forked from tarm/serial
-
Notifications
You must be signed in to change notification settings - Fork 1
/
serial_windows.go
327 lines (280 loc) · 7.28 KB
/
serial_windows.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
// +build windows
package serial
import (
"fmt"
"os"
"sync"
"syscall"
"time"
"unsafe"
)
type Port struct {
f *os.File
fd syscall.Handle
rl sync.Mutex
wl sync.Mutex
ro *syscall.Overlapped
wo *syscall.Overlapped
}
type structDCB struct {
DCBlength, BaudRate uint32
flags [4]byte
wReserved, XonLim, XoffLim uint16
ByteSize, Parity, StopBits byte
XonChar, XoffChar, ErrorChar, EofChar, EvtChar byte
wReserved1 uint16
}
type structTimeouts struct {
ReadIntervalTimeout uint32
ReadTotalTimeoutMultiplier uint32
ReadTotalTimeoutConstant uint32
WriteTotalTimeoutMultiplier uint32
WriteTotalTimeoutConstant uint32
}
func openPort(name string, baud int, databits byte, parity Parity, stopbits StopBits, readTimeout time.Duration) (p *Port, err error) {
if len(name) > 0 && name[0] != '\\' {
name = "\\\\.\\" + name
}
h, err := syscall.CreateFile(syscall.StringToUTF16Ptr(name),
syscall.GENERIC_READ|syscall.GENERIC_WRITE,
0,
nil,
syscall.OPEN_EXISTING,
syscall.FILE_ATTRIBUTE_NORMAL|syscall.FILE_FLAG_OVERLAPPED,
0)
if err != nil {
return nil, err
}
f := os.NewFile(uintptr(h), name)
defer func() {
if err != nil {
f.Close()
}
}()
if err = setCommState(h, baud, databits, parity, stopbits); err != nil {
return nil, err
}
if err = setupComm(h, 64, 64); err != nil {
return nil, err
}
if err = setCommTimeouts(h, readTimeout); err != nil {
return nil, err
}
if err = setCommMask(h); err != nil {
return nil, err
}
ro, err := newOverlapped()
if err != nil {
return nil, err
}
wo, err := newOverlapped()
if err != nil {
return nil, err
}
port := new(Port)
port.f = f
port.fd = h
port.ro = ro
port.wo = wo
return port, nil
}
func (p *Port) Close() error {
return p.f.Close()
}
func (p *Port) Write(buf []byte) (int, error) {
p.wl.Lock()
defer p.wl.Unlock()
if err := resetEvent(p.wo.HEvent); err != nil {
return 0, err
}
var n uint32
err := syscall.WriteFile(p.fd, buf, &n, p.wo)
if err != nil && err != syscall.ERROR_IO_PENDING {
return int(n), err
}
return getOverlappedResult(p.fd, p.wo)
}
func (p *Port) Read(buf []byte) (int, error) {
if p == nil || p.f == nil {
return 0, fmt.Errorf("Invalid port on read")
}
p.rl.Lock()
defer p.rl.Unlock()
if err := resetEvent(p.ro.HEvent); err != nil {
return 0, err
}
var done uint32
err := syscall.ReadFile(p.fd, buf, &done, p.ro)
if err != nil && err != syscall.ERROR_IO_PENDING {
return int(done), err
}
return getOverlappedResult(p.fd, p.ro)
}
// Discards data written to the port but not transmitted,
// or data received but not read
func (p *Port) Flush() error {
return purgeComm(p.fd)
}
var (
nSetCommState,
nSetCommTimeouts,
nSetCommMask,
nSetupComm,
nGetOverlappedResult,
nCreateEvent,
nResetEvent,
nPurgeComm,
nFlushFileBuffers uintptr
)
func init() {
k32, err := syscall.LoadLibrary("kernel32.dll")
if err != nil {
panic("LoadLibrary " + err.Error())
}
defer syscall.FreeLibrary(k32)
nSetCommState = getProcAddr(k32, "SetCommState")
nSetCommTimeouts = getProcAddr(k32, "SetCommTimeouts")
nSetCommMask = getProcAddr(k32, "SetCommMask")
nSetupComm = getProcAddr(k32, "SetupComm")
nGetOverlappedResult = getProcAddr(k32, "GetOverlappedResult")
nCreateEvent = getProcAddr(k32, "CreateEventW")
nResetEvent = getProcAddr(k32, "ResetEvent")
nPurgeComm = getProcAddr(k32, "PurgeComm")
nFlushFileBuffers = getProcAddr(k32, "FlushFileBuffers")
}
func getProcAddr(lib syscall.Handle, name string) uintptr {
