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Added expr, from Edward Betts <edward@debian.org>, with some fixups
and docs added by me. -Erik
This commit is contained in:
Eric Andersen
parent
43c8c38bbf
commit
1b355ebba6
3
AUTHORS
3
AUTHORS
@ -12,6 +12,9 @@ Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
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Tons of new stuff, major rewrite of most of the
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core apps, tons of new apps as noted in header files.
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Edward Betts <edward@debian.org>
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expr, hostid, logname, tty, wc, whoami, yes
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John Beppu <beppu@lineo.com>
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du, head, nslookup, sort, tee, uniq
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1
TODO
1
TODO
@ -22,7 +22,6 @@ around to it some time. If you have any good ideas, please let me know.
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* rdate
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* hwclock
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* stty
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* expr
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* wget (or whatever I call it)
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* tftp
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* ftp
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@ -76,6 +76,9 @@ const struct BB_applet applets[] = {
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#ifdef BB_ECHO
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{"echo", echo_main, _BB_DIR_BIN, echo_usage},
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#endif
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#ifdef BB_EXPR
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{"expr", expr_main, _BB_DIR_USR_BIN, expr_usage},
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#endif
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#ifdef BB_TRUE_FALSE
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{"false", false_main, _BB_DIR_BIN, false_usage},
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#endif
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@ -5,6 +5,6 @@
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ls -1 ` \
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gcc -E -dM busybox.def.h | \
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sed -n -e '/^.*BB_FEATURE.*$/d;s/^#define.*\<BB_\(.*\)\>/\1.c/gp;' \
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| tr [:upper:] [:lower:] | sort
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| tr '[:upper:]' '[:lower:]' | sort
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` 2>/dev/null | sed -e 's/\.c$/\.o/g'
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@ -250,6 +250,44 @@ const char echo_usage[] =
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;
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#endif
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#if defined BB_EXPR
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const char expr_usage[] =
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"expr EXPRESSION\n"
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#ifndef BB_FEATURE_TRIVIAL_HELP
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"\nPrints the value of EXPRESSION to standard output.\n\n"
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"EXPRESSION may be:\n"
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"ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2\n"
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"ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0\n"
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"ARG1 < ARG2 ARG1 is less than ARG2\n"
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"ARG1 <= ARG2 ARG1 is less than or equal to ARG2\n"
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"ARG1 = ARG2 ARG1 is equal to ARG2\n"
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"ARG1 != ARG2 ARG1 is unequal to ARG2\n"
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"ARG1 >= ARG2 ARG1 is greater than or equal to ARG2\n"
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"ARG1 > ARG2 ARG1 is greater than ARG2\n"
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"ARG1 + ARG2 arithmetic sum of ARG1 and ARG2\n"
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"ARG1 - ARG2 arithmetic difference of ARG1 and ARG2\n"
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"ARG1 * ARG2 arithmetic product of ARG1 and ARG2\n"
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"ARG1 / ARG2 arithmetic quotient of ARG1 divided by ARG2\n"
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"ARG1 % ARG2 arithmetic remainder of ARG1 divided by ARG2\n"
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"STRING : REGEXP anchored pattern match of REGEXP in STRING\n"
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"match STRING REGEXP same as STRING : REGEXP\n"
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"substr STRING POS LENGTH substring of STRING, POS counted from 1\n"
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"index STRING CHARS index in STRING where any CHARS is found, or 0\n"
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"length STRING length of STRING\n"
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"quote TOKEN interpret TOKEN as a string, even if it is a \n"
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" keyword like `match' or an operator like `/'\n"
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"( EXPRESSION ) value of EXPRESSION\n\n"
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"Beware that many operators need to be escaped or quoted for shells.\n"
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"Comparisons are arithmetic if both ARGs are numbers, else\n"
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"lexicographical. Pattern matches return the string matched between \n"
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"\\( and \\) or null; if \\( and \\) are not used, they return the number \n"
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"of characters matched or 0.\n"
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#endif
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;
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#endif
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#if defined BB_TRUE_FALSE
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const char false_usage[] =
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"false\n"
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@ -76,6 +76,9 @@ const struct BB_applet applets[] = {
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#ifdef BB_ECHO
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{"echo", echo_main, _BB_DIR_BIN, echo_usage},
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#endif
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#ifdef BB_EXPR
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{"expr", expr_main, _BB_DIR_USR_BIN, expr_usage},
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#endif
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#ifdef BB_TRUE_FALSE
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{"false", false_main, _BB_DIR_BIN, false_usage},
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#endif
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@ -27,6 +27,7 @@
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#define BB_DU
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#define BB_DUMPKMAP
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#define BB_ECHO
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#define BB_EXPR
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#define BB_FBSET
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#define BB_FDFLUSH
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#define BB_FIND
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@ -5,6 +5,6 @@
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ls -1 ` \
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gcc -E -dM busybox.def.h | \
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sed -n -e '/^.*BB_FEATURE.*$/d;s/^#define.*\<BB_\(.*\)\>/\1.c/gp;' \
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| tr [:upper:] [:lower:] | sort
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| tr '[:upper:]' '[:lower:]' | sort
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` 2>/dev/null | sed -e 's/\.c$/\.o/g'
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531
coreutils/expr.c
Normal file
531
coreutils/expr.c
Normal file
@ -0,0 +1,531 @@
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/* vi: set sw=4 ts=4: */
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/*
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* Mini expr implementation for busybox
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*
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* based on GNU expr Mike Parker.
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* Copyright (C) 86, 1991-1997, 1999 Free Software Foundation, Inc.
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*
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* Busybox modifications
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* Copyright (c) 2000 Edward Betts <edward@debian.org>.
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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 gnu
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* general public license for more details.
