Remove gems/magic_ring_buffer.h

Since its introduction four years ago, the utility remained
largely unused.

Fixes #4403
This commit is contained in:
Norman Feske 2022-02-03 12:03:45 +01:00
parent d4d875f2e6
commit 62b4871c5c
11 changed files with 0 additions and 254 deletions

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@ -1,155 +0,0 @@
/*
* \brief Region magic ring buffer
* \author Emery Hemingway
* \date 2018-02-01
*/
/*
* Copyright (C) 2018 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__GEMS__RING_BUFFER_H_
#define _INCLUDE__GEMS__RING_BUFFER_H_
/* Genode includes */
#include <base/attached_ram_dataspace.h>
#include <rm_session/connection.h>
#include <region_map/client.h>
#include <dataspace/client.h>
namespace Genode {
template <typename TYPE>
struct Magic_ring_buffer;
}
/**
* A ring buffer that uses a single dataspace mapped twice in consecutive
* regions. This allows any operation that is less or equal to the size of
* the buffer to be read or written in a single pass.
*/
template <typename TYPE>
class Genode::Magic_ring_buffer
{
private:
Magic_ring_buffer(Magic_ring_buffer const &);
Magic_ring_buffer &operator = (Magic_ring_buffer const &);
Genode::Env &_env;
Ram_dataspace_capability _buffer_ds;
size_t const _ds_size = Dataspace_client(_buffer_ds).size();
size_t const _capacity = _ds_size / sizeof(TYPE);
Rm_connection _rm_connection { _env };
/* create region map (reserve address space) */
Region_map_client _rm { _rm_connection.create(_ds_size*2) };
/* attach map to global region map */
TYPE *_buffer = (TYPE *)_env.rm().attach(_rm.dataspace());
size_t _wpos = 0;
size_t _rpos = 0;
public:
/**
* Ring capacity of TYPE items
*/
size_t capacity() { return _capacity; }
/**
* Constructor
*
* \param TYPE Ring item type, size of type must be a
* power of two and less than the page size
*
* \param env Env for dataspace allocation and mapping
* \param num_bytes Size of ring in bytes, may be rounded up
* to the next page boundry
*
* \throw Region_map::Region_conflict
* \throw Out_of_ram
* \throw Out_of_caps
*
*/
Magic_ring_buffer(Genode::Env &env, size_t num_bytes)
: _env(env), _buffer_ds(_env.pd().alloc(num_bytes))
{
if (_ds_size % sizeof(TYPE)) {
error("Magic_ring_buffer cannot hold unaligned TYPE");
throw Exception();
}
/* attach buffer dataspace twice into reserved region */
_rm.attach_at(_buffer_ds, 0, _ds_size);
_rm.attach_at(_buffer_ds, _ds_size, _ds_size);
}
~Magic_ring_buffer()
{
/* detach dataspace from reserved region */
_rm.detach((addr_t)_ds_size);
_rm.detach((addr_t)0);
/* detach reserved region */
_env.rm().detach((addr_t)_buffer);
/* free buffer */
_env.ram().free(_buffer_ds);
}
/**
* Number of items that may be written to ring
*/
size_t write_avail() const
{
if (_wpos > _rpos)
return ((_rpos - _wpos + _capacity) % _capacity) - 2;
else if (_wpos < _rpos)
return _rpos - _wpos;
else
return _capacity - 2;
}
/**
* Number of items that may be read from ring
*/
size_t read_avail() const
{
if (_wpos > _rpos)
return _wpos - _rpos;
else
return (_wpos - _rpos + _capacity) % _capacity;
}
/**
* Pointer to ring write address
*/
TYPE *write_addr() const { return &_buffer[_wpos]; }
/**
* Pointer to ring read address
*/
TYPE *read_addr() const { return &_buffer[_rpos]; }
/**
* Advance the ring write pointer
*/
void fill(size_t items) {
_wpos = (_wpos+items) % _capacity; }
/**
* Advance the ring read pointer
*/
void drain(size_t items) {
_rpos = (_rpos+items) % _capacity; }
};
#endif

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Test of Genodes magic-ring-buffer implementation.

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_/src/init
_/src/test-magic_ring_buffer

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2022-01-18 b93a983aa7d731e2235d65498abc3e301f163578

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<runtime ram="32M" caps="1000" binary="init">
<events>
<timeout meaning="failed" sec="10" />
<log meaning="succeeded">child "test-magic_ring_buffer" exited with exit value 0</log>
<log meaning="failed">Error: </log>
</events>
<content>
<rom label="ld.lib.so"/>
<rom label="test-magic_ring_buffer"/>
</content>
<config>
<parent-provides>
<service name="CPU"/>
<service name="LOG"/>
<service name="PD"/>
<service name="RM"/>
<service name="ROM"/>
</parent-provides>
<default-route>
<any-service> <parent/> </any-service>
</default-route>
<start name="test-magic_ring_buffer" caps="64">
<resource name="RAM" quantum="2M"/>
</start>
</config>
</runtime>

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SRC_DIR = src/test/magic_ring_buffer
include $(GENODE_DIR)/repos/base/recipes/src/content.inc

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2022-01-18 bb72eddaf80e7d0f98c6c954f176acd4e0963bd6

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base
gems

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@ -689,7 +689,6 @@ set default_test_pkgs {
test-libc_vfs_ram
test-log
test-lx_block
test-magic_ring_buffer
test-mmio
test-new_delete
test-nic_loopback

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/*
* \brief Magic ring buffer test
* \author Emery Hemingway
* \date 2018-04-04
*/
/*
* Copyright (C) 2018 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
/* Genode includes */
#include <base/component.h>
#include <base/log.h>
/* gems includes */
#include <gems/magic_ring_buffer.h>
void Component::construct(Genode::Env &env)
{
using namespace Genode;
Magic_ring_buffer<int> ring_buffer(env, 4097);
log("--- magic ring buffer test, ", ring_buffer.capacity(), " int ring ---");
size_t const count = ring_buffer.capacity()/3;
size_t total = 0;
for (size_t j = 0; j < 99; ++j) {
for (size_t i = 0; i < count; ++i) {
ring_buffer.write_addr()[i] = (int)i;
}
ring_buffer.fill(count);
for (size_t i = 0; i < count; ++i) {
if (ring_buffer.read_addr()[i] != (int)i) {
error("ring buffer corruption, ",
ring_buffer.read_addr()[i], " != ", i);
env.parent().exit((int)(total + i));
return;
}
}
ring_buffer.drain(count);
total += count;
}
log("--- test complete, ", total, " ints passed through ring ---");
env.parent().exit(0);
}

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TARGET = test-magic_ring_buffer
SRC_CC = main.cc
LIBS = base