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Diffstat (limited to 'src/msg.hpp')
-rw-r--r-- | src/msg.hpp | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/src/msg.hpp b/src/msg.hpp new file mode 100644 index 0000000..3356e36 --- /dev/null +++ b/src/msg.hpp @@ -0,0 +1,148 @@ +/* + 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 |