Initial commit

vendor/github.com/hjson/hjson-go/parseNumber.go

@@ -0,0 +1,108 @@
+package hjson
+
+import (
+	"errors"
+	"math"
+	"strconv"
+)
+
+type parseNumber struct {
+	data []byte
+	at   int  // The index of the current character
+	ch   byte // The current character
+}
+
+func (p *parseNumber) next() bool {
+	// get the next character.
+	len := len(p.data)
+	if p.at < len {
+		p.ch = p.data[p.at]
+		p.at++
+		return true
+	}
+	if p.at == len {
+		p.at++
+		p.ch = 0
+	}
+	return false
+}
+
+func (p *parseNumber) peek(offs int) byte {
+	pos := p.at + offs
+	if pos >= 0 && pos < len(p.data) {
+		return p.data[pos]
+	}
+	return 0
+}
+
+func startsWithNumber(text []byte) bool {
+	if _, err := tryParseNumber(text, true); err == nil {
+		return true
+	}
+	return false
+}
+
+func tryParseNumber(text []byte, stopAtNext bool) (float64, error) {
+	// Parse a number value.
+
+	p := parseNumber{text, 0, ' '}
+	leadingZeros := 0
+	testLeading := true
+	p.next()
+	if p.ch == '-' {
+		p.next()
+	}
+	for p.ch >= '0' && p.ch <= '9' {
+		if testLeading {
+			if p.ch == '0' {
+				leadingZeros++
+			} else {
+				testLeading = false
+			}
+		}
+		p.next()
+	}
+	if testLeading {
+		leadingZeros--
+	} // single 0 is allowed
+	if p.ch == '.' {
+		for p.next() && p.ch >= '0' && p.ch <= '9' {
+		}
+	}
+	if p.ch == 'e' || p.ch == 'E' {
+		p.next()
+		if p.ch == '-' || p.ch == '+' {
+			p.next()
+		}
+		for p.ch >= '0' && p.ch <= '9' {
+			p.next()
+		}
+	}
+
+	end := p.at
+
+	// skip white/to (newline)
+	for p.ch > 0 && p.ch <= ' ' {
+		p.next()
+	}
+
+	if stopAtNext {
+		// end scan if we find a punctuator character like ,}] or a comment
+		if p.ch == ',' || p.ch == '}' || p.ch == ']' ||
+			p.ch == '#' || p.ch == '/' && (p.peek(0) == '/' || p.peek(0) == '*') {
+			p.ch = 0
+		}
+	}
+
+	if p.ch > 0 || leadingZeros != 0 {
+		return 0, errors.New("Invalid number")
+	}
+	number, err := strconv.ParseFloat(string(p.data[0:end-1]), 64)
+	if err != nil {
+		return 0, err
+	}
+	if math.IsInf(number, 0) || math.IsNaN(number) {
+		return 0, errors.New("Invalid number")
+	}
+	return number, nil
+}