[FFmpeg-devel] [PATCH 1/3] lavu/bprint: implement av_bprint_strftime().

[Clément Bœsch]

On Sat, Nov 10, 2012 at 07:49:45PM +0100, Nicolas George wrote:
> TODO bump & APIchanges
> 
> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> ---
>  libavutil/bprint.c    |   26 ++++++++++++++++++++++++++
>  libavutil/bprint.h    |    8 ++++++++
>  tests/ref/fate/bprint |    1 +
>  3 files changed, 35 insertions(+)
> 
> diff --git a/libavutil/bprint.c b/libavutil/bprint.c
> index 9d8e7c1..aed1f46 100644
> --- a/libavutil/bprint.c
> +++ b/libavutil/bprint.c
> @@ -21,6 +21,7 @@
>  #include <stdarg.h>
>  #include <stdio.h>
>  #include <string.h>
> +#include <time.h>
>  #include "avassert.h"
>  #include "bprint.h"
>  #include "common.h"
> @@ -129,6 +130,25 @@ void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
>      av_bprint_grow(buf, n);
>  }
>  
> +void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm)
> +{
> +    unsigned room;
> +    size_t l;
> +
> +    if (!*fmt)
> +        return;
> +    while (1) {
> +        room = av_bprint_room(buf);
> +        if (!room)
> +            return;
> +        if ((l = strftime(buf->str + buf->len, room, fmt, tm)))
> +            break;
> +        if (av_bprint_alloc(buf, room <= INT_MAX / 2 ? room * 2 : INT_MAX))
> +            return;
> +    }
> +    av_bprint_grow(buf, l);
> +}
> +
>  void av_bprint_get_buffer(AVBPrint *buf, unsigned size,
>                            unsigned char **mem, unsigned *actual_size)
>  {
> @@ -201,6 +221,7 @@ int main(void)
>  {
>      AVBPrint b;
>      char buf[256];
> +    struct tm testtime = { .tm_year = 100, .tm_mon = 11, .tm_mday = 20 };
>  
>      av_bprint_init(&b, 0, -1);
>      bprint_pascal(&b, 5);
> @@ -235,6 +256,11 @@ int main(void)
>      bprint_pascal(&b, 25);
>      printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(buf), b.len);
>  
> +    av_bprint_init(&b, 0, -1);
> +    av_bprint_strftime(&b, "%Y-%m-%d", &testtime);
> +    printf("strftime: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str);
> +    av_bprint_finalize(&b, NULL);
> +
>      return 0;
>  }
>  
> diff --git a/libavutil/bprint.h b/libavutil/bprint.h
> index c09b61f..6f2f083 100644
> --- a/libavutil/bprint.h
> +++ b/libavutil/bprint.h
> @@ -125,6 +125,14 @@ void av_bprintf(AVBPrint *buf, const char *fmt, ...) av_printf_format(2, 3);
>   */
>  void av_bprint_chars(AVBPrint *buf, char c, unsigned n);
>  
> +struct tm;
> +/**
> + * Append a formated date and time to a print buffer.
> + * Note: due do poor design of the standard strftime function, it can only

I think you meant "due *to*"

> + * be used when no overflow is possible.

Could you be more specific about what the user is supposed to do, or what
unexpected behaviour could happen? Also, the function doesn't return any
success/failure status, is that a good idea given the "poor design" of the
function called within?

> + */
> +void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm);
> +
>  /**
>   * Allocate bytes in the buffer for external use.
>   *
> diff --git a/tests/ref/fate/bprint b/tests/ref/fate/bprint
> index e027fa1..3c72ac7 100644
> --- a/tests/ref/fate/bprint
> +++ b/tests/ref/fate/bprint
> @@ -12,3 +12,4 @@ Short text in automatic buffer: 174/174
>  Long text in automatic buffer: 1000/2834
>  Long text count only buffer: 0/2834
>  Long text count only buffer: 255/2834
> +strftime: 255/10 "2000-12-20"

Apart from that, I think that's a good idea, and thus LGTM.

-- 
Clément B.
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