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115 lines
3.0 KiB
C++
115 lines
3.0 KiB
C++
/*
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Copyright (c) 2007-2010 iMatix Corporation
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This file is part of 0MQ.
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0MQ is free software; you can redistribute it and/or modify it under
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the terms of the Lesser GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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0MQ is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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Lesser GNU General Public License for more details.
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You should have received a copy of the Lesser GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ZMQ_MSG_STORE_HPP_INCLUDED__
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#define __ZMQ_MSG_STORE_HPP_INCLUDED__
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#include "../include/zmq.h"
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#include <string>
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#include "stdint.hpp"
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namespace zmq
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{
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// This class implements a message store. Messages are retrieved from
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// the store in the same order as they entered it.
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class msg_store_t
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{
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public:
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enum { default_block_size = 8192 };
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// Creates message store.
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msg_store_t (int64_t filesize_, size_t block_size_ = default_block_size);
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~msg_store_t ();
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int init ();
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// Stores the message into the message store. The function
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// returns false if the message store is full; true otherwise.
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bool store (zmq_msg_t *msg_);
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// Fetches the oldest message from the message store. It is an error
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// to call this function when the message store is empty.
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void fetch (zmq_msg_t *msg_);
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void commit ();
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void rollback ();
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// Returns true if the message store is empty; false otherwise.
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bool empty ();
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// Returns true if and only if the store is full.
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bool full ();
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private:
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// Copies data from a memory buffer to the backing file.
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// Wraps around when reaching maximum file size.
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void copy_from_file (void *buffer_, size_t count_);
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// Copies data from the backing file to the memory buffer.
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// Wraps around when reaching end-of-file.
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void copy_to_file (const void *buffer_, size_t count_);
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// Returns the buffer space available.
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int64_t buffer_space ();
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void fill_buf (char *buf, int64_t pos);
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void save_write_buf ();
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// File descriptor to the backing file.
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int fd;
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// Name of the backing file.
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std::string filename;
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// Maximum size of the backing file.
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int64_t filesize;
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// File offset associated with the fd file descriptor.
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int64_t file_pos;
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// File offset the next message will be stored at.
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int64_t write_pos;
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// File offset the next message will be read from.
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int64_t read_pos;
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int64_t commit_pos;
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size_t block_size;
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char *buf1;
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char *buf2;
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char *read_buf;
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char *write_buf;
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int64_t write_buf_start_addr;
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};
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}
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#endif
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