PP_NARG

pp_narg.h

/**
 * Copyright (C)  2018 Jan Chren (rindeal)
 *
 * This program 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, version 3 of the License.
 *
 * 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. If not, see <https://www.gnu.org/licenses/>.
 *
 * SPDX-License-Identifier: GPL-3.0-only
 */

#define PP_NARG(...) \
	PP_NARG_(0, ## __VA_ARGS__, PP_NARG_RSEQ_N_())
#define PP_NARG_(...) \
	PP_NARG_ARG_N_(__VA_ARGS__)
#define PP_NARG_ARG_N_( \
	  _0,   _1,   _2,   _3,   _4,   _5,   _6,   _7,   _8,   _9, \
	 _10,  _11,  _12,  _13,  _14,  _15,  _16,  _17,  _18,  _19, \
	 _20,  _21,  _22,  _23,  _24,  _25,  _26,  _27,  _28,  _29, \
	 _30,  _31,  _32,  _33,  _34,  _35,  _36,  _37,  _38,  _39, \
	 _40,  _41,  _42,  _43,  _44,  _45,  _46,  _47,  _48,  _49, \
	 _50,  _51,  _52,  _53,  _54,  _55,  _56,  _57,  _58,  _59, \
	 _60,  _61,  _62,  _63,  _64,  _65,  _66,  _67,  _68,  _69, \
	 _70,  _71,  _72,  _73,  _74,  _75,  _76,  _77,  _78,  _79, \
	 _80,  _81,  _82,  _83,  _84,  _85,  _86,  _87,  _88,  _89, \
	 _90,  _91,  _92,  _93,  _94,  _95,  _96,  _97,  _98,  _99, \
	_100, _101, _102, _103, _104, _105, _106, _107, _108, _109, \
	_110, _111, _112, _113, _114, _115, _116, _117, _118, _119, \
	_120, _121, _122, _123, _124, _125, _126, _127, _128,   N, ...) N
#define PP_NARG_RSEQ_N_() \
	 128,  127,  126,  125,  124,  123,  122,  121,  120, \
	 119,  118,  117,  116,  115,  114,  113,  112,  111,  110, \
	 109,  108,  107,  106,  105,  104,  103,  102,  101,  100, \
	  99,   98,   97,   96,   95,   94,   93,   92,   91,   90, \
	  89,   88,   87,   86,   85,   84,   83,   82,   81,   80, \
	  79,   78,   77,   76,   75,   74,   73,   72,   71,   70, \
	  69,   68,   67,   66,   65,   64,   63,   62,   61,   60, \
	  59,   58,   57,   56,   55,   54,   53,   52,   51,   50, \
	  49,   48,   47,   46,   45,   44,   43,   42,   41,   40, \
	  39,   38,   37,   36,   35,   34,   33,   32,   31,   30, \
	  29,   28,   27,   26,   25,   24,   23,   22,   21,   20, \
	  19,   18,   17,   16,   15,   14,   13,   12,   11,   10, \
	   9,    8,    7,    6,    5,    4,    3,    2,    1,    0

pp_narg_gen.sh

#!/bin/bash
##
# Copyright (C)  2018 Jan Chren (rindeal)
#
# This program 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, version 3 of the License.
#
# 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. If not, see <https://www.gnu.org/licenses/>.
#
# SPDX-License-Identifier: GPL-3.0-only
##


MAX_ARGS=128

MAIN_NAME="PP_NARG"
ARG_N_NAME="${MAIN_NAME}_ARG_N_"
RSEQ_N_NAME="${MAIN_NAME}_RSEQ_N_"

INDENT=$'\t'
BR_=' \\\n'
EOL_='\n'

ASSERT=0


printf "#define ${MAIN_NAME}(...)${BR_}"
printf "${INDENT}${MAIN_NAME}_(0, ## __VA_ARGS__, ${RSEQ_N_NAME}())${EOL_}"

printf "#define ${MAIN_NAME}_(...)${BR_}"
printf "${INDENT}${ARG_N_NAME}(__VA_ARGS__)${EOL_}"

printf "#define ${ARG_N_NAME}("
for (( i = 0 ; i <= MAX_ARGS ; i++ ))
do
    if (( i%10 == 0 ))
    then
        printf "${BR_}${INDENT}"
    else
        printf " "
    fi
    printf "%4s," "_${i}"
done
printf "%4s, ...) N${EOL_}" "N"

printf "#define ${RSEQ_N_NAME}()${BR_}${INDENT}"
for (( i = MAX_ARGS ; i >= 0 ; i-- ))
do
    if (( i == 0 ))
    then
        printf "%4s${EOL_}" "${i}"
        break
    fi

    printf "%4s," "${i}"
    if (( i%10 == 0 ))
    then
        printf "${BR_}${INDENT}"
    else
        printf " "
    fi
done

if (( ASSERT ))
then
    echo
    echo
    printf "#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))${EOL_}"
    printf "int main(void) {${EOL_}"
    for (( i = 0 ; i <= MAX_ARGS ; i ++ ))
    do
        printf "BUILD_BUG_ON( ${MAIN_NAME}("
        for (( j = 1 ; j <= i ; j++ ))
        do
            printf "a${j}"
            if (( j != i ))
            then
                printf ", "
            fi
        done
        printf ") != ${i} );${EOL_}"
    done
    printf "}${EOL_}"
fi