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*
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* you should have received a copy of the gnu general public license
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* along with this program; if not, write to the free software
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* foundation, inc., 59 temple place, suite 330, boston, ma 02111-1307 usa
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*
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*/
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/* This program evaluates expressions. Each token (operator, operand,
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* parenthesis) of the expression must be a seperate argument. The
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* parser used is a reasonably general one, though any incarnation of
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* it is language-specific. It is especially nice for expressions.
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*
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* No parse tree is needed; a new node is evaluated immediately.
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* One function can handle multiple operators all of equal precedence,
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* provided they all associate ((x op x) op x). */
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#include "internal.h"
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#include <stdio.h>
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#include <sys/types.h>
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#include <regex.h>
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/* The kinds of value we can have. */
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enum valtype {
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integer,
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string
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};
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typedef enum valtype TYPE;
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/* A value is.... */
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struct valinfo {
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TYPE type; /* Which kind. */
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union { /* The value itself. */
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int i;
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char *s;
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} u;
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};
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typedef struct valinfo VALUE;
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/* The arguments given to the program, minus the program name. */
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static char **args;
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static VALUE *docolon (VALUE *sv, VALUE *pv);
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static VALUE *eval (void);
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static VALUE *int_value (int i);
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static VALUE *str_value (char *s);
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static int nextarg (char *str);
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static int null (VALUE *v);
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static int toarith (VALUE *v);
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static void freev (VALUE *v);
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static void tostring (VALUE *v);
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int expr_main (int argc, char **argv)
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{
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VALUE *v;
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if (argc == 1) {
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fatalError("too few arguments\n");
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}
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args = argv + 1;
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v = eval ();
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if (*args)
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fatalError ("syntax error\n");
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if (v->type == integer)
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printf ("%d\n", v->u.i);
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else
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printf ("%s\n", v->u.s);
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exit (null (v));
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}
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/* Return a VALUE for I. */
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static VALUE *int_value (int i)
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{
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VALUE *v;
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v = xmalloc (sizeof(VALUE));
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v->type = integer;
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v->u.i = i;
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return v;
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}
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/* Return a VALUE for S. */
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static VALUE *str_value (char *s)
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{
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VALUE *v;
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v = xmalloc (sizeof(VALUE));
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v->type = string;
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v->u.s = strdup (s);
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return v;
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}
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/* Free VALUE V, including structure components. */
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static void freev (VALUE *v)
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{
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if (v->type == string)
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free (v->u.s);
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free (v);
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}
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/* Return nonzero if V is a null-string or zero-number. */
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static int null (VALUE *v)
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{
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switch (v->type) {
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case integer:
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return v->u.i == 0;
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case string:
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return v->u.s[0] == '\0' || strcmp (v->u.s, "0") == 0;
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default:
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abort ();
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}
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}
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/* Coerce V to a string value (can't fail). */
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static void tostring (VALUE *v)
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{
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char *temp;
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if (v->type == integer) {
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temp = xmalloc (4 * (sizeof (int) / sizeof (char)));
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sprintf (temp, "%d", v->u.i);
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v->u.s = temp;
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v->type = string;
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}
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}
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/* Coerce V to an integer value. Return 1 on success, 0 on failure. */
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static int toarith (VALUE *v)
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{
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int i;
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switch (v->type) {
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case integer:
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return 1;
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case string:
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i = 0;
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/* Don't interpret the empty string as an integer. */
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if (v->u.s == 0)
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return 0;
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i = atoi(v->u.s);
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free (v->u.s);
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v->u.i = i;
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v->type = integer;
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return 1;
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default:
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abort ();
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}
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}
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/* Return nonzero if the next token matches STR exactly.
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STR must not be NULL. */
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static int
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nextarg (char *str)
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{
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if (*args == NULL)
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return 0;
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return strcmp (*args, str) == 0;
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}
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/* The comparison operator handling functions. */
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#define cmpf(name, rel) \
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static int name (l, r) VALUE *l; VALUE *r; \
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{ \
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if (l->type == string || r->type == string) { \
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tostring (l); \
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tostring (r); \
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return strcmp (l->u.s, r->u.s) rel 0; \
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} \
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else \
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return l->u.i rel r->u.i; \
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}
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cmpf (less_than, <)
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cmpf (less_equal, <=)
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cmpf (equal, ==)
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cmpf (not_equal, !=)
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cmpf (greater_equal, >=)
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cmpf (greater_than, >)
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#undef cmpf
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/* The arithmetic operator handling functions. */
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#define arithf(name, op) \
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static \
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int name (l, r) VALUE *l; VALUE *r; \
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{ \
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if (!toarith (l) || !toarith (r)) \
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fatalError ("non-numeric argument\n"); \
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return l->u.i op r->u.i; \
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}
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#define arithdivf(name, op) \
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int name (l, r) VALUE *l; VALUE *r; \
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{ \
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if (!toarith (l) || !toarith (r)) \
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fatalError ( "non-numeric argument\n"); \
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if (r->u.i == 0) \
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fatalError ( "division by zero\n"); \
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return l->u.i op r->u.i; \
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}
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arithf (plus, +)
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arithf (minus, -)
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arithf (multiply, *)
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arithdivf (divide, /)
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arithdivf (mod, %)
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#undef arithf
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#undef arithdivf
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/* Do the : operator.
