static arith_t
ash_arith(const char *s)
{
- arith_eval_hooks_t math_hooks;
+ arith_state_t math_state;
arith_t result;
- int errcode = 0;
- math_hooks.lookupvar = lookupvar;
- math_hooks.setvar = setvar2;
- //math_hooks.endofname = endofname;
+ math_state.lookupvar = lookupvar;
+ math_state.setvar = setvar2;
+ //math_state.endofname = endofname;
INT_OFF;
- result = arith(s, &errcode, &math_hooks);
- if (errcode < 0) {
- if (errcode == -3)
+ result = arith(&math_state, s);
+ if (math_state.errcode < 0) {
+ if (math_state.errcode == -3)
ash_msg_and_raise_error("exponent less than 0");
- if (errcode == -2)
+ if (math_state.errcode == -2)
ash_msg_and_raise_error("divide by zero");
- if (errcode == -5)
+ if (math_state.errcode == -5)
ash_msg_and_raise_error("expression recursion loop detected");
raise_error_syntax(s);
}
#if ENABLE_SH_MATH_SUPPORT
static arith_t expand_and_evaluate_arith(const char *arg, int *errcode_p)
{
- arith_eval_hooks_t hooks;
+ arith_state_t math_state;
arith_t res;
char *exp_str;
- hooks.lookupvar = get_local_var_value;
- hooks.setvar = set_local_var_from_halves;
- //hooks.endofname = endofname;
+ math_state.lookupvar = get_local_var_value;
+ math_state.setvar = set_local_var_from_halves;
+ //math_state.endofname = endofname;
exp_str = encode_then_expand_string(arg, /*process_bkslash:*/ 1, /*unbackslash:*/ 1);
- res = arith(exp_str ? exp_str : arg, errcode_p, &hooks);
+ res = arith(&math_state, exp_str ? exp_str : arg);
+ *errcode_p = math_state.errcode;
free(exp_str);
return res;
}
#include "libbb.h"
#include "math.h"
-#define a_e_h_t arith_eval_hooks_t
-#define lookupvar (math_hooks->lookupvar)
-#define setvar (math_hooks->setvar )
-//#define endofname (math_hooks->endofname)
+#define lookupvar (math_state->lookupvar)
+#define setvar (math_state->setvar )
+//#define endofname (math_state->endofname)
typedef unsigned char operator;
static chk_var_recursive_looped_t *prev_chk_var_recursive;
static int
-arith_lookup_val(v_n_t *t, a_e_h_t *math_hooks)
+arith_lookup_val(arith_state_t *math_state, v_n_t *t)
{
if (t->var) {
const char *p = lookupvar(t->var);
if (p) {
- int errcode;
chk_var_recursive_looped_t *cur;
chk_var_recursive_looped_t cur_save;
cur_save.next = cur;
prev_chk_var_recursive = &cur_save;
- t->val = arith(p, &errcode, math_hooks);
+ t->val = arith(math_state, p);
/* restore previous ptr after recursion */
prev_chk_var_recursive = cur;
- return errcode;
+ return math_state->errcode;
}
/* allow undefined var as 0 */
t->val = 0;
* stack. For an unary operator it will only change the top element, but a
* binary operator will pop two arguments and push the result */
static NOINLINE int
-arith_apply(operator op, v_n_t *numstack, v_n_t **numstackptr, a_e_h_t *math_hooks)
+arith_apply(arith_state_t *math_state, operator op, v_n_t *numstack, v_n_t **numstackptr)
{
#define NUMPTR (*numstackptr)
v_n_t *numptr_m1;
arith_t numptr_val, rez;
- int ret_arith_lookup_val;
+ int err;
/* There is no operator that can work without arguments */
if (NUMPTR == numstack)
numptr_m1 = NUMPTR - 1;
/* Check operand is var with noninteger value */
- ret_arith_lookup_val = arith_lookup_val(numptr_m1, math_hooks);
- if (ret_arith_lookup_val)
- return ret_arith_lookup_val;
+ err = arith_lookup_val(math_state, numptr_m1);
+ if (err)
+ return err;
rez = numptr_m1->val;
if (op == TOK_UMINUS)
numptr_m1 = NUMPTR - 1;
if (op != TOK_ASSIGN) {
/* check operand is var with noninteger value for not '=' */
- ret_arith_lookup_val = arith_lookup_val(numptr_m1, math_hooks);
- if (ret_arith_lookup_val)
- return ret_arith_lookup_val;
+ err = arith_lookup_val(math_state, numptr_m1);
+ if (err)
+ return err;
}
if (op == TOK_CONDITIONAL) {
numptr_m1->contidional_second_val = rez;
}
arith_t
-arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
+arith(arith_state_t *math_state, const char *expr)
{
operator lasttok;
int errcode;
}
if (numstack->var) {
/* expression is $((var)) only, lookup now */
- errcode = arith_lookup_val(numstack, math_hooks);
+ errcode = arith_lookup_val(math_state, numstack);
}
goto ret;
}
break;
}
}
- errcode = arith_apply(prev_op, numstack, &numstackptr, math_hooks);
+ errcode = arith_apply(math_state, prev_op, numstack, &numstackptr);
if (errcode)
goto ret;
}
err:
numstack->val = errcode = -1;
ret:
- *perrcode = errcode;
+ math_state->errcode = errcode;
return numstack->val;
}
/* The math library has just one function:
*
- * arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t *hooks);
+ * arith_t arith(arith_state_t *states, const char *expr);
*
- * The first argument is the math string to parse. All normal expansions must
- * be done already. i.e. no dollar symbols should be present.
