Convert go to v

[emma-eva]

Describe the feature

Convert this go code to v code:

package main

import (
	"errors"
	"io"
	"math"
	"reflect"
	"sync"
	"fmt"
	"strings"
)


type ByteOrder interface {
	Uint16([]byte) uint16
	Uint32([]byte) uint32
	Uint64([]byte) uint64
}

var LittleEndian littleEndian
type littleEndian struct{}

func (littleEndian) Uint16(b []byte) uint16 {
	return uint16(b[0]) | uint16(b[1])<<8
}

func (littleEndian) Uint32(b []byte) uint32 {
	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}

func (littleEndian) Uint64(b []byte) uint64 {
	return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
		uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}

func Read(r io.Reader, order ByteOrder, data interface{}) error {
	if n := intDataSize(data); n != 0 {
		bs := make([]byte, n)
		if _, err := io.ReadFull(r, bs); err != nil {
			return err
		}
		switch data := data.(type) {
		case *bool:
			*data = bs[0] != 0
		case *int8:
			*data = int8(bs[0])
		case *uint8:
			*data = bs[0]
		case *int16:
			*data = int16(order.Uint16(bs))
		case *uint16:
			*data = order.Uint16(bs)
		case *int32:
			*data = int32(order.Uint32(bs))
		case *uint32:
			*data = order.Uint32(bs)
		case *int64:
			*data = int64(order.Uint64(bs))
		case *uint64:
			*data = order.Uint64(bs)
		case *float32:
			*data = math.Float32frombits(order.Uint32(bs))
		case *float64:
			*data = math.Float64frombits(order.Uint64(bs))
		case []bool:
			for i, x := range bs {
				data[i] = x != 0
			}
		case []int8:
			for i, x := range bs {
				data[i] = int8(x)
			}
		case []uint8:
			copy(data, bs)
		case []int16:
			for i := range data {
				data[i] = int16(order.Uint16(bs[2*i:]))
			}
		case []uint16:
			for i := range data {
				data[i] = order.Uint16(bs[2*i:])
			}
		case []int32:
			for i := range data {
				data[i] = int32(order.Uint32(bs[4*i:]))
			}
		case []uint32:
			for i := range data {
				data[i] = order.Uint32(bs[4*i:])
			}
		case []int64:
			for i := range data {
				data[i] = int64(order.Uint64(bs[8*i:]))
			}
		case []uint64:
			for i := range data {
				data[i] = order.Uint64(bs[8*i:])
			}
		case []float32:
			for i := range data {
				data[i] = math.Float32frombits(order.Uint32(bs[4*i:]))
			}
		case []float64:
			for i := range data {
				data[i] = math.Float64frombits(order.Uint64(bs[8*i:]))
			}
		default:
			n = 0
		}
		if n != 0 {
			return nil
		}
	}

	v := reflect.ValueOf(data)
	size := -1
	switch v.Kind() {
		case reflect.Pointer:
			v = v.Elem()
			size = dataSize(v)
		case reflect.Slice:
			size = dataSize(v)
	}
	if size < 0 {
		return errors.New("Read: invalid type " + reflect.TypeOf(data).String())
	}
	d := &decoder{order: order, buf: make([]byte, size)}
	if _, err := io.ReadFull(r, d.buf); err != nil {
		return err
	}
	d.value(v)
	return nil
}

func Size(v interface{}) int {
	return dataSize(reflect.Indirect(reflect.ValueOf(v)))
}

var structSize sync.Map

func dataSize(v reflect.Value) int {
	switch v.Kind() {
	case reflect.Slice:
		if s := sizeof(v.Type().Elem()); s >= 0 {
			return s * v.Len()
		}
		return -1

	case reflect.Struct:
		t := v.Type()
		if size, ok := structSize.Load(t); ok {
			return size.(int)
		}
		size := sizeof(t)
		structSize.Store(t, size)
		return size

	default:
		return sizeof(v.Type())
	}
}

func sizeof(t reflect.Type) int {
	switch t.Kind() {
	case reflect.Array:
		if s := sizeof(t.Elem()); s >= 0 {
			return s * t.Len()
		}

	case reflect.Struct:
		sum := 0
		for i, n := 0, t.NumField(); i < n; i++ {
			s := sizeof(t.Field(i).Type)
			if s < 0 {
				return -1
			}
			sum += s
		}
		return sum

	case reflect.Bool,
		reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
		reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
		reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
		return int(t.Size())
	}

	return -1
}

type coder struct {
	order  ByteOrder
	buf    []byte
	offset int
}

type decoder coder

func (d *decoder) bool() bool {
	x := d.buf[d.offset]
	d.offset++
	return x != 0
}

func (d *decoder) uint8() uint8 {
	x := d.buf[d.offset]
	d.offset++
	return x
}

func (d *decoder) uint16() uint16 {
	x := d.order.Uint16(d.buf[d.offset : d.offset+2])
	d.offset += 2
	return x
}

func (d *decoder) uint32() uint32 {
	x := d.order.Uint32(d.buf[d.offset : d.offset+4])
	d.offset += 4
	return x
}

func (d *decoder) uint64() uint64 {
	x := d.order.Uint64(d.buf[d.offset : d.offset+8])
	d.offset += 8
	return x
}

