Deal with disappearing cpus

Reinit if cpu is brought offline/online, e.g. `echo 0 > /sys/devices/system/cpu/cpu1/online`

Fix #737

src/cpu.cpp

@@ -131,6 +131,7 @@ bool CPUStats::Init()
             CPUData cpu = {};
             cpu.totalTime = 1;
             cpu.totalPeriod = 1;
+            sscanf(line.c_str(), "cpu%4d ", &cpu.cpu_id);
             m_cpuData.push_back(cpu);
 
         } else if (starts_with(line, "btime ")) {
@@ -199,12 +200,12 @@ bool CPUStats::UpdateCPUData()
                 return false;
             }
 
-            if ((size_t)cpuid >= m_cpuData.size()) {
-                SPDLOG_DEBUG("Cpu id '{}' is out of bounds, reiniting", cpuid);
+            if (cpu_count + 1 > m_cpuData.size() || m_cpuData[cpu_count].cpu_id != cpuid) {
+                SPDLOG_DEBUG("Cpu id '{}' is out of bounds or wrong index, reiniting", cpuid);
                 return Reinit();
             }
 
-            CPUData& cpuData = m_cpuData[cpuid];
+            CPUData& cpuData = m_cpuData[cpu_count];
             calculateCPUData(cpuData, usertime, nicetime, systemtime, idletime, ioWait, irq, softIrq, steal, guest, guestnice);
             cpuid = -1;
             cpu_count++;
@@ -225,14 +226,14 @@ bool CPUStats::UpdateCPUData()
 bool CPUStats::UpdateCoreMhz() {
     m_coreMhz.clear();
     FILE *fp;
-    for (size_t i = 0; i < m_cpuData.size(); i++)
+    for (auto& cpu : m_cpuData)
     {
-        std::string path = "/sys/devices/system/cpu/cpu" + std::to_string(i) + "/cpufreq/scaling_cur_freq";
+        std::string path = "/sys/devices/system/cpu/cpu" + std::to_string(cpu.cpu_id) + "/cpufreq/scaling_cur_freq";
         if ((fp = fopen(path.c_str(), "r"))){
             int64_t temp;
             if (fscanf(fp, "%" PRId64, &temp) != 1)
                 temp = 0;
-            m_cpuData[i].mhz = temp / 1000;
+            cpu.mhz = temp / 1000;
             fclose(fp);
         }
     }

src/cpu.h

@@ -36,6 +36,8 @@ typedef struct CPUData_ {
    unsigned long long int softIrqPeriod;
    unsigned long long int stealPeriod;
    unsigned long long int guestPeriod;
+
+   int cpu_id;
    float percent;
    int mhz;
    int temp;

src/hud_elements.cpp

@@ -265,14 +265,13 @@ void HudElements::cpu_stats(){
 
 void HudElements::core_load(){
     if (HUDElements.params->enabled[OVERLAY_PARAM_ENABLED_core_load]){
-         int i = 0;
          for (const CPUData &cpuData : cpuStats.GetCPUData())
          {
             ImGui::TableNextRow(); ImGui::TableNextColumn();
             ImGui::TextColored(HUDElements.colors.cpu, "CPU");
             ImGui::SameLine(0, 1.0f);
             ImGui::PushFont(HUDElements.sw_stats->font1);
-            ImGui::TextColored(HUDElements.colors.cpu,"%i", i);
+            ImGui::TextColored(HUDElements.colors.cpu,"%i", cpuData.cpu_id);
             ImGui::PopFont();
             ImGui::TableNextColumn();
             auto text_color = HUDElements.colors.text;
@@ -302,7 +301,6 @@ void HudElements::core_load(){
             ImGui::PushFont(HUDElements.sw_stats->font1);
             ImGui::Text("MHz");
             ImGui::PopFont();
-            i++;
          }
     }
 }