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SV is the VALUE for the lhs (the string),
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PV is the VALUE for the rhs (the pattern). */
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static VALUE *docolon (VALUE *sv, VALUE *pv)
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{
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VALUE *v;
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const char *errmsg;
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struct re_pattern_buffer re_buffer;
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struct re_registers re_regs;
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int len;
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tostring (sv);
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tostring (pv);
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if (pv->u.s[0] == '^') {
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fprintf (stderr, "\
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warning: unportable BRE: `%s': using `^' as the first character\n\
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of a basic regular expression is not portable; it is being ignored",
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pv->u.s);
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}
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len = strlen (pv->u.s);
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memset (&re_buffer, 0, sizeof (re_buffer));
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memset (&re_regs, 0, sizeof (re_regs));
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re_buffer.allocated = 2 * len;
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re_buffer.buffer = (unsigned char *) xmalloc (re_buffer.allocated);
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re_buffer.translate = 0;
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re_syntax_options = RE_SYNTAX_POSIX_BASIC;
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errmsg = re_compile_pattern (pv->u.s, len, &re_buffer);
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if (errmsg) {
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fatalError("%s\n", errmsg);
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}
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len = re_match (&re_buffer, sv->u.s, strlen (sv->u.s), 0, &re_regs);
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if (len >= 0) {
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/* Were \(...\) used? */
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if (re_buffer.re_nsub > 0) { /* was (re_regs.start[1] >= 0) */
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sv->u.s[re_regs.end[1]] = '\0';
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v = str_value (sv->u.s + re_regs.start[1]);
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}
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else
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v = int_value (len);
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}
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else {
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/* Match failed -- return the right kind of null. */
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if (re_buffer.re_nsub > 0)
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v = str_value ("");
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else
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v = int_value (0);
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}
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free (re_buffer.buffer);
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return v;
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}
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/* Handle bare operands and ( expr ) syntax. */
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static VALUE *eval7 (void)
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{
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VALUE *v;
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if (!*args)
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fatalError ( "syntax error\n");
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if (nextarg ("(")) {
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args++;
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v = eval ();
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if (!nextarg (")"))
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fatalError ( "syntax error\n");
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args++;
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return v;
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}
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if (nextarg (")"))
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fatalError ( "syntax error\n");
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return str_value (*args++);
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}
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/* Handle match, substr, index, length, and quote keywords. */
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static VALUE *eval6 (void)
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{
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VALUE *l, *r, *v, *i1, *i2;
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if (nextarg ("quote")) {
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args++;
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if (!*args)
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fatalError ( "syntax error\n");
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return str_value (*args++);
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}
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else if (nextarg ("length")) {
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args++;
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r = eval6 ();
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tostring (r);
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v = int_value (strlen (r->u.s));
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freev (r);
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return v;
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}
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else if (nextarg ("match")) {
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args++;
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l = eval6 ();
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r = eval6 ();
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v = docolon (l, r);
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freev (l);
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freev (r);
|
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return v;
|
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}
|
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else if (nextarg ("index")) {
|
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args++;
|
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l = eval6 ();
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r = eval6 ();
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tostring (l);
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tostring (r);
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v = int_value (strcspn (l->u.s, r->u.s) + 1);
|
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if (v->u.i == (int) strlen (l->u.s) + 1)
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v->u.i = 0;
|
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freev (l);
|
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freev (r);
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return v;
|
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}
|
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else if (nextarg ("substr")) {
