Ring buffer claims that no synchronization is needed
when there is a single producer and single consumer.
However, recent changes have broken that promise since
indexes rewind mechanism was modifing head and tail
when consuming. Patch fixes that by spliting rewinding
of indexes so that producer rewinds tail only and
consumer rewinds head.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Add ring_buf_size_get() to get the number of bytes currently available
in the ring buffer.
Add ring_buf_peek() to read data from the head of a ring buffer without
removal.
Fixes#37145
Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>
Allow NULL data buffers to be provided to `ring_buf_get` and
`ring_buf_item_get`, in which case data will be discarded instead of
copied out to the user.
Fixes#33488.
Signed-off-by: Jordan Yates <jordan.yates@data61.csiro.au>
This symbol is reserved and usage of reserved symbols violates the
coding guidelines. (MISRA 21.2)
NAME
fgetpos, fseek, fsetpos, ftell, rewind - reposition a stream
SYNOPSIS
#include <stdio.h>
void rewind(FILE *stream);
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Previously, ring buffer had capacity of provided buffer size - 1. This
trick was used to distinguish between empty and full states. It had one
drawback: ring buffer could not be used as a pool of equal sized buffers
(using ring_buf_put_claim and ring_buf_get_claim).
Reworked internals to use non wrapping head and tail. Since they are
non wrapping, there is no issue with distinguishing between empty and
full. Since this appraoch would be vulnerable to wrapping on 32 bit
boundary, added a mechanism which periodically reduces all indexes to
avoid 32 bit wrapping.
After this rework, buffer has one byte more capacity. Simple test shows
slight performance improvement.
Updated tests to reflect increased capacity and added test to check if
it is possible to continuesly allocated 2 buffers of half ring buffer
size.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
move ring_buffer.h to sys/ring_buffer.h and
create a shim for backward-compatibility.
No functional changes to the headers.
A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES.
Related to #16539
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Some function return values were not handled. Added assert in case
those functions return error. It is possible only if same ring buffer
instance is used without any protection from multiple contexts.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
There are issues using lowercase min and max macros when compiling a C++
application with a third-party toolchain such as GNU ARM Embedded when
using some STL headers i.e. <chrono>.
This is because there are actual C++ functions called min and max
defined in some of the STL headers and these macros interfere with them.
By changing the macros to UPPERCASE, which is consistent with almost all
other pre-processor macros this naming conflict is avoided.
All files that use these macros have been updated.
Signed-off-by: Carlos Stuart <carlosstuart1970@gmail.com>
lib/ was starting to get messy and inconsitent. Files being either
dumped in the root or in sub-directories without a clear plan.
Move all library components into one single folder and call it 'os'.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
