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/* lzo2a_d.ch -- implementation of the LZO2A decompression algorithm
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   This file is part of the LZO real-time data compression library.
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   Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
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   Copyright (C) 1996 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></markus@oberhumer.com>
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   http://www.oberhumer.com/opensource/lzo/
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 */
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#include "lzo1_d.ch"
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/***********************************************************************
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// decompress a block of data.
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************************************************************************/
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#define _NEEDBYTE   NEED_IP(1)
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#define _NEXTBYTE   (*ip++)
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LZO_PUBLIC(int)
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DO_DECOMPRESS    ( const lzo_bytep in , lzo_uint  in_len,
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                         lzo_bytep out, lzo_uintp out_len,
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                         lzo_voidp wrkmem )
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{
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    register lzo_bytep op;
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    register const lzo_bytep ip;
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    register const lzo_bytep m_pos;
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    lzo_uint t;
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    const lzo_bytep const ip_end = in + in_len;
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#if defined(HAVE_ANY_OP)
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    lzo_bytep const op_end = out + *out_len;
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#endif
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    lzo_uint32 b = 0;       /* bit buffer */
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    unsigned k = 0;         /* bits in bit buffer */
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    LZO_UNUSED(wrkmem);
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    op = out;
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    ip = in;
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    while (TEST_IP && TEST_OP)
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    {
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        NEEDBITS(1);
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        if (MASKBITS(1) == 0)
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        {
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            DUMPBITS(1);
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            /* a literal */
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            NEED_IP(1); NEED_OP(1);
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            *op++ = *ip++;
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            continue;
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        }
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        DUMPBITS(1);
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        NEEDBITS(1);
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        if (MASKBITS(1) == 0)
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        {
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            DUMPBITS(1);
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            /* a M1 match */
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            NEEDBITS(2);
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            t = M1_MIN_LEN + (lzo_uint) MASKBITS(2);
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            DUMPBITS(2);
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            NEED_IP(1); NEED_OP(t);
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            m_pos = op - 1 - *ip++;
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            assert(m_pos >= out); assert(m_pos < op);
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            TEST_LB(m_pos);
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            MEMCPY_DS(op,m_pos,t);
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            continue;
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        }
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        DUMPBITS(1);
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        NEED_IP(2);
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        t = *ip++;
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        m_pos = op;
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        m_pos -= (t & 31) | (((lzo_uint) *ip++) << 5);
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        t >>= 5;
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        if (t == 0)
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        {
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#if (N >= 8192)
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            NEEDBITS(1);
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            t = MASKBITS(1);
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            DUMPBITS(1);
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            if (t == 0)
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                t = 10 - 1;
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            else
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            {
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                /* a M3 match */
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                m_pos -= 8192;      /* t << 13 */
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                t = M3_MIN_LEN - 1;
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            }
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#else
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            t = 10 - 1;
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#endif
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            NEED_IP(1);
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            while (*ip == 0)
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            {
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                t += 255;
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                ip++;
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                NEED_IP(1);
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            }
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            t += *ip++;
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        }
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        else
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        {
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#if defined(LZO_EOF_CODE)
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            if (m_pos == op)
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                goto eof_found;
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#endif
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            t += 2;
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        }
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        assert(m_pos >= out); assert(m_pos < op);
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        TEST_LB(m_pos);
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        NEED_OP(t);
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        MEMCPY_DS(op,m_pos,t);
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    }
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#if defined(LZO_EOF_CODE)
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#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
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    /* no EOF code was found */
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    *out_len = pd(op, out);
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    return LZO_E_EOF_NOT_FOUND;
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#endif
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eof_found:
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    assert(t == 1);
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#endif
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    *out_len = pd(op, out);
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    return (ip == ip_end ? LZO_E_OK :
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           (ip < ip_end  ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
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#if defined(HAVE_NEED_IP)
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input_overrun:
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    *out_len = pd(op, out);
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    return LZO_E_INPUT_OVERRUN;
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#endif
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#if defined(HAVE_NEED_OP)
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output_overrun:
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    *out_len = pd(op, out);
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    return LZO_E_OUTPUT_OVERRUN;
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#endif
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#if defined(LZO_TEST_OVERRUN_LOOKBEHIND)
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lookbehind_overrun:
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    *out_len = pd(op, out);
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    return LZO_E_LOOKBEHIND_OVERRUN;
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#endif
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}
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/*
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vi:ts=4:et
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*/
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