svn commit: r223882 - head/bin/expr
Stefan Esser
se at FreeBSD.org
Sat Jul 9 12:14:57 UTC 2011
Author: se
Date: Sat Jul 9 12:14:57 2011
New Revision: 223882
URL: http://svn.freebsd.org/changeset/base/223882
Log:
Some refactoring for easier maintenance of the code. This is a follow-up
to re-establishment of 64bit arithmetic, but is committed separately, to
not obscure that conversion. This commit does not change the observed
behaviour of expr in any way. Style will be fixed in a follow-up commit.
Modified:
head/bin/expr/expr.y
Modified: head/bin/expr/expr.y
==============================================================================
--- head/bin/expr/expr.y Sat Jul 9 12:05:53 2011 (r223881)
+++ head/bin/expr/expr.y Sat Jul 9 12:14:57 2011 (r223882)
@@ -40,13 +40,16 @@ struct val {
} u;
} ;
+char **av;
+int nonposix;
struct val *result;
void assert_to_integer(struct val *);
-int chk_div(intmax_t, intmax_t);
-int chk_minus(intmax_t, intmax_t, intmax_t);
-int chk_plus(intmax_t, intmax_t, intmax_t);
-int chk_times(intmax_t, intmax_t, intmax_t);
+void assert_div(intmax_t, intmax_t);
+void assert_minus(intmax_t, intmax_t, intmax_t);
+void assert_plus(intmax_t, intmax_t, intmax_t);
+void assert_times(intmax_t, intmax_t, intmax_t);
+int compare_vals(struct val *, struct val *);
void free_value(struct val *);
int is_integer(const char *);
int isstring(struct val *);
@@ -73,8 +76,6 @@ int yyerror(const char *);
int yylex(void);
int yyparse(void);
-static int nonposix;
-char **av;
%}
%union
@@ -344,138 +345,77 @@ op_and(struct val *a, struct val *b)
}
}
-struct val *
-op_eq(struct val *a, struct val *b)
+int
+compare_vals(struct val *a, struct val *b)
{
- struct val *r;
+ int r;
- if (isstring (a) || isstring (b)) {
- to_string (a);
- to_string (b);
- r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) == 0));
+ if (isstring(a) || isstring(b)) {
+ to_string(a);
+ to_string(b);
+ r = strcoll(a->u.s, b->u.s);
} else {
assert_to_integer(a);
assert_to_integer(b);
- r = make_integer ((intmax_t)(a->u.i == b->u.i));
+ if (a->u.i > b->u.i)
+ r = 1;
+ else if (a->u.i < b->u.i)
+ r = -1;
+ else
+ r = 0;
}
- free_value (a);
- free_value (b);
- return r;
+ free_value(a);
+ free_value(b);
+ return (r);
}
struct val *
-op_gt(struct val *a, struct val *b)
+op_eq(struct val *a, struct val *b)
{
- struct val *r;
-
- if (isstring (a) || isstring (b)) {
- to_string (a);
- to_string (b);
- r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) > 0));
- } else {
- assert_to_integer(a);
- assert_to_integer(b);
- r = make_integer ((intmax_t)(a->u.i > b->u.i));
- }
+ return (make_integer((intmax_t)(compare_vals(a, b) == 0)));
+}
- free_value (a);
- free_value (b);
- return r;
+struct val *
+op_gt(struct val *a, struct val *b)
+{
+ return (make_integer((intmax_t)(compare_vals(a, b) > 0)));
}
struct val *
op_lt(struct val *a, struct val *b)
{
- struct val *r;
-
- if (isstring (a) || isstring (b)) {
- to_string (a);
- to_string (b);
- r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) < 0));
- } else {
- assert_to_integer(a);
- assert_to_integer(b);
- r = make_integer ((intmax_t)(a->u.i < b->u.i));
- }
-
- free_value (a);
- free_value (b);
- return r;
+ return (make_integer((intmax_t)(compare_vals(a, b) < 0)));
}
struct val *
op_ge(struct val *a, struct val *b)
{
- struct val *r;
-
- if (isstring (a) || isstring (b)) {
- to_string (a);
- to_string (b);
- r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) >= 0));
- } else {
- assert_to_integer(a);
- assert_to_integer(b);
- r = make_integer ((intmax_t)(a->u.i >= b->u.i));
- }
-
- free_value (a);
- free_value (b);
- return r;
+ return (make_integer((intmax_t)(compare_vals(a, b) >= 0)));
}
struct val *
op_le(struct val *a, struct val *b)
{
- struct val *r;
-
- if (isstring (a) || isstring (b)) {
- to_string (a);
- to_string (b);
- r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) <= 0));
- } else {
- assert_to_integer(a);
- assert_to_integer(b);
- r = make_integer ((intmax_t)(a->u.i <= b->u.i));
