94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
/*
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* Copyright (C) 2012 Jan Luebbe <j.luebbe@pengutronix.de>
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*
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* Partially based on code from BusyBox.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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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*
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*/
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#include <common.h>
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#include <command.h>
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#include <environment.h>
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#include <errno.h>
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#include <init.h>
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#include <malloc.h>
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#include <xfuncs.h>
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#include <math.h>
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static void setvar(const char *name, const char *val)
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{
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setenv(name, val); /* return value is always 0 */
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}
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static arith_t run_arith(const char *s)
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{
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arith_state_t math_state;
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arith_t result;
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math_state.lookupvar = getenv;
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math_state.setvar = setvar;
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math_state.endofname = arith_endofname;
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result = arith(&math_state, s);
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if (math_state.errmsg)
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printf("let: %s\n", math_state.errmsg);
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return result;
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}
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static int do_let(int argc, char *argv[])
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{
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arith_t i;
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argv++;
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if (!*argv) {
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printf("let: expression expected\n");
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return COMMAND_ERROR_USAGE;
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}
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do {
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i = run_arith(*argv);
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} while (*++argv);
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return !i;
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}
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BAREBOX_CMD_HELP_START(let)
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BAREBOX_CMD_HELP_TEXT ("Supported operations are in order of decreasing precedence:")
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BAREBOX_CMD_HELP_TEXT (" X++, X--")
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BAREBOX_CMD_HELP_TEXT (" ++X, --X")
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BAREBOX_CMD_HELP_TEXT (" +X, -X")
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BAREBOX_CMD_HELP_TEXT (" !X, ~X")
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BAREBOX_CMD_HELP_TEXT (" X**Y")
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BAREBOX_CMD_HELP_TEXT (" X*Y, X/Y, X%Y")
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BAREBOX_CMD_HELP_TEXT (" X+Y, X-Y")
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BAREBOX_CMD_HELP_TEXT (" X<<Y, X>>Y")
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BAREBOX_CMD_HELP_TEXT (" X<Y, X<=Y, X>=Y, X>Y")
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BAREBOX_CMD_HELP_TEXT (" X==Y, X!=Y")
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BAREBOX_CMD_HELP_TEXT (" X&Y")
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BAREBOX_CMD_HELP_TEXT (" X^Y")
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BAREBOX_CMD_HELP_TEXT (" X|Y")
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BAREBOX_CMD_HELP_TEXT (" X&&Y")
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BAREBOX_CMD_HELP_TEXT (" X||Y")
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BAREBOX_CMD_HELP_TEXT (" X?Y:Z")
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BAREBOX_CMD_HELP_TEXT (" X*=Y, X/=Y, X%=Y")
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BAREBOX_CMD_HELP_TEXT (" X=Y, X&=Y, X|=Y, X^=Y, X+=Y, X-=Y, X<<=Y, X>>=Y")
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BAREBOX_CMD_HELP_END
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BAREBOX_CMD_START(let)
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.cmd = do_let,
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BAREBOX_CMD_DESC("evaluate arithmetic expressions")
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BAREBOX_CMD_OPTS("EXPR [EXPR ...]")
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BAREBOX_CMD_GROUP(CMD_GRP_SCRIPT)
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BAREBOX_CMD_HELP(cmd_let_help)
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BAREBOX_CMD_END
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