[FFmpeg-devel] [PATCH] SHA-256 support

[Michael Niedermayer]

On Tue, Jun 09, 2009 at 08:13:40AM +0300, Kostya wrote:
> On Mon, Jun 08, 2009 at 08:07:14PM +0200, Diego Biurrun wrote:
> > On Mon, Jun 08, 2009 at 08:34:37PM +0300, Kostya wrote:
> > > $subj, I'll need that for RTMP
> > > This implementation is made from code by Aaron D. Gifford and
> > > lavu/sha1.c
> > > Conformance vectors are passed on both endian architectures.
> > 
> > > #ifndef AVUTIL_SHA1_H
> > > #define AVUTIL_SHA1_H
> > 
> > This is not the filename.
> 
> Oops, fixed
> 
> > > static void transform(uint32_t state[5], const uint8_t buffer[64]){
> > 
> > extra good karma for K&R function declarations
> > 
> > >     for( i = 0; i < len; i++ ){
> > >         ctx->buffer[ j++ ] = data[i];
> > >         if( 64 == j ){
> > 
> > You inconsistently format all those if/for statements throughout the
> > file.  I suggest sticking to K&R style, which you already use in most
> > places.
> 
> Ahem, I consistently copypaste code from other parts of ffmpeg (in this
> case source is libavutil/sha1.c).
>  
> > > #ifdef TEST
> > > #include <stdio.h>
> > > #undef printf
> > 
> > Add this file to the list of testprogs in the Makefile.
> 
> done
> 
> > Diego

>  Makefile |    1 +
[...]
> /* Hash a single 512-bit block. This is the core of the algorithm. */
> 
> static void transform(uint32_t state[5], const uint8_t buffer[64])

doxy?


> {
>     unsigned int i, a, b, c, d, e, f, g, h;
>     uint32_t block[80];
>     uint32_t T1, T2;
> 
>     a = state[0];
>     b = state[1];
>     c = state[2];
>     d = state[3];
>     e = state[4];
>     f = state[5];
>     g = state[6];
>     h = state[7];
> 
>     for (i = 0; i < 64; i++) {
>         if (i < 16) {
>             T1 = block[i] = be2me_32(((const uint32_t*)buffer)[i]);
>         } else {
>             block[i & 0xF] +=            block[(i +  9) & 0xF]
>                             + sigma0_256(block[(i +  1) & 0xF])
>                             + sigma1_256(block[(i + 14) & 0xF]);
>             T1 = block[i & 0xF];
>         }

you have lost some optimizations from our sha1 here, 

also sha224 should be supported because its almost identical

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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