[Spice-devel] [spice v2 2/2] utils: Remove the LL suffix from NSEC_PER_SEC
Uri Lublin
uril at redhat.com
Thu Jun 13 12:18:00 UTC 2019
On 6/13/19 2:47 PM, Frediano Ziglio wrote:
>>
>> On 6/13/19 1:23 PM, Frediano Ziglio wrote:
>>>>
>>>> This constant fits in a 32 bit signed integer so it does not need the
>>>> suffix. However some of the derived constants don't so use an uint64_t
>>>> cast to avoid the long vs long long confusion (such as in print
>>>> statements).
>>>> Also some of the expressions these constants are used in may overflow so
>>>> perform the appropriate casts in those locations. This makes it clearer
>>>> that these operations are 64 bit.
>>
>> Hi,
>>
>> Wouldn't it be simpler to replace the LL suffix with
>> a prefix of (uint64_t) ?
>>
>> -#define NSEC_PER_SEC 1000000000LL
>> +#define NSEC_PER_SEC (uint64_t)1000000000
>>
>> That way there is no worry about overflows.
>>
>> Uri.
>>
>
> You could also use the INT64_C macro for this, but Francois is trying to do
> the opposite, not have the constant 64 bit in order to make the compiler able
> to decide to use 32 bit arithmetic if it wants.
He tries "to avoid the long vs long long confusion"
I agree it's easier to printf an integer than an int64_t.
>
> Note that "LL" is signed while uint64_t is unsigned, this could change some
> math causing some nasty behaviour, I remember once I changed some code "easily"
> like that and I got a nice buffer overflow for free.
Yes, you're right. Can be (int64) prefix.
And people say there is no such thing as a free nice buffer overflow :)
Uri.
>
>>
>>>>
>>>> Signed-off-by: Francois Gouget <fgouget at codeweavers.com>
>>>> ---
>>>>
>>>> v2: Cast COMMON_CLIENT_TIMEOUT to an int64_t instead of an uint64_t.
>>>
>>> I would personally use signed for all timeouts, specifically also
>>> DISPLAY_CLIENT_MIGRATE_DATA_TIMEOUT, MJPEG_WARMUP_TIME and
>>> RED_STREAM_INPUT_FPS_TIMEOUT.
>>>
>>> Beside that patch is good.
>>>
>>>
>>>> v1:
>>>> https://lists.freedesktop.org/archives/spice-devel/2019-May/049193.html
>>>>
>>>> server/common-graphics-channel.h | 2 +-
>>>> server/dcc.h | 2 +-
>>>> server/gstreamer-encoder.c | 2 +-
>>>> server/mjpeg-encoder.c | 2 +-
>>>> server/utils.h | 4 ++--
>>>> server/video-stream.c | 4 ++--
>>>> server/video-stream.h | 2 +-
>>>> 7 files changed, 9 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/server/common-graphics-channel.h
>>>> b/server/common-graphics-channel.h
>>>> index d23f0c695..cccd24d44 100644
>>>> --- a/server/common-graphics-channel.h
>>>> +++ b/server/common-graphics-channel.h
>>>> @@ -27,7 +27,7 @@ G_BEGIN_DECLS
>>>>
>>>> bool common_channel_client_config_socket(RedChannelClient *rcc);
>>>>
>>>> -#define COMMON_CLIENT_TIMEOUT (NSEC_PER_SEC * 30)
>>>> +#define COMMON_CLIENT_TIMEOUT (((int64_t)NSEC_PER_SEC) * 30)
>>>>
>>>> #define TYPE_COMMON_GRAPHICS_CHANNEL common_graphics_channel_get_type()
>>>>
>>>> diff --git a/server/dcc.h b/server/dcc.h
>>>> index 76c078bf5..da8697762 100644
>>>> --- a/server/dcc.h
>>>> +++ b/server/dcc.h
>>>> @@ -66,7 +66,7 @@ GType display_channel_client_get_type(void)
>>>> G_GNUC_CONST;
>>>> #define PALETTE_CACHE_HASH_KEY(id) ((id) & PALETTE_CACHE_HASH_MASK)
>>>> #define CLIENT_PALETTE_CACHE_SIZE 128
>>>>
>>>> -#define DISPLAY_CLIENT_MIGRATE_DATA_TIMEOUT (NSEC_PER_SEC * 10)
>>>> +#define DISPLAY_CLIENT_MIGRATE_DATA_TIMEOUT (((uint64_t)NSEC_PER_SEC) *
>>>> 10)
>>>> #define DISPLAY_CLIENT_RETRY_INTERVAL 10000 //micro
>>>>
>>>> /* Each drawable can refer to at most 3 images: src, brush and mask */
>>>> diff --git a/server/gstreamer-encoder.c b/server/gstreamer-encoder.c
>>>> index 5f39ed877..91dd475ac 100644
>>>> --- a/server/gstreamer-encoder.c
>>>> +++ b/server/gstreamer-encoder.c
>>>> @@ -556,7 +556,7 @@ static void update_next_frame_mm_time(SpiceGstEncoder
>>>> *encoder)
>>>> /* Figure out how many frames to drop to not exceed the current bit
>>>> rate.
