/*************************************************************************
* Copyright (C) 2002 Intel Corporation
*
* Licensed under the Apache License,  Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* 	http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law  or agreed  to  in  writing,  software
* distributed under  the License  is  distributed  on  an  "AS IS"  BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the  specific  language  governing  permissions  and
* limitations under the License.
*************************************************************************/

/* 
//  Purpose:
//     Intel(R) Integrated Performance Primitives. Cryptography Primitives.
//     Unsigned internal BNU32 misc functionality
// 
//  Contents:
//     cpToOctStr_BNU32()
// 
*/

#include "owncp.h"
#include "pcpbnuimpl.h"
#include "pcpbnumisc.h"
#include "pcpbnu32misc.h"

/*F*
//    Name: cpFromOctStr_BNU32
//
// Purpose: Convert Oct String into BNU representation.
//
// Returns:
//          size of BNU in BNU_CHUNK_T chunks
//
// Parameters:
//    pOctStr     pointer to the source octet string
//    strLen      octet string length
//    pBNU        pointer to the target BN
//
*F*/

IPP_OWN_DEFN (cpSize, cpFromOctStr_BNU32, (Ipp32u* pBNU, const Ipp8u* pOctStr, cpSize strLen))
{
   cpSize bnuSize=0;
   *pBNU = 0;

   /* start from the end of string */
   for(; strLen>=4; bnuSize++,strLen-=4) {
      /* pack 4 bytes into single Ipp32u value*/
      *pBNU++ = (Ipp32u)(( pOctStr[strLen-4]<<(8*3) )
               +( pOctStr[strLen-3]<<(8*2) )
               +( pOctStr[strLen-2]<<(8*1) )
               +  pOctStr[strLen-1]);
   }

   /* convert the beginning of the string */
   if(strLen) {
      Ipp32u x;
      for(x=0; strLen>0; strLen--) {
         Ipp32u d = *pOctStr++;
         x = x*256 + d;
       }
       *pBNU++ = x;
       bnuSize++;
   }

   return bnuSize? bnuSize : 1;
}
