fsm/test_rmcom.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>    /* for memset() */
   4
   5 #include "fsm.h"
   6 #include "states.h"
   7 #include "types.h"
   8
   9 #define EVT_NO_START_COMMENT  1
  10 #define EVT_NO_END_COMMENT    2
  11 #define EVT_START_COMMENT     3
  12 #define EVT_END_COMMENT       4
  13
  14 #define ST_NO_COMMENT         1
  15 #define ST_COMMENT            2
  16
  17 /* Function prototypes */
  18 unsigned int get_evt_key(const fsm_t *fsm, char **p);
  19 void print_char(void *data);
  20 void dief(const char *p);
  21
  22 /*
  23  * get_evt_key() works like an "event generator".
  24  * It examines the current state of FSM along with
  25  * the input we feed it, and then generates an
  26  * appropriate event.
  27  *
  28  * fsm_process_event() acts as an "event consumer",
  29  * handling each one of the previously generated events.
  30  */
  31 unsigned int get_evt_key(const fsm_t *fsm, char **p)
  32 {
  33     unsigned int stkey;
  34
  35     /* Get current state of FSM */
  36     stkey = fsm_get_current_state(fsm);
  37
  38     if (stkey == ST_NO_COMMENT) {
  39         if (**p == '/' && (*p)[1] == '*') {
  40             *p += 2;
  41             return EVT_START_COMMENT;
  42         }
  43         else {
  44             *p += 1;
  45             return EVT_NO_START_COMMENT;
  46         }
  47     }
  48     else if (stkey == ST_COMMENT) {
  49         if (**p == '*' && (*p)[1] == '/') {
  50             *p += 2;
  51             return EVT_END_COMMENT;
  52         }
  53         else {
  54             *p += 1;
  55             return EVT_NO_END_COMMENT;
  56         }
  57     }
  58
  59     /* Normally, this would never be reached */
  60     *p += 1;
  61     return -1;
  62 }
  63
  64 void print_char(void *data)
  65 {
  66     printf("%c", *(char *)data);
  67 }
  68
  69 int main(int argc, char *argv[])
  70 {
  71     char buf[256];    /* must be big enough, or else beginning of comment might split */
  72     state_t *st_no_comment;
  73     state_t *st_comment;
  74     fsm_t *fsm;
  75     FILE *fp;
  76     char *p;
  77
  78     /* Check argument count */
  79     if (argc != 2) {
  80         fprintf(stderr, "Usage: %s file.c\n", argv[0]);
  81         exit(EXIT_FAILURE);
  82     }
  83
  84     /* Open file to parse */
  85     if ((fp = fopen(argv[1], "r")) == NULL) {
  86         perror("fopen()");
  87         exit(EXIT_FAILURE);
  88     }
  89
  90     /* Initialize fsm */
  91     fsm_init(&fsm, 2<<8, 5, 0);
  92
  93     /* Initialize states */
  94     if (state_init(&st_no_comment, 2<<5, 2) == ST_NOMEM) {
  95         fsm_free(fsm);
  96         dief("state_init(): ST_NOMEM");
  97     }
  98     if (state_init(&st_comment, 2<<5, 2) == ST_NOMEM) {
  99         fsm_free(fsm);
 100         state_free(st_no_comment);
 101         dief("state_init(): ST_NOMEM");
 102     }
 103
 104     /* Construct state transition table */
 105     if ((state_add_evt(st_no_comment,  EVT_NO_START_COMMENT, "", print_char, st_no_comment) == ST_NOMEM) ||
 106         (state_add_evt(st_no_comment,  EVT_START_COMMENT,    "", NULL,       st_comment   ) == ST_NOMEM) ||
 107         (state_add_evt(st_comment,     EVT_NO_END_COMMENT,   "", NULL,       st_comment   ) == ST_NOMEM) ||
 108         (state_add_evt(st_comment,     EVT_END_COMMENT,      "", NULL,       st_no_comment))) {
 109         dief("state_add_evt(): ST_NOMEM");
 110         fsm_free(fsm);
 111     }
 112
 113     /* Add states */
 114     fsm_add_state(fsm, ST_NO_COMMENT, st_no_comment);
 115     fsm_add_state(fsm, ST_COMMENT, st_comment);
 116
 117     /* Set initial state */
 118     fsm_set_state(fsm, ST_NO_COMMENT);
 119
 120     /* Parse file */
 121     while (!feof(fp)) {
 122         memset(buf, 0, sizeof buf);
 123         if (fgets(buf, sizeof buf, fp) == NULL && !feof(fp)) {
 124             perror("fgets()");
 125             break;
 126         }
 127         p = buf;
 128         while (*p != '\0')
 129             fsm_process_event(fsm, get_evt_key(fsm, &p), p);
 130     }
 131
 132     /* Free memory */
 133     fsm_free(fsm);
 134
 135     /* Close file */
 136     (void)fclose(fp);
 137
 138     return EXIT_SUCCESS;
 139 }
 140
 141 void dief(const char *p)
 142 {
 143     fprintf(stderr, "error: %s\n", p);
 144     exit(EXIT_FAILURE);
 145 }