ack/util/cpp/LLlex.c
1987-01-06 15:16:53 +00:00

373 lines
7 KiB
C

/* $Header$ */
/* L E X I C A L A N A L Y Z E R */
#include "idfsize.h"
#include "numsize.h"
#include "strsize.h"
#include <alloc.h>
#include "input.h"
#include "idf.h"
#include "LLlex.h"
#include "Lpars.h"
#include "class.h"
#include "bits.h"
/* Data about the token yielded */
struct token dot;
int ReplaceMacros = 1; /* replacing macros */
int AccFileSpecifier = 0; /* return filespecifier <...> */
int AccDefined = 0; /* accept "defined(...)" */
int UnknownIdIsZero = 0; /* interpret unknown id as integer 0 */
char *string_token();
PushLex()
{
DOT = 0;
}
PopLex()
{}
int
LLlex()
{
return (DOT != EOF) ? GetToken(&dot) : EOF;
}
#define BUFSIZ 1024
int
GetToken(ptok)
register struct token *ptok;
{
char buf[BUFSIZ];
register int c, nch;
again: /* rescan the input after an error or replacement */
LoadChar(c);
go_on:
if ((c & 0200) && c != EOI)
fatal("non-ascii '\\%03o' read", c & 0377);
switch (class(c)) { /* detect character class */
case STNL:
LineNumber++;
return ptok->tk_symb = EOF;
case STSKIP:
goto again;
case STGARB: /* garbage character */
if (c == '\\') {
/* a '\\' is allowed in #if/#elif expression */
LoadChar(c);
if (class(c) == STNL) { /* vt , ff ? */
++LineNumber;
goto again;
}
PushBack();
c = '\\';
}
if (040 < c && c < 0177)
error("garbage char %c", c);
else
error("garbage char \\%03o", c);
goto again;
case STSIMP: /* a simple character, no part of compound token*/
if (c == '/') { /* probably the start of comment */
LoadChar(c);
if (c == '*') { /* start of comment */
skipcomment();
goto again;
}
else {
PushBack();
c = '/'; /* restore c */
}
}
return ptok->tk_symb = c;
case STCOMP: /* maybe the start of a compound token */
LoadChar(nch); /* character lookahead */
switch (c) {
case '!':
if (nch == '=')
return ptok->tk_symb = NOTEQUAL;
PushBack();
return ptok->tk_symb = c;
case '&':
if (nch == '&')
return ptok->tk_symb = AND;
PushBack();
return ptok->tk_symb = c;
case '<':
if (AccFileSpecifier) {
PushBack(); /* pushback nch */
ptok->tk_str =
string_token("file specifier", '>');
return ptok->tk_symb = FILESPECIFIER;
}
if (nch == '<')
return ptok->tk_symb = LEFT;
if (nch == '=')
return ptok->tk_symb = LESSEQ;
PushBack();
return ptok->tk_symb = c;
case '=':
if (nch == '=')
return ptok->tk_symb = EQUAL;
/* The following piece of code tries to recognise
old-fashioned assignment operators `=op'
*/
error("illegal character");
goto go_on;
case '>':
if (nch == '=')
return ptok->tk_symb = GREATEREQ;
if (nch == '>')
return ptok->tk_symb = RIGHT;
PushBack();
return ptok->tk_symb = c;
case '|':
if (nch == '|')
return ptok->tk_symb = OR;
PushBack();
return ptok->tk_symb = c;
}
case STIDF:
{
extern int idfsize; /* ??? */
register char *tg = &buf[0];
register char *maxpos = &buf[idfsize];
register struct idf *idef;
#define tstmac(bx) if (!(bits[c] & bx)) goto nomac
#define cpy if (Unstacked) EnableMacros(); *tg++ = c
#define load LoadChar(c); if (!in_idf(c)) goto endidf
#ifdef DOBITS
cpy; tstmac(bit0); load;
cpy; tstmac(bit1); load;
cpy; tstmac(bit2); load;
cpy; tstmac(bit3); load;
cpy; tstmac(bit4); load;
cpy; tstmac(bit5); load;
cpy; tstmac(bit6); load;
cpy; tstmac(bit7); load;
#endif
for(;;) {