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args++;
|
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l = eval6 ();
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i1 = eval6 ();
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i2 = eval6 ();
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tostring (l);
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if (!toarith (i1) || !toarith (i2)
|
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|| i1->u.i > (int) strlen (l->u.s)
|
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|| i1->u.i <= 0 || i2->u.i <= 0)
|
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v = str_value ("");
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else {
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v = xmalloc (sizeof(VALUE));
|
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v->type = string;
|
||||
v->u.s = strncpy ((char *) xmalloc (i2->u.i + 1),
|
||||
l->u.s + i1->u.i - 1, i2->u.i);
|
||||
v->u.s[i2->u.i] = 0;
|
||||
}
|
||||
freev (l);
|
||||
freev (i1);
|
||||
freev (i2);
|
||||
return v;
|
||||
}
|
||||
else
|
||||
return eval7 ();
|
||||
}
|
||||
|
||||
/* Handle : operator (pattern matching).
|
||||
Calls docolon to do the real work. */
|
||||
|
||||
static VALUE *eval5 (void)
|
||||
{
|
||||
VALUE *l, *r, *v;
|
||||
|
||||
l = eval6 ();
|
||||
while (nextarg (":")) {
|
||||
args++;
|
||||
r = eval6 ();
|
||||
v = docolon (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = v;
|
||||
}
|
||||
return l;
|
||||
}
|
||||
|
||||
/* Handle *, /, % operators. */
|
||||
|
||||
static VALUE *eval4 (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
int (*fxn) (), val;
|
||||
|
||||
l = eval5 ();
|
||||
while (1) {
|
||||
if (nextarg ("*"))
|
||||
fxn = multiply;
|
||||
else if (nextarg ("/"))
|
||||
fxn = divide;
|
||||
else if (nextarg ("%"))
|
||||
fxn = mod;
|
||||
else
|
||||
return l;
|
||||
args++;
|
||||
r = eval5 ();
|
||||
val = (*fxn) (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = int_value (val);
|
||||
}
|
||||
}
|
||||
|
||||
/* Handle +, - operators. */
|
||||
|
||||
static VALUE *eval3 (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
int (*fxn) (), val;
|
||||
|
||||
l = eval4 ();
|
||||
while (1) {
|
||||
if (nextarg ("+"))
|
||||
fxn = plus;
|
||||
else if (nextarg ("-"))
|
||||
fxn = minus;
|
||||
else
|
||||
return l;
|
||||
args++;
|
||||
r = eval4 ();
|
||||
val = (*fxn) (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = int_value (val);
|
||||
}
|
||||
}
|
||||
|
||||
/* Handle comparisons. */
|
||||
|
||||
static VALUE *eval2 (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
int (*fxn) (), val;
|
||||
|
||||
l = eval3 ();
|
||||
while (1) {
|
||||
if (nextarg ("<"))
|
||||
fxn = less_than;
|
||||
else if (nextarg ("<="))
|
||||
fxn = less_equal;
|
||||
else if (nextarg ("=") || nextarg ("=="))
|
||||
fxn = equal;
|
||||
else if (nextarg ("!="))
|
||||
fxn = not_equal;
|
||||
else if (nextarg (">="))
|
||||
fxn = greater_equal;
|
||||
else if (nextarg (">"))
|
||||
fxn = greater_than;
|
||||
else
|
||||
return l;
|
||||
args++;
|
||||
r = eval3 ();
|
||||
toarith (l);
|
||||
toarith (r);
|
||||
val = (*fxn) (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = int_value (val);
|
||||
}
|
||||
}
|
||||
|
||||
/* Handle &. */
|
||||
|
||||
static VALUE *eval1 (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
|
||||
l = eval2 ();
|
||||
while (nextarg ("&")) {
|
||||
args++;
|
||||
r = eval2 ();
|
||||
if (null (l) || null (r)) {
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = int_value (0);
|
||||
}
|
||||
else
|
||||
freev (r);
|
||||
}
|
||||
return l;
|
||||
}
|
||||
|
||||
/* Handle |. */
|
||||
|
||||
static VALUE *eval (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
|
||||
l = eval1 ();
|
||||
while (nextarg ("|")) {
|
||||
args++;
|
||||
r = eval1 ();
|
||||
if (null (l)) {
|
||||
freev (l);
|
||||
l = r;
|
||||
}
|
||||
else
|
||||
freev (r);
|
||||
}
|
||||
return l;
|
||||
}
|
||||
@ -2,7 +2,7 @@
|
||||
/*
|
||||
* Mini wc implementation for busybox
|
||||
*
|
||||
* by Edward Betts <edward@debian.org>
|
||||
* Copyright (C) 2000 Edward Betts <edward@debian.org>
|
||||
*
|
||||
* 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
|
||||
|
||||
@ -497,6 +497,45 @@ Example:
|
||||
|
||||
-------------------------------
|
||||
|
||||
=item echo
|
||||
|
||||
|
||||
Usage: expr EXPRESSION
|
||||
|
||||
Prints the value of EXPRESSION to standard output.
|
||||
|
||||
EXPRESSION may be:
|
||||
|
||||
ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2
|
||||
ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0
|
||||
ARG1 < ARG2 ARG1 is less than ARG2
|
||||
ARG1 <= ARG2 ARG1 is less than or equal to ARG2
|
||||
ARG1 = ARG2 ARG1 is equal to ARG2
|
||||
ARG1 != ARG2 ARG1 is unequal to ARG2
|
||||
ARG1 >= ARG2 ARG1 is greater than or equal to ARG2
|
||||
ARG1 > ARG2 ARG1 is greater than ARG2
|
||||
ARG1 + ARG2 arithmetic sum of ARG1 and ARG2
|
||||
ARG1 - ARG2 arithmetic difference of ARG1 and ARG2
|
||||
ARG1 * ARG2 arithmetic product of ARG1 and ARG2
|
||||
ARG1 / ARG2 arithmetic quotient of ARG1 divided by ARG2
|
||||
ARG1 % ARG2 arithmetic remainder of ARG1 divided by ARG2
|
||||
STRING : REGEXP anchored pattern match of REGEXP in STRING
|
||||
match STRING REGEXP same as STRING : REGEXP
|
||||
substr STRING POS LENGTH substring of STRING, POS counted from 1
|
||||
index STRING CHARS index in STRING where any CHARS is found, or 0
|
||||
length STRING length of STRING
|
||||
quote TOKEN interpret TOKEN as a string, even if it is a
|
||||
keyword like `match' or an operator like `/'
|
||||
( EXPRESSION ) value of EXPRESSION
|
||||
|
||||
Beware that many operators need to be escaped or quoted for shells.
|
||||
Comparisons are arithmetic if both ARGs are numbers, else
|
||||
lexicographical. Pattern matches return the string matched between
|
||||
\( and \) or null; if \( and \) are not used, they return the number
|
||||
of characters matched or 0.
|
||||
|
||||
-------------------------------
|
||||
|
||||
=item false
|
||||
|
||||
Returns an exit code of FALSE (1)
|
||||
@ -2112,4 +2151,4 @@ Enrique Zanardi <ezanardi@ull.es>
|
||||
|
||||
=cut
|
||||
|
||||
# $Id: busybox.pod,v 1.65 2000/09/01 16:12:57 andersen Exp $
|
||||
# $Id: busybox.pod,v 1.66 2000/09/05 17:37:48 andersen Exp $
|
||||
|
||||
@ -879,6 +879,58 @@
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="expr">
|
||||
<title>expr</title>
|
||||
|
||||
<para>
|
||||
Usage: expr EXPRESSION
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Prints the value of EXPRESSION to standard output.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
EXPRESSION may be:
|
||||
</para>
|
||||
|
||||
<para>
|
||||
<screen>
|
||||
ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2
|
||||
ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0
|
||||
ARG1 < ARG2 ARG1 is less than ARG2
|
||||
ARG1 <= ARG2 ARG1 is less than or equal to ARG2
|
||||
ARG1 = ARG2 ARG1 is equal to ARG2
|
||||
ARG1 != ARG2 ARG1 is unequal to ARG2
|
||||
ARG1 >= ARG2 ARG1 is greater than or equal to ARG2
|
||||
ARG1 > ARG2 ARG1 is greater than ARG2
|
||||
ARG1 + ARG2 arithmetic sum of ARG1 and ARG2
|
||||
ARG1 - ARG2 arithmetic difference of ARG1 and ARG2
|
||||
ARG1 * ARG2 arithmetic product of ARG1 and ARG2
|
||||
ARG1 / ARG2 arithmetic quotient of ARG1 divided by ARG2
|
||||
ARG1 % ARG2 arithmetic remainder of ARG1 divided by ARG2
|
||||
STRING : REGEXP anchored pattern match of REGEXP in STRING
|
||||
match STRING REGEXP same as STRING : REGEXP
|
||||
substr STRING POS LENGTH substring of STRING, POS counted from 1
|
||||
index STRING CHARS index in STRING where any CHARS is found, or 0
|
||||
length STRING length of STRING
|
||||
quote TOKEN interpret TOKEN as a string, even if it is a
|
||||
keyword like `match' or an operator like `/'
|
||||
( EXPRESSION ) value of EXPRESSION
|
||||
</screen>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Beware that many operators need to be escaped or quoted for shells.
