#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);
}