- }
-
- free_value (a);
- free_value (b);
- return r;
+ return (make_integer((intmax_t)(compare_vals(a, b) <= 0)));
}
struct val *
op_ne(struct val *a, struct val *b)
{
- struct val *r;
-
- if (isstring (a) || isstring (b)) {
- to_string (a);
- to_string (b);
- r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) != 0));
- } else {
- assert_to_integer(a);
- assert_to_integer(b);
- r = make_integer ((intmax_t)(a->u.i != b->u.i));
- }
-
- free_value (a);
- free_value (b);
- return r;
+ return (make_integer((intmax_t)(compare_vals(a, b) != 0)));
}
-int
-chk_plus(intmax_t a, intmax_t b, intmax_t r)
+void
+assert_plus(intmax_t a, intmax_t b, intmax_t r)
{
-
- /* sum of two positive numbers must be positive */
- if (a > 0 && b > 0 && r <= 0)
- return 1;
- /* sum of two negative numbers must be negative */
- if (a < 0 && b < 0 && r >= 0)
- return 1;
- /* all other cases are OK */
- return 0;
+ /*
+ * sum of two positive numbers must be positive,
+ * sum of two negative numbers must be negative
+ */
+ if ((a > 0 && b > 0 && r <= 0) ||
+ (a < 0 && b < 0 && r >= 0))
+ errx(ERR_EXIT, "overflow");
}
struct val *
@@ -487,28 +427,22 @@ op_plus(struct val *a, struct val *b)
assert_to_integer(b);
r = make_integer(a->u.i + b->u.i);
- if (chk_plus(a->u.i, b->u.i, r->u.i)) {
- errx(ERR_EXIT, "overflow");
- }
+ assert_plus(a->u.i, b->u.i, r->u.i);
free_value (a);
free_value (b);
return r;
}
-int
-chk_minus(intmax_t a, intmax_t b, intmax_t r)
+void
+assert_minus(intmax_t a, intmax_t b, intmax_t r)
{
/* special case subtraction of INTMAX_MIN */
- if (b == INTMAX_MIN) {
- if (a >= 0)
- return 1;
- else
- return 0;
- }
- /* this is allowed for b != INTMAX_MIN */
- return chk_plus (a, -b, r);
+ if (b == INTMAX_MIN && a < 0)
+ errx(ERR_EXIT, "overflow");
+ /* check addition of negative subtrahend */
+ assert_plus(a, -b, r);
}
struct val *
@@ -520,25 +454,22 @@ op_minus(struct val *a, struct val *b)
assert_to_integer(b);
r = make_integer(a->u.i - b->u.i);
- if (chk_minus(a->u.i, b->u.i, r->u.i)) {
- errx(ERR_EXIT, "overflow");
- }
+ assert_minus(a->u.i, b->u.i, r->u.i);
free_value (a);
free_value (b);
return r;
}
-int
-chk_times(intmax_t a, intmax_t b, intmax_t r)
+void
+assert_times(intmax_t a, intmax_t b, intmax_t r)
{
- /* special case: first operand is 0, no overflow possible */
- if (a == 0)
- return 0;
- /* verify that result of division matches second operand */
- if (r / a != b)
- return 1;
- return 0;
+ /*
+ * if first operand is 0, no overflow is possible,
+ * else result of division test must match second operand
+ */
+ if (a != 0 && r / a != b)
+ errx(ERR_EXIT, "overflow");
}
struct val *
@@ -550,24 +481,21 @@ op_times(struct val *a, struct val *b)
assert_to_integer(b);
r = make_integer(a->u.i * b->u.i);
- if (chk_times(a->u.i, b->u.i, r->u.i)) {
- errx(ERR_EXIT, "overflow");
- }
+ assert_times(a->u.i, b->u.i, r->u.i);
free_value (a);
free_value (b);
return (r);
}
-int
-chk_div(intmax_t a, intmax_t b)
+void
+assert_div(intmax_t a, intmax_t b)
{
- /* div by zero has been taken care of before */
+ if (b == 0)
+ errx(ERR_EXIT, "division by zero");
/* only INTMAX_MIN / -1 causes overflow */
if (a == INTMAX_MIN && b == -1)
- return 1;
- /* everything else is OK */
- return 0;
+ errx(ERR_EXIT, "overflow");
}
struct val *
@@ -578,12 +506,8 @@ op_div(struct val *a, struct val *b)
assert_to_integer(a);
assert_to_integer(b);
- if (b->u.i == 0) {
- errx(ERR_EXIT, "division by zero");
- }
- if (chk_div(a->u.i, b->u.i)) {
- errx(ERR_EXIT, "overflow");
- }
+ /* assert based on operands only, not on result */
+ assert_div(a->u.i, b->u.i);
r = make_integer(a->u.i / b->u.i);
free_value (a);
@@ -598,9 +522,8 @@ op_rem(struct val *a, struct val *b)
assert_to_integer(a);
assert_to_integer(b);
- if (b->u.i == 0) {
- errx(ERR_EXIT, "division by zero");
- }
+ /* pass a=1 to only check for div by zero */
+ assert_div(1, b->u.i);
r = make_integer(a->u.i % b->u.i);
free_value (a);
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