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#include "os.h"
#include <libsec.h>

/*
 *  rfc1321 requires that I include this.  The code is new.  The constants
 *  all come from the rfc (hence the copyright).  We trade a table for the
 *  macros in rfc.  The total size is a lot less. -- presotto
 *
 *      Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
 *      rights reserved.
 *
 *      License to copy and use this software is granted provided that it
 *      is identified as the "RSA Data Security, Inc. MD5 Message-Digest
 *      Algorithm" in all material mentioning or referencing this software
 *      or this function.
 *
 *      License is also granted to make and use derivative works provided
 *      that such works are identified as "derived from the RSA Data
 *      Security, Inc. MD5 Message-Digest Algorithm" in all material
 *      mentioning or referencing the derived work.
 *
 *      RSA Data Security, Inc. makes no representations concerning either
 *      the merchantability of this software or the suitability of this
 *      software forany particular purpose. It is provided "as is"
 *      without express or implied warranty of any kind.
 *      These notices must be retained in any copies of any part of this
 *      documentation and/or software.
 */

static void encode(uchar*, u32int*, ulong);

extern void _md5block(uchar*, ulong, u32int*);

MD5state*
md5(uchar *p, ulong len, uchar *digest, MD5state *s)
{
        u32int x[16];
        uchar buf[128];
        int i;
        uchar *e;

        if(s == nil){
                s = malloc(sizeof(*s));
                if(s == nil)
                        return nil;
                memset(s, 0, sizeof(*s));
                s->malloced = 1;
        }

        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->seeded = 1;
        }

        /* fill out the partial 64 byte block from previous calls */
        if(s->blen){
                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){
                        _md5block(s->buf, s->blen, s->state);
                        s->len += s->blen;
                        s->blen = 0;
                }
        }

        /* do 64 byte blocks */
        i = len & ~0x3f;
        if(i){
                _md5block(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<<3;
        x[1] = s->len>>29;
        encode(p+len, x, 8);

        /* digest the last part */
        _md5block(p, len+8, s->state);
        s->len += len;

        /* return result and free state */
        encode(digest, s->state, MD5dlen);
        if(s->malloced == 1)
                free(s);
        return nil;
}

/*
 *      encodes input (u32int) 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;
                *output++ = x >> 8;
                *output++ = x >> 16;
                *output++ = x >> 24;
        }
}

DigestState*
hmac_md5(uchar *p, ulong len, uchar *key, ulong klen, uchar *digest,
        DigestState *s)
{
        return hmac_x(p, len, key, klen, digest, s, md5, MD5dlen);
}