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-rw-r--r--expr.c535
1 files changed, 0 insertions, 535 deletions
diff --git a/expr.c b/expr.c
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--- a/expr.c
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@@ -1,535 +0,0 @@
-/* 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). */
-
-/* no getopt needed */
-
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <regex.h>
-#include <sys/types.h>
-#include "busybox.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) {
- error_msg_and_die("too few arguments");
- }
-
- args = argv + 1;
-
- v = eval ();
- if (*args)
- error_msg_and_die ("syntax error");
-
- if (v->type == integer)
- printf ("%d\n", v->u.i);
- else
- puts (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)) \
- error_msg_and_die ("non-numeric argument"); \
- return l->u.i op r->u.i; \
-}
-
-#define arithdivf(name, op) \
-static int name (l, r) VALUE *l; VALUE *r; \
-{ \
- if (!toarith (l) || !toarith (r)) \
- error_msg_and_die ( "non-numeric argument"); \
- if (r->u.i == 0) \
- error_msg_and_die ( "division by zero"); \
- 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) {
- error_msg_and_die("%s", 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)
- error_msg_and_die ( "syntax error");
-
- if (nextarg ("(")) {
- args++;
- v = eval ();
- if (!nextarg (")"))
- error_msg_and_die ( "syntax error");
- args++;
- return v;
- }
-
- if (nextarg (")"))
- error_msg_and_die ( "syntax error");
-
- 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)
- error_msg_and_die ( "syntax error");
- 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;
-}