From: philburk <philburk@0f58301d-fd10-0410-b4af-bbb618454e57>
Date: Fri, 19 Apr 2002 18:31:54 +0000 (+0000)
Subject: Detect Win XP and Win 2K properly when determining latency.
X-Git-Tag: V18~15
X-Git-Url: https://andrewgundersen.net/repos?a=commitdiff_plain;h=18d252bbfe86477e27780ad1b962d2ce5bec5d8f;p=portaudio

Detect Win XP and Win 2K properly when determining latency.
---

diff --git a/pa_win_ds/pa_dsound.c b/pa_win_ds/pa_dsound.c
index 96f4753..877c01d 100644
--- a/pa_win_ds/pa_dsound.c
+++ b/pa_win_ds/pa_dsound.c
@@ -33,6 +33,7 @@
 /* Modifications
  *    7/19/01 Mike Berry - casts for compiling with __MWERKS__ CodeWarrior
  *    9/27/01 Phil Burk - use number of frames instead of real-time for CPULoad calculation.
+ *    4/19/02 Phil Burk - Check for Win XP for system latency calculation.
  */
 /* Compiler flags:
  SUPPORT_AUDIO_CAPTURE - define this flag if you want to SUPPORT_AUDIO_CAPTURE
@@ -49,10 +50,12 @@
 #include "pa_host.h"
 #include "pa_trace.h"
 #include "dsound_wrapper.h"
+
 #define PRINT(x) { printf x; fflush(stdout); }
 #define ERR_RPT(x) PRINT(x)
 #define DBUG(x)  /* PRINT(x) */
 #define DBUGX(x) /* PRINT(x) */
+
 #define PA_USE_HIGH_LATENCY   (0)
 #if PA_USE_HIGH_LATENCY
 #define PA_WIN_9X_LATENCY     (500)
@@ -61,6 +64,9 @@
 #define PA_WIN_9X_LATENCY     (140)
 #define PA_WIN_NT_LATENCY     (280)
 #endif
+
+#define PA_WIN_WDM_LATENCY       (120)
+
 /* Trigger an underflow for testing purposes. Should normally be (0). */
 #define PA_SIMULATE_UNDERFLOW (0)
 #if PA_SIMULATE_UNDERFLOW
@@ -68,6 +74,7 @@ static  gUnderCallbackCounter = 0;
 #define UNDER_START_GAP       (10)
 #define UNDER_STOP_GAP        (UNDER_START_GAP + 4)
 #endif
+
 /************************************************* Definitions ********/
 typedef struct internalPortAudioStream internalPortAudioStream;
 typedef struct internalPortAudioDevice
@@ -78,6 +85,7 @@ typedef struct internalPortAudioDevice
     PaDeviceInfo                     pad_Info;
 }
 internalPortAudioDevice;
+
 /* Define structure to contain all DirectSound and Windows specific data. */
 typedef struct PaHostSoundControl
 {
@@ -93,6 +101,7 @@ typedef struct PaHostSoundControl
     double           pahsc_InverseTicksPerUserBuffer;
 }
 PaHostSoundControl;
+
 /************************************************* Shared Data ********/
 /* FIXME - put Mutex around this shared data. */
 static int sNumDevices = 0;
@@ -115,6 +124,7 @@ static BOOL CALLBACK Pa_CountDevProc(LPGUID lpGUID,
 static Pa_QueryDevices( void );
 static void CALLBACK Pa_TimerCallback(UINT uID, UINT uMsg,
                                       DWORD dwUser, DWORD dw1, DWORD dw2);
+
 /********************************* BEGIN CPU UTILIZATION MEASUREMENT ****/
 static void Pa_StartUsageCalculation( internalPortAudioStream   *past )
 {
@@ -123,6 +133,7 @@ static void Pa_StartUsageCalculation( internalPortAudioStream   *past )
     /* Query system timer for usage analysis and to prevent overuse of CPU. */
     QueryPerformanceCounter( &pahsc->pahsc_EntryCount );
 }
+
 static void Pa_EndUsageCalculation( internalPortAudioStream   *past )
 {
     LARGE_INTEGER CurrentCount = { 0, 0 };
@@ -142,6 +153,7 @@ static void Pa_EndUsageCalculation( internalPortAudioStream   *past )
                            (LOWPASS_COEFFICIENT_1 * newUsage);
     }
 }
+
 /****************************************** END CPU UTILIZATION *******/
 static PaError Pa_QueryDevices( void )
 {
@@ -873,6 +885,38 @@ PaError PaHost_CloseStream( internalPortAudioStream   *past )
     past->past_DeviceData = NULL;
     return paNoError;
 }
+
+/* Set minimal latency based on whether NT or Win95.
+ * NT has higher latency.
+ */
+static int PaHost_GetMinSystemLatency( void )
+{
+    int minLatencyMsec;
+    /* Set minimal latency based on whether NT or other OS.
+     * NT has higher latency.
+     */
+    OSVERSIONINFO osvi;
+	osvi.dwOSVersionInfoSize = sizeof( osvi );
+	GetVersionEx( &osvi );
+    DBUG(("PA - PlatformId = 0x%x\n", osvi.dwPlatformId ));
+    DBUG(("PA - MajorVersion = 0x%x\n", osvi.dwMajorVersion ));
+    DBUG(("PA - MinorVersion = 0x%x\n", osvi.dwMinorVersion ));
+    /* Check for NT */
+	if( (osvi.dwMajorVersion == 4) && (osvi.dwPlatformId == 2) )
+	{
+		minLatencyMsec = PA_WIN_NT_LATENCY;
+	}
+	else if(osvi.dwMajorVersion >= 5)
+	{
+		minLatencyMsec = PA_WIN_WDM_LATENCY;
+	}
+	else
+	{
+		minLatencyMsec = PA_WIN_9X_LATENCY;
+	}
+    return minLatencyMsec;
+}
+
 /*************************************************************************
 ** Determine minimum number of buffers required for this host based
 ** on minimum latency. Latency can be optionally set by user by setting
@@ -888,7 +932,6 @@ PaError PaHost_CloseStream( internalPortAudioStream   *past )
 int Pa_GetMinNumBuffers( int framesPerBuffer, double sampleRate )
 {
     char      envbuf[PA_ENV_BUF_SIZE];
-    DWORD     hostVersion;
     DWORD     hresult;
     int       minLatencyMsec = 0;
     double    msecPerBuffer = (1000.0 * framesPerBuffer) / sampleRate;
@@ -901,12 +944,7 @@ int Pa_GetMinNumBuffers( int framesPerBuffer, double sampleRate )
     }
     else
     {
-        /* Set minimal latency based on whether NT or Win95.
-         * NT has higher latency.
-         */
-        hostVersion = GetVersion();
-        /* High bit clear if NT */
-        minLatencyMsec = ( (hostVersion & 0x80000000) == 0 ) ? PA_WIN_NT_LATENCY : PA_WIN_9X_LATENCY  ;
+        minLatencyMsec = PaHost_GetMinSystemLatency();
 #if PA_USE_HIGH_LATENCY
         PRINT(("PA - Minimum Latency set to %d msec!\n", minLatencyMsec ));
 #endif