addr, err := syscall.GetProcAddress(lib, name)
if err != nil {
panic(name + " " + err.Error())
}
return addr
}
func setCommState(h syscall.Handle, baud int, databits byte, parity Parity, stopbits StopBits) error {
var params structDCB
params.DCBlength = uint32(unsafe.Sizeof(params))
params.flags[0] = 0x01 // fBinary
params.flags[0] |= 0x10 // Assert DSR
params.BaudRate = uint32(baud)
params.ByteSize = databits
switch parity {
case ParityNone:
params.Parity = 0
case ParityOdd:
params.Parity = 1
case ParityEven:
params.Parity = 2
case ParityMark:
params.Parity = 3
case ParitySpace:
params.Parity = 4
default:
return ErrBadParity
}
switch stopbits {
case Stop1:
params.StopBits = 0
case Stop1Half:
params.StopBits = 1
case Stop2:
params.StopBits = 2
default:
return ErrBadStopBits
}
r, _, err := syscall.Syscall(nSetCommState, 2, uintptr(h), uintptr(unsafe.Pointer(¶ms)), 0)
if r == 0 {
return err
}
return nil
}
func setCommTimeouts(h syscall.Handle, readTimeout time.Duration) error {
var timeouts structTimeouts
const MAXDWORD = 1<<32 - 1
// blocking read by default
var timeoutMs int64 = MAXDWORD - 1
if readTimeout > 0 {
// non-blocking read
timeoutMs = readTimeout.Nanoseconds() / 1e6
if timeoutMs < 1 {
timeoutMs = 1
} else if timeoutMs > MAXDWORD-1 {
timeoutMs = MAXDWORD - 1
}
}
/* From http://msdn.microsoft.com/en-us/library/aa363190(v=VS.85).aspx
For blocking I/O see below:
Remarks:
If an application sets ReadIntervalTimeout and
ReadTotalTimeoutMultiplier to MAXDWORD and sets
ReadTotalTimeoutConstant to a value greater than zero and
less than MAXDWORD, one of the following occurs when the
ReadFile function is called:
If there are any bytes in the input buffer, ReadFile returns
immediately with the bytes in the buffer.
If there are no bytes in the input buffer, ReadFile waits
until a byte arrives and then returns immediately.
If no bytes arrive within the time specified by
ReadTotalTimeoutConstant, ReadFile times out.
*/
timeouts.ReadIntervalTimeout = MAXDWORD
timeouts.ReadTotalTimeoutMultiplier = MAXDWORD
timeouts.ReadTotalTimeoutConstant = uint32(timeoutMs)
r, _, err := syscall.Syscall(nSetCommTimeouts, 2, uintptr(h), uintptr(unsafe.Pointer(&timeouts)), 0)
if r == 0 {
return err
}
return nil
}
func setupComm(h syscall.Handle, in, out int) error {
r, _, err := syscall.Syscall(nSetupComm, 3, uintptr(h), uintptr(in), uintptr(out))
if r == 0 {
return err
}
return nil
}
func setCommMask(h syscall.Handle) error {
const EV_RXCHAR = 0x0001
r, _, err := syscall.Syscall(nSetCommMask, 2, uintptr(h), EV_RXCHAR, 0)
if r == 0 {
return err
}
return nil
}
func resetEvent(h syscall.Handle) error {
r, _, err := syscall.Syscall(nResetEvent, 1, uintptr(h), 0, 0)
if r == 0 {
return err
}
return nil
}
func purgeComm(h syscall.Handle) error {
const PURGE_TXABORT = 0x0001
const PURGE_RXABORT = 0x0002
const PURGE_TXCLEAR = 0x0004
const PURGE_RXCLEAR = 0x0008
r, _, err := syscall.Syscall(nPurgeComm, 2, uintptr(h),
PURGE_TXABORT|PURGE_RXABORT|PURGE_TXCLEAR|PURGE_RXCLEAR, 0)
if r == 0 {
return err
}
return nil
}
func newOverlapped() (*syscall.Overlapped, error) {
var overlapped syscall.Overlapped
r, _, err := syscall.Syscall6(nCreateEvent, 4, 0, 1, 0, 0, 0, 0)
if r == 0 {
return nil, err
}
overlapped.HEvent = syscall.Handle(r)
return &overlapped, nil
}
func getOverlappedResult(h syscall.Handle, overlapped *syscall.Overlapped) (int, error) {
var n int
r, _, err := syscall.Syscall6(nGetOverlappedResult, 4,
uintptr(h),
uintptr(unsafe.Pointer(overlapped)),
uintptr(unsafe.Pointer(&n)), 1, 0, 0)
if r == 0 {
return n, err
}
return n, nil
}