Initial import

.gitmodules

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+[submodule "threadpool"]
+	path = threadpool
+	url = https://github.com/afeinberg/threadpool

SConstruct

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+# -*-python-*-
+
+import os
+
+env = Environment()
+env.Append(CPPFLAGS='-g -Wall -Wextra')
+env.Append(CPPPATH=[os.path.join(os.curdir, "threadpool")])
+env.Program(target='parhost',
+            source=['parhost.cc'],
+            LIBS=['boost_thread-mt'])

parhost.cc

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+#include <cstdlib>
+#include <cstring>
+#include <netdb.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+
+#include <iostream>
+#include <string>
+
+#include <boost/bind.hpp>
+#include "boost/threadpool.hpp"
+
+#ifndef NI_MAXHOST
+#define NI_MAXHOST 1025
+#endif
+
+namespace {
+
+const int k_default_maxthreads = 32;
+const int k_nameinfo_maxhost = NI_MAXHOST;
+        
+using namespace boost::threadpool;
+
+void lookup(const std::string &buf);
+void submit_tasks(int max_threads);
+
+void lookup(const std::string &buf) {
+    struct addrinfo hints;
+    struct addrinfo *ai;
+    int rc;
+   
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = AF_UNSPEC;
+    
+    if ((rc = getaddrinfo(buf.c_str(), NULL, &hints, &ai)) != 0) {
+        std::cerr << "getaddrinfo(): " << gai_strerror(rc) << std::endl;
+    } else if (ai != NULL) {
+        char hostname[k_nameinfo_maxhost] = "";
+        rc = getnameinfo(ai->ai_addr,
+                         ai->ai_addrlen,
+                         hostname,
+                         k_nameinfo_maxhost,
+                         NULL,
+                         0,
+                         0);
+        if (rc != 0) {
+            std::cerr << "getnameinfo(): " << gai_strerror(rc) << std::endl;
+        } else {
+            if (*hostname != '\0') {
+                std::cout << buf << " -> " << hostname << std::endl;
+            } else {
+                std::cout << buf << " -> ? " << std::endl;
+            }
+        }
+    }
+    
+    freeaddrinfo(ai);
+}
+
+void submit_tasks(int max_threads) {
+    pool tp(max_threads);    
+    std::string line;
+    while (std::getline(std::cin, line)) {
+        tp.schedule(boost::bind(lookup, line));
+    }    
+}
+
+} // namespace
+
+
+int main(int argc, char **argv) {
+    int max_threads = argc < 2 ? k_default_maxthreads : atoi(argv[1]);
+    submit_tasks(max_threads);
+    return EXIT_SUCCESS;
+}