util/fifo8: Allow fifo8_pop_buf() to not populate popped length

There might be cases where we know the number of bytes we can
pop from the FIFO, or we simply don't care how many bytes is
returned. Allow fifo8_pop_buf() to take a NULL numptr.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Francisco Iglesias <frasse.iglesias@gmail.com>
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: <20231109192814.95977-2-philmd@linaro.org>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

1 files changed, 8 insertions, 4 deletions

diff --git a/util/fifo8.c b/util/fifo8.c
index de8fd0f1c5..2eeed56e80 100644
--- a/util/fifo8.c
+++ b/util/fifo8.c
@@ -66,16 +66,20 @@ uint8_t fifo8_pop(Fifo8 *fifo)
     return ret;
 }
 
-const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num)
+const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *numptr)
 {
     uint8_t *ret;
+    uint32_t num;
 
     assert(max > 0 && max <= fifo->num);
-    *num = MIN(fifo->capacity - fifo->head, max);
+    num = MIN(fifo->capacity - fifo->head, max);
     ret = &fifo->data[fifo->head];
-    fifo->head += *num;
+    fifo->head += num;
     fifo->head %= fifo->capacity;
-    fifo->num -= *num;
+    fifo->num -= num;
+    if (numptr) {
+        *numptr = num;
+    }
     return ret;
 }