GEEKING

App/util/Android/MemoryStats.cpp

@@ -0,0 +1,108 @@
+#include "util/MemoryStats.h"
+
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <regex>
+
+namespace RBX
+{
+using RBX::MemoryStats::memsize_t;
+
+class MemInfo
+{
+    // Next 3 fields summed define how much memory is actually free.
+    memsize_t cacheKB;
+    memsize_t bufferKB;
+    memsize_t memfreeKB;
+
+    memsize_t totalKB;
+
+    bool readLine(const std::string& line, const std::string& target, memsize_t* field)
+    {
+        if (0 == line.find(target))
+        {
+            std::string expr = target + "\\s*(\\d+).*";
+            std::regex e(expr);
+            std::smatch sm;
+            if (std::regex_search(line, sm, e)) {
+                if (sm.size() >= 1) {
+                    std::string o = sm[1].str(); // gets the first capture group
+                    std::sscanf(o.c_str(), "%llu", field);
+                }
+            }
+            
+            return true;
+        }
+        return false;
+    }
+
+public:
+    MemInfo() : cacheKB(1), bufferKB(1), memfreeKB(1), totalKB(3)
+    {
+        std::ifstream fin("/proc/meminfo");
+
+        unsigned fieldsLoaded = 0;
+        while (fin && !fin.eof() && fieldsLoaded < 4)
+        {
+            std::string line;
+            std::getline(fin, line);
+
+            if (readLine(line, "MemTotal:", &totalKB))
+            {
+                ++fieldsLoaded;
+            }
+
+            if (readLine(line, "MemFree:", &memfreeKB))
+            {
+                ++fieldsLoaded;
+            }
+
+            if (readLine(line, "Buffers:", &bufferKB))
+            {
+                ++fieldsLoaded;
+
+            }
+
+            if (readLine(line, "Cached:", &cacheKB))
+            {
+                ++fieldsLoaded;
+            }
+        }
+    }
+
+    memsize_t freeBytes() const
+    {
+        return (memfreeKB + bufferKB + cacheKB) * 1024;
+    }
+
+    memsize_t totalBytes() const
+    {
+        return totalKB * 1024;
+    }
+};
+} // namespace rbx
+
+namespace RBX {
+namespace MemoryStats {
+
+memsize_t usedMemoryBytes()
+{
+    MemInfo mi;
+    return mi.totalBytes() - mi.freeBytes();
+}
+
+memsize_t freeMemoryBytes()
+{
+    MemInfo mi;
+    return mi.freeBytes();
+}
+
+memsize_t totalMemoryBytes()
+{
+    MemInfo mi;
+    return mi.totalBytes();
+}
+
+} // namespace MemoryStats
+} // namespace RBX