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.
This commit is contained in:
Stefan Eßer
parent
fa717604a4
commit
6fbe7bf4f2
215
bin/expr/expr.y
215
bin/expr/expr.y
@ -40,13 +40,16 @@ struct val {
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} u;
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} ;
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char **av;
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int nonposix;
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struct val *result;
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void assert_to_integer(struct val *);
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int chk_div(intmax_t, intmax_t);
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int chk_minus(intmax_t, intmax_t, intmax_t);
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int chk_plus(intmax_t, intmax_t, intmax_t);
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int chk_times(intmax_t, intmax_t, intmax_t);
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void assert_div(intmax_t, intmax_t);
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void assert_minus(intmax_t, intmax_t, intmax_t);
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void assert_plus(intmax_t, intmax_t, intmax_t);
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void assert_times(intmax_t, intmax_t, intmax_t);
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int compare_vals(struct val *, struct val *);
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void free_value(struct val *);
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int is_integer(const char *);
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int isstring(struct val *);
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@ -73,8 +76,6 @@ int yyerror(const char *);
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int yylex(void);
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int yyparse(void);
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static int nonposix;
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char **av;
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%}
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%union
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@ -344,138 +345,77 @@ op_and(struct val *a, struct val *b)
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}
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}
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struct val *
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op_eq(struct val *a, struct val *b)
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int
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compare_vals(struct val *a, struct val *b)
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{
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struct val *r;
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int r;
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if (isstring (a) || isstring (b)) {
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to_string (a);
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to_string (b);
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r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) == 0));
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if (isstring(a) || isstring(b)) {
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to_string(a);
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to_string(b);
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r = strcoll(a->u.s, b->u.s);
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} else {
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer ((intmax_t)(a->u.i == b->u.i));
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if (a->u.i > b->u.i)
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r = 1;
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else if (a->u.i < b->u.i)
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r = -1;
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else
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r = 0;
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}
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free_value (a);
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free_value (b);
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return r;
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free_value(a);
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free_value(b);
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return (r);
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}
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struct val *
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op_eq(struct val *a, struct val *b)
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{
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return (make_integer((intmax_t)(compare_vals(a, b) == 0)));
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}
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struct val *
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op_gt(struct val *a, struct val *b)
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{
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struct val *r;
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if (isstring (a) || isstring (b)) {
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to_string (a);
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to_string (b);
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r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) > 0));
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} else {
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer ((intmax_t)(a->u.i > b->u.i));
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}
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free_value (a);
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free_value (b);
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return r;
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return (make_integer((intmax_t)(compare_vals(a, b) > 0)));
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}
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struct val *
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op_lt(struct val *a, struct val *b)
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{
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struct val *r;
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if (isstring (a) || isstring (b)) {
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to_string (a);
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to_string (b);
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r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) < 0));
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} else {
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer ((intmax_t)(a->u.i < b->u.i));
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}
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free_value (a);
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free_value (b);
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return r;
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return (make_integer((intmax_t)(compare_vals(a, b) < 0)));
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}
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struct val *
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op_ge(struct val *a, struct val *b)
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{
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struct val *r;
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if (isstring (a) || isstring (b)) {
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to_string (a);
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to_string (b);
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r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) >= 0));
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} else {
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer ((intmax_t)(a->u.i >= b->u.i));
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}
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free_value (a);
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free_value (b);
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return r;
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return (make_integer((intmax_t)(compare_vals(a, b) >= 0)));
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}
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struct val *
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op_le(struct val *a, struct val *b)
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{
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struct val *r;
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if (isstring (a) || isstring (b)) {
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to_string (a);
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to_string (b);
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r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) <= 0));
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} else {
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer ((intmax_t)(a->u.i <= b->u.i));
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}
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free_value (a);
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free_value (b);
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return r;
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return (make_integer((intmax_t)(compare_vals(a, b) <= 0)));
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}
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struct val *
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op_ne(struct val *a, struct val *b)
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{
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struct val *r;
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if (isstring (a) || isstring (b)) {
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to_string (a);
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to_string (b);
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r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) != 0));
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} else {
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer ((intmax_t)(a->u.i != b->u.i));
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}
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free_value (a);
