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#include <u.h>
#include <libc.h>
#include <libsec.h>
static void encode(uchar*, u32int*, ulong);
extern void _sha1block(uchar*, ulong, u32int*);
/*
* we require len to be a multiple of 64 for all but
* the last call. There must be room in the input buffer
* to pad.
*/
ulong lastlen;
SHA1state*
sha1(uchar *p, ulong len, uchar *digest, SHA1state *s)
{
uchar buf[128];
u32int x[16];
int i;
uchar *e;
lastlen = len;
if(s == nil){
s = malloc(sizeof(*s));
if(s == nil)
return nil;
memset(s, 0, sizeof(*s));
s->malloced = 1;
assert(!s->seeded);
assert(!s->blen);
}
if(s->seeded == 0){
/* seed the state, these constants would look nicer big-endian */
s->state[0] = 0x67452301;
s->state[1] = 0xefcdab89;
s->state[2] = 0x98badcfe;
s->state[3] = 0x10325476;
s->state[4] = 0xc3d2e1f0;
s->seeded = 1;
}
assert(len < 100000);
/* fill out the partial 64 byte block from previous calls */
if(s->blen){
assert(s);
i = 64 - s->blen;
if(len < i)
i = len;
memmove(s->buf + s->blen, p, i);
len -= i;
s->blen += i;
p += i;
if(s->blen == 64){
_sha1block(s->buf, s->blen, s->state);
s->len += s->blen;
s->blen = 0;
}
}
assert(len < 1000000);
/* do 64 byte blocks */
i = len & ~0x3f;
if(i){
assert(i < 1000000);
_sha1block(p, i, s->state);
s->len += i;
len -= i;
p += i;
}
/* save the left overs if not last call */
if(digest == 0){
if(len){
memmove(s->buf, p, len);
s->blen += len;
}
return s;
}
/*
* this is the last time through, pad what's left with 0x80,
* 0's, and the input count to create a multiple of 64 bytes
*/
if(s->blen){
p = s->buf;
len = s->blen;
} else {
memmove(buf, p, len);
p = buf;
}
s->len += len;
e = p + len;
if(len < 56)
i = 56 - len;
else
i = 120 - len;
memset(e, 0, i);
*e = 0x80;
len += i;
/* append the count */
x[0] = s->len>>29;
x[1] = s->len<<3;
encode(p+len, x, 8);
/* digest the last part */
_sha1block(p, len+8, s->state);
s->len += len+8;
/* return result and free state */
encode(digest, s->state, SHA1dlen);
if(s->malloced == 1)
free(s);
return nil;
}
/*
* encodes input (ulong) into output (uchar). Assumes len is
* a multiple of 4.
*/
static void
encode(uchar *output, u32int *input, ulong len)
{
u32int x;
uchar *e;
for(e = output + len; output < e;) {
x = *input++;
*output++ = x >> 24;
*output++ = x >> 16;
*output++ = x >> 8;
*output++ = x;
}
}
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