1package mstypes
2
3import (
4	"bufio"
5	"encoding/binary"
6	"fmt"
7	"io"
8)
9
10// Byte sizes of primitive types
11const (
12	SizeBool   = 1
13	SizeChar   = 1
14	SizeUint8  = 1
15	SizeUint16 = 2
16	SizeUint32 = 4
17	SizeUint64 = 8
18	SizeEnum   = 2
19	SizeSingle = 4
20	SizeDouble = 8
21	SizePtr    = 4
22)
23
24// Reader reads simple byte stream data into a Go representations
25type Reader struct {
26	r *bufio.Reader // source of the data
27}
28
29// NewReader creates a new instance of a simple Reader.
30func NewReader(r io.Reader) *Reader {
31	reader := new(Reader)
32	reader.r = bufio.NewReader(r)
33	return reader
34}
35
36func (r *Reader) Read(p []byte) (n int, err error) {
37	return r.r.Read(p)
38}
39
40func (r *Reader) Uint8() (uint8, error) {
41	b, err := r.r.ReadByte()
42	if err != nil {
43		return uint8(0), err
44	}
45	return uint8(b), nil
46}
47
48func (r *Reader) Uint16() (uint16, error) {
49	b, err := r.ReadBytes(SizeUint16)
50	if err != nil {
51		return uint16(0), err
52	}
53	return binary.LittleEndian.Uint16(b), nil
54}
55
56func (r *Reader) Uint32() (uint32, error) {
57	b, err := r.ReadBytes(SizeUint32)
58	if err != nil {
59		return uint32(0), err
60	}
61	return binary.LittleEndian.Uint32(b), nil
62}
63
64func (r *Reader) Uint64() (uint64, error) {
65	b, err := r.ReadBytes(SizeUint64)
66	if err != nil {
67		return uint64(0), err
68	}
69	return binary.LittleEndian.Uint64(b), nil
70}
71
72func (r *Reader) FileTime() (f FileTime, err error) {
73	f.LowDateTime, err = r.Uint32()
74	if err != nil {
75		return
76	}
77	f.HighDateTime, err = r.Uint32()
78	if err != nil {
79		return
80	}
81	return
82}
83
84// UTF16String returns a string that is UTF16 encoded in a byte slice. n is the number of bytes representing the string
85func (r *Reader) UTF16String(n int) (str string, err error) {
86	//Length divided by 2 as each run is 16bits = 2bytes
87	s := make([]rune, n/2, n/2)
88	for i := 0; i < len(s); i++ {
89		var u uint16
90		u, err = r.Uint16()
91		if err != nil {
92			return
93		}
94		s[i] = rune(u)
95	}
96	str = string(s)
97	return
98}
99
100// readBytes returns a number of bytes from the NDR byte stream.
101func (r *Reader) ReadBytes(n int) ([]byte, error) {
102	//TODO make this take an int64 as input to allow for larger values on all systems?
103	b := make([]byte, n, n)
104	m, err := r.r.Read(b)
105	if err != nil || m != n {
106		return b, fmt.Errorf("error reading bytes from stream: %v", err)
107	}
108	return b, nil
109}
110