Blame src/lzo1b_r.ch

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/* lzo1b_r.ch -- literal run handling for the the LZO1B/LZO1C algorithm
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   This file is part of the LZO real-time data compression library.
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   Copyright (C) 1996-2014 Markus Franz Xaver Johannes Oberhumer
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   All Rights Reserved.
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   The LZO library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU General Public License as
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   published by the Free Software Foundation; either version 2 of
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   the License, or (at your option) any later version.
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   The LZO library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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   GNU General Public License for more details.
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   You should have received a copy of the GNU General Public License
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   along with the LZO library; see the file COPYING.
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   If not, write to the Free Software Foundation, Inc.,
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   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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   Markus F.X.J. Oberhumer
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   <markus@oberhumer.com>
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   http://www.oberhumer.com/opensource/lzo/
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 */
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/***********************************************************************
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// store a literal run (internal)
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************************************************************************/
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LZO_PUBLIC(lzo_bytep )
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STORE_RUN ( lzo_bytep const oo, const lzo_bytep const ii, lzo_uint r_len)
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{
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    lzo_bytep op;
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    const lzo_bytep ip;
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    lzo_uint t;
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    LZO_STATS(lzo_stats->literals += r_len);
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    op = oo;
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    ip = ii;
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    assert(r_len > 0);
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    /* code a long R0 run */
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    if (r_len >= 512)
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    {
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        unsigned r_bits = 6;        /* 256 << 6 == 16384 */
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        lzo_uint tt = 32768u;
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        while (r_len >= (t = tt))
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        {
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            r_len -= t;
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            *op++ = 0; *op++ = (R0FAST - R0MIN) + 7;
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            MEMCPY8_DS(op, ip, t);
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            LZO_STATS(lzo_stats->r0long_runs++);
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        }
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        tt >>= 1;
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        do {
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            if (r_len >= (t = tt))
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            {
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                r_len -= t;
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                *op++ = 0; *op++ = LZO_BYTE((R0FAST - R0MIN) + r_bits);
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                MEMCPY8_DS(op, ip, t);
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                LZO_STATS(lzo_stats->r0long_runs++);
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            }
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            tt >>= 1;
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        } while (--r_bits > 0);
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    }
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    assert(r_len < 512);
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    while (r_len >= (t = R0FAST))
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    {
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        r_len -= t;
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        *op++ = 0; *op++ = (R0FAST - R0MIN);
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        MEMCPY8_DS(op, ip, t);
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        LZO_STATS(lzo_stats->r0fast_runs++);
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    }
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    t = r_len;
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    if (t >= R0MIN)
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    {
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        /* code a short R0 run */
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        *op++ = 0; *op++ = LZO_BYTE(t - R0MIN);
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        MEMCPY_DS(op, ip, t);
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        LZO_STATS(lzo_stats->r0short_runs++);
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    }
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    else if (t > 0)
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    {
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        /* code a short literal run */
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        LZO_STATS(lzo_stats->lit_runs++);
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        LZO_STATS(lzo_stats->lit_run[t]++);
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        *op++ = LZO_BYTE(t);
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        MEMCPY_DS(op, ip, t);
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    }
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    return op;
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}
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/*
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vi:ts=4:et
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*/
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