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+/*
+ Copyright (c) 2009-2011 250bpm s.r.o.
+ Copyright (c) 2007-2009 iMatix Corporation
+ Copyright (c) 2011 VMware, Inc.
+ Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
+
+ This file is part of 0MQ.
+
+ 0MQ is free software; you can redistribute it and/or modify it under
+ the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ 0MQ is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef __ZMQ_MSG_HPP_INCLUDE__
+#define __ZMQ_MSG_HPP_INCLUDE__
+
+#include <stddef.h>
+#include <stdio.h>
+
+#include "config.hpp"
+#include "atomic_counter.hpp"
+
+// Signature for free function to deallocate the message content.
+// Note that it has to be declared as "C" so that it is the same as
+// zmq_free_fn defined in zmq.h.
+extern "C"
+{
+ typedef void (msg_free_fn) (void *data, void *hint);
+}
+
+namespace zmq
+{
+
+ // Note that this structure needs to be explicitly constructed
+ // (init functions) and destructed (close function).
+
+ class msg_t
+ {
+ public:
+
+ // Mesage flags.
+ enum
+ {
+ more = 1,
+ identity = 64,
+ shared = 128
+ };
+
+ bool check ();
+ int init ();
+ int init_size (size_t size_);
+ int init_data (void *data_, size_t size_, msg_free_fn *ffn_,
+ void *hint_);
+ int init_delimiter ();
+ int close ();
+ int move (msg_t &src_);
+ int copy (msg_t &src_);
+ void *data ();
+ size_t size ();
+ unsigned char flags ();
+ void set_flags (unsigned char flags_);
+ void reset_flags (unsigned char flags_);
+ bool is_identity () const;
+ bool is_delimiter ();
+ bool is_vsm ();
+
+ // After calling this function you can copy the message in POD-style
+ // refs_ times. No need to call copy.
+ void add_refs (int refs_);
+
+ // Removes references previously added by add_refs. If the number of
+ // references drops to 0, the message is closed and false is returned.
+ bool rm_refs (int refs_);
+
+ private:
+
+ // Size in bytes of the largest message that is still copied around
+ // rather than being reference-counted.
+ enum {max_vsm_size = 29};
+
+ // Shared message buffer. Message data are either allocated in one
+ // continuous block along with this structure - thus avoiding one
+ // malloc/free pair or they are stored in used-supplied memory.
+ // In the latter case, ffn member stores pointer to the function to be
+ // used to deallocate the data. If the buffer is actually shared (there
+ // are at least 2 references to it) refcount member contains number of
+ // references.
+ struct content_t
+ {
+ void *data;
+ size_t size;
+ msg_free_fn *ffn;
+ void *hint;
+ zmq::atomic_counter_t refcnt;
+ };
+
+ // Different message types.
+ enum type_t
+ {
+ type_min = 101,
+ type_vsm = 101,
+ type_lmsg = 102,
+ type_delimiter = 103,
+ type_max = 103
+ };
+
+ // Note that fields shared between different message types are not
+ // moved to tha parent class (msg_t). This way we ger tighter packing
+ // of the data. Shared fields can be accessed via 'base' member of
+ // the union.
+ union {
+ struct {
+ unsigned char unused [max_vsm_size + 1];
+ unsigned char type;
+ unsigned char flags;
+ } base;
+ struct {
+ unsigned char data [max_vsm_size];
+ unsigned char size;
+ unsigned char type;
+ unsigned char flags;
+ } vsm;
+ struct {
+ content_t *content;
+ unsigned char unused [max_vsm_size + 1 - sizeof (content_t*)];
+ unsigned char type;
+ unsigned char flags;
+ } lmsg;
+ struct {
+ unsigned char unused [max_vsm_size + 1];
+ unsigned char type;
+ unsigned char flags;
+ } delimiter;
+ } u;
+ };
+
+}
+
+#endif