minix/lib/libmagicrt/include/magic_eval_lib.h

   1 /* evaluate.h (C) 2000-2002 Kyzer/CSG. */
   2 /* Released under the terms of the GNU General Public Licence version 2. */
   3 /* http://www.kyzer.me.uk/code/evaluate/ */
   4
   5 #include <stddef.h>
   6 #include <stdlib.h>
   7
   8 #define T_INT    0
   9 #define T_REAL   1
  10
  11 /* value */
  12 struct val {
  13   long   ival; /* if type = T_INT, this is the result */
  14   double rval; /* if type = T_REAL, this is the result */
  15   char   type; /* either T_INT or T_REAL */
  16 };
  17
  18 /* variable */
  19 struct var {
  20   struct var *next; /* next variable in table or NULL */
  21   struct val val;   /* value of variable */
  22   char   *name;     /* name of variable */
  23 };
  24
  25 /* variable table */
  26 struct vartable {
  27   struct var *first; /* first entry in variable table */
  28   struct memh *mh;
  29 };
  30
  31 /* creates a new variable table (NULL if no memory) */
  32 struct vartable *create_vartable(void);
  33
  34 /* frees a variable table */
  35 void free_vartable(struct vartable *vt);
  36
  37 /* gets a variable from a variable table (NULL if not found) */
  38 struct var *get_var(struct vartable *vt, char *name);
  39
  40 /* puts a variable into a variable table (NULL if no memory) */
  41 struct var *put_var(struct vartable *vt, char *name, struct val *value);
  42
  43 /* callbacks */
  44 typedef struct val*(*get_var_cb_t)(char*, struct val*);
  45 typedef struct val*(*get_func_result_cb_t)(char*, struct val*, struct val*);
  46 void eval_set_cb_get_var(get_var_cb_t cb);
  47 void eval_set_cb_get_func_result(get_func_result_cb_t cb);
  48
  49 /* THE FUNCTION YOU WANT TO CALL */
  50
  51 /* given a string to evaluate (not NULL), a result to put the answer in
  52  * (not NULL) and optionally your own variable table (NULL for 'internal
  53  * only' vartable), will return an error code (and result, etc)
  54  */
  55 int evaluate(char *eval, struct val *result, struct vartable *variables);
  56
  57 /* errors */
  58 #define RESULT_OK               0       /* all OK                       */
  59 #define ERROR_SYNTAX            2       /* invalid expression           */
  60 #define ERROR_VARNOTFOUND       3       /* variable not found           */
  61 #define ERROR_FUNCNOTFOUND      4       /* function not found           */
  62 #define ERROR_NOMEM             8       /* not enough memory available  */
  63 #define ERROR_DIV0              9       /* division by zero             */
  64 #define ERROR_BUSY             10       /* busy now                     */
  65
  66 /* configuration */
  67 #define TOKEN_DEBUG             0
  68 #define EVAL_DEBUG              0
  69 #define EVAL_MALLOC             0
  70 #define USE_MATH_LIB            0
  71 #define MEM_DEBUG               0
  72 #define MEM_LOW_FOOTPRINT       1
  73 #define VAR_FROM_ENV            0
  74