77 lines
1.1 KiB
C
77 lines
1.1 KiB
C
#include <stdio.h>
|
|
|
|
FILE *infile = stdin;
|
|
|
|
#define BUF_SIZE 16
|
|
char buf[BUF_SIZE], /* Bufer to save backc()-characters */
|
|
*bufptr = buf; /* Pointer to space for backc()-character */
|
|
int yylineno = 1;
|
|
|
|
|
|
char nextc()
|
|
{
|
|
if ( bufptr > buf)
|
|
return( *--bufptr);
|
|
else
|
|
return( getc( infile));
|
|
}
|
|
|
|
|
|
backc( c)
|
|
char c;
|
|
{
|
|
if ( bufptr > buf + BUF_SIZE)
|
|
error( "backc(), no space in buffer left!");
|
|
else {
|
|
if ( c == '\n')
|
|
yylineno--;
|
|
*bufptr++ = c;
|
|
}
|
|
}
|
|
|
|
|
|
char scanc()
|
|
|
|
/* Get next character, but delete al C-comments */
|
|
|
|
{
|
|
char c;
|
|
|
|
c = nextc();
|
|
while ( c == '/') {
|
|
c = nextc();
|
|
if ( c == '*') { /* start of comment */
|
|
while ( nextc() != '*' || nextc() != '/')
|
|
;
|
|
c = nextc();
|
|
}
|
|
else {
|
|
backc( c);
|
|
return( '/');
|
|
}
|
|
}
|
|
if ( c == '\n')
|
|
yylineno++;
|
|
return( c);
|
|
}
|
|
|
|
|
|
FILE *switch_input( new)
|
|
FILE *new;
|
|
|
|
/* Return the current FILE, if buf[] can't be cleaned NULL will be returned */
|
|
|
|
{
|
|
char *ptr; FILE *old;
|
|
|
|
/* Clean buf[] */
|
|
for ( ptr = buf; ptr < bufptr; ptr++)
|
|
if ( ungetc( *ptr, infile) == EOF && *ptr != EOF)
|
|
return( NULL);
|
|
|
|
bufptr = buf;
|
|
old = infile;
|
|
infile = new;
|
|
return( old);
|
|
}
|