[FFmpeg-devel] [PATCH 03/12] lavu/aes: add runtime dispatch for crypt function

[Michael Niedermayer]

On Mon, Oct 26, 2015 at 03:25:45AM -0500, Rodger Combs wrote:
> ---
>  libavutil/aes.c          | 47 +++++++++++++++++++++++++++++++----------------
>  libavutil/aes_internal.h |  1 +
>  2 files changed, 32 insertions(+), 16 deletions(-)
> 
> diff --git a/libavutil/aes.c b/libavutil/aes.c
> index 61e9dd1..4fa01ea 100644
> --- a/libavutil/aes.c
> +++ b/libavutil/aes.c
> @@ -126,31 +126,44 @@ static inline void aes_crypt(AVAES *a, int s, const uint8_t *sbox,
>      subshift(&a->state[0], s, sbox);
>  }
>  
> -void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
> -                  int count, uint8_t *iv, int decrypt)
> +static void aes_encrypt(AVAES *a, uint8_t *dst, const uint8_t *src,
> +                        int count, uint8_t *iv, int rounds)
>  {
>      while (count--) {
>          addkey_s(&a->state[1], src, &a->round_key[a->rounds]);
> -        if (decrypt) {
> -            aes_crypt(a, 0, inv_sbox, dec_multbl);
> -            if (iv) {
> -                addkey_s(&a->state[0], iv, &a->state[0]);
> -                memcpy(iv, src, 16);
> -            }
> -            addkey_d(dst, &a->state[0], &a->round_key[0]);
> -        } else {
> -            if (iv)
> -                addkey_s(&a->state[1], iv, &a->state[1]);
> -            aes_crypt(a, 2, sbox, enc_multbl);
> -            addkey_d(dst, &a->state[0], &a->round_key[0]);
> -            if (iv)
> -                memcpy(iv, dst, 16);
> +        if (iv)
> +            addkey_s(&a->state[1], iv, &a->state[1]);
> +        aes_crypt(a, 2, sbox, enc_multbl);
> +        addkey_d(dst, &a->state[0], &a->round_key[0]);
> +        if (iv)
> +            memcpy(iv, dst, 16);
> +        src += 16;
> +        dst += 16;
> +    }
> +}
> +

> +static void aes_decrypt(AVAES *a, uint8_t *dst, const uint8_t *src,
> +                        int count, uint8_t *iv, int rounds)
> +{
> +    while (count--) {
> +        addkey_s(&a->state[1], src, &a->round_key[a->rounds]);

could be simplified by using the funtction argument "rounds"

patch ok either way

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Good people do not need laws to tell them to act responsibly, while bad
people will find a way around the laws. -- Plato
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