File: bitbuffer_inline.h

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/*
 *	TwoLAME: an optimized MPEG Audio Layer Two encoder
 *
 *	Copyright (C) 2001-2004 Michael Cheng
 *	Copyright (C) 2004-2006 The TwoLAME Project
 *
 *	This library is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU Lesser General Public
 *	License as published by the Free Software Foundation; either
 *	version 2.1 of the License, or (at your option) any later version.
 *
 *	This library is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *	Lesser General Public License for more details.
 *
 *	You should have received a copy of the GNU Lesser General Public
 *	License along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  $Id$
 *
 */


/* write 1 bit from the bit stream */
static inline void buffer_put1bit(bit_stream * bs, int bit)
{
    bs->totbit++;

    bs->buf[bs->buf_byte_idx] |= (bit & 0x1) << (bs->buf_bit_idx - 1);
    bs->buf_bit_idx--;
    if (!bs->buf_bit_idx) {
        bs->buf_bit_idx = 8;
        bs->buf_byte_idx++;
        if (bs->buf_byte_idx >= bs->buf_size) {
            // empty_buffer (bs, minimum);
            fprintf(stderr, "buffer_put1bit: error. bit_stream buffer needs to be bigger\n");
            return;
        }
        bs->buf[bs->buf_byte_idx] = 0;
    }
}

/* write N bits into the bit stream */
static inline void buffer_putbits(bit_stream * bs, unsigned int val, int N)
{
    static const int putmask[9] = { 0x0, 0x1, 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff };
    register int j = N;
    register int k, tmp;

    bs->totbit += N;
    while (j > 0) {
        k = MIN(j, bs->buf_bit_idx);
        tmp = val >> (j - k);
        bs->buf[bs->buf_byte_idx] |= (tmp & putmask[k]) << (bs->buf_bit_idx - k);
        bs->buf_bit_idx -= k;
        if (!bs->buf_bit_idx) {
            bs->buf_bit_idx = 8;
            bs->buf_byte_idx++;
            if (bs->buf_byte_idx >= bs->buf_size) {
                // empty_buffer (bs, minimum);
                fprintf(stderr, "buffer_putbits: error. bit_stream buffer needs to be bigger\n");
                return;
            }
            bs->buf[bs->buf_byte_idx] = 0;
        }
        j -= k;
    }
}

// vim:ts=4:sw=4:nowrap: