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-rw-r--r--vendor/golang.org/x/text/internal/format/parser.go357
1 files changed, 357 insertions, 0 deletions
diff --git a/vendor/golang.org/x/text/internal/format/parser.go b/vendor/golang.org/x/text/internal/format/parser.go
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+++ b/vendor/golang.org/x/text/internal/format/parser.go
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+// 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 format
+
+import (
+ "reflect"
+ "unicode/utf8"
+)
+
+// A Parser parses a format string. The result from the parse are set in the
+// struct fields.
+type Parser struct {
+ Verb rune
+
+ WidthPresent bool
+ PrecPresent bool
+ Minus bool
+ Plus bool
+ Sharp bool
+ Space bool
+ Zero bool
+
+ // For the formats %+v %#v, we set the plusV/sharpV flags
+ // and clear the plus/sharp flags since %+v and %#v are in effect
+ // different, flagless formats set at the top level.
+ PlusV bool
+ SharpV bool
+
+ HasIndex bool
+
+ Width int
+ Prec int // precision
+
+ // retain arguments across calls.
+ Args []interface{}
+ // retain current argument number across calls
+ ArgNum int
+
+ // reordered records whether the format string used argument reordering.
+ Reordered bool
+ // goodArgNum records whether the most recent reordering directive was valid.
+ goodArgNum bool
+
+ // position info
+ format string
+ startPos int
+ endPos int
+ Status Status
+}
+
+// Reset initializes a parser to scan format strings for the given args.
+func (p *Parser) Reset(args []interface{}) {
+ p.Args = args
+ p.ArgNum = 0
+ p.startPos = 0
+ p.Reordered = false
+}
+
+// Text returns the part of the format string that was parsed by the last call
+// to Scan. It returns the original substitution clause if the current scan
+// parsed a substitution.
+func (p *Parser) Text() string { return p.format[p.startPos:p.endPos] }
+
+// SetFormat sets a new format string to parse. It does not reset the argument
+// count.
+func (p *Parser) SetFormat(format string) {
+ p.format = format
+ p.startPos = 0
+ p.endPos = 0
+}
+
+// Status indicates the result type of a call to Scan.
+type Status int
+
+const (
+ StatusText Status = iota
+ StatusSubstitution
+ StatusBadWidthSubstitution
+ StatusBadPrecSubstitution
+ StatusNoVerb
+ StatusBadArgNum
+ StatusMissingArg
+)
+
+// ClearFlags reset the parser to default behavior.
+func (p *Parser) ClearFlags() {
+ p.WidthPresent = false
+ p.PrecPresent = false
+ p.Minus = false
+ p.Plus = false
+ p.Sharp = false
+ p.Space = false
+ p.Zero = false
+
+ p.PlusV = false
+ p.SharpV = false
+
+ p.HasIndex = false
+}
+
+// Scan scans the next part of the format string and sets the status to
+// indicate whether it scanned a string literal, substitution or error.
+func (p *Parser) Scan() bool {
+ p.Status = StatusText
+ format := p.format
+ end := len(format)
+ if p.endPos >= end {
+ return false
+ }
+ afterIndex := false // previous item in format was an index like [3].
+
+ p.startPos = p.endPos
+ p.goodArgNum = true
+ i := p.startPos
+ for i < end && format[i] != '%' {
+ i++
+ }
+ if i > p.startPos {
+ p.endPos = i
+ return true
+ }
+ // Process one verb
+ i++
+
+ p.Status = StatusSubstitution
+
+ // Do we have flags?
+ p.ClearFlags()
+
+simpleFormat:
+ for ; i < end; i++ {
+ c := p.format[i]
+ switch c {
+ case '#':
+ p.Sharp = true
+ case '0':
+ p.Zero = !p.Minus // Only allow zero padding to the left.
+ case '+':
+ p.Plus = true
+ case '-':
+ p.Minus = true
+ p.Zero = false // Do not pad with zeros to the right.
+ case ' ':
+ p.Space = true
+ default:
+ // Fast path for common case of ascii lower case simple verbs
+ // without precision or width or argument indices.
+ if 'a' <= c && c <= 'z' && p.ArgNum < len(p.Args) {
+ if c == 'v' {
+ // Go syntax
+ p.SharpV = p.Sharp
+ p.Sharp = false
+ // Struct-field syntax
+ p.PlusV = p.Plus
+ p.Plus = false
+ }
+ p.Verb = rune(c)
+ p.ArgNum++
+ p.endPos = i + 1
+ return true
+ }
+ // Format is more complex than simple flags and a verb or is malformed.
+ break simpleFormat
+ }
+ }
+
+ // Do we have an explicit argument index?
+ i, afterIndex = p.updateArgNumber(format, i)
+
+ // Do we have width?
+ if i < end && format[i] == '*' {
+ i++
+ p.Width, p.WidthPresent = p.intFromArg()
+
+ if !p.WidthPresent {
+ p.Status = StatusBadWidthSubstitution
+ }
+
+ // We have a negative width, so take its value and ensure
+ // that the minus flag is set
+ if p.Width < 0 {
+ p.Width = -p.Width
+ p.Minus = true
+ p.Zero = false // Do not pad with zeros to the right.