func (d *decoder) int8() int8 { return int8(d.uint8()) }
func (d *decoder) int16() int16 { return int16(d.uint16()) }
func (d *decoder) int32() int32 { return int32(d.uint32()) }
func (d *decoder) int64() int64 { return int64(d.uint64()) }

func (d *decoder) value(v reflect.Value) {
	switch v.Kind() {
	case reflect.Array:
		l := v.Len()
		for i := 0; i < l; i++ {
			d.value(v.Index(i))
		}

	case reflect.Struct:
		t := v.Type()
		l := v.NumField()
		for i := 0; i < l; i++ {
			if v := v.Field(i); v.CanSet() || t.Field(i).Name != "_" {
				d.value(v)
			} else {
				d.skip(v)
			}
		}

	case reflect.Slice:
		l := v.Len()
		for i := 0; i < l; i++ {
			d.value(v.Index(i))
		}

	case reflect.Bool:
		v.SetBool(d.bool())

	case reflect.Int8:
		v.SetInt(int64(d.int8()))
	case reflect.Int16:
		v.SetInt(int64(d.int16()))
	case reflect.Int32:
		v.SetInt(int64(d.int32()))
	case reflect.Int64:
		v.SetInt(d.int64())

	case reflect.Uint8:
		v.SetUint(uint64(d.uint8()))
	case reflect.Uint16:
		v.SetUint(uint64(d.uint16()))
	case reflect.Uint32:
		v.SetUint(uint64(d.uint32()))
	case reflect.Uint64:
		v.SetUint(d.uint64())

	case reflect.Float32:
		v.SetFloat(float64(math.Float32frombits(d.uint32())))
	case reflect.Float64:
		v.SetFloat(math.Float64frombits(d.uint64()))

	case reflect.Complex64:
		v.SetComplex(complex(
			float64(math.Float32frombits(d.uint32())),
			float64(math.Float32frombits(d.uint32())),
		))
	case reflect.Complex128:
		v.SetComplex(complex(
			math.Float64frombits(d.uint64()),
			math.Float64frombits(d.uint64()),
		))
	}
}

func (d *decoder) skip(v reflect.Value) {
	d.offset += dataSize(v)
}

func intDataSize(data interface{}) int {
	switch data := data.(type) {
	case bool, int8, uint8, *bool, *int8, *uint8:
		return 1
	case []bool:
		return len(data)
	case []int8:
		return len(data)
	case []uint8:
		return len(data)
	case int16, uint16, *int16, *uint16:
		return 2
	case []int16:
		return 2 * len(data)
	case []uint16:
		return 2 * len(data)
	case int32, uint32, *int32, *uint32:
		return 4
	case []int32:
		return 4 * len(data)
	case []uint32:
		return 4 * len(data)
	case int64, uint64, *int64, *uint64:
		return 8
	case []int64:
		return 8 * len(data)
	case []uint64:
		return 8 * len(data)
	case float32, *float32:
		return 4
	case float64, *float64:
		return 8
	case []float32:
		return 4 * len(data)
	case []float64:
		return 8 * len(data)
	}
	return 0
}

func main() {
    r := strings.NewReader("\x01\x00\x00\x00\x00\x00\x00\x00")
    var data int32
    order := LittleEndian

    err := Read(r, order, &data)
    if err != nil {
        fmt.Println("Error:", err)
    } else {
        fmt.Println(data)
    }
}

Use Case

Binary read

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

Version used

latest

Environment details (OS name and version, etc.)

convert to v plz

Note

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[ArtemkaKun]

Have you tried https://modules.vlang.io/os.html#read_bytes ?

[emma-eva]

Have you tried https://modules.vlang.io/os.html#read_bytes ?

read_bytes work like go binary? does have little endian support?

[ArtemkaKun]

Idk, never worked with binary stuff before. You can also check https://modules.vlang.io/encoding.binary.html, maybe this is what you are looking for

[HimanshuMahto]

Hey, @ArtemkaKun @emma-eva could you please assign me this issue to work on? It would be great to start from here a new contributor.

[HimanshuMahto]

Hey, @JalonSolov could you please tell me the location of the code? Please

[JalonSolov]

Which code do you mean?

[HimanshuMahto]

the above one. Which i need to convert into vlang. @JalonSolov

[JalonSolov]

As far as I'm aware, that is the source of the code. Just copy it and paste it into a file.

[HimanshuMahto]

ok, so could you give me any suggestion on what the file's name should be and what should be its location? @JalonSolov

[HimanshuMahto]

@JalonSolov, done with almost 50% of the code conversion. Could you tell me the name of the file I need to keep and the location of this file?

[JalonSolov]

I think that would be up to @emma-eva as the source of the code.

[HimanshuMahto]

Hey, @JalonSolov I won't be able to do this. sorry!

[JalonSolov]

As I see it, this isn't a V issue at all. It's a request to convert some Go code to V. The purpose of the conversion is unknown, other than perhaps a way to prove it can be done.

[emma-eva]

@JalonSolov, done with almost 50% of the code conversion. Could you tell me the name of the file I need to keep and the location of this file?

Here is full binary code url: https://github.com/golang/go/tree/master/src/encoding/binary