/* sw.h -- swaptrick filter

   This file is part of the UPX executable compressor.

   Copyright (C) Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 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
   <markus@oberhumer.com>               <ezerotven+github@gmail.com>
 */

/*************************************************************************
// 16-bit swaptrick ("naive")
**************************************************************************/

#define SW16(f, cond, get, set)                                                                    \
    byte *b = f->buf;                                                                              \
    byte *b_end = b + f->buf_len - 3;                                                              \
    do {                                                                                           \
        if (cond) {                                                                                \
            b += 1;                                                                                \
            unsigned a = (unsigned) (b - f->buf);                                                  \
            f->lastcall = a;                                                                       \
            set(b, get(b));                                                                        \
            f->calls++;                                                                            \
            b += 2 - 1;                                                                            \
        }                                                                                          \
    } while (++b < b_end);                                                                         \
    if (f->lastcall)                                                                               \
        f->lastcall += 2;                                                                          \
    return 0;

// filter
static int f_sw16_e8(Filter *f) { SW16(f, (*b == 0xe8), get_le16, set_be16) }

static int f_sw16_e9(Filter *f) { SW16(f, (*b == 0xe9), get_le16, set_be16) }

static int f_sw16_e8e9(Filter *f) { SW16(f, (*b == 0xe8 || *b == 0xe9), get_le16, set_be16) }

// unfilter
static int u_sw16_e8(Filter *f) { SW16(f, (*b == 0xe8), get_be16, set_le16) }

static int u_sw16_e9(Filter *f) { SW16(f, (*b == 0xe9), get_be16, set_le16) }

static int u_sw16_e8e9(Filter *f) { SW16(f, (*b == 0xe8 || *b == 0xe9), get_be16, set_le16) }

// scan
static int s_sw16_e8(Filter *f) { SW16(f, (*b == 0xe8), get_le16, set_dummy) }

static int s_sw16_e9(Filter *f) { SW16(f, (*b == 0xe9), get_le16, set_dummy) }

static int s_sw16_e8e9(Filter *f) { SW16(f, (*b == 0xe8 || *b == 0xe9), get_le16, set_dummy) }

#undef SW16

/*************************************************************************
// 32-bit swaptrick ("naive")
**************************************************************************/

#define SW32(f, cond, get, set)                                                                    \
    byte *b = f->buf;                                                                              \
    byte *b_end = b + f->buf_len - 5;                                                              \
    do {                                                                                           \
        if (cond) {                                                                                \
            b += 1;                                                                                \
            unsigned a = (unsigned) (b - f->buf);                                                  \
            f->lastcall = a;                                                                       \
            set(b, get(b));                                                                        \
            f->calls++;                                                                            \
            b += 4 - 1;                                                                            \
        }                                                                                          \
    } while (++b < b_end);                                                                         \
    if (f->lastcall)                                                                               \
        f->lastcall += 4;                                                                          \
    return 0;

// filter
static int f_sw32_e8(Filter *f) { SW32(f, (*b == 0xe8), get_le32, set_be32) }

static int f_sw32_e9(Filter *f) { SW32(f, (*b == 0xe9), get_le32, set_be32) }

static int f_sw32_e8e9(Filter *f) { SW32(f, (*b == 0xe8 || *b == 0xe9), get_le32, set_be32) }

// unfilter
static int u_sw32_e8(Filter *f) { SW32(f, (*b == 0xe8), get_be32, set_le32) }

static int u_sw32_e9(Filter *f) { SW32(f, (*b == 0xe9), get_be32, set_le32) }

static int u_sw32_e8e9(Filter *f) { SW32(f, (*b == 0xe8 || *b == 0xe9), get_be32, set_le32) }

// scan
static int s_sw32_e8(Filter *f) { SW32(f, (*b == 0xe8), get_le32, set_dummy) }

static int s_sw32_e9(Filter *f) { SW32(f, (*b == 0xe9), get_le32, set_dummy) }

static int s_sw32_e8e9(Filter *f) { SW32(f, (*b == 0xe8 || *b == 0xe9), get_le32, set_dummy) }

#undef SW32

/* vim:set ts=4 sw=4 et: */