|
||||
Comparisons are arithmetic if both ARGs are numbers, else
|
||||
lexicographical. Pattern matches return the string matched between
|
||||
\( and \) or null; if \( and \) are not used, they return the number
|
||||
of characters matched or 0.
|
||||
</para>
|
||||
|
||||
</sect1>
|
||||
|
||||
|
||||
<sect1 id="false">
|
||||
<title>false</title>
|
||||
|
||||
|
||||
531
expr.c
Normal file
531
expr.c
Normal file
@ -0,0 +1,531 @@
|
||||
/* vi: set sw=4 ts=4: */
|
||||
/*
|
||||
* Mini expr implementation for busybox
|
||||
*
|
||||
* based on GNU expr Mike Parker.
|
||||
* Copyright (C) 86, 1991-1997, 1999 Free Software Foundation, Inc.
|
||||
*
|
||||
* Busybox modifications
|
||||
* Copyright (c) 2000 Edward Betts <edward@debian.org>.
|
||||
*
|
||||
* 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; 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; if not, write to the free software
|
||||
* foundation, inc., 59 temple place, suite 330, boston, ma 02111-1307 usa
|
||||
*
|
||||
*/
|
||||
|
||||
/* This program evaluates expressions. Each token (operator, operand,
|
||||
* parenthesis) of the expression must be a seperate argument. The
|
||||
* parser used is a reasonably general one, though any incarnation of
|
||||
* it is language-specific. It is especially nice for expressions.
|
||||
*
|
||||
* No parse tree is needed; a new node is evaluated immediately.
|
||||
* One function can handle multiple operators all of equal precedence,
|
||||
* provided they all associate ((x op x) op x). */
|
||||
|
||||
#include "internal.h"
|
||||
#include <stdio.h>
|
||||
#include <sys/types.h>
|
||||
|
||||
#include <regex.h>
|
||||
|
||||
/* The kinds of value we can have. */
|
||||
enum valtype {
|
||||
integer,
|
||||
string
|
||||
};
|
||||
typedef enum valtype TYPE;
|
||||
|
||||
/* A value is.... */
|
||||
struct valinfo {
|
||||
TYPE type; /* Which kind. */
|
||||
union { /* The value itself. */
|
||||
int i;
|
||||
char *s;
|
||||
} u;
|
||||
};
|
||||
typedef struct valinfo VALUE;
|
||||
|
||||
/* The arguments given to the program, minus the program name. */
|
||||
static char **args;
|
||||
|
||||
static VALUE *docolon (VALUE *sv, VALUE *pv);
|
||||
static VALUE *eval (void);
|
||||
static VALUE *int_value (int i);
|
||||
static VALUE *str_value (char *s);
|
||||
static int nextarg (char *str);
|
||||
static int null (VALUE *v);
|
||||
static int toarith (VALUE *v);
|
||||
static void freev (VALUE *v);
|
||||
static void tostring (VALUE *v);
|
||||
|
||||
int expr_main (int argc, char **argv)
|
||||
{
|
||||
VALUE *v;
|
||||
|
||||
if (argc == 1) {
|
||||
fatalError("too few arguments\n");
|
||||
}
|
||||
|
||||
args = argv + 1;
|
||||
|
||||
v = eval ();
|
||||
if (*args)
|
||||
fatalError ("syntax error\n");
|
||||
|
||||
if (v->type == integer)
|
||||
printf ("%d\n", v->u.i);
|
||||
else
|
||||
printf ("%s\n", v->u.s);
|
||||
|
||||
exit (null (v));
|
||||
}
|
||||
|
||||
/* Return a VALUE for I. */
|
||||
|
||||
static VALUE *int_value (int i)
|
||||
{
|
||||
VALUE *v;
|
||||
|
||||
v = xmalloc (sizeof(VALUE));
|
||||
v->type = integer;
|
||||
v->u.i = i;
|
||||
return v;
|
||||
}
|
||||
|
||||
/* Return a VALUE for S. */
|
||||
|
||||
static VALUE *str_value (char *s)
|
||||
{
|
||||
VALUE *v;
|
||||
|
||||
v = xmalloc (sizeof(VALUE));
|
||||
v->type = string;
|
||||
v->u.s = strdup (s);
|
||||
return v;
|
||||
}
|
||||
|
||||
/* Free VALUE V, including structure components. */
|
||||
|
||||
static void freev (VALUE *v)
|
||||
{
|
||||
if (v->type == string)
|
||||
free (v->u.s);
|
||||
free (v);
|
||||
}
|
||||
|
||||
/* Return nonzero if V is a null-string or zero-number. */
|
||||
|
||||
static int null (VALUE *v)
|
||||
{
|
||||
switch (v->type) {
|
||||
case integer:
|
||||
return v->u.i == 0;
|
||||
case string:
|
||||
return v->u.s[0] == '\0' || strcmp (v->u.s, "0") == 0;
|
||||
default:
|
||||
abort ();
|
||||
}
|
||||
}
|
||||
|
||||
/* Coerce V to a string value (can't fail). */
|
||||
|
||||
static void tostring (VALUE *v)
|
||||
{
|
||||
char *temp;
|
||||
|
||||
if (v->type == integer) {
|
||||
temp = xmalloc (4 * (sizeof (int) / sizeof (char)));
|
||||
sprintf (temp, "%d", v->u.i);
|
||||
v->u.s = temp;
|
||||
v->type = string;
|
||||
}
|
||||
}
|
||||
|
||||
/* Coerce V to an integer value. Return 1 on success, 0 on failure. */
|
||||
|
||||
static int toarith (VALUE *v)
|
||||
{
|
||||
int i;
|
||||
|
||||
switch (v->type) {
|
||||
case integer:
|
||||
return 1;
|
||||
case string:
|
||||
i = 0;
|
||||
/* Don't interpret the empty string as an integer. */
|
||||
if (v->u.s == 0)
|
||||
return 0;
|
||||
i = atoi(v->u.s);
|
||||
free (v->u.s);
|
||||
v->u.i = i;
|
||||
v->type = integer;
|
||||
return 1;
|
||||
default:
|
||||
abort ();
|
||||
}
|
||||
}
|
||||
|
||||
/* Return nonzero if the next token matches STR exactly.
