argN); arg == nil {
+		// Default to Other.
+	} else if x, ok := arg.(number.VisibleDigits); ok {
+		d := x.Digits(nil, lang, scale)
+		form, n = cardinal.matchDisplayDigits(lang, &d)
+	} else if x, ok := arg.(Interface); ok {
+		// This covers lists and formatters from the number package.
+		form, n = x.PluralForm(lang, scale)
+	} else {
+		var f number.Formatter
+		switch kind {
+		case kindScale:
+			f.InitDecimal(lang)
+			f.SetScale(scale)
+		case kindScientific:
+			f.InitScientific(lang)
+			f.SetScale(scale)
+		case kindPrecision:
+			f.InitDecimal(lang)
+			f.SetPrecision(scale)
+		case kindDefault:
+			// sensible default
+			f.InitDecimal(lang)
+			if k := reflect.TypeOf(arg).Kind(); reflect.Int <= k && k <= reflect.Uintptr {
+				f.SetScale(0)
+			} else {
+				f.SetScale(2)
+			}
+		}
+		var dec number.Decimal // TODO: buffer in Printer
+		dec.Convert(f.RoundingContext, arg)
+		v := number.FormatDigits(&dec, f.RoundingContext)
+		if !v.NaN && !v.Inf {
+			form, n = cardinal.matchDisplayDigits(d.Language(), &v)
+		}
+	}
+	for !d.Done() {
+		f := d.DecodeUint()
+		if (f == '=' && n == int(d.DecodeUint())) ||
+			(f == '<' && 0 <= n && n < int(d.DecodeUint())) ||
+			form == Form(f) ||
+			Other == Form(f) {
+			return d.ExecuteMessage()
+		}
+		d.SkipMessage()
+	}
+	return false
+}