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Some refactoring for easier maintenance of the code. This is a follow-up

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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.
This commit is contained in:
se 2011-07-09 12:14:57 +00:00
parent 7984e12a6b
commit e3f8938f5c
1 changed files with 69 additions and 146 deletions
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215
bin/expr/expr.y
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@ -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_eq(struct val *a, struct val *b)
{
return (make_integer((intmax_t)(compare_vals(a, b) == 0)));
}
struct val *
op_gt(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_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);