>>>> * Use nanoseconds to avoid precision loss.
>>>> */
>>>> - uint64_t delay_ns = -encoder->vbuffer_free * 8 * NSEC_PER_SEC /
>>>> encoder->bit_rate;
>>>> + uint64_t delay_ns = ((uint64_t)-encoder->vbuffer_free) * 8 *
>>>> NSEC_PER_SEC / encoder->bit_rate;
>>>> uint32_t drops = (delay_ns + period_ns - 1) / period_ns; /* round up
>>>> */
>>>> spice_debug("drops=%u vbuffer %d/%d", drops, encoder->vbuffer_free,
>>>> encoder->vbuffer_size);
>>>> diff --git a/server/mjpeg-encoder.c b/server/mjpeg-encoder.c
>>>> index 4a02e7c8b..d22e7d18b 100644
>>>> --- a/server/mjpeg-encoder.c
>>>> +++ b/server/mjpeg-encoder.c
>>>> @@ -65,7 +65,7 @@ static const int
>>>> mjpeg_quality_samples[MJPEG_QUALITY_SAMPLE_NUM] = {20, 30, 40,
>>>> * are not necessarily related to mis-estimation of the bit rate, and we
>>>> would
>>>> * like to wait till the stream stabilizes.
>>>> */
>>>> -#define MJPEG_WARMUP_TIME (NSEC_PER_SEC * 3)
>>>> +#define MJPEG_WARMUP_TIME (((uint64_t)NSEC_PER_SEC) * 3)
>>>>
>>>> /* The compressed buffer initial size. */
>>>> #define MJPEG_INITIAL_BUFFER_SIZE (32 * 1024)
>>>> diff --git a/server/utils.h b/server/utils.h
>>>> index 54bc9d490..4bbd45dff 100644
>>>> --- a/server/utils.h
>>>> +++ b/server/utils.h
>>>> @@ -52,7 +52,7 @@ static inline int test_bit(int index, uint32_t val)
>>>>
>>>> typedef int64_t red_time_t;
>>>>
>>>> -#define NSEC_PER_SEC 1000000000LL
>>>> +#define NSEC_PER_SEC 1000000000
>>>> #define NSEC_PER_MILLISEC 1000000
>>>> #define NSEC_PER_MICROSEC 1000
>>>>
>>>> @@ -62,7 +62,7 @@ static inline red_time_t
>>>> spice_get_monotonic_time_ns(void)
>>>> struct timespec time;
>>>>
>>>> clock_gettime(CLOCK_MONOTONIC, &time);
>>>> - return NSEC_PER_SEC * time.tv_sec + time.tv_nsec;
>>>> + return ((uint64_t)NSEC_PER_SEC) * time.tv_sec + time.tv_nsec;
>>>> }
>>>>
>>>> #define MSEC_PER_SEC 1000
>>>> diff --git a/server/video-stream.c b/server/video-stream.c
>>>> index 4ac25af8b..7a2dca7dd 100644
>>>> --- a/server/video-stream.c
>>>> +++ b/server/video-stream.c
>>>> @@ -415,8 +415,8 @@ static void
>>>> display_channel_create_stream(DisplayChannel
>>>> *display, Drawable *dra
>>>> * the nearest integer, for instance 24 for 23.976.
>>>> */
>>>> uint64_t duration = drawable->creation_time -
>>>> drawable->first_frame_time;
>>>> - if (duration > NSEC_PER_SEC * drawable->frames_count / MAX_FPS) {
>>>> - stream->input_fps = (NSEC_PER_SEC * drawable->frames_count +
>>>> duration / 2) / duration;
>>>> + if (duration > ((uint64_t)NSEC_PER_SEC) * drawable->frames_count /
>>>> MAX_FPS) {
>>>> + stream->input_fps = (((uint64_t)NSEC_PER_SEC) *
>>>> drawable->frames_count + duration / 2) / duration;
>>>> } else {
>>>> stream->input_fps = MAX_FPS;
>>>> }
>>>> diff --git a/server/video-stream.h b/server/video-stream.h
>>>> index 46b076fd7..6c18d00f7 100644
>>>> --- a/server/video-stream.h
>>>> +++ b/server/video-stream.h
>>>> @@ -34,7 +34,7 @@
>>>> #define RED_STREAM_GRADUAL_FRAMES_START_CONDITION 0.2
>>>> #define RED_STREAM_FRAMES_RESET_CONDITION 100
>>>> #define RED_STREAM_MIN_SIZE (96 * 96)
>>>> -#define RED_STREAM_INPUT_FPS_TIMEOUT (NSEC_PER_SEC * 5)
>>>> +#define RED_STREAM_INPUT_FPS_TIMEOUT (((uint64_t)NSEC_PER_SEC) * 5)
>>>> #define RED_STREAM_CHANNEL_CAPACITY 0.8
>>>> /* the client's stream report frequency is the minimum of the 2 values
>>>> below
>>>> */
>>>> #define RED_STREAM_CLIENT_REPORT_WINDOW 5 // #frames
>>>
>>> Frediano
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