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package strconv
import (
"math"
)
func ParseDecimal(b []byte) (float64, int) {
i := 0
start := i
dot := -1
trunk := -1
n := uint64(0)
for ; i < len(b); i++ {
c := b[i]
if '0' <= c && c <= '9' {
if trunk == -1 {
if math.MaxUint64/10 < n {
trunk = i
} else {
n *= 10
n += uint64(c - '0')
}
}
} else if dot == -1 && c == '.' {
dot = i
} else {
break
}
}
if i == start || i == start+1 && dot == start {
return 0.0, 0
}
f := float64(n)
mantExp := int64(0)
if dot != -1 {
if trunk == -1 {
trunk = i
}
mantExp = int64(trunk - dot - 1)
} else if trunk != -1 {
mantExp = int64(trunk - i)
}
exp := -mantExp
// copied from strconv/atof.go
if exp == 0 {
return f, i
} else if 0 < exp && exp <= 15+22 { // int * 10^k
// If exponent is big but number of digits is not,
// can move a few zeros into the integer part.
if 22 < exp {
f *= float64pow10[exp-22]
exp = 22
}
if -1e15 <= f && f <= 1e15 {
return f * float64pow10[exp], i
}
} else if exp < 0 && -22 <= exp { // int / 10^k
return f / float64pow10[-exp], i
}
return f * math.Pow10(int(-mantExp)), i
}
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