getcto.h

UPX 源代码

/* getcto.h -- calltrick util

   This file is part of the UPX executable compressor.

   Copyright (C) 1996-2007 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1996-2007 Laszlo Molnar
   All Rights Reserved.

   UPX and the UCL library are free software; you can redistribute them
   and/or modify them 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.

   This program 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 this program; see the file COPYING.
   If not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Markus F.X.J. Oberhumer              Laszlo Molnar
   <[e-mail]>          <[e-mail]>
 */



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

static int getcto(Filter *f, const unsigned char *buf, const int n=256)
{
    int ic = n;

    if (f->preferred_ctos)
    {
        for (const int *pc = f->preferred_ctos; *pc >= 0; pc++)
        {
            if (*pc < n && buf[*pc] == 0)
            {
                ic = *pc;
                break;
            }
        }
    }

#if 0
    // just a test to see if certain ctos would improve compression
    if (ic >= n)
        for (ic = 0; ic < n; ic += 16)
            if (buf[ic] == 0)
                break;
#endif
    if (ic >= n)
        for (ic = 0; ic < n; ic++)
            if (buf[ic] == 0)
                break;

    if (ic >= n)
        //throwCantPack("call trick problem");
        return -1;

    f->cto = (unsigned char) ic;
    return ic;
}



/*
vi:ts=4:et:nowrap
*/