Problem: irregular loop conditions

Solution: use standard loop constructs and optimize some loops

src/ctx.cpp

@@ -117,12 +117,13 @@ zmq::ctx_t::~ctx_t ()
 
     //  Ask I/O threads to terminate. If stop signal wasn't sent to I/O
     //  thread subsequent invocation of destructor would hang-up.
-    for (io_threads_t::size_type i = 0; i != _io_threads.size (); i++) {
+    const io_threads_t::size_type io_threads_size = _io_threads.size ();
+    for (io_threads_t::size_type i = 0; i != io_threads_size; i++) {
         _io_threads[i]->stop ();
     }
 
     //  Wait till I/O threads actually terminate.
-    for (io_threads_t::size_type i = 0; i != _io_threads.size (); i++) {
+    for (io_threads_t::size_type i = 0; i != io_threads_size; i++) {
         LIBZMQ_DELETE (_io_threads[i]);
     }
 
@@ -176,9 +177,10 @@ int zmq::ctx_t::terminate ()
         if (_pid != getpid ()) {
             // we are a forked child process. Close all file descriptors
             // inherited from the parent.
-            for (sockets_t::size_type i = 0; i != _sockets.size (); i++)
+            for (sockets_t::size_type i = 0, size = _sockets.size (); i != size;
+                 i++) {
                 _sockets[i]->get_mailbox ()->forked ();
-
+            }
             _term_mailbox.forked ();
         }
 #endif
@@ -193,8 +195,10 @@ int zmq::ctx_t::terminate ()
             //  First send stop command to sockets so that any blocking calls
             //  can be interrupted. If there are no sockets we can ask reaper
             //  thread to stop.
-            for (sockets_t::size_type i = 0; i != _sockets.size (); i++)
+            for (sockets_t::size_type i = 0, size = _sockets.size (); i != size;
+                 i++) {
                 _sockets[i]->stop ();
+            }
             if (_sockets.empty ())
                 _reaper->stop ();
         }
@@ -239,8 +243,10 @@ int zmq::ctx_t::shutdown ()
             //  Send stop command to sockets so that any blocking calls
             //  can be interrupted. If there are no sockets we can ask reaper
             //  thread to stop.
-            for (sockets_t::size_type i = 0; i != _sockets.size (); i++)
+            for (sockets_t::size_type i = 0, size = _sockets.size (); i != size;
+                 i++) {
                 _sockets[i]->stop ();
+            }
             if (_sockets.empty ())
                 _reaper->stop ();
         }
@@ -666,9 +672,10 @@ zmq::io_thread_t *zmq::ctx_t::choose_io_thread (uint64_t affinity_)
     //  Find the I/O thread with minimum load.
     int min_load = -1;
     io_thread_t *selected_io_thread = NULL;
-    for (io_threads_t::size_type i = 0; i != _io_threads.size (); i++) {
+    for (io_threads_t::size_type i = 0, size = _io_threads.size (); i != size;
+         i++) {
         if (!affinity_ || (affinity_ & (uint64_t (1) << i))) {
-            int load = _io_threads[i]->get_load ();
+            const int load = _io_threads[i]->get_load ();
             if (selected_io_thread == NULL || load < min_load) {
                 min_load = load;
                 selected_io_thread = _io_threads[i];

src/generic_mtrie_impl.hpp

@@ -427,13 +427,14 @@ void zmq::generic_mtrie_t<T>::match (prefix_t data_,
                                      void (*func_) (value_t *pipe_, Arg arg_),
                                      Arg arg_)
 {
-    generic_mtrie_t *current = this;
-    while (true) {
+    for (generic_mtrie_t *current = this; current; data_++, size_--) {
         //  Signal the pipes attached to this node.
         if (current->_pipes) {
-            for (typename pipes_t::iterator it = current->_pipes->begin ();
-                 it != current->_pipes->end (); ++it)
+            for (typename pipes_t::iterator it = current->_pipes->begin (),
+                                            end = current->_pipes->end ();
+                 it != end; ++it) {
                 func_ (*it, arg_);
+            }
         }
 
         //  If we are at the end of the message, there's nothing more to match.
@@ -444,25 +445,20 @@ void zmq::generic_mtrie_t<T>::match (prefix_t data_,
         if (current->_count == 0)
             break;
 
