From 28fbf33b3f6925dff8fcf1bae217d850d604a1d3 Mon Sep 17 00:00:00 2001 From: Mark Cave-Ayland Date: Wed, 28 Aug 2024 13:22:56 +0100 Subject: [PATCH] fifo8: add fifo8_peek_buf() function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This is a wrapper function around fifo8_peekpop_buf() that allows the caller to peek into the FIFO, including handling the case where there is a wraparound of the internal FIFO buffer. Signed-off-by: Mark Cave-Ayland Reviewed-by: Octavian Purdila Reviewed-by: Alistair Francis Reviewed-by: Philippe Mathieu-Daudé Tested-by: Philippe Mathieu-Daudé Message-ID: <20240828122258.928947-8-mark.cave-ayland@ilande.co.uk> Signed-off-by: Philippe Mathieu-Daudé --- include/qemu/fifo8.h | 14 ++++++++++++++ util/fifo8.c | 5 +++++ 2 files changed, 19 insertions(+) diff --git a/include/qemu/fifo8.h b/include/qemu/fifo8.h index d1d06754d8..d09984b146 100644 --- a/include/qemu/fifo8.h +++ b/include/qemu/fifo8.h @@ -76,6 +76,20 @@ uint8_t fifo8_pop(Fifo8 *fifo); */ uint32_t fifo8_pop_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen); +/** + * fifo8_peek_buf: + * @fifo: FIFO to read from + * @dest: the buffer to write the data into (can be NULL) + * @destlen: size of @dest and maximum number of bytes to peek + * + * Peek a number of elements from the FIFO up to a maximum of @destlen. + * The peeked data is copied into the @dest buffer. + * Care is taken when the data wraps around in the ring buffer. + * + * Returns: number of bytes peeked. + */ +uint32_t fifo8_peek_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen); + /** * fifo8_pop_bufptr: * @fifo: FIFO to pop from diff --git a/util/fifo8.c b/util/fifo8.c index 1031ffbe7e..a8f5cea158 100644 --- a/util/fifo8.c +++ b/util/fifo8.c @@ -140,6 +140,11 @@ uint32_t fifo8_pop_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen) return fifo8_peekpop_buf(fifo, dest, destlen, true); } +uint32_t fifo8_peek_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen) +{ + return fifo8_peekpop_buf(fifo, dest, destlen, false); +} + void fifo8_drop(Fifo8 *fifo, uint32_t len) { len -= fifo8_pop_buf(fifo, NULL, len);