This commit fixes a bug in no-split and allow-split ring buffers free buffer size calculation.
When the free size available in the buffers less than the size of one item header,
the function prvGetCurMaxSizeNoSplit/AllowSplit() incorrectly returned the maxItemSize instead of 0.
This is due to the comparision between a negative and a positive value
where both operands are treated as unsigned during the comparision operation,
thereby treating the negative operand as a large integer.
Also added new unit tests to test buffer-full and almost-full conditions
where this scenario is likely to be hit.
Closes https://github.com/espressif/esp-idf/issues/7344
Closes https://github.com/espressif/esp-idf/pull/7371
The following 2 compiler warnings are only reproducible when setting:
OPTIMIZATION_FLAGS = -Ofast
esp-idf/components/soc/esp32/rtc_clk.c:
In function 'rtc_clk_cpu_freq_get':
esp-idf/components/soc/esp32/rtc_clk.c:506:12:
error: 'freq' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
return freq;
esp-idf/components/esp_ringbuf/ringbuf.c:
In function 'xRingbufferReceiveSplitFromISR':
esp-idf/components/esp_ringbuf/ringbuf.c:934:26:
error: 'pvTempTailItem' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
*ppvTailItem = pvTempTailItem;
Closes https://github.com/espressif/esp-idf/pull/2878