-        //  If there's one subnode (optimisation).
         if (current->_count == 1) {
-            if (data_[0] != current->_min)
+            //  If there's one subnode (optimisation).
+            if (data_[0] != current->_min) {
                 break;
+            }
             current = current->_next.node;
-            data_++;
-            size_--;
-            continue;
+        } else {
+            //  If there are multiple subnodes.
+            if (data_[0] < current->_min
+                || data_[0] >= current->_min + current->_count) {
+                break;
+            }
+            current = current->_next.table[data_[0] - current->_min];
         }
-
-        //  If there are multiple subnodes.
-        if (data_[0] < current->_min
-            || data_[0] >= current->_min + current->_count)
-            break;
-        if (!current->_next.table[data_[0] - current->_min])
-            break;
-        current = current->_next.table[data_[0] - current->_min];
-        data_++;
-        size_--;
     }
 }
 

src/ipc_listener.cpp

@@ -253,9 +253,10 @@ bool zmq::ipc_listener_t::filter (fd_t sock_)
 
     if (!(pw = getpwuid (cred.uid)))
         return false;
-    for (options_t::ipc_gid_accept_filters_t::const_iterator it =
-           options.ipc_gid_accept_filters.begin ();
-         it != options.ipc_gid_accept_filters.end (); it++) {
+    for (options_t::ipc_gid_accept_filters_t::const_iterator
+           it = options.ipc_gid_accept_filters.begin (),
+           end = options.ipc_gid_accept_filters.end ();
+         it != end; it++) {
         if (!(gr = getgrgid (*it)))
             continue;
         for (char **mem = gr->gr_mem; *mem; mem++) {

src/pipe.cpp

@@ -188,7 +188,7 @@ bool zmq::pipe_t::read (msg_t *msg_)
     if (unlikely (_state != active && _state != waiting_for_delimiter))
         return false;
 
-    for (bool payload_read = false; !payload_read;) {
+    while (true) {
         if (!_in_pipe->read (msg_)) {
             _in_active = false;
             return false;
@@ -198,8 +198,9 @@ bool zmq::pipe_t::read (msg_t *msg_)
         if (unlikely (msg_->is_credential ())) {
             const int rc = msg_->close ();
             zmq_assert (rc == 0);
-        } else
-            payload_read = true;
+        } else {
+            break;
+        }
     }
 
     //  If delimiter was read, start termination process of the pipe.

src/radix_tree.cpp

@@ -34,6 +34,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <iterator>
 #include <vector>
 
 node_t::node_t (unsigned char *data_) : _data (data_)
@@ -187,7 +188,7 @@ zmq::radix_tree_t::radix_tree_t () : _root (make_node (0, 0, 0)), _size (0)
 
 static void free_nodes (node_t node_)
 {
-    for (size_t i = 0; i < node_.edgecount (); ++i)
+    for (size_t i = 0, count = node_.edgecount (); i < count; ++i)
         free_nodes (node_.node_at (i));
     free (node_._data);
 }
@@ -234,18 +235,19 @@ match_result_t zmq::radix_tree_t::match (const unsigned char *key_,
     size_t parent_edge_index = 0;
 
     while (current_node.prefix_length () > 0 || current_node.edgecount () > 0) {
+        const unsigned char *const prefix = current_node.prefix ();
+        const size_t prefix_length = current_node.prefix_length ();
+
         for (prefix_byte_index = 0;
-             prefix_byte_index < current_node.prefix_length ()
-             && key_byte_index < key_size_;
+             prefix_byte_index < prefix_length && key_byte_index < key_size_;
              ++prefix_byte_index, ++key_byte_index) {
-            if (current_node.prefix ()[prefix_byte_index]
-                != key_[key_byte_index])
+            if (prefix[prefix_byte_index] != key_[key_byte_index])
                 break;
         }
 
         // Even if a prefix of the key matches and we're doing a
         // lookup, this means we've found a matching subscription.
-        if (is_lookup_ && prefix_byte_index == current_node.prefix_length ()
+        if (is_lookup_ && prefix_byte_index == prefix_length
             && current_node.refcount () > 0) {
             key_byte_index = key_size_;
             break;
@@ -253,14 +255,14 @@ match_result_t zmq::radix_tree_t::match (const unsigned char *key_,
 
         // There was a mismatch or we've matched the whole key, so
         // there's nothing more to do.
-        if (prefix_byte_index != current_node.prefix_length ()
-            || key_byte_index == key_size_)
+        if (prefix_byte_index != prefix_length || key_byte_index == key_size_)
             break;
 
         // We need to match the rest of the key. Check if there's an
         // outgoing edge from this node.
         node_t next_node = current_node;
-        for (size_t i = 0; i < current_node.edgecount (); ++i) {
+        for (size_t i = 0, edgecount = current_node.edgecount (); i < edgecount;
+             ++i) {
             if (current_node.first_byte_at (i) == key_[key_byte_index]) {
                 parent_edge_index = edge_index;
                 edge_index = i;
@@ -543,18 +545,20 @@ visit_keys (node_t node_,
             void (*func_) (unsigned char *data_, size_t size_, void *arg_),
             void *arg_)
 {
-    for (size_t i = 0; i < node_.prefix_length (); ++i)
-        buffer_.push_back (node_.prefix ()[i]);
+    const size_t prefix_length = node_.prefix_length ();
+    buffer_.reserve (buffer_.size () + prefix_length);
+    std::copy (node_.prefix (), node_.prefix () + prefix_length,
+               std::back_inserter (buffer_));
 
     if (node_.refcount () > 0) {
         zmq_assert (!buffer_.empty ());
         func_ (&buffer_[0], buffer_.size (), arg_);
     }
 
