CpuUsage: support no wait detection on Windows

src/detection/cpuUsage/cpuUsage.c

@@ -0,0 +1,58 @@
+#include "fastfetch.h"
+#include "cpuUsage.h"
+
+#ifndef FF_DETECTION_CPUUSAGE_NOWAIT
+
+#include "common/time.h"
+
+#include <stdint.h>
+
+// We need to use uint64_t because sizeof(long) == 4 on Windows
+const char* ffGetCpuUsageInfo(uint64_t* inUseAll, uint64_t* totalAll);
+
+static uint64_t inUseAll1, totalAll1, startTime;
+
+void ffPrepareCPUUsage()
+{
+    startTime = ffTimeGetTick();
+    ffGetCpuUsageInfo(&inUseAll1, &totalAll1);
+}
+
+const char* ffGetCpuUsageResult(double* result)
+{
+    const char* error = NULL;
+    if(startTime == 0)
+    {
+        error = ffGetCpuUsageInfo(&inUseAll1, &totalAll1);
+        if(error)
+            return error;
+        ffTimeSleep(1000);
+    }
+    else
+    {
+        uint64_t duration = ffTimeGetTick() - startTime;
+        if(duration < 1000)
+            ffTimeSleep(1000 - (uint32_t) duration);
+    }
+
+    uint64_t inUseAll2, totalAll2;
+    error = ffGetCpuUsageInfo(&inUseAll2, &totalAll2);
+    if(error)
+        return error;
+
+    *result = (double)(inUseAll2 - inUseAll1) / (double)(totalAll2 - totalAll1) * 100;
+
+    return NULL;
+}
+
+#else //FF_DETECTION_CPUUSAGE_NOWAIT
+
+const char* ffGetCpuUsageResultNoWait(double* result);
+
+void ffPrepareCPUUsage() {}
+
+const char* ffGetCpuUsageResult(double* result) {
+    return ffGetCpuUsageResultNoWait(result);
+}
+
+#endif //FF_DETECTION_CPUUSAGE_NOWAIT