/*
* Check for (and convert) trigraphs.
*/
static int
chktg(void)
{
int ch;
if ((ch = inpch()) != '?') {
unch(ch);
return 0;
}
switch (ch = inpch()) {
case '=': return '#';
case '(': return '[';
case ')': return ']';
case '<': return '{';
case '>': return '}';
case '/': return '\\';
case '\'': return '^';
case '!': return '|';
case '-': return '~';
}
unch(ch);
unch('?');
return 0;
}
/*
* Check for (and convert) trigraphs.
*/
int
chktg()
{
int c;
if ((c = inpch()) != '?') {
unch(c);
return 0;
}
switch (c = inpch()) {
case '=': c = '#'; break;
case '(': c = '['; break;
case ')': c = ']'; break;
case '<': c = '{'; break;
case '>': c = '}'; break;
case '/': c = '\\'; break;
case '\'': c = '^'; break;
case '!': c = '|'; break;
case '-': c = '~'; break;
default:
unch(c);
unch('?');
c = 0;
}
return c;
}
/*
* check for (and eat) end-of-line
*/
static int
chkeol(void)
{
int ch;
ch = inpch();
if (ch == '\r') {
ch = inpch();
if (ch == '\n')
return '\n';
unch(ch);
unch('\r');
return 0;
}
if (ch == '\n')
return '\n';
unch(ch);
return 0;
}
/*
* return next char, after converting trigraphs and
* skipping escaped line endings
*/
static inline int
inch(void)
{
int ch;
for (;;) {
ch = inpch();
if (ch == '?' && (ch = chktg()) == 0)
return '?';
if (ch != '\\' || chkeol() == 0)
return ch;
ifiles->escln++;
}
}
static int
inch(void)
{
int c;
again: switch (c = inpch()) {
case '\\': /* continued lines */
msdos: if ((c = inpch()) == '\n') {
ifiles->lineno++;
goto again;
} else if (c == '\r')
goto msdos;
unch(c);
return '\\';
case '?': /* trigraphs */
if ((c = chktg())) {
unch(c);
goto again;
}
return '?';
default:
return c;
}
}
static int
inpch(void)
{
int len;
if (ifiles->curptr < ifiles->maxread)
return *ifiles->curptr++;
if (ifiles->infil == -1)
return -1;
if ((len = read(ifiles->infil, ifiles->buffer, CPPBUF)) < 0)
error("read error on file %s", ifiles->orgfn);
if (len == 0)
return -1;
ifiles->curptr = ifiles->buffer;
ifiles->maxread = ifiles->buffer + len;
return inpch();
}
int
yylex()
{
static int ifdef, noex;
struct symtab *nl;
int ch, c2;
while ((ch = sloscan()) == WSPACE)
;
if (ch < 128 && spechr[ch] & C_2)
c2 = inpch();
else
c2 = 0;
#define C2(a,b,c) case a: if (c2 == b) return c; break
switch (ch) {
C2('=', '=', EQ);
C2('!', '=', NE);
C2('|', '|', OROR);
C2('&', '&', ANDAND);
case '<':
if (c2 == '<') return LS;
if (c2 == '=') return LE;
break;
case '>':
if (c2 == '>') return RS;
if (c2 == '=') return GE;
break;
case '+':
case '-':
if (ch == c2)
badop("");
break;
case '/':
if (Cflag == 0 || c2 != '*')
break;
/* Found comment that need to be skipped */
for (;;) {
ch = inpch();
c1: if (ch != '*')
continue;
if ((ch = inpch()) == '/')
break;
goto c1;
}
return yylex();
case NUMBER:
if (yytext[0] == '\'') {
yylval.node.op = NUMBER;
yylval.node.nd_val = charcon((usch *)yytext);
} else
cvtdig(yytext[0] != '0' ? 10 :
yytext[1] == 'x' || yytext[1] == 'X' ? 16 : 8);
return NUMBER;
case IDENT:
if (strcmp(yytext, "defined") == 0) {
ifdef = 1;
return DEFINED;
}
nl = lookup((usch *)yytext, FIND);
if (ifdef) {
yylval.node.nd_val = nl != NULL;
ifdef = 0;
} else if (nl && noex == 0) {
usch *c, *och = stringbuf;
c = gotident(nl);
unch(1);
unpstr(c);
stringbuf = och;
noex = 1;
return yylex();
} else {
yylval.node.nd_val = 0;
}
yylval.node.op = NUMBER;
return NUMBER;
case 1: /* WARN */
noex = 0;
return yylex();
default:
return ch;
}
unch(c2);
return ch;
}