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free_value (b);
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return r;
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return (make_integer((intmax_t)(compare_vals(a, b) != 0)));
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}
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int
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chk_plus(intmax_t a, intmax_t b, intmax_t r)
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void
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assert_plus(intmax_t a, intmax_t b, intmax_t r)
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{
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/* sum of two positive numbers must be positive */
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if (a > 0 && b > 0 && r <= 0)
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return 1;
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/* sum of two negative numbers must be negative */
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if (a < 0 && b < 0 && r >= 0)
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return 1;
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/* all other cases are OK */
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return 0;
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/*
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* sum of two positive numbers must be positive,
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* sum of two negative numbers must be negative
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*/
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if ((a > 0 && b > 0 && r <= 0) ||
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(a < 0 && b < 0 && r >= 0))
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errx(ERR_EXIT, "overflow");
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}
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struct val *
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@ -487,28 +427,22 @@ op_plus(struct val *a, struct val *b)
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assert_to_integer(b);
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r = make_integer(a->u.i + b->u.i);
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if (chk_plus(a->u.i, b->u.i, r->u.i)) {
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errx(ERR_EXIT, "overflow");
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}
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assert_plus(a->u.i, b->u.i, r->u.i);
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free_value (a);
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free_value (b);
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return r;
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}
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int
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chk_minus(intmax_t a, intmax_t b, intmax_t r)
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void
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assert_minus(intmax_t a, intmax_t b, intmax_t r)
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{
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/* special case subtraction of INTMAX_MIN */
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if (b == INTMAX_MIN) {
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if (a >= 0)
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return 1;
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else
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return 0;
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}
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/* this is allowed for b != INTMAX_MIN */
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return chk_plus (a, -b, r);
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if (b == INTMAX_MIN && a < 0)
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errx(ERR_EXIT, "overflow");
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/* check addition of negative subtrahend */
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assert_plus(a, -b, r);
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}
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struct val *
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@ -520,25 +454,22 @@ op_minus(struct val *a, struct val *b)
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assert_to_integer(b);
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r = make_integer(a->u.i - b->u.i);
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if (chk_minus(a->u.i, b->u.i, r->u.i)) {
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errx(ERR_EXIT, "overflow");
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}
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assert_minus(a->u.i, b->u.i, r->u.i);
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free_value (a);
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free_value (b);
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return r;
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}
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int
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chk_times(intmax_t a, intmax_t b, intmax_t r)
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void
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assert_times(intmax_t a, intmax_t b, intmax_t r)
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{
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/* special case: first operand is 0, no overflow possible */
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if (a == 0)
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return 0;
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/* verify that result of division matches second operand */
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if (r / a != b)
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return 1;
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return 0;
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/*
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* if first operand is 0, no overflow is possible,
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* else result of division test must match second operand
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*/
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if (a != 0 && r / a != b)
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errx(ERR_EXIT, "overflow");
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}
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struct val *
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@ -550,24 +481,21 @@ op_times(struct val *a, struct val *b)
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assert_to_integer(b);
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r = make_integer(a->u.i * b->u.i);
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if (chk_times(a->u.i, b->u.i, r->u.i)) {
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errx(ERR_EXIT, "overflow");
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}
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assert_times(a->u.i, b->u.i, r->u.i);
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free_value (a);
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free_value (b);
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return (r);
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}
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int
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chk_div(intmax_t a, intmax_t b)
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void
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assert_div(intmax_t a, intmax_t b)
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{
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/* div by zero has been taken care of before */
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if (b == 0)
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errx(ERR_EXIT, "division by zero");
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/* only INTMAX_MIN / -1 causes overflow */
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if (a == INTMAX_MIN && b == -1)
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return 1;
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/* everything else is OK */
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return 0;
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errx(ERR_EXIT, "overflow");
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}
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struct val *
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@ -578,12 +506,8 @@ op_div(struct val *a, struct val *b)
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assert_to_integer(a);
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assert_to_integer(b);
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if (b->u.i == 0) {
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errx(ERR_EXIT, "division by zero");
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}
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if (chk_div(a->u.i, b->u.i)) {
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errx(ERR_EXIT, "overflow");
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}
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/* assert based on operands only, not on result */
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assert_div(a->u.i, b->u.i);
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r = make_integer(a->u.i / b->u.i);
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free_value (a);
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@ -598,9 +522,8 @@ op_rem(struct val *a, struct val *b)
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assert_to_integer(a);
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assert_to_integer(b);
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if (b->u.i == 0) {
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errx(ERR_EXIT, "division by zero");
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}
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/* pass a=1 to only check for div by zero */
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assert_div(1, b->u.i);
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r = make_integer(a->u.i % b->u.i);
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free_value (a);
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