+ * The expr argument is the math string to parse. All normal expansions must
+ * be done already. i.e. no dollar symbols should be present.
*
- * The second argument is a semi-detailed error description in case something
- * goes wrong in the parsing steps. Currently, those values are (for
- * compatibility, you should assume all negative values are errors):
- * 0 - no errors (yay!)
- * -1 - unspecified problem
- * -2 - divide by zero
- * -3 - exponent less than 0
- * -5 - expression recursion loop detected
+ * The state argument is a pointer to a struct of hooks for your shell (see below),
+ * and a semi-detailed error code. Currently, those values are (for
+ * compatibility, you should assume all negative values are errors):
+ * 0 - no errors (yay!)
+ * -1 - unspecified problem
+ * -2 - divide by zero
+ * -3 - exponent less than 0
+ * -5 - expression recursion loop detected
*
- * The third argument is a struct pointer of hooks for your shell (see below).
- *
- * The function returns the answer to the expression. So if you called it
- * with the expression:
- * "1 + 2 + 3"
- * You would obviously get back 6.
+ * The function returns the answer to the expression. So if you called it
+ * with the expression:
+ * "1 + 2 + 3"
+ * you would obviously get back 6.
*/
/* To add support to a shell, you need to implement three functions:
*
- * lookupvar() - look up and return the value of a variable
+ * lookupvar() - look up and return the value of a variable
*
- * If the shell does:
- * foo=123
- * Then the code:
- * const char *val = lookupvar("foo");
- * Will result in val pointing to "123"
+ * If the shell does:
+ * foo=123
+ * Then the code:
+ * const char *val = lookupvar("foo");
+ * will result in val pointing to "123"
*
- * setvar() - set a variable to some value
+ * setvar() - set a variable to some value
*
- * If the arithmetic expansion does something like:
- * $(( i = 1))
- * Then the math code will make a call like so:
- * setvar("i", "1", 0);
- * The storage for the first two parameters are not allocated, so your
- * shell implementation will most likely need to strdup() them to save.
+ * If the arithmetic expansion does something like:
+ * $(( i = 1))
+ * then the math code will make a call like so:
+ * setvar("i", "1", 0);
+ * The storage for the first two parameters are not allocated, so your
+ * shell implementation will most likely need to strdup() them to save.
*
- * endofname() - return the end of a variable name from input
+ * endofname() - return the end of a variable name from input
*
- * The arithmetic code does not know about variable naming conventions.
- * So when it is given an experession, it knows something is not numeric,
- * but it is up to the shell to dictate what is a valid identifiers.
- * So when it encounters something like:
- * $(( some_var + 123 ))
- * It will make a call like so:
- * end = endofname("some_var + 123");
- * So the shell needs to scan the input string and return a pointer to the
- * first non-identifier string. In this case, it should return the input
- * pointer with an offset pointing to the first space. The typical
- * implementation will return the offset of first char that does not match
- * the regex (in C locale): ^[a-zA-Z_][a-zA-Z_0-9]*
+ * The arithmetic code does not know about variable naming conventions.
+ * So when it is given an experession, it knows something is not numeric,
+ * but it is up to the shell to dictate what is a valid identifiers.
+ * So when it encounters something like:
+ * $(( some_var + 123 ))
+ * It will make a call like so:
+ * end = endofname("some_var + 123");
+ * So the shell needs to scan the input string and return a pointer to the
+ * first non-identifier string. In this case, it should return the input
+ * pointer with an offset pointing to the first space. The typical
+ * implementation will return the offset of first char that does not match
+ * the regex (in C locale): ^[a-zA-Z_][a-zA-Z_0-9]*
*/
/* To make your life easier when dealing with optional 64bit math support,
typedef void FAST_FUNC (*arith_var_set_t)(const char *name, const char *val);
//typedef const char* FAST_FUNC (*arith_var_endofname_t)(const char *name);
-typedef struct arith_eval_hooks {
+typedef struct arith_state_t {
arith_var_lookup_t lookupvar;
arith_var_set_t setvar;
// arith_var_endofname_t endofname;
-} arith_eval_hooks_t;
+ int errcode;
+} arith_state_t;
-arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t*);
+arith_t arith(arith_state_t *state, const char *expr);
POP_SAVED_FUNCTION_VISIBILITY
projects / oweals / busybox.git / commitdiff