/*
* getsym - get next symbol from input stream.
*
* getsym is the basic lexical analyzer. It builds
* basic tokens out of the characters on the input
* stream and sets the following global variables:
*
* lastch: A look behind buffer.
* lastst: type of last symbol read.
* laststr: last string constant read.
* lastid: last identifier read.
* ival: last integer constant read.
* rval: last real constant read.
*
* getsym should be called for all your input needs...
*/
void getsym(void)
{
if (backupchar != - 1)
{
lastst = backupchar;
backupchar = - 1;
return ;
}
if (! *lptr)
{
if ((lastst == eol && lastch == - 1) || lastst == eof)
lastst = eof;
else
lastst = eol;
getch();
return ;
}
while (iswhitespacechar(lastch))
{
getch();
if (! *lptr)
{
lastst = eol;
getch();
return ;
}
}
if (lastch == - 1)
lastst = eof;
else if (isdigit(lastch))
getnum();
else if (isstartchar(lastch))
{
getid();
searchkw();
}
else
getsym2();
}
static int gettok (FILE *fp, char *val, size_t valsize)
{
int lastc;
int c;
char *p;
char *bufend;
*val = '\0';
do {
while ( (c = getc (fp)) != EOF && isspace (c) )
;
if ( c == '#' ) /* single line comment ? */
{
while ( (c = getc (fp)) != EOF && c != '\n' )
;
continue;
}
if ( c == EOF )
return EOF;
if ( c == '{' || c == '}' || c == ';' )
continue;
if ( c == '/' ) /* begin of C comment ? */
{
if ( (c = getc (fp)) == '*' ) /* yes! */
{
lastc = EOF; /* read until end of c comment */
while ( (c = getc (fp)) != EOF && !(lastc == '*' && c == '/') )
lastc = c;
}
else if ( c == '/' ) /* is it a C single line comment ? */
{
while ( (c = getc (fp)) != EOF && c != '\n' )
;
}
else /* no ! */
ungetc (c, fp);
continue;
}
if ( c == '\"' )
{
p = val;
bufend = val + valsize - 1;
while ( (c = getc (fp)) != EOF && p < bufend && c != '\"' )
*p++ = c;
*p = '\0';
/* if string buffer is too small, eat up rest of string */
while ( c != EOF && c != '\"' )
c = getc (fp);
return TOK_STRING;
}
p = val;
bufend = val + valsize - 1;
do
*p++ = tolower (c);
while ( (c = getc (fp)) != EOF && p < bufend && (isalnum (c) || c == '-') );
*p = '\0';
ungetc (c, fp);
if ( (c = searchkw (val)) != TOK_UNKNOWN )
return c;
} while ( c != EOF );
return EOF;
}