|
||||
STR must not be NULL. */
|
||||
|
||||
static int
|
||||
nextarg (char *str)
|
||||
{
|
||||
if (*args == NULL)
|
||||
return 0;
|
||||
return strcmp (*args, str) == 0;
|
||||
}
|
||||
|
||||
/* The comparison operator handling functions. */
|
||||
|
||||
#define cmpf(name, rel) \
|
||||
static int name (l, r) VALUE *l; VALUE *r; \
|
||||
{ \
|
||||
if (l->type == string || r->type == string) { \
|
||||
tostring (l); \
|
||||
tostring (r); \
|
||||
return strcmp (l->u.s, r->u.s) rel 0; \
|
||||
} \
|
||||
else \
|
||||
return l->u.i rel r->u.i; \
|
||||
}
|
||||
cmpf (less_than, <)
|
||||
cmpf (less_equal, <=)
|
||||
cmpf (equal, ==)
|
||||
cmpf (not_equal, !=)
|
||||
cmpf (greater_equal, >=)
|
||||
cmpf (greater_than, >)
|
||||
|
||||
#undef cmpf
|
||||
|
||||
/* The arithmetic operator handling functions. */
|
||||
|
||||
#define arithf(name, op) \
|
||||
static \
|
||||
int name (l, r) VALUE *l; VALUE *r; \
|
||||
{ \
|
||||
if (!toarith (l) || !toarith (r)) \
|
||||
fatalError ("non-numeric argument\n"); \
|
||||
return l->u.i op r->u.i; \
|
||||
}
|
||||
|
||||
#define arithdivf(name, op) \
|
||||
int name (l, r) VALUE *l; VALUE *r; \
|
||||
{ \
|
||||
if (!toarith (l) || !toarith (r)) \
|
||||
fatalError ( "non-numeric argument\n"); \
|
||||
if (r->u.i == 0) \
|
||||
fatalError ( "division by zero\n"); \
|
||||
return l->u.i op r->u.i; \
|
||||
}
|
||||
|
||||
arithf (plus, +)
|
||||
arithf (minus, -)
|
||||
arithf (multiply, *)
|
||||
arithdivf (divide, /)
|
||||
arithdivf (mod, %)
|
||||
|
||||
#undef arithf
|
||||
#undef arithdivf
|
||||
|
||||
/* Do the : operator.
|
||||
SV is the VALUE for the lhs (the string),
|
||||
PV is the VALUE for the rhs (the pattern). */
|
||||
|
||||
static VALUE *docolon (VALUE *sv, VALUE *pv)
|
||||
{
|
||||
VALUE *v;
|
||||
const char *errmsg;
|
||||
struct re_pattern_buffer re_buffer;
|
||||
struct re_registers re_regs;
|
||||
int len;
|
||||
|
||||
tostring (sv);
|
||||
tostring (pv);
|
||||
|
||||
if (pv->u.s[0] == '^') {
|
||||
fprintf (stderr, "\
|
||||
warning: unportable BRE: `%s': using `^' as the first character\n\
|
||||
of a basic regular expression is not portable; it is being ignored",
|
||||
pv->u.s);
|
||||
}
|
||||
|
||||
len = strlen (pv->u.s);
|
||||
memset (&re_buffer, 0, sizeof (re_buffer));
|
||||
memset (&re_regs, 0, sizeof (re_regs));
|
||||
re_buffer.allocated = 2 * len;
|
||||
re_buffer.buffer = (unsigned char *) xmalloc (re_buffer.allocated);
|
||||
re_buffer.translate = 0;
|
||||
re_syntax_options = RE_SYNTAX_POSIX_BASIC;
|
||||
errmsg = re_compile_pattern (pv->u.s, len, &re_buffer);
|
||||
if (errmsg) {
|
||||
fatalError("%s\n", errmsg);
|
||||
}
|
||||
|
||||
len = re_match (&re_buffer, sv->u.s, strlen (sv->u.s), 0, &re_regs);
|
||||
if (len >= 0) {
|
||||
/* Were \(...\) used? */
|
||||
if (re_buffer.re_nsub > 0) { /* was (re_regs.start[1] >= 0) */
|
||||
sv->u.s[re_regs.end[1]] = '\0';
|
||||
v = str_value (sv->u.s + re_regs.start[1]);
|
||||
}
|
||||
else
|
||||
v = int_value (len);
|
||||
}
|
||||
else {
|
||||
/* Match failed -- return the right kind of null. */
|
||||
if (re_buffer.re_nsub > 0)
|
||||
v = str_value ("");
|
||||
else
|
||||
v = int_value (0);
|
||||
}
|
||||
free (re_buffer.buffer);
|
||||
return v;
|
||||
}
|
||||
|
||||
/* Handle bare operands and ( expr ) syntax. */
|
||||
|
||||
static VALUE *eval7 (void)
|
||||
{
|
||||
VALUE *v;
|
||||
|
||||
if (!*args)
|
||||
fatalError ( "syntax error\n");
|
||||
|
||||
if (nextarg ("(")) {
|
||||
args++;
|
||||
v = eval ();
|
||||
if (!nextarg (")"))
|
||||
fatalError ( "syntax error\n");
|
||||
args++;
|
||||
return v;
|
||||
}
|
||||
|
||||
if (nextarg (")"))
|
||||
fatalError ( "syntax error\n");
|
||||
|
||||
return str_value (*args++);
|
||||
}
|
||||
|
||||
/* Handle match, substr, index, length, and quote keywords. */
|
||||
|
||||
static VALUE *eval6 (void)
|
||||
{
|
||||
VALUE *l, *r, *v, *i1, *i2;
|
||||
|
||||
