pp.c

   1 /*--------------------------------------------------------------*/
   2 /* pp.c --                                                      */
   3 /*                                                              */
   4 /* This helper program emulates m4 pre-processor behavior.      */
   5 /*                                                              */
   6 /* As of July 2006, XCircuit no longer uses m4, having replaced */
   7 /* it with "sed" scripts.  However, since this C code was       */
   8 /* written to bypass the lack of "m4" under Windows, it is      */
   9 /* still required to bypass the lack of "sed" under Windows.    */
  10 /* The "m4" emulation is maintained.  However, the m4 files     */
  11 /* have been rewritten to remove the awkward "ifelse" syntax,   */
  12 /* which has been replaced with a simpler "<variable_name>"     */
  13 /* at the beginning of each variable-dependent line.  This      */
  14 /* program also handles those situations.                       */
  15 /*--------------------------------------------------------------*/
  16
  17 #include <stdio.h>
  18 #include <string.h>
  19
  20 typedef struct _pattern {
  21         char *pattern;
  22         char *string;
  23         struct _pattern *next;
  24 } pattern;
  25
  26 pattern* parse_args(int* argc, char ***argv)
  27 {
  28         int i, len = 0;
  29         pattern *p = (pattern*)malloc(sizeof(pattern));
  30
  31         p->pattern = "`eval'";
  32         p->string = "eval";
  33         p->next = NULL;
  34
  35         for (i=1; i<(*argc); i++) {
  36                 if (strncmp((*argv)[i], "-D", 2) == 0) {
  37                         char *c = strchr((*argv)[i], '=');
  38                         pattern *new_p;
  39                         if (c == NULL) {
  40                                 printf("Invalid argument: %s\n", (*argv[i]));
  41                                 exit(-1);
  42                         }
  43                         new_p = (pattern*)malloc(sizeof(pattern));
  44                         new_p->next = p;
  45                         p = new_p;
  46                         c[0] = '\0';
  47                         p->pattern = strdup((*argv)[i]+2);
  48                         if (c[1] == '"') {
  49                                 char *c2;
  50                                 c += 2;
  51                                 c2 = strchr(c, '"');
  52                                 if (c2 != NULL)
  53                                         c2[0] = '\0';
  54                         } else {
  55                                 char *c2;
  56                                 c++;
  57                                 c2 = strchr(c, ' ');
  58                                 if (c2 != NULL)
  59                                         c2[0] = '\0';
  60                         }
  61                         p->string = strdup(c);
  62                         /*fprintf(stderr, "%s -> %s\n", p->pattern, p->string);*/
  63                         len++;
  64                 }
  65         }
  66
  67         *argc -= len+1;
  68         *argv += len+1;
  69
  70         return p;
  71 }
  72
  73 int main(int argc, char **argv)
  74 {
  75         char buffer[4096];
  76         char buffer2[4096];
  77         char *c;
  78         int i;
  79         pattern *patterns, *p;
  80         FILE *fin;
  81
  82         patterns = parse_args(&argc, &argv);
  83
  84         if (argc > 0) {
  85                 fin = fopen(argv[0], "r");
  86                 if (fin == NULL) {
  87                         printf("Unable to open file: %s\n", argv[0]);
  88                         exit(-1);
  89                 }
  90         }
  91         else
  92                 fin = stdin;
  93
  94         while (1) {
  95                 if (fgets(buffer, 4096, fin) == 0)
  96                         exit(0);
  97                 p = patterns;
  98                 while (p) {
  99                         while ((c = strstr(buffer, p->pattern)) != NULL) {
 100                                 c[0] = '\0';
 101
 102                                 /* Handle variable-dependent lines */
 103                                 if (c == buffer && !strcmp(p->string, "1")) {
 104                                         strcpy(buffer2, c + strlen(p->pattern) + 1);
 105                                         strcpy(buffer, buffer2);
 106                                 }
 107                                 else if (c == buffer && !strcmp(p->string, "0")) {
 108                                         p = NULL;
 109                                         break;
 110                                 }
 111                                 else {
 112                                         strcpy(buffer2, buffer);
 113                                         strcat(buffer2, p->string);
 114                                         strcat(buffer2, c + strlen(p->pattern));
 115                                         strcpy(buffer, buffer2);
 116                                 }
 117                         }
 118                         if (p == NULL) break;
 119                         p = p->next;
 120                 }
 121                 if (buffer[0] != '\0')
 122                         printf("%s", buffer);
 123         }
 124
 125         if (argc > 0)
 126                 fclose(fin);
 127
 128         return 0;
 129 }