-    for (size_t i = 0; i < node_.edgecount (); ++i)
+    for (size_t i = 0, edgecount = node_.edgecount (); i < edgecount; ++i) {
         visit_keys (node_.node_at (i), buffer_, func_, arg_);
-    for (size_t i = 0; i < node_.prefix_length (); ++i)
-        buffer_.pop_back ();
+    }
+    buffer_.resize (buffer_.size () - prefix_length);
 }
 
 void zmq::radix_tree_t::apply (

src/socket_base.cpp

@@ -1469,8 +1469,9 @@ void zmq::socket_base_t::process_term (int linger_)
     unregister_endpoints (this);
 
     //  Ask all attached pipes to terminate.
-    for (pipes_t::size_type i = 0; i != _pipes.size (); ++i)
+    for (pipes_t::size_type i = 0, size = _pipes.size (); i != size; ++i) {
         _pipes[i]->terminate (false);
+    }
     register_term_acks (static_cast<int> (_pipes.size ()));
 
     //  Continue the termination process immediately.
@@ -1515,7 +1516,7 @@ int zmq::socket_base_t::query_pipes_stats ()
         errno = EAGAIN;
         return -1;
     }
-    for (pipes_t::size_type i = 0; i != _pipes.size (); ++i) {
+    for (pipes_t::size_type i = 0, size = _pipes.size (); i != size; ++i) {
         _pipes[i]->send_stats_to_peer (this);
     }
 
@@ -1525,7 +1526,7 @@ int zmq::socket_base_t::query_pipes_stats ()
 void zmq::socket_base_t::update_pipe_options (int option_)
 {
     if (option_ == ZMQ_SNDHWM || option_ == ZMQ_RCVHWM) {
-        for (pipes_t::size_type i = 0; i != _pipes.size (); ++i) {
+        for (pipes_t::size_type i = 0, size = _pipes.size (); i != size; ++i) {
             _pipes[i]->set_hwms (options.rcvhwm, options.sndhwm);
             _pipes[i]->send_hwms_to_peer (options.sndhwm, options.rcvhwm);
         }

src/socket_base.hpp

@@ -376,8 +376,9 @@ class routing_socket_base_t : public socket_base_t
     template <typename Func> bool any_of_out_pipes (Func func_)
     {
         bool res = false;
-        for (out_pipes_t::iterator it = _out_pipes.begin ();
-             it != _out_pipes.end () && !res; ++it) {
+        for (out_pipes_t::iterator it = _out_pipes.begin (),
+                                   end = _out_pipes.end ();
+             it != end && !res; ++it) {
             res |= func_ (*it->second.pipe);
         }
 

src/tcp_listener.cpp

@@ -232,8 +232,10 @@ zmq::fd_t zmq::tcp_listener_t::accept ()
 
     if (!options.tcp_accept_filters.empty ()) {
         bool matched = false;
-        for (options_t::tcp_accept_filters_t::size_type i = 0;
-             i != options.tcp_accept_filters.size (); ++i) {
+        for (options_t::tcp_accept_filters_t::size_type
+               i = 0,
+               size = options.tcp_accept_filters.size ();
+             i != size; ++i) {
             if (options.tcp_accept_filters[i].match_address (
                   reinterpret_cast<struct sockaddr *> (&ss), ss_len)) {
                 matched = true;

src/thread.cpp

@@ -355,8 +355,9 @@ void zmq::thread_t::
     if (!_thread_affinity_cpus.empty ()) {
         cpu_set_t cpuset;
         CPU_ZERO (&cpuset);
-        for (std::set<int>::const_iterator it = _thread_affinity_cpus.begin ();
-             it != _thread_affinity_cpus.end (); it++) {
+        for (std::set<int>::const_iterator it = _thread_affinity_cpus.begin (),
+                                           end = _thread_affinity_cpus.end ();
+             it != end; it++) {
             CPU_SET ((int) (*it), &cpuset);
         }
         rc =

src/ws_encoder.cpp

@@ -117,7 +117,8 @@ void zmq::ws_encoder_t::size_ready ()
           static_cast<unsigned char *> (_masked_msg.data ());
         unsigned char *src =
           static_cast<unsigned char *> (in_progress ()->data ());
-        for (size_t i = 0; i < in_progress ()->size (); ++i, mask_index++)
+        for (size_t i = 0, size = in_progress ()->size (); i < size;
+             ++i, mask_index++)
             dest[i] = src[i] ^ _mask[mask_index % 4];
 
         next_step (_masked_msg.data (), _masked_msg.size (),