/***************************************************************************
 *     Copyright (c) 2003-2008, Broadcom Corporation
 *     All Rights Reserved
 *     Confidential Property of Broadcom Corporation
 *
 *  THIS SOFTWARE MAY ONLY BE USED SUBJECT TO AN EXECUTED SOFTWARE LICENSE
 *  AGREEMENT  BETWEEN THE USER AND BROADCOM.  YOU HAVE NO RIGHT TO USE OR
 *  EXPLOIT THIS MATERIAL EXCEPT SUBJECT TO THE TERMS OF SUCH AN AGREEMENT.
 *
 * $brcm_Workfile: $
 * $brcm_Revision: $
 * $brcm_Date: $
 *
 * Module Description: private message parsing api
 *
 * Revision History:
 *
 * $brcm_Log: $
 * 
 *
 ***************************************************************************/

#include "bstd.h"
#include "bdbg.h"

#include "getbits.h"

/*
  Return bit_count of bits from the bitstream. bit_count can be anywhere
  from 0 to 16. The bit_state_t structure has to be reset after 536870911
  bytes as bindex is 32 bit value. This is not a practical limitation.
 */
unsigned int get_bits(size_t bit_count, struct bit_state_t * bs)
{
    unsigned int bits;
    unsigned char * pbits;
    size_t data_index;
    if(0 == bit_count){
        return 0;
    }
    data_index = bs->bindex >> 3;
    pbits = &bs->data[data_index];
    bits = pbits[0];
    bits <<= 8;
    bits |= pbits[1];
    bits <<= 8;
    bits |= pbits[2];
    bits <<= 8;
    bits <<= bs->bindex & 0x7;
    bits >>= (32 - bit_count);
    bs->bindex += bit_count;
    return bits;
}
/* Return bit_count of bits from bitstream. bit_count can be anywhere from 0 
   to 32. This function can be called only when bit field to be returned is 
   aligned on a byte boundary. Most new standards follow this rule.
 */
unsigned int get_bits_aligned(size_t bit_count, struct bit_state_t * bs)
{
    unsigned int bits;
    unsigned char * pbits;
    size_t data_index;

    if(0 == bit_count){
        return 0;
    }
    BDBG_ASSERT(0 == (bs->bindex & 0x7));
    data_index = bs->bindex >> 3;
    pbits = &bs->data[data_index];
    bits = pbits[0];
    bits <<= 8;
    bits |= pbits[1];
    bits <<= 8;
    bits |= pbits[2];
    bits <<= 8;
    bits |= pbits[3];
    bits >>= (32 - bit_count);
    bs->bindex += bit_count;
    return bits;
}