1 files changed, 160 insertions, 0 deletions
diff --git a/statistics.cpp b/statistics.cpp
new file mode 100644
index 0000000..800a4e5
--- /dev/null
+++ b/statistics.cpp
@@ -0,0 +1,160 @@
+#include "config.h"
+#include "statistics.hpp"
+#include <algorithm>
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include <sys/time.h>
+
+#include <iostream>
+#include <sstream>
+
+#define PROC_NET_DEV "/proc/net/dev"
+
+namespace statistics {
+
+Interface::Interface(const std::string& name) : name_(name), updated_(false) {}
+
+class InterfaceNameMatchesPredicate {
+    public:
+	InterfaceNameMatchesPredicate(const std::string& name) : name_(name) {}
+
+	bool operator() (const Interface& interface) const { 
+	    return name_ == interface.getName(); 
+	}
+    private:
+	std::string name_;
+};
+
+class InterfaceNotUpdatedPredicate {
+    public:
+	bool operator() (const Interface& interface) const { 
+	    return !interface.getUpdated(); 
+	}
+};
+
+void Interface::update(const Statistics& statistics) {
+    memcpy(statistics_ + 1, statistics_ + 0, sizeof(Statistics));
+    memcpy(statistics_, &statistics, sizeof(Statistics));
+   
+    const Statistics& x0 = statistics_[1];
+    const Statistics& x1 = statistics_[0];
+    
+    double timeDelta = 
+	(x1.timestamp.tv_sec - x0.timestamp.tv_sec) * 1.
+      + (x1.timestamp.tv_usec - x0.timestamp.tv_usec) * .000001;
+
+    receiveSpeed_ = (x1.rx_bytes - x0.rx_bytes) / timeDelta;
+    transmitSpeed_ = (x1.tx_bytes - x0.tx_bytes) / timeDelta;
+
+    updated_ = true;
+}
+
+void Reader::update() {
+    // Open /proc/net/dev
+    FILE *dev = fopen(PROC_NET_DEV, "r");
+    if (!dev) {
+		std::cerr << "cannot open " << PROC_NET_DEV << "\n";
+		exit(EXIT_FAILURE);
+	}
+
+    try {
+	// Clear the 'updated' flag for all interfaces
+	for (Interfaces::iterator interface = interfaces_.begin();
+		interface != interfaces_.end(); ++interface)
+	    interface->setUpdated(false);
+
+	// Read /proc/dev/net
+	while (!feof(dev)) {
+	    char buf[500];
+	    char *name, *statistics_string;
+	    Statistics stats;
+	    struct timezone unused_timezone;
+
+	    // Read a line
+	    fgets(buf, sizeof(buf), dev);
+	    gettimeofday(&stats.timestamp, &unused_timezone);
+
+	    // Find the colon separating the name from the statistics
+	    statistics_string = strchr(buf, ':');
+	    if (!statistics_string) continue;
+
+	    // Get a pointer to the statistics
+	    *statistics_string = 0;
+	    ++statistics_string;
+
+	    // Remove leading whitespace from the name
+	    name = buf;
+	    while (*name == ' ' || *name == '\t') ++name;
+	    
+	    // Parse the statistics
+	    if (sscanf(statistics_string, "%Lu %Lu %Lu %Lu %Lu %Lu %Lu %Lu "
+					  "%Lu %Lu %Lu %Lu %Lu %Lu %Lu %Lu",
+			    &stats.rx_bytes, &stats.rx_packets, 
+			    &stats.rx_errs, &stats.rx_drop, 
+			    &stats.rx_fifo, &stats.rx_frame, 
+			    &stats.rx_compressed, &stats.rx_multicast,
+			    &stats.tx_bytes, &stats.tx_packets, 
+			    &stats.tx_errs, &stats.tx_drop, 
+			    &stats.tx_fifo, &stats.tx_frame, 
+			    &stats.tx_compressed, &stats.tx_multicast) 
+		    == 16) {
+		
+		// Find the interface with the same name
+		Interfaces::iterator interface 
+		    = std::find_if(interfaces_.begin(), interfaces_.end(), 
+			InterfaceNameMatchesPredicate(name));
+		
+		if (interface == interfaces_.end()) {
+		    // This is a new interface; add it to the list
+		    interfaces_.push_back(Interface(name));
+		    interface = interfaces_.end();
+		    --interface;
+		}
+		
+		// Update the interface
+		interface->update(stats);
+	    }
+	}
+
+	// Remove all interfaces for which the updated flag was not set
+	interfaces_.remove_if(InterfaceNotUpdatedPredicate());
+	
+	// Close the file
+	fclose(dev);
+    }
+    catch (...) {
+	fclose(dev);
+	throw;
+    }
+}
+
+void Interface::setUpdated(bool updated) {
+    updated_ = updated;
+}
+
+bool Interface::getUpdated() const {
+    return updated_;
+}
+
+const std::string& Interface::getName() const {
+    return name_;
+}
+
+double Interface::getReceiveSpeed() const {
+    return receiveSpeed_;
+}
+
+double Interface::getTransmitSpeed() const {
+    return transmitSpeed_;
+}
+
+const Reader::Interfaces& Reader::getInterfaces() const {
+    return interfaces_;
+}
+
+} // namespace statistics