ReactOS  0.4.14-dev-376-gaedba84
detect.c
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1 /*
2  * PROJECT: ReactOS Sound System "MME Buddy" NT4 Library
3  * LICENSE: GPL - See COPYING in the top level directory
4  * FILE: lib/drivers/sound/mment4/detect.c
5  *
6  * PURPOSE: Assists in locating Windows NT4 compatible sound devices,
7  * which mostly use the same device naming convention and/or
8  * store their created device names within their service key
9  * within the registry.
10  *
11  * PROGRAMMERS: Andrew Greenwood (silverblade@reactos.org)
12 */
13 
14 #include "precomp.h"
15 
16 #include <mment4.h>
17 #include <mmebuddy_debug.h>
18 
19 /*
20  This is the "nice" way to discover audio devices in NT4 - go into the
21  service registry key and enumerate the Parameters\Device*\Devices
22  values. The value names represent the device name, whereas the data
23  assigned to them identifies the type of device.
24 */
29  IN SOUND_DEVICE_DETECTED_PROC SoundDeviceDetectedProc)
30 {
31  HKEY Key;
32  DWORD KeyIndex = 0;
33 
35 
36  /* Device type zero means "all" */
38  DeviceType == 0 );
39 
40  while ( OpenSoundDeviceRegKey(ServiceName, KeyIndex, &Key) == MMSYSERR_NOERROR )
41  {
42  HKEY DevicesKey;
43  DWORD ValueType = REG_NONE, ValueIndex = 0;
44  DWORD MaxNameLength = 0, ValueNameLength = 0;
45  PWSTR DevicePath = NULL, ValueName = NULL;
46  DWORD ValueDataLength = sizeof(DWORD);
48 
49  if ( RegOpenKeyEx(Key,
51  0,
52  KEY_READ,
53  &DevicesKey) == ERROR_SUCCESS )
54  {
55  /* Find out how much memory is needed for the key name */
56  if ( RegQueryInfoKey(DevicesKey,
57  NULL, NULL, NULL, NULL, NULL, NULL, NULL,
58  &MaxNameLength,
59  NULL, NULL, NULL) != ERROR_SUCCESS )
60  {
61  SND_ERR(L"Failed to query registry key information\n");
62  RegCloseKey(DevicesKey);
64 
65  return MMSYSERR_ERROR;
66  }
67 
68  DevicePath = AllocateWideString(MaxNameLength +
69  strlen("\\\\.\\"));
70 
71  /* Check that the memory allocation was successful */
72  if ( ! DevicePath )
73  {
74  /* There's no point in going further */
75  RegCloseKey(DevicesKey);
77 
78  return MMSYSERR_NOMEM;
79  }
80 
81  /* Insert the device path prefix */
82  wsprintf(DevicePath, L"\\\\.\\");
83 
84  /* The offset of the string following this prefix */
85  ValueName = DevicePath + strlen("\\\\.\\");
86 
87  /* Copy this so that it may be overwritten - include NULL */
88  ValueNameLength = MaxNameLength + sizeof(WCHAR);
89 
90  SND_TRACE(L"Interested in devices beginning with %wS\n", DevicePath);
91 
92  while ( RegEnumValue(DevicesKey,
93  ValueIndex,
94  ValueName,
95  &ValueNameLength,
96  NULL,
97  &ValueType,
98  (LPBYTE) &ValueData,
99  &ValueDataLength) == ERROR_SUCCESS )
100  {
101  /* Device types are stored as DWORDs */
102  if ( ( ValueType == REG_DWORD ) &&
103  ( ValueDataLength == sizeof(DWORD) ) )
104  {
105  if ( ( DeviceType == 0 ) ||
106  ( DeviceType == ValueData ) )
107  {
108  SND_TRACE(L"Found device: %wS\n", DevicePath);
109  SoundDeviceDetectedProc(ValueData, DevicePath);
110  }
111  }
112 
113  /* Reset variables for the next iteration */
114  ValueNameLength = MaxNameLength + sizeof(WCHAR);
115  ZeroMemory(ValueName, (MaxNameLength+1)*sizeof(WCHAR));
116  /*ZeroWideString(ValueName);*/
117  ValueDataLength = sizeof(DWORD);
118  ValueData = 0;
120 
121  ++ ValueIndex;
122  }
123 
124  FreeMemory(DevicePath);
125 
126  RegCloseKey(DevicesKey);
127  }
128  else
129  {
130  SND_WARN(L"Unable to open the Devices key!\n");
131  }
132 
133  ++ KeyIndex;
134 
135  RegCloseKey(Key);
136  }
137 
138  return MMSYSERR_NOERROR;
139 }
140 
141 /*
142  Brute-force device detection, using a base device name (eg: \\.\WaveOut).
143 
144  This will add the device number as a suffix to the end of the string and
145  attempt to open the device based on that name. On success, it will
146  increment the device number and repeat this process.
147 
148  When it runs out of devices, it will give up.
149 */
150 MMRESULT
153  IN PWSTR BaseDeviceName,
154  IN SOUND_DEVICE_DETECTED_PROC SoundDeviceDetectedProc)
155 {
156  SIZE_T DeviceNameLength = 0;
158  ULONG Index = 0;
160  BOOLEAN DoSearch = TRUE;
161 
163 
164  DeviceNameLength = wcslen(BaseDeviceName);
165  /* Consider the length of the number */
166  DeviceNameLength += GetDigitCount(Index);
167 
168  DeviceName = AllocateWideString(DeviceNameLength);
169 
170  if ( ! DeviceName )
171  {
172  return MMSYSERR_NOMEM;
173  }
174 
175  while ( DoSearch )
176  {
177  /* Nothing like a nice clean device name */
179  wsprintf(DeviceName, L"%ls%d", BaseDeviceName, Index);
180 
182  TRUE,
184  {
185  /* Notify the callback function */
186  SND_TRACE(L"Found device: %wS\n", DeviceName);
187  SoundDeviceDetectedProc(DeviceType, DeviceName);
188 
190 
191  ++ Index;
192  }
193  else
194  {
195  DoSearch = FALSE;
196  }
197  }
198 
200 
201  return MMSYSERR_NOERROR;
202 }
#define IN
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MMRESULT DetectNt4SoundDevices(IN MMDEVICE_TYPE DeviceType, IN PWSTR BaseDeviceName, IN SOUND_DEVICE_DETECTED_PROC SoundDeviceDetectedProc)
Definition: detect.c:151
#define KEY_READ
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Definition: typedefs.h:54
DeviceType
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Definition: mmsystem.h:103
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Definition: detect.c:26
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