1 files changed, 67 insertions, 0 deletions
diff --git a/simpleperf/environment.cpp b/simpleperf/environment.cpp
new file mode 100644
index 00000000..14c256a5
--- /dev/null
+++ b/simpleperf/environment.cpp
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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 "environment.h"
+
+#include <stdlib.h>
+#include <vector>
+
+#include <base/logging.h>
+
+#include "utils.h"
+
+std::vector<int> GetOnlineCpus() {
+  std::vector<int> result;
+  FILE* fp = fopen("/sys/devices/system/cpu/online", "re");
+  if (fp == nullptr) {
+    PLOG(ERROR) << "can't open online cpu information";
+    return result;
+  }
+
+  LineReader reader(fp);
+  char* line;
+  if ((line = reader.ReadLine()) != nullptr) {
+    result = GetOnlineCpusFromString(line);
+  }
+  CHECK(!result.empty()) << "can't get online cpu information";
+  return result;
+}
+
+std::vector<int> GetOnlineCpusFromString(const std::string& s) {
+  std::vector<int> result;
+  bool have_dash = false;
+  const char* p = s.c_str();
+  char* endp;
+  long cpu;
+  // Parse line like: 0,1-3, 5, 7-8
+  while ((cpu = strtol(p, &endp, 10)) != 0 || endp != p) {
+    if (have_dash && result.size() > 0) {
+      for (int t = result.back() + 1; t < cpu; ++t) {
+        result.push_back(t);
+      }
+    }
+    have_dash = false;
+    result.push_back(cpu);
+    p = endp;
+    while (!isdigit(*p) && *p != '\0') {
+      if (*p == '-') {
+        have_dash = true;
+      }
+      ++p;
+    }
+  }
+  return result;
+}