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author | Philippe Mathieu-Daudé <philmd@linaro.org> | 2023-11-09 20:28:06 +0100 |
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committer | Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> | 2024-01-10 06:58:50 +0000 |
commit | 995d8348eb3d8ddf24882ed384a5c50eaf3aeae9 (patch) | |
tree | 1d34bcb4c80369fde0a8b9ad176ce4799dc8320a /include | |
parent | cd04033dbeb0bbdd613780ff4b412fc3d3c768d6 (diff) | |
download | qemu-995d8348eb3d8ddf24882ed384a5c50eaf3aeae9.zip qemu-995d8348eb3d8ddf24882ed384a5c50eaf3aeae9.tar.gz qemu-995d8348eb3d8ddf24882ed384a5c50eaf3aeae9.tar.bz2 |
util/fifo8: Introduce fifo8_peek_buf()
To be able to peek at FIFO content without popping it,
introduce the fifo8_peek_buf() method by factoring
common content from fifo8_pop_buf().
Reviewed-by: Francisco Iglesias <frasse.iglesias@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20231109192814.95977-3-philmd@linaro.org>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Diffstat (limited to 'include')
-rw-r--r-- | include/qemu/fifo8.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/include/qemu/fifo8.h b/include/qemu/fifo8.h index d0d02bc..c6295c6 100644 --- a/include/qemu/fifo8.h +++ b/include/qemu/fifo8.h @@ -94,6 +94,33 @@ uint8_t fifo8_pop(Fifo8 *fifo); const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *numptr); /** + * fifo8_peek_buf: read upto max bytes from the fifo + * @fifo: FIFO to read from + * @max: maximum number of bytes to peek + * @numptr: pointer filled with number of bytes returned (can be NULL) + * + * Peek into a number of elements from the FIFO up to a maximum of max. + * The buffer containing the data peeked into is returned. This buffer points + * directly into the FIFO backing store. Since data is invalidated once any + * of the fifo8_* APIs are called on the FIFO, it is the caller responsibility + * to access it before doing further API calls. + * + * The function may return fewer bytes than requested when the data wraps + * around in the ring buffer; in this case only a contiguous part of the data + * is returned. + * + * The number of valid bytes returned is populated in *numptr; will always + * return at least 1 byte. max must not be 0 or greater than the number of + * bytes in the FIFO. + * + * Clients are responsible for checking the availability of requested data + * using fifo8_num_used(). + * + * Returns: A pointer to peekable data. + */ +const uint8_t *fifo8_peek_buf(Fifo8 *fifo, uint32_t max, uint32_t *numptr); + +/** * fifo8_reset: * @fifo: FIFO to reset * |