+ }
+ afterIndex = false
+ } else {
+ p.Width, p.WidthPresent, i = parsenum(format, i, end)
+ if afterIndex && p.WidthPresent { // "%[3]2d"
+ p.goodArgNum = false
+ }
+ }
+
+ // Do we have precision?
+ if i+1 < end && format[i] == '.' {
+ i++
+ if afterIndex { // "%[3].2d"
+ p.goodArgNum = false
+ }
+ i, afterIndex = p.updateArgNumber(format, i)
+ if i < end && format[i] == '*' {
+ i++
+ p.Prec, p.PrecPresent = p.intFromArg()
+ // Negative precision arguments don't make sense
+ if p.Prec < 0 {
+ p.Prec = 0
+ p.PrecPresent = false
+ }
+ if !p.PrecPresent {
+ p.Status = StatusBadPrecSubstitution
+ }
+ afterIndex = false
+ } else {
+ p.Prec, p.PrecPresent, i = parsenum(format, i, end)
+ if !p.PrecPresent {
+ p.Prec = 0
+ p.PrecPresent = true
+ }
+ }
+ }
+
+ if !afterIndex {
+ i, afterIndex = p.updateArgNumber(format, i)
+ }
+ p.HasIndex = afterIndex
+
+ if i >= end {
+ p.endPos = i
+ p.Status = StatusNoVerb
+ return true
+ }
+
+ verb, w := utf8.DecodeRuneInString(format[i:])
+ p.endPos = i + w
+ p.Verb = verb
+
+ switch {
+ case verb == '%': // Percent does not absorb operands and ignores f.wid and f.prec.
+ p.startPos = p.endPos - 1
+ p.Status = StatusText
+ case !p.goodArgNum:
+ p.Status = StatusBadArgNum
+ case p.ArgNum >= len(p.Args): // No argument left over to print for the current verb.
+ p.Status = StatusMissingArg
+ case verb == 'v':
+ // Go syntax
+ p.SharpV = p.Sharp
+ p.Sharp = false
+ // Struct-field syntax
+ p.PlusV = p.Plus
+ p.Plus = false
+ fallthrough
+ default:
+ p.ArgNum++
+ }
+ return true
+}
+
+// intFromArg gets the ArgNumth element of Args. On return, isInt reports
+// whether the argument has integer type.
+func (p *Parser) intFromArg() (num int, isInt bool) {
+ if p.ArgNum < len(p.Args) {
+ arg := p.Args[p.ArgNum]
+ num, isInt = arg.(int) // Almost always OK.
+ if !isInt {
+ // Work harder.
+ switch v := reflect.ValueOf(arg); v.Kind() {
+ case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+ n := v.Int()
+ if int64(int(n)) == n {
+ num = int(n)
+ isInt = true
+ }
+ case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+ n := v.Uint()
+ if int64(n) >= 0 && uint64(int(n)) == n {
+ num = int(n)
+ isInt = true
+ }
+ default:
+ // Already 0, false.
+ }
+ }
+ p.ArgNum++
+ if tooLarge(num) {
+ num = 0
+ isInt = false
+ }
+ }
+ return
+}
+
+// parseArgNumber returns the value of the bracketed number, minus 1
+// (explicit argument numbers are one-indexed but we want zero-indexed).
+// The opening bracket is known to be present at format[0].
+// The returned values are the index, the number of bytes to consume
+// up to the closing paren, if present, and whether the number parsed
+// ok. The bytes to consume will be 1 if no closing paren is present.
+func parseArgNumber(format string) (index int, wid int, ok bool) {
+ // There must be at least 3 bytes: [n].
+ if len(format) < 3 {
+ return 0, 1, false
+ }
+
+ // Find closing bracket.
+ for i := 1; i < len(format); i++ {
+ if format[i] == ']' {
+ width, ok, newi := parsenum(format, 1, i)
+ if !ok || newi != i {
+ return 0, i + 1, false
+ }
+ return width - 1, i + 1, true // arg numbers are one-indexed and skip paren.
+ }
+ }
+ return 0, 1, false
+}
+
+// updateArgNumber returns the next argument to evaluate, which is either the value of the passed-in
+// argNum or the value of the bracketed integer that begins format[i:]. It also returns
+// the new value of i, that is, the index of the next byte of the format to process.
+func (p *Parser) updateArgNumber(format string, i int) (newi int, found bool) {
+ if len(format) <= i || format[i] != '[' {
+ return i, false
+ }
+ p.Reordered = true
+ index, wid, ok := parseArgNumber(format[i:])
+ if ok && 0 <= index && index < len(p.Args) {
+ p.ArgNum = index
+ return i + wid, true
+ }
+ p.goodArgNum = false
+ return i + wid, ok
+}
+
+// tooLarge reports whether the magnitude of the integer is
+// too large to be used as a formatting width or precision.
+func tooLarge(x int) bool {
+ const max int = 1e6
+ return x > max || x < -max
+}
+
+// parsenum converts ASCII to integer. num is 0 (and isnum is false) if no number present.
+func parsenum(s string, start, end int) (num int, isnum bool, newi int) {
+ if start >= end {
+ return 0, false, end
+ }
+ for newi = start; newi < end && '0' <= s[newi] && s[newi] <= '9'; newi++ {
+ if tooLarge(num) {
+ return 0, false, end // Overflow; crazy long number most likely.
+ }
+ num = num*10 + int(s[newi]-'0')
+ isnum = true
+ }
+ return
+}