Re: [PATCH 7/9] fifo8: add fifo8_peek_buf() function

[Octavian Purdila <tavip@google.com>]

On Wed, Aug 28, 2024 at 5:23 AM Mark Cave-Ayland
<mark.cave-ayland@ilande.co.uk> wrote:
>
> This is a wrapper function around fifo8_peekpop_buf() that allows the caller to
> peek into FIFO, including handling the case where there is a wraparound of the
> internal FIFO buffer.
>
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

Reviewed-by: Octavian Purdila <tavip@google.com>

> ---
>  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);
> --
> 2.39.2
>