CpuUsage: support JSON config

src/detection/cpuusage/cpuusage.c

@@ -0,0 +1,43 @@
+#include "fastfetch.h"
+#include "detection/cpuusage/cpuusage.h"
+#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;
+
+void ffPrepareCPUUsage()
+{
+    ffGetCpuUsageInfo(&inUseAll1, &totalAll1);
+}
+
+const char* ffGetCpuUsageResult(double* result)
+{
+    const char* error = NULL;
+    if(inUseAll1 == 0 && totalAll1 == 0)
+    {
+        error = ffGetCpuUsageInfo(&inUseAll1, &totalAll1);
+        if(error)
+            return error;
+        ffTimeSleep(200);
+    }
+
+    while(true)
+    {
+        uint64_t inUseAll2, totalAll2;
+        error = ffGetCpuUsageInfo(&inUseAll2, &totalAll2);
+        if(error)
+            return error;
+
+        if(inUseAll2 != inUseAll1)
+        {
+            *result = (double)(inUseAll2 - inUseAll1) / (double)(totalAll2 - totalAll1) * 100;
+            return NULL;
+        }
+        else
+            ffTimeSleep(200);
+    }
+}