[FFmpeg-devel] [PATCH 2/3] base64: optimize av_base64_encode()

[Reimar Döffinger]

On Fri, Jan 20, 2012 at 10:57:19PM +0100, Michael Niedermayer wrote:
> This makes the code 2-3 times as fast
> 
> Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> ---
>  libavutil/base64.c |   10 ++++++++++
>  1 files changed, 10 insertions(+), 0 deletions(-)
> 
> diff --git a/libavutil/base64.c b/libavutil/base64.c
> index a791a8e..80ab44b 100644
> --- a/libavutil/base64.c
> +++ b/libavutil/base64.c
> @@ -26,6 +26,7 @@
>  
>  #include "common.h"
>  #include "base64.h"
> +#include "intreadwrite.h"
>  
>  /* ---------------- private code */
>  static const uint8_t map2[] =
> @@ -82,6 +83,15 @@ char *av_base64_encode(char *out, int out_size, const uint8_t *in, int in_size)
>          out_size < AV_BASE64_SIZE(in_size))
>          return NULL;
>      ret = dst = out;
> +    while (bytes_remaining > 3) {
> +        i_bits = AV_RB32(in);
> +        in += 3; bytes_remaining -= 3;
> +        *dst++ = b64[ i_bits>>26        ];
> +        *dst++ = b64[(i_bits>>20) & 0x3F];
> +        *dst++ = b64[(i_bits>>14) & 0x3F];
> +        *dst++ = b64[(i_bits>>8 ) & 0x3F];
> +    }

Looks fine to me, though I am not sure if it is a bit unfortunate
we are not requiring alignment on the buffers...