if (nextarg ("quote")) {
|
||||
args++;
|
||||
if (!*args)
|
||||
fatalError ( "syntax error\n");
|
||||
return str_value (*args++);
|
||||
}
|
||||
else if (nextarg ("length")) {
|
||||
args++;
|
||||
r = eval6 ();
|
||||
tostring (r);
|
||||
v = int_value (strlen (r->u.s));
|
||||
freev (r);
|
||||
return v;
|
||||
}
|
||||
else if (nextarg ("match")) {
|
||||
args++;
|
||||
l = eval6 ();
|
||||
r = eval6 ();
|
||||
v = docolon (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
return v;
|
||||
}
|
||||
else if (nextarg ("index")) {
|
||||
args++;
|
||||
l = eval6 ();
|
||||
r = eval6 ();
|
||||
tostring (l);
|
||||
tostring (r);
|
||||
v = int_value (strcspn (l->u.s, r->u.s) + 1);
|
||||
if (v->u.i == (int) strlen (l->u.s) + 1)
|
||||
v->u.i = 0;
|
||||
freev (l);
|
||||
freev (r);
|
||||
return v;
|
||||
}
|
||||
else if (nextarg ("substr")) {
|
||||
args++;
|
||||
l = eval6 ();
|
||||
i1 = eval6 ();
|
||||
i2 = eval6 ();
|
||||
tostring (l);
|
||||
if (!toarith (i1) || !toarith (i2)
|
||||
|| i1->u.i > (int) strlen (l->u.s)
|
||||
|| i1->u.i <= 0 || i2->u.i <= 0)
|
||||
v = str_value ("");
|
||||
else {
|
||||
v = xmalloc (sizeof(VALUE));
|
||||
v->type = string;
|
||||
v->u.s = strncpy ((char *) xmalloc (i2->u.i + 1),
|
||||
l->u.s + i1->u.i - 1, i2->u.i);
|
||||
v->u.s[i2->u.i] = 0;
|
||||
}
|
||||
freev (l);
|
||||
freev (i1);
|
||||
freev (i2);
|
||||
return v;
|
||||
}
|
||||
else
|
||||
return eval7 ();
|
||||
}
|
||||
|
||||
/* Handle : operator (pattern matching).
|
||||
Calls docolon to do the real work. */
|
||||
|
||||
static VALUE *eval5 (void)
|
||||
{
|
||||
VALUE *l, *r, *v;
|
||||
|
||||
l = eval6 ();
|
||||
while (nextarg (":")) {
|
||||
args++;
|
||||
r = eval6 ();
|
||||
v = docolon (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = v;
|
||||
}
|
||||
return l;
|
||||
}
|
||||
|
||||
/* Handle *, /, % operators. */
|
||||
|
||||
static VALUE *eval4 (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
int (*fxn) (), val;
|
||||
|
||||
l = eval5 ();
|
||||
while (1) {
|
||||
if (nextarg ("*"))
|
||||
fxn = multiply;
|
||||
else if (nextarg ("/"))
|
||||
fxn = divide;
|
||||
else if (nextarg ("%"))
|
||||
fxn = mod;
|
||||
else
|
||||
return l;
|
||||
args++;
|
||||
r = eval5 ();
|
||||
val = (*fxn) (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = int_value (val);
|
||||
}
|
||||
}
|
||||
|
||||
/* Handle +, - operators. */
|
||||
|
||||
static VALUE *eval3 (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
int (*fxn) (), val;
|
||||
|
||||
l = eval4 ();
|
||||
while (1) {
|
||||
if (nextarg ("+"))
|
||||
fxn = plus;
|
||||
else if (nextarg ("-"))
|
||||
fxn = minus;
|
||||
else
|
||||
return l;
|
||||
args++;
|
||||
r = eval4 ();
|
||||
val = (*fxn) (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = int_value (val);
|
||||
}
|
||||
}
|
||||
|
||||
/* Handle comparisons. */
|
||||
|
||||
static VALUE *eval2 (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
int (*fxn) (), val;
|
||||
|
||||
l = eval3 ();
|
||||
while (1) {
|
||||
if (nextarg ("<"))
|
||||
fxn = less_than;
|
||||
else if (nextarg ("<="))
|
||||
fxn = less_equal;
|
||||
else if (nextarg ("=") || nextarg ("=="))
|
||||
fxn = equal;
|
||||
else if (nextarg ("!="))
|
||||
fxn = not_equal;
|
||||
else if (nextarg (">="))
|
||||
fxn = greater_equal;
|
||||
else if (nextarg (">"))
|
||||
fxn = greater_than;
|
||||
else
|
||||
return l;
|
||||
args++;
|
||||
r = eval3 ();
|
||||
toarith (l);
|
||||
toarith (r);
|
||||
val = (*fxn) (l, r);
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = int_value (val);
|
||||
}
|
||||
}
|
||||
|
||||
/* Handle &. */
|
||||
|
||||
static VALUE *eval1 (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
|
||||
l = eval2 ();
|
||||
while (nextarg ("&")) {
|
||||
args++;
|
||||
r = eval2 ();
|
||||
if (null (l) || null (r)) {
|
||||
freev (l);
|
||||
freev (r);
|
||||
l = int_value (0);
|
||||
}
|
||||
else
|
||||
freev (r);
|
||||
}
|
