decode_float_4v2.go

// nolint
// Copyright 20xx The Alipay Authors.
//
// @authors[0]: bingwu.ybw(bingwu.ybw@antfin.com|detailyang@gmail.com)
// @authors[1]: robotx(robotx@antfin.com)
//
// *Legal Disclaimer*
// Within this source code, the comments in Chinese shall be the original, governing version. Any comment in other languages are for reference only. In the event of any conflict between the Chinese language version comments and other language version comments, the Chinese language version shall prevail.
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//
//

package sofahessian

import (
	"bufio"
	"math"
)

func DecodeFloat64Hessian4V2(o *DecodeContext, reader *bufio.Reader) (float64, error) {
	var i float64
	err := DecodeFloat64ToHessian4V2(o, reader, &i)
	return i, err
}

func DecodeFloat64ToHessian4V2(o *DecodeContext, reader *bufio.Reader, i *float64) error {
	if o.tracer != nil {
		o.tracer.OnTraceStart("decodefloat64")
		defer o.tracer.OnTraceStop("decodefloat64")
	}

	c1, err := reader.ReadByte()
	if err != nil {
		return err
	}

	if c1 == 0x44 {
		u64, err := readUint64FromReader(reader)
		if err != nil {
			return err
		}
		*i = math.Float64frombits(u64)
		return nil
	}

	switch c1 {
	case 0x5b:
		*i = 0.0
		return nil

	case 0x5c:
		*i = 1.0
		return nil

	case 0x5d:
		c2, err := reader.ReadByte()
		if err != nil {
			return err
		}
		*i = float64(int8(c2))
		return nil

	case 0x5e:
		i16, err := readInt16FromReader(reader)
		if err != nil {
			return err
		}
		*i = float64(i16)
		return nil

	case 0x5f:
		i32, err := readInt32FromReader(reader)
		if err != nil {
			return err
		}
		*i = float64(i32) * 0.001
		return nil
	}

	return ErrDecodeMalformedDouble
}