/*
 * Copyright (c) 2001-2007, Tom St Denis
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
 */
#include "tomcrypt.h"
#include <stdarg.h>
/**
  @file hash_memory_multi.c
  Hash (multiple buffers) memory helper, Tom St Denis
*/

/**
  Hash multiple (non-adjacent) blocks of memory at once.  
  @param hash   The index of the hash you wish to use
  @param out    [out] Where to store the digest
  @param outlen [in/out] Max size and resulting size of the digest
  @param in     The data you wish to hash
  @param inlen  The length of the data to hash (octets)
  @param ...    tuples of (data,len) pairs to hash, terminated with a (NULL,x) (x=don't care)
  @return CRYPT_OK if successful
*/  
int hash_memory_multi(int hash, unsigned char *out, unsigned long *outlen,
                      const unsigned char *in, unsigned long inlen, ...)
{
    hash_state          *md;
    int                  err;
    va_list              args;
    const unsigned char *curptr;
    unsigned long        curlen;

    LTC_ARGCHK(in     != NULL);
    LTC_ARGCHK(out    != NULL);
    LTC_ARGCHK(outlen != NULL);

    if ((err = hash_is_valid(hash)) != CRYPT_OK) {
        return err;
    }

    if (*outlen < hash_descriptor[hash]->hashsize) {
       *outlen = hash_descriptor[hash]->hashsize;
       return CRYPT_BUFFER_OVERFLOW;
    }

    md = XMALLOC(sizeof(hash_state));
    if (md == NULL) {
       return CRYPT_MEM;
    }

    if ((err = hash_descriptor[hash]->init(md)) != CRYPT_OK) {
       goto LBL_ERR;
    }

    va_start(args, inlen);
    curptr = in; 
    curlen = inlen;
    for (;;) {
       /* process buf */
       if ((err = hash_descriptor[hash]->process(md, curptr, curlen)) != CRYPT_OK) {
          goto LBL_ERR;
       }
       /* step to next */
       curptr = va_arg(args, const unsigned char*);
       if (curptr == NULL) {
          break;
       }
       curlen = va_arg(args, unsigned long);
    }
    err = hash_descriptor[hash]->done(md, out);
    *outlen = hash_descriptor[hash]->hashsize;
LBL_ERR:
#ifdef LTC_CLEAN_STACK
    zeromem(md, sizeof(hash_state));
#endif
    XFREE(md);
    va_end(args);
    return err;
}

/* $Source: /cvs/libtom/libtomcrypt/src/hashes/helper/hash_memory_multi.c,v $ */
/* $Revision: 1.6 $ */
/* $Date: 2006/12/28 01:27:23 $ */
