go-json/decode_float.go

56 lines
1.1 KiB
Go

package json
import (
"errors"
"strconv"
"unsafe"
)
type floatDecoder struct {
op func(uintptr, float64)
}
func newFloatDecoder(op func(uintptr, float64)) *floatDecoder {
return &floatDecoder{op: op}
}
func (d *floatDecoder) decodeByte(ctx *context) ([]byte, error) {
buf := ctx.buf
cursor := ctx.cursor
buflen := ctx.buflen
for ; cursor < buflen; cursor++ {
switch buf[cursor] {
case ' ', '\n', '\t', '\r':
continue
case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
start := cursor
cursor++
for ; cursor < buflen; cursor++ {
tk := int(buf[cursor])
if (int('0') <= tk && tk <= int('9')) || tk == '.' || tk == 'e' || tk == 'E' {
continue
}
break
}
num := ctx.buf[start:cursor]
ctx.cursor = cursor
return num, nil
}
}
return nil, errors.New("unexpected error number")
}
func (d *floatDecoder) decode(ctx *context, p uintptr) error {
bytes, err := d.decodeByte(ctx)
if err != nil {
return err
}
s := *(*string)(unsafe.Pointer(&bytes))
f64, err := strconv.ParseFloat(s, 64)
if err != nil {
return err
}
d.op(p, f64)
return nil
}