RepoMirrors
/
ffmpeg
mirror of https://git.ffmpeg.org/ffmpeg.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

2 other variants of how to implement the core part 

benchmarks welcome ...

Originally committed as revision 8367 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2007-03-13 00:17:55 +00:00
parent 086b0ad8ca
commit 6573578d7b
1 changed files with 79 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

83
libavutil/sha1.c
View File

@ -14,6 +14,11 @@ typedef struct AVSHA1 {
#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0b(v,w,x,y,z,i) z+((w&(x^y))^y) +block[i]+0x5A827999+rol(v,5);
#define R2b(v,w,x,y,z,i) z+( w^x ^y) +block[i]+0x6ED9EBA1+rol(v,5);
#define R3b(v,w,x,y,z,i) z+(((w|x)&y)|(w&x))+block[i]+0x8F1BBCDC+rol(v,5);
#define R4b(v,w,x,y,z,i) z+( w^x ^y) +block[i]+0xCA62C1D6+rol(v,5);
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y) +block[i]+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=( w^x ^y) +block[i]+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+block[i]+0x8F1BBCDC+rol(v,5);w=rol(w,30);
@ -21,22 +26,91 @@ typedef struct AVSHA1 {
/* Hash a single 512-bit block. This is the core of the algorithm. */
//#define VARIANT1
//#define VARIANT2
static void transform(uint32_t state[5], uint8_t buffer[64]){
unsigned int a, b, c, d, e, i;
uint32_t block[80];
unsigned int i;
#ifdef VARIANT1
uint32_t s[85];
#else
unsigned int a, b, c, d, e;
#endif
for(i=0; i<16; i++)
block[i]= be2me_32(((uint32_t*)buffer)[i]);
for(;i<80; i++)
block[i]= rol(block[i-3]^block[i-8]^block[i-14]^block[i-16],1);
/* Copy context->state[] to working vars */
#ifdef VARIANT1
s[0]= state[4];
s[1]= state[3];
s[2]= state[2];
s[3]= state[1];
s[4]= state[0];
for(i=0; i<20; i++){
s[5+i]= R0b(s[4+i], s[3+i], s[2+i], s[1+i], s[i], i);
s[3+i]= rol(s[3+i],30);
}
for(; i<40; i++){
s[5+i]= R2b(s[4+i], s[3+i], s[2+i], s[1+i], s[i], i);
s[3+i]= rol(s[3+i],30);
}
for(; i<60; i++){
s[5+i]= R3b(s[4+i], s[3+i], s[2+i], s[1+i], s[i], i);
s[3+i]= rol(s[3+i],30);
}
for(; i<80; i++){
s[5+i]= R4b(s[4+i], s[3+i], s[2+i], s[1+i], s[i], i);
s[3+i]= rol(s[3+i],30);
}
state[0] += s[84];
state[1] += s[83];
state[2] += s[82];
state[3] += s[81];
state[4] += s[80];
#else
a = state[0];
b = state[1];
c = state[2];
d = state[3];
e = state[4];
#ifdef VARIANT2
for(i=0; i<20; i++){
int t= R0b(a,b,c,d,e,i);
e= d;
d= c;
c= rol(b,30);
b= a;
a= t;
}
for(; i<40; i++){
int t= R2b(a,b,c,d,e,i);
e= d;
d= c;
c= rol(b,30);
b= a;
a= t;
}
for(; i<60; i++){
int t= R3b(a,b,c,d,e,i);
e= d;
d= c;
c= rol(b,30);
b= a;
a= t;
}
for(; i<80; i++){
int t= R4b(a,b,c,d,e,i);
e= d;
d= c;
c= rol(b,30);
b= a;
a= t;
}
#else
for(i=0; i<20; i+=5){
R0(a,b,c,d,e,0+i); R0(e,a,b,c,d,1+i); R0(d,e,a,b,c,2+i); R0(c,d,e,a,b,3+i); R0(b,c,d,e,a,4+i);
}
@ -49,12 +123,13 @@ static void transform(uint32_t state[5], uint8_t buffer[64]){
for(; i<80; i+=5){
R4(a,b,c,d,e,0+i); R4(e,a,b,c,d,1+i); R4(d,e,a,b,c,2+i); R4(c,d,e,a,b,3+i); R4(b,c,d,e,a,4+i);
}
#endif
state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;
state[4] += e;
#endif
}
void av_sha1_init(AVSHA1* context){