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// SPDX-FileCopyrightText: 2022 UnionTech Software Technology Co., Ltd.
//
// SPDX-License-Identifier: GPL-3.0-or-later
package x
import (
"bytes"
"errors"
)
var ErrDataLenShort = errors.New("data length is short")
type Reader struct {
pos int
data []byte
}
func NewReaderFromData(data []byte) *Reader {
return &Reader{
data: data,
}
}
func (r *Reader) Pos() int {
return r.pos
}
func (r *Reader) Read1b() uint8 {
v := r.data[r.pos]
r.pos++
return v
}
func (r *Reader) Read2b() uint16 {
v := uint16(r.data[r.pos])
v |= uint16(r.data[r.pos+1]) << 8
r.pos += 2
return v
}
func (r *Reader) Read4b() uint32 {
v := uint32(r.data[r.pos])
v |= uint32(r.data[r.pos+1]) << 8
v |= uint32(r.data[r.pos+2]) << 16
v |= uint32(r.data[r.pos+3]) << 24
r.pos += 4
return v
}
func (r *Reader) MustReadBytes(n int) []byte {
v := r.data[r.pos : r.pos+n]
r.pos += n
return v
}
func (r *Reader) ReadBytes(n int) ([]byte, error) {
if !r.RemainAtLeast(n) {
return nil, ErrDataLenShort
}
v := r.data[r.pos : r.pos+n]
r.pos += n
return v, nil
}
func (r *Reader) ReadBytesWithPad(n int) ([]byte, error) {
total := n + Pad(n)
if !r.RemainAtLeast(total) {
return nil, ErrDataLenShort
}
v := r.data[r.pos : r.pos+n]
r.pos += total
return v, nil
}
func (r *Reader) ReadString(n int) (string, error) {
v, err := r.ReadBytes(n)
if err != nil {
return "", err
}
return string(v), nil
}
func (r *Reader) ReadStrWithPad(n int) (string, error) {
v, err := r.ReadBytesWithPad(n)
if err != nil {
return "", err
}
return string(v), nil
}
func (r *Reader) ReadNulTermStr() string {
idx := bytes.IndexByte(r.data[r.pos:], 0)
var v []byte
if idx == -1 {
v = r.data[r.pos:]
r.pos = len(r.data)
} else {
v = r.data[r.pos : r.pos+idx]
r.pos += idx
}
return string(v)
}
func (r *Reader) ReadBool() bool {
return Uint8ToBool(r.Read1b())
}
func (r *Reader) ReadPad(n int) {
if r.pos+n > len(r.data) {
panic("index out of range")
}
r.pos += n
}
func (r *Reader) Reset() {
r.pos = 0
}
func (r *Reader) RemainAtLeast(n int) bool {
return r.pos+n <= len(r.data)
}
func (r *Reader) RemainAtLeast4b(n int) bool {
return r.RemainAtLeast(n << 2)
}
func (r *Reader) ReadReplyHeader() (data uint8, length uint32) {
r.ReadPad(1)
data = r.Read1b()
// seq
r.ReadPad(2)
// length
length = r.Read4b() // 2
return
}
func (r *Reader) ReadEventHeader() (data uint8, seq uint16) {
r.ReadPad(1)
data = r.Read1b()
// seq
seq = r.Read2b() // 1
return
}
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