if (tg < maxpos) {
cpy;
}
load;
}
endidf:
PushBack();
*tg = '\0'; /* mark the end of the identifier */
if (ReplaceMacros) {
idef = findidf(buf);
if ((idef && idef->id_macro && replace(idef))) {
goto again;
}
}
nomac:
LoadChar(c);
while (in_idf(c)) {
if (tg < maxpos) *tg++ = c;
LoadChar(c);
}
PushBack();
*tg++ = '\0'; /* mark the end of the identifier */
if (UnknownIdIsZero) {
ptok->tk_val = 0;
return ptok->tk_symb = INTEGER;
}
ptok->tk_str = Malloc(idfsize + 1);
strcpy(ptok->tk_str, buf);
return ptok->tk_symb = IDENTIFIER;
}
case STCHAR: /* character constant */
{
register int val = 0, size = 0;
LoadChar(c);
if (c == '\'')
error("character constant too short");
else
while (c != '\'') {
if (c == '\n') {
error("newline in character constant");
LineNumber++;
break;
}
if (c == '\\') {
LoadChar(c);
if (c == '\n') {
LoadChar(c);
LineNumber++;
continue;
}
c = quoted(c);
}
val = val*256 + c;
size++;
LoadChar(c);
}
if (size > sizeof(int))
error("character constant too long");
ptok->tk_val = val;
return ptok->tk_symb = INTEGER;
}
case STNUM:
{
register char *np = &buf[1];
register int base = 10;
register int vch;
register int val = 0;
if (c == '0') {
*np++ = c;
LoadChar(c);
if (c == 'x' || c == 'X') {
base = 16;
LoadChar(c);
}
else
base = 8;
}
while (vch = val_in_base(c, base), vch >= 0) {
val = val*base + vch;
if (np < &buf[NUMSIZE])
*np++ = c;
LoadChar(c);
}
if (c == 'l' || c == 'L')
LoadChar(c);
PushBack();
ptok->tk_val = val;
return ptok->tk_symb = INTEGER;
}
case STSTR:
ptok->tk_str = string_token("string", '"');
return ptok->tk_symb = STRING;
case STEOI: /* end of text on source file */
return ptok->tk_symb = EOF;
default:
crash("Impossible character class");
}
/*NOTREACHED*/
}
skipcomment()
{
register int c;
NoUnstack++;
LoadChar(c);
do {
while (c != '*') {
if (class(c) == STNL)
++LineNumber;
else
if (c == EOI) {
NoUnstack--;
return;
}
LoadChar(c);
}
/* Last Character seen was '*' */
LoadChar(c);
} while (c != '/');
NoUnstack--;
}
char *
string_token(nm, stop_char)
char *nm;
{
register int c;
register int str_size;
register char *str = Malloc(str_size = ISTRSIZE);
register int pos = 0;
LoadChar(c);
while (c != stop_char) {
if (c == '\n') {
error("newline in %s", nm);
LineNumber++;
break;
}
if (c == EOI) {
error("end-of-file inside %s", nm);
break;
}
if (c == '\\') {
LoadChar(c);
if (c == '\n') {
LineNumber++;
LoadChar(c);
continue;
}
c = quoted(c);
}
str[pos++] = c;
if (pos == str_size)
str = Srealloc(str, str_size += RSTRSIZE);
LoadChar(c);
}
str[pos++] = '\0'; /* for filenames etc. */
return str;
}
int
quoted(c)
register int c;
{
/* quoted() replaces an escaped character sequence by the
character meant.
*/
/* first char after backslash already in c */
if (!is_oct(c)) { /* a quoted char */
switch (c) {
case 'n':
c = '\n';
break;
case 't':
c = '\t';
break;
case 'b':
c = '\b';
break;
case 'r':
c = '\r';
break;
case 'f':
c = '\f';
break;
}
}
else { /* a quoted octal */
register int oct = 0, cnt = 0;
do {
oct = oct*8 + (c-'0');
LoadChar(c);
} while (is_oct(c) && ++cnt < 3);
PushBack();
c = oct;
}
return c&0377;
}
/* provisional */
int
val_in_base(c, base)
register int c;
{
return
is_dig(c) ? c - '0' :
base != 16 ? -1 :
is_hex(c) ? (c - 'a' + 10) & 017 :
-1;
}