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dot_tmux/plugins/tmux-mem-cpu-load/linux/cpu.cc

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+/* vim: tabstop=2 shiftwidth=2 expandtab textwidth=80 linebreak wrap
+ *
+ * Copyright 2012 Matthew McCormick
+ * Copyright 2015 Pawel 'l0ner' Soltys
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string>
+#include <fstream>
+#include <unistd.h> // usleep
+
+#include "cpu.h"
+#include "luts.h"
+
+uint32_t get_cpu_count()
+{
+  return sysconf( _SC_NPROCESSORS_ONLN );
+}
+
+float cpu_percentage( unsigned cpu_usage_delay )
+{
+  std::string line;
+  size_t substr_start = 0;
+  size_t substr_len;
+
+  // cpu stats
+  // user, nice, system, idle
+  // in that order
+  unsigned long long stats[CP_STATES];
+
+  std::ifstream stat_file( "/proc/stat" );
+  getline( stat_file, line );
+  stat_file.close();
+
+  // skip "cpu"
+  substr_len = line.find_first_of( " ", 3 );
+  // parse cpu line
+  for( unsigned i=0; i < 4; i++ )
+  {
+    substr_start = line.find_first_not_of( " ", substr_len );
+    substr_len   = line.find_first_of( " ", substr_start );
+    stats[i] = std::stoll( line.substr( substr_start, substr_len ) );
+  }
+
+  usleep( cpu_usage_delay );
+
+  stat_file.open( "/proc/stat" );
+  getline( stat_file, line );
+  stat_file.close();
+
+  // skip "cpu"
+  substr_len = line.find_first_of( " ", 3 );
+  // parse cpu line
+  for( unsigned i=0; i < 4; i++ )
+  {
+    substr_start = line.find_first_not_of( " ", substr_len );
+    substr_len   = line.find_first_of    ( " ", substr_start );
+    stats[i] = std::stoll( line.substr( substr_start, substr_len ) ) - stats[i];
+  }
+
+  return static_cast<float>( 
+    stats[CP_USER] + stats[CP_NICE] + stats[CP_SYS]
+    ) / static_cast<float>( 
+        stats[CP_USER] + stats[CP_NICE] + stats[CP_SYS] + stats[CP_IDLE] 
+    ) * 100.0;
+}
+