||||
return l;
|
||||
}
|
||||
|
||||
/* Handle |. */
|
||||
|
||||
static VALUE *eval (void)
|
||||
{
|
||||
VALUE *l, *r;
|
||||
|
||||
l = eval1 ();
|
||||
while (nextarg ("|")) {
|
||||
args++;
|
||||
r = eval1 ();
|
||||
if (null (l)) {
|
||||
freev (l);
|
||||
l = r;
|
||||
}
|
||||
else
|
||||
freev (r);
|
||||
}
|
||||
return l;
|
||||
}
|
||||
@ -110,6 +110,7 @@ extern const struct BB_applet applets[];
|
||||
|
||||
extern int ar_main(int argc, char **argv);
|
||||
extern int basename_main(int argc, char **argv);
|
||||
extern int bogomips_main(int argc, char **argv);
|
||||
extern int busybox_main(int argc, char** argv);
|
||||
extern int cat_main(int argc, char** argv);
|
||||
extern int chmod_chown_chgrp_main(int argc, char** argv);
|
||||
@ -129,6 +130,7 @@ extern int du_main(int argc, char** argv);
|
||||
extern int dumpkmap_main(int argc, char** argv);
|
||||
extern int dutmp_main(int argc, char** argv);
|
||||
extern int echo_main(int argc, char** argv);
|
||||
extern int expr_main(int argc, char** argv);
|
||||
extern int false_main(int argc, char** argv);
|
||||
extern int fbset_main(int argc, char** argv);
|
||||
extern int fdisk_main(int argc, char** argv);
|
||||
@ -240,6 +242,7 @@ extern const char du_usage[];
|
||||
extern const char dumpkmap_usage[];
|
||||
extern const char dutmp_usage[];
|
||||
extern const char echo_usage[];
|
||||
extern const char expr_usage[];
|
||||
extern const char false_usage[];
|
||||
extern const char fdflush_usage[];
|
||||
extern const char find_usage[];
|
||||
|
||||
38
usage.c
38
usage.c
@ -250,6 +250,44 @@ const char echo_usage[] =
|
||||
;
|
||||
#endif
|
||||
|
||||
#if defined BB_EXPR
|
||||
const char expr_usage[] =
|
||||
"expr EXPRESSION\n"
|
||||
#ifndef BB_FEATURE_TRIVIAL_HELP
|
||||
"\nPrints the value of EXPRESSION to standard output.\n\n"
|
||||
"EXPRESSION may be:\n"
|
||||
"ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2\n"
|
||||
"ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0\n"
|
||||
"ARG1 < ARG2 ARG1 is less than ARG2\n"
|
||||
"ARG1 <= ARG2 ARG1 is less than or equal to ARG2\n"
|
||||
"ARG1 = ARG2 ARG1 is equal to ARG2\n"
|
||||
"ARG1 != ARG2 ARG1 is unequal to ARG2\n"
|
||||
"ARG1 >= ARG2 ARG1 is greater than or equal to ARG2\n"
|
||||
"ARG1 > ARG2 ARG1 is greater than ARG2\n"
|
||||
"ARG1 + ARG2 arithmetic sum of ARG1 and ARG2\n"
|
||||
"ARG1 - ARG2 arithmetic difference of ARG1 and ARG2\n"
|
||||
"ARG1 * ARG2 arithmetic product of ARG1 and ARG2\n"
|
||||
"ARG1 / ARG2 arithmetic quotient of ARG1 divided by ARG2\n"
|
||||
"ARG1 % ARG2 arithmetic remainder of ARG1 divided by ARG2\n"
|
||||
"STRING : REGEXP anchored pattern match of REGEXP in STRING\n"
|
||||
"match STRING REGEXP same as STRING : REGEXP\n"
|
||||
"substr STRING POS LENGTH substring of STRING, POS counted from 1\n"
|
||||
"index STRING CHARS index in STRING where any CHARS is found, or 0\n"
|
||||
"length STRING length of STRING\n"
|
||||
"quote TOKEN interpret TOKEN as a string, even if it is a \n"
|
||||
" keyword like `match' or an operator like `/'\n"
|
||||
"( EXPRESSION ) value of EXPRESSION\n\n"
|
||||
"Beware that many operators need to be escaped or quoted for shells.\n"
|
||||
"Comparisons are arithmetic if both ARGs are numbers, else\n"
|
||||
"lexicographical. Pattern matches return the string matched between \n"
|
||||
"\\( and \\) or null; if \\( and \\) are not used, they return the number \n"
|
||||
"of characters matched or 0.\n"
|
||||
|
||||
#endif
|
||||
;
|
||||
#endif
|
||||
|
||||
|
||||
#if defined BB_TRUE_FALSE
|
||||
const char false_usage[] =
|
||||
"false\n"
|
||||
|
||||
2
wc.c
2
wc.c
@ -2,7 +2,7 @@
|
||||
/*
|
||||
* Mini wc implementation for busybox
|
||||
*
|
||||
* by Edward Betts <edward@debian.org>
|
||||
* Copyright (C) 2000 Edward Betts <edward@debian.org>
|
||||
*
|
||||
* 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
|
||||
|
||||
Loading…
Reference in New Issue
Block a user