/* ** filter file based on keyword argument ** David Eppstein / UC Irvine / 14 Oct 1995 ** ** calling convention: filter key void bad() { printf("Content-type: text/html\n\n"); printf(" Bad filter input\n"); printf("

Bad filter input

\nBad input to keyword filter program,\n"); printf("unable to process request.\n

\n"); exit(0); } main(ac,av) int ac; char **av; { int c; int copying = 1; char * keyptr = 0; enum { text, dot, bracket, newline, keytest, comment, backslash } state = newline; if (ac != 2) bad(); while ((c = getchar()) != EOF) switch(state) { case text: /* in middle of line */ if (copying) putchar(c); if (c == '\n') state = newline; break; case dot: /* like text but w/o copying newline itself */ if (c == '\n') state = newline; else if (copying) putchar(c); break; case bracket: if (c == '\n') { if (copying) putchar('>'); state = newline; } else if (copying) putchar(c); break; case newline: /* at start of line, test for backslash */ if (c == '\\') state = backslash; else { if (copying) putchar(c); if (c != '\n') state = text; } break; case keytest: /* testing key and if equal toggling copying */ if (c == '\n') { /* newline marks end of key */ state = newline; if (keyptr != 0 && *keyptr == '0円') copying = !copying; } else if (c == '*') { /* got to a star, found partial match */ state = comment; /* ignore rest of line and toggle copying */ copying = !copying; } else if (keyptr != 0 && *keyptr == c) keyptr++; else state = comment; /* didnt match, ignore rest of line */ break; case comment: /* ignoring chars till newline */ if (c == '\n') state = newline; break; case backslash: switch(c) { case '(': case ')': case '[': case ']': if (copying) { putchar('\\'); putchar(c); } state = text; break; case '\\': /* send through a backslash */ if (copying) putchar(c); state = text; break; case '+': /* start copying */ copying = 1; state = comment; break; case '-': /* stop copying */ copying = 0; state = comment; break; case '.': /* copy line w/o newline */ state = dot; break; case '@': /* protect angle bracket */ if (copying) putchar('<'); state = bracket; break; case '!': /* test key and if equal toggle copying */ state = keytest; keyptr = av[1]; break; case '#': /* comment */ default: state = comment; break; } } }