Re: [Boost-users] boost::circular buffer- avoid memory allocation

Subject: Re: [Boost-users] boost::circular buffer- avoid memory allocation
From: Jan Gaspar (jano_gaspar_at_[hidden])
Date: 2010-05-24 16:52:14

Hi Lloyd,
 
not sure I understand the problem correctly but here is some sample code

struct buffer {
    char data[1024];
};

boost::circular_buffer<buffer> cb(10); // allocation done here (10*1024)

// producer
buffer generated_data;
generated_data.data[0] = ...
generated_data.data[1] = ...
// ...

cb.push_back(generated_data); // no allocation here; just copy


// consumer
buffer consumed_data = cb.front(); // no deallocation; just copy
cb.pop_front(); // remove the read buffer

char c0 = consumed_data.data[0];
char c1 = consumed_data.data[1];
// ...


Also see the Bounded Buffer example in the circular_buffer's documentation.

Regards,

Jan








________________________________
From: Lloyd <lloyd_at_[hidden]>
To: boost-users_at_[hidden]
Sent: Mon, 24 May, 2010 7:34:24
Subject: [Boost-users] boost::circular buffer- avoid memory allocation

  
Hello,
 
We are using circular buffer. The producer 
generates the data (a 1024byte char buffer) and the consumer reads it from 
circular buffer. In normal case the producer allocates the memory for each item. 
we believe this is very inefficient, so that we are going for circular buffer. 
How can we make the circualr buffer to allocate the memory in advace and make it 
possible for the producer and consumer to share it.
 
For example if the buffer is of 10 nodes, the 
totoal memory allocated by circular buffer would be 10*1024, isn't 
it?
 
How can the producer get the pointer to the next 
free node available in the circular buffer? (so as to avoid memory allocation by 
the producer)
How can the consumer get pointer to the data 
to be read next?
 
The sample available in boost::circular buffer 
describes it with a simple integer based example. I think this kind of problem 
is not addressed in it. Some hint will be very useful. 
 
Thanks,
 Lloyd
 
 

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