This fixes multiple bugs with ring buffers and re-factors the code. The public
API has not changed, however the underlying implementation have various private
functions have been changed. The following behavioral changes have been made
- Size of ring buffers for No-Split/Allow-Split buffers will not be rounded
up to the nearest 32-bit aligned size. This was done to simplify the
implementation
- Item size for No-Split/Allow-Split buffers will also be rounded up to the
nearest 32-bit aligned size.
The following bugs have been fixed
- In copyItemToRingbufAllowSplit(), when copying an item where the aligned
size is smaller than the remaining length, the function does not consider
the case where the true size of the item is less than 4 bytes.
- The copy functions will automatically wrap around the write pointers when
the remaining length of the buffer is not large enough to fit a header, but
does not consider if wrapping around will cause an overlap with the read
pointer. This will make a full buffer be mistaken for an empty buffer
closes#1711
- xRingbufferSend() can get stuck in a infinite loop when the size of the
free memory is larger than the needed_size, but too small to fit in the ring
buffer due to alignment and extra overhead of wrapping around.
closes#1846
- Fixed documentation with ring buffer queue set API
- Adding and removing from queue set does not consider the case where the
read/write semaphores actually hold a value.
The following functions have been deprecated
- xRingbufferIsNextItemWrapped() due to lack of thread safety
- xRingbufferAddToQueueSetWrite() and xRingbufferRemoveFromQueueSetWrite()
as adding the queue sets only work under receive operations.
The following functions have been added
- xRingbufferReceiveSplit() and xRingbufferReceiveSplitFromISR() as a thread
safe way to receive from allow-split buffers
- vRingbufferGetInfo()
Documentation for ring buffers has also been added.
Add function xRingbufferCanRead & xRingbufferCanWrite
to be able use queue sets. Without it is not possible
to check to which ringbuffer returned semaphore belongs.
This is a wrapper API for creating a Ring Buffer, which ensures that
the ringbuffer can hold the given number of items, each item being of the
same given length.
Signed-off-by: Piyush Shah <piyush@espressif.com>
Useful to check if the next item to receive is wrapped or not.
This is valid only if the ring buffer is initialised with type
RINGBUF_TYPE_ALLOWSPLIT.
This is as per the feature request here:
https://github.com/espressif/esp-idf/issues/806
Signed-off-by: Piyush Shah <piyush@espressif.com>
The earlier available API (xRingbufferGetMaxItemSize())just gives
a static max entry value possible for given ring buffer.
There was a feature request for an API which could provide
a real time available buffer size. See below:
https://github.com/espressif/esp-idf/issues/806
Signed-off-by: Piyush Shah <piyush@espressif.com>
It was observed that if the ring buffer size provided by application
is not a multiple of 4, some checks were failing (as read_ptr and write_ptr
could shoot beyond the ring buffer boundary), thereby causing asserts.
Simply wrapping around the pointers for such cases fixes the issue.
Moreover, because of the logic for maintaining 4-byte boundary,
it was also possible that a wrap-around occurred for some data,
even when the actual size remaining was sufficient for it.
Eg. Buffer available: 34, data size: 34, 4-byte aligned size: 36
Since the logic compares against 36, it writes 34 bytes and does a
wraparound. But since all 34 bytes are already written, there is
nothing to write after wrapping. It is better to just re-set the
write pointer to the dtart of ring buffer in such cases.
Tested send/receive for various arbitrary sizes of data and for
arbitrary sizes of ring buffer.
Alternative Solutions:
1) Allow only sizes which are multiples of 4, and return error otherwise.
Appropriate code and documentation change would be required
2) Allow arbitrary sizes, but internally add upto 3 bytes to make
the total size a multiple of 4
Signed-off-by: Piyush Shah <piyush@espressif.com>
Default esp-idf builds now show -Wextra warnings (except for a few:
signed/unsigned comparison, unused parameters, old-style C declarations.)
CI building of examples runs with that level raised to -Werror, to catch
those changes going into the main repo.
