mirror of
https://github.com/nspcc-dev/neo-go.git
synced 2024-11-23 13:38:35 +00:00
145 lines
3.3 KiB
Go
145 lines
3.3 KiB
Go
package io
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"io"
|
|
"reflect"
|
|
)
|
|
|
|
// BinWriter is a convenient wrapper around a io.Writer and err object.
|
|
// Used to simplify error handling when writing into a io.Writer
|
|
// from a struct with many fields.
|
|
type BinWriter struct {
|
|
w io.Writer
|
|
u64 []byte
|
|
u32 []byte
|
|
u16 []byte
|
|
u8 []byte
|
|
Err error
|
|
}
|
|
|
|
// NewBinWriterFromIO makes a BinWriter from io.Writer.
|
|
func NewBinWriterFromIO(iow io.Writer) *BinWriter {
|
|
u64 := make([]byte, 8)
|
|
u32 := u64[:4]
|
|
u16 := u64[:2]
|
|
u8 := u64[:1]
|
|
return &BinWriter{w: iow, u64: u64, u32: u32, u16: u16, u8: u8}
|
|
}
|
|
|
|
// WriteU64LE writes an uint64 value into the underlying io.Writer in
|
|
// little-endian format.
|
|
func (w *BinWriter) WriteU64LE(u64 uint64) {
|
|
binary.LittleEndian.PutUint64(w.u64, u64)
|
|
w.WriteBytes(w.u64)
|
|
}
|
|
|
|
// WriteU32LE writes an uint32 value into the underlying io.Writer in
|
|
// little-endian format.
|
|
func (w *BinWriter) WriteU32LE(u32 uint32) {
|
|
binary.LittleEndian.PutUint32(w.u32, u32)
|
|
w.WriteBytes(w.u32)
|
|
}
|
|
|
|
// WriteU16LE writes an uint16 value into the underlying io.Writer in
|
|
// little-endian format.
|
|
func (w *BinWriter) WriteU16LE(u16 uint16) {
|
|
binary.LittleEndian.PutUint16(w.u16, u16)
|
|
w.WriteBytes(w.u16)
|
|
}
|
|
|
|
// WriteU16BE writes an uint16 value into the underlying io.Writer in
|
|
// big-endian format.
|
|
func (w *BinWriter) WriteU16BE(u16 uint16) {
|
|
binary.BigEndian.PutUint16(w.u16, u16)
|
|
w.WriteBytes(w.u16)
|
|
}
|
|
|
|
// WriteB writes a byte into the underlying io.Writer.
|
|
func (w *BinWriter) WriteB(u8 byte) {
|
|
w.u8[0] = u8
|
|
w.WriteBytes(w.u8)
|
|
}
|
|
|
|
// WriteBool writes a boolean value into the underlying io.Writer encoded as
|
|
// a byte with values of 0 or 1.
|
|
func (w *BinWriter) WriteBool(b bool) {
|
|
var i byte
|
|
if b {
|
|
i = 1
|
|
}
|
|
w.WriteB(i)
|
|
}
|
|
|
|
// WriteArray writes a slice or an array arr into w. Note that nil slices and
|
|
// empty slices are gonna be treated the same resulting in equal zero-length
|
|
// array encoded.
|
|
func (w *BinWriter) WriteArray(arr interface{}) {
|
|
switch val := reflect.ValueOf(arr); val.Kind() {
|
|
case reflect.Slice, reflect.Array:
|
|
if w.Err != nil {
|
|
return
|
|
}
|
|
|
|
typ := val.Type().Elem()
|
|
|
|
w.WriteVarUint(uint64(val.Len()))
|
|
for i := 0; i < val.Len(); i++ {
|
|
el, ok := val.Index(i).Interface().(encodable)
|
|
if !ok {
|
|
el, ok = val.Index(i).Addr().Interface().(encodable)
|
|
if !ok {
|
|
panic(typ.String() + " is not encodable")
|
|
}
|
|
}
|
|
|
|
el.EncodeBinary(w)
|
|
}
|
|
default:
|
|
panic("not an array")
|
|
}
|
|
}
|
|
|
|
// WriteVarUint writes a uint64 into the underlying writer using variable-length encoding.
|
|
func (w *BinWriter) WriteVarUint(val uint64) {
|
|
if w.Err != nil {
|
|
return
|
|
}
|
|
|
|
if val < 0xfd {
|
|
w.WriteB(byte(val))
|
|
return
|
|
}
|
|
if val < 0xFFFF {
|
|
w.WriteB(byte(0xfd))
|
|
w.WriteU16LE(uint16(val))
|
|
return
|
|
}
|
|
if val < 0xFFFFFFFF {
|
|
w.WriteB(byte(0xfe))
|
|
w.WriteU32LE(uint32(val))
|
|
return
|
|
}
|
|
|
|
w.WriteB(byte(0xff))
|
|
w.WriteU64LE(val)
|
|
}
|
|
|
|
// WriteBytes writes a variable byte into the underlying io.Writer without prefix.
|
|
func (w *BinWriter) WriteBytes(b []byte) {
|
|
if w.Err != nil {
|
|
return
|
|
}
|
|
_, w.Err = w.w.Write(b)
|
|
}
|
|
|
|
// WriteVarBytes writes a variable length byte array into the underlying io.Writer.
|
|
func (w *BinWriter) WriteVarBytes(b []byte) {
|
|
w.WriteVarUint(uint64(len(b)))
|
|
w.WriteBytes(b)
|
|
}
|
|
|
|
// WriteString writes a variable length string into the underlying io.Writer.
|
|
func (w *BinWriter) WriteString(s string) {
|
|
w.WriteVarBytes([]byte(s))
|
|
}
|