lzo-2.03/src/lzo_util.c

/* lzo_util.c -- utilities for the LZO library

   This file is part of the LZO real-time data compression library.

   Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
   All Rights Reserved.

   The LZO library is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of
   the License, or (at your option) any later version.

   The LZO 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with the LZO library; see the file COPYING.
   If not, write to the Free Software Foundation, Inc.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

   Markus F.X.J. Oberhumer
   <markus@oberhumer.com>
   http://www.oberhumer.com/opensource/lzo/
 */


#include "lzo_conf.h"


/***********************************************************************
//
************************************************************************/

/* If you use the LZO library in a product, I would appreciate that you
 * keep this copyright string in the executable of your product.
.*/

const char __lzo_copyright[] =
#if !defined(__LZO_IN_MINLZO)
    /* save space as some people want a really small decompressor */
    LZO_VERSION_STRING;
#else
    "\r\n\n"
    "LZO data compression library.\n"
    "$Copyright: LZO (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Markus Franz Xaver Johannes Oberhumer\n"
    "<markus@oberhumer.com>\n"
    "http://www.oberhumer.com $\n\n"
    "$Id: LZO version: v" LZO_VERSION_STRING ", " LZO_VERSION_DATE " $\n"
    "$Built: " __DATE__ " " __TIME__ " $\n"
    "$Info: " LZO_INFO_STRING " $\n";
#endif


LZO_PUBLIC(const lzo_bytep)
lzo_copyright(void)
{
#if (LZO_OS_DOS16 && LZO_CC_TURBOC)
    return (lzo_voidp) __lzo_copyright;
#else
    return (const lzo_bytep) __lzo_copyright;
#endif
}

LZO_PUBLIC(unsigned)
lzo_version(void)
{
    return LZO_VERSION;
}

LZO_PUBLIC(const char *)
lzo_version_string(void)
{
    return LZO_VERSION_STRING;
}

LZO_PUBLIC(const char *)
lzo_version_date(void)
{
    return LZO_VERSION_DATE;
}

LZO_PUBLIC(const lzo_charp)
_lzo_version_string(void)
{
    return LZO_VERSION_STRING;
}

LZO_PUBLIC(const lzo_charp)
_lzo_version_date(void)
{
    return LZO_VERSION_DATE;
}


/***********************************************************************
// adler32 checksum
// adapted from free code by Mark Adler <madler@alumni.caltech.edu>
// see http://www.zlib.org/
************************************************************************/

#define LZO_BASE 65521u /* largest prime smaller than 65536 */
#define LZO_NMAX 5552
/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */

#define LZO_DO1(buf,i)  s1 += buf[i]; s2 += s1
#define LZO_DO2(buf,i)  LZO_DO1(buf,i); LZO_DO1(buf,i+1);
#define LZO_DO4(buf,i)  LZO_DO2(buf,i); LZO_DO2(buf,i+2);
#define LZO_DO8(buf,i)  LZO_DO4(buf,i); LZO_DO4(buf,i+4);
#define LZO_DO16(buf,i) LZO_DO8(buf,i); LZO_DO8(buf,i+8);

LZO_PUBLIC(lzo_uint32)
lzo_adler32(lzo_uint32 adler, const lzo_bytep buf, lzo_uint len)
{
    lzo_uint32 s1 = adler & 0xffff;
    lzo_uint32 s2 = (adler >> 16) & 0xffff;
    unsigned k;

    if (buf == NULL)
        return 1;

    while (len > 0)
    {
        k = len < LZO_NMAX ? (unsigned) len : LZO_NMAX;
        len -= k;
        if (k >= 16) do
        {
            LZO_DO16(buf,0);
            buf += 16;
            k -= 16;
        } while (k >= 16);
        if (k != 0) do
        {
            s1 += *buf++;
            s2 += s1;
        } while (--k > 0);
        s1 %= LZO_BASE;
        s2 %= LZO_BASE;
    }
    return (s2 << 16) | s1;
}

#undef LZO_DO1
#undef LZO_DO2
#undef LZO_DO4
#undef LZO_DO8
#undef LZO_DO16


/*
vi:ts=4:et
*/