Message ID | 1391119327-18190-2-git-send-email-b.galvani@gmail.com |
---|---|
State | New |
Headers | show |
On Fri, Jan 31, 2014 at 8:02 AM, Beniamino Galvani <b.galvani@gmail.com> wrote: > The patch adds functions fifo8_push_all() and fifo8_pop_buf() which > can be used respectively to push the content of a memory buffer to the > fifo and to pop multiple bytes obtaining a pointer to the fifo backing > buffer. > > In addition, it implements fifo8_num_free() and fifo8_num_used() which > allow to check if a multi-byte operation can be performed. > In an ideal world its two patches. Although its totally not worth a respin if Peter is happy to take as-is. > Signed-off-by: Beniamino Galvani <b.galvani@gmail.com> Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> > --- > include/qemu/fifo8.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++ > util/fifo8.c | 46 +++++++++++++++++++++++++++++++++++++ > 2 files changed, 107 insertions(+) > > diff --git a/include/qemu/fifo8.h b/include/qemu/fifo8.h > index d318f71..8820780 100644 > --- a/include/qemu/fifo8.h > +++ b/include/qemu/fifo8.h > @@ -44,6 +44,19 @@ void fifo8_destroy(Fifo8 *fifo); > void fifo8_push(Fifo8 *fifo, uint8_t data); > > /** > + * fifo8_push_all: > + * @fifo: FIFO to push to > + * @data: data to push > + * @size: number of bytes to push > + * > + * Push a byte array to the FIFO. Behaviour is undefined if the FIFO is full. > + * Clients are responsible for checking the space left in the FIFO using > + * fifo8_num_free(). > + */ > + > +void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num); > + > +/** > * fifo8_pop: > * @fifo: fifo to pop from > * > @@ -56,6 +69,32 @@ void fifo8_push(Fifo8 *fifo, uint8_t data); > uint8_t fifo8_pop(Fifo8 *fifo); > > /** > + * fifo8_pop_buf: > + * @fifo: FIFO to pop from > + * @max: maximum number of bytes to pop > + * @num: actual number of returned bytes > + * > + * Pop a number of elements from the FIFO up to a maximum of max. The buffer > + * containing the popped data is returned. This buffer points directly into > + * the FIFO backing store and data is invalidated once any of the fifo8_* APIs > + * are called on the FIFO. > + * > + * 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 *num; 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 popped data. > + */ > +const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num); > + > +/** > * fifo8_reset: > * @fifo: FIFO to reset > * > @@ -86,6 +125,28 @@ bool fifo8_is_empty(Fifo8 *fifo); > > bool fifo8_is_full(Fifo8 *fifo); > > +/** > + * fifo8_num_free: > + * @fifo: FIFO to check > + * > + * Return the number of free bytes in the FIFO. > + * > + * Returns: Number of free bytes. > + */ > + > +uint32_t fifo8_num_free(Fifo8 *fifo); > + > +/** > + * fifo8_num_used: > + * @fifo: FIFO to check > + * > + * Return the number of used bytes in the FIFO. > + * > + * Returns: Number of used bytes. > + */ > + > +uint32_t fifo8_num_used(Fifo8 *fifo); > + > extern const VMStateDescription vmstate_fifo8; > > #define VMSTATE_FIFO8(_field, _state) { \ > diff --git a/util/fifo8.c b/util/fifo8.c > index 013e903..a7503c2 100644 > --- a/util/fifo8.c > +++ b/util/fifo8.c > @@ -37,6 +37,27 @@ void fifo8_push(Fifo8 *fifo, uint8_t data) > fifo->num++; > } > > +void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num) > +{ > + uint32_t start, avail; > + > + if (fifo->num + num > fifo->capacity) { > + abort(); > + } > + > + start = (fifo->head + fifo->num) % fifo->capacity; > + > + if (start + num <= fifo->capacity) { > + memcpy(&fifo->data[start], data, num); > + } else { > + avail = fifo->capacity - start; > + memcpy(&fifo->data[start], data, avail); > + memcpy(&fifo->data[0], &data[avail], num - avail); > + } > + > + fifo->num += num; > +} > + > uint8_t fifo8_pop(Fifo8 *fifo) > { > uint8_t ret; > @@ -50,6 +71,21 @@ uint8_t fifo8_pop(Fifo8 *fifo) > return ret; > } > > +const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num) > +{ > + uint8_t *ret; > + > + if (max == 0 || max > fifo->num) { > + abort(); > + } > + *num = MIN(fifo->capacity - fifo->head, max); > + ret = &fifo->data[fifo->head]; > + fifo->head += *num; > + fifo->head %= fifo->capacity; > + fifo->num -= *num; > + return ret; > +} > + > void fifo8_reset(Fifo8 *fifo) > { > fifo->num = 0; > @@ -65,6 +101,16 @@ bool fifo8_is_full(Fifo8 *fifo) > return (fifo->num == fifo->capacity); > } > > +uint32_t fifo8_num_free(Fifo8 *fifo) > +{ > + return fifo->capacity - fifo->num; > +} > + > +uint32_t fifo8_num_used(Fifo8 *fifo) > +{ > + return fifo->num; > +} > + > const VMStateDescription vmstate_fifo8 = { > .name = "Fifo8", > .version_id = 1, > -- > 1.7.10.4 > >
