win32: detect number of CPUs using affinity

Signed-off-by: Janne Grunau <janne-libav@jannau.net>

configure

@@ -1084,9 +1084,9 @@ HAVE_LIST="
     fork
     getaddrinfo
     gethrtime
+    GetProcessAffinityMask
     GetProcessMemoryInfo
     GetProcessTimes
-    GetSystemInfo
     getrusage
     gnu_as
     ibm_asm
@@ -2864,8 +2864,8 @@ check_func  sysctl
 check_func_headers io.h setmode
 check_func_headers lzo/lzo1x.h lzo1x_999_compress
 check_lib2 "windows.h psapi.h" GetProcessMemoryInfo -lpsapi
+check_func_headers windows.h GetProcessAffinityMask
 check_func_headers windows.h GetProcessTimes
-check_func_headers windows.h GetSystemInfo
 check_func_headers windows.h MapViewOfFile
 check_func_headers windows.h VirtualAlloc
 

libavcodec/pthread.c

@@ -35,7 +35,7 @@
 #define _GNU_SOURCE
 #include <sched.h>
 #endif
-#if HAVE_GETSYSTEMINFO
+#if HAVE_GETPROCESSAFFINITYMASK
 #include <windows.h>
 #endif
 #if HAVE_SYSCTL
@@ -169,10 +169,11 @@ static int get_logical_cpus(AVCodecContext *avctx)
     if (!ret) {
         nb_cpus = CPU_COUNT(&cpuset);
     }
-#elif HAVE_GETSYSTEMINFO
-    SYSTEM_INFO sysinfo;
-    GetSystemInfo(&sysinfo);
-    nb_cpus = sysinfo.dwNumberOfProcessors;
+#elif HAVE_GETPROCESSAFFINITYMASK
+    DWORD_PTR proc_aff, sys_aff;
+    ret = GetProcessAffinityMask(GetCurrentProcess(), &proc_aff, &sys_aff);
+    if (ret)
+        nb_cpus = av_popcount64(proc_aff);
 #elif HAVE_SYSCTL && defined(HW_NCPU)
     int mib[2] = { CTL_HW, HW_NCPU };
     size_t len = sizeof(nb_cpus);