Added expr, from Edward Betts <edward@debian.org>, with some fixups

and docs added by me.
 -Erik

2 files changed, 532 insertions, 1 deletions

diff --git a/coreutils/expr.c b/coreutils/expr.c
new file mode 100644
index 0000000..9e3c04a
--- /dev/null
+++ b/coreutils/expr.c
@@ -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;
+}
diff --git a/coreutils/wc.c b/coreutils/wc.c
index 02e2b2a..ca5b368 100644
--- a/coreutils/wc.c
+++ b/coreutils/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