diff --git a/include/qemu/fifo8.h b/include/qemu/fifo8.h index d318f71..8820780 100644 --- a/include/qemu/fifo8.h +++ b/include/qemu/fifo8.h @@ -44,6 +44,19 @@ void fifo8_destroy(Fifo8 *fifo); void fifo8_push(Fifo8 *fifo, uint8_t data); /** + * fifo8_push_all: + * @fifo: FIFO to push to + * @data: data to push + * @size: number of bytes to push + * + * Push a byte array to the FIFO. Behaviour is undefined if the FIFO is full. + * Clients are responsible for checking the space left in the FIFO using + * fifo8_num_free(). + */ + +void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num); + +/** * fifo8_pop: * @fifo: fifo to pop from * @@ -56,6 +69,32 @@ void fifo8_push(Fifo8 *fifo, uint8_t data); uint8_t fifo8_pop(Fifo8 *fifo); /** + * fifo8_pop_buf: + * @fifo: FIFO to pop from + * @max: maximum number of bytes to pop + * @num: actual number of returned bytes + * + * Pop a number of elements from the FIFO up to a maximum of max. The buffer + * containing the popped data is returned. This buffer points directly into + * the FIFO backing store and data is invalidated once any of the fifo8_* APIs + * are called on the FIFO. + * + * 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 *num; 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 popped data. + */ +const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num); + +/** * fifo8_reset: * @fifo: FIFO to reset * @@ -86,6 +125,28 @@ bool fifo8_is_empty(Fifo8 *fifo); bool fifo8_is_full(Fifo8 *fifo); +/** + * fifo8_num_free: + * @fifo: FIFO to check + * + * Return the number of free bytes in the FIFO. + * + * Returns: Number of free bytes. + */ + +uint32_t fifo8_num_free(Fifo8 *fifo); + +/** + * fifo8_num_used: + * @fifo: FIFO to check + * + * Return the number of used bytes in the FIFO. + * + * Returns: Number of used bytes. + */ + +uint32_t fifo8_num_used(Fifo8 *fifo); + extern const VMStateDescription vmstate_fifo8; #define VMSTATE_FIFO8(_field, _state) { \ diff --git a/util/fifo8.c b/util/fifo8.c index 013e903..a7503c2 100644 --- a/util/fifo8.c +++ b/util/fifo8.c @@ -37,6 +37,27 @@ void fifo8_push(Fifo8 *fifo, uint8_t data) fifo->num++; } +void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num) +{ + uint32_t start, avail; + + if (fifo->num + num > fifo->capacity) { + abort(); + } + + start = (fifo->head + fifo->num) % fifo->capacity; + + if (start + num <= fifo->capacity) { + memcpy(&fifo->data[start], data, num); + } else { + avail = fifo->capacity - start; + memcpy(&fifo->data[start], data, avail); + memcpy(&fifo->data[0], &data[avail], num - avail); + } + + fifo->num += num; +} + uint8_t fifo8_pop(Fifo8 *fifo) { uint8_t ret; @@ -50,6 +71,21 @@ uint8_t fifo8_pop(Fifo8 *fifo) return ret; } +const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num) +{ + uint8_t *ret; + + if (max == 0 || max > fifo->num) { + abort(); + } + *num = MIN(fifo->capacity - fifo->head, max); + ret = &fifo->data[fifo->head]; + fifo->head += *num; + fifo->head %= fifo->capacity; + fifo->num -= *num; + return ret; +} + void fifo8_reset(Fifo8 *fifo) { fifo->num = 0; @@ -65,6 +101,16 @@ bool fifo8_is_full(Fifo8 *fifo) return (fifo->num == fifo->capacity); } +uint32_t fifo8_num_free(Fifo8 *fifo) +{ + return fifo->capacity - fifo->num; +} + +uint32_t fifo8_num_used(Fifo8 *fifo) +{ + return fifo->num; +} + const VMStateDescription vmstate_fifo8 = { .name = "Fifo8", .version_id = 1,
The patch adds functions fifo8_push_all() and fifo8_pop_buf() which can be used respectively to push the content of a memory buffer to the fifo and to pop multiple bytes obtaining a pointer to the fifo backing buffer. In addition, it implements fifo8_num_free() and fifo8_num_used() which allow to check if a multi-byte operation can be performed. Signed-off-by: Beniamino Galvani <b.galvani@gmail.com> --- include/qemu/fifo8.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++ util/fifo8.c | 46 +++++++++++++++++++++++++++++++++++++ 2 files changed, 107 insertions(+)