outlen.c

Next BIOS Source code : Extensible Firmware Interface

/*-----------------------------------------------------------------------
 *      File:   outlen.c
 *
Copyright (c)  1999 - 2002 Intel Corporation. All rights reserved
This software and associated documentation (if any) is furnished
under a license and may only be used or copied in accordance
with the terms of the license. Except as permitted by such
license, no part of this software or documentation may be
reproduced, stored in a retrieval system, or transmitted in any
form or by any means without the express written consent of
Intel Corporation.

 *-----------------------------------------------------------------------
 */
/* 
 * INTEL CONFIDENTIAL 
 * This file, software, or program is supplied under the terms of a 
 * license agreement or nondisclosure agreement with Intel Corporation 
 * and may not be copied or disclosed except in accordance with the 
 * terms of that agreement. This file, software, or program contains 
 * copyrighted material and/or trade secret information of Intel 
 * Corporation, and must be treated as such. Intel reserves all rights 
 * in this material, except as the license agreement or nondisclosure 
 * agreement specifically indicate. 
 */ 
/* 
 * WARNING: EXPORT RESTRICTED. 
 * This software is subject to the U.S. Export Administration Regulations 
 * and other U.S. law, and may not be exported or re-exported to certain 
 * countries (currently Afghanistan (Taliban-controlled areas), Cuba, Iran, 
 * Iraq, Libya, North Korea, Serbia (except Kosovo), Sudan and Syria) or to 
 * persons or entities prohibited from receiving U.S. exports (including Denied 
 * Parties, Specially Designated Nationals, and entities on the Bureau of 
 * Export Administration Entity List or involved with missile technology or 
 * nuclear, chemical or biological weapons).
 */ 
/*
 * DISCLAIMER: CODE QUALITY AND DOCUMENTATION
 * Basic Encoding Rules and Distinguished Encoding Rules (BER/DER) routines.
 * This is alpha-quality code and modifications should be expected for the
 * next release.  This code is provided by Intel "as is", and Intel makes no
 * warranties, express, implied or statutory, and expressly disclaims any
 * warranties of merchantability, noninfringement of intellectual property
 * rights, and fitness for a particular purpose.
 */

#include "ber_der.h"

/*------------------------------------------------------------------------------
 * Name: BER_OutputLength
 *
 * Description:
 * This function encodes the little-endian, unsigned binary length as a 
 * BER/DER length field. 
 * It returns the number of octets used to encode the length.
 *
 * Parameters: 
 * Value   (input) - The length as a little-endian unsigned binary integer.
 * Octets (output) - The buffer into which the DER-encoded length will be copied.
 *
 * Returns: 
 * The number of octets used to represent the length in BER/DER encoding.
 *
 * Error Codes:
 * None.
 *----------------------------------------------------------------------------*/
uint32 
BER_OutputLength(       /* return number of bytes it took to store the length */
    uint32 Value,       /* length as binary integer */
    uint8 *Octets)      /* output buffer */
{
    uint32 noctets; /* number of length octets past the first */
    uint8  *val;    /* pointer to a single byte within Value */

    /* If the short form length can be used, */
    /* set the output value equal to the first byte of the input value */
    if (Value < LONG_LEN_REQD)
        *Octets = (uint8) Value;
    else {
        /* If the long form length must be used, */

        /* Initialize temporary values */
        val = (uint8*) &Value;
        noctets = BER_LengthOfLength(Value) - 1;

        /* Set the initial byte equal to 0x80 + the number of additional bytes */
        *Octets++ = (uint8) (LONG_LEN_INDICATOR + noctets);

        /* Set the following bytes to the big endian representation */
        /* of the input Value */
        while (noctets > 0) {
            Octets[--noctets] = *val;
            val++;
        }
    } 

    return BER_LengthOfLength(Value);
}