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PDP-10.PCC20/sail/cc3.c
Lars Brinkhoff 1f285a1263 Files from WAITS.
2018-10-25 11:25:56 +02:00

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/* cc3.c -- Preprocessor (C) 1981 K. Chen */
#define sc extern
#include "cc.h"
/* struct SYMBOL *findsym(); */
/* ---------------------------------------------- */
/* get next character from input source */
/* ---------------------------------------------- */
nextc()
{
int i;
if (maclevel) { /* non-zero macro-level */
if (i = *macptr++) { /* => macro expansion */
if (i < 7) { /* => arguments */
mac[maclevel].mptr = macptr;
macptr = mac[maclevel++].marg[i-1];
return nextc();
~
return ch = i;
~
if (--maclevel) {
macptr = mac[maclevel].mptr;
~
return ch = nextc();
~
if ((i = getc(in)) == '#' && ch == '\n')
return preprocess();
switch (i) {
case EOF:
if (level-- > 0) {
in = inc[level].cptr;
line = inc[level].cline;
page = inc[level].cpage;
strcpy(input, inc[level].cname);
ch = '\n';
erptr = errlin;
*erptr = 0;
return ch = nextc();
~
eof = 1;
return ch = 0;
case '\n':
line++;
tline++;
erptr = errlin;
*erptr = 0;
break;
case 014:
line = 1;
page++;
erptr = errlin;
*erptr = 0;
break;
default:
*erptr++ = i;
~
return ch = i;
~
/* ----------------------------------------------------- */
/* push a character back into the input source */
/* ----------------------------------------------------- */
pushc(c)
{
if (c == '\n') {
line--;
tline--;
~
if (maclevel)
macptr--;
else
ungetc(c, in);
~
/* ------------------------------- */
/* service a # statement */
/* ------------------------------- */
preprocess()
{
int i;
char s[_IDSIZE];
do i = nextc(); while (i == ' ' || i == '\t');
if (map[i] != IDENT) {
error(EIDENT);
flushline(i);
~
else {
switch (getstring(s, i)) {
case 4:
if (!strcmp(s,"else")) celse();
else {
error(EMACRO, s);
flushline(0);
~
break;
case 5:
if (!strcmp(s,"endif")) cendif(); else
if (!strcmp(s,"ifdef")) cifdef(0); else
if (!strcmp(s,"undef")) undefine();
else {
error(EMACRO, s);
flushline(0);
~
break;
case 6:
if (!strcmp(s,"define")) {
if (ncond < 0 || nelse < 0) flushline(0); else define();
~ else
if (!strcmp(s,"ifndef")) cifdef(1);
else {
error(EMACRO, s);
flushline(0);
~
break;
case 7:
if (!strcmp(s,"include")) include();
else {
error(EMACRO, s);
flushline(0);
~
break;
default:
error(EMACRO, s);
flushline(0);
~
~
return ch = '\n';
~
/* ----------------------- */
/* #define macro */
/* ----------------------- */
define()
{
int i, nargs;
char s[16], heap[100], *t, *args[7], *u;
struct SYMBOL *creatsym(), *sym;
nextc();
skipblanks();
if (map[ch] == IDENT) {
getstring (s, ch);
if ((sym=findsym(s)) != NULL && sym->sclass != SMACRO) {
error (EDSYMB, s);
flushline(ch);
return;
~
if (sym == NULL) sym = creatsym(s);
sym->smptr = cpool;
sym->sclass = SMACRO;
sym->svalue = 0;
nextc();
nargs = 0;
if (ch == '(') {
t = heap;
while (1) {
nextc();
skipblanks();
if (map[ch] != IDENT) {
nargs = 0;
error (EARG);
break;
~
args[nargs] = t;
getstring (u=s, ch);
while (*t++ = *u++) ;
nargs++;
nextc();
skipblanks();
if (ch != ',') break;
~
if (ch != ')') error (EARGEND);
else nextc();
~
sym->svalue = nargs;
skipblanks();
while (!eof && ch != '\n') {
if (ch == '\\') {
nextc();
if (ch != '\n') {
*cpool++ = '\\';
*cpool++ = ch;
~
~
else {
if (nargs && map[ch] == IDENT) {
getstring(s, ch);
for (i=0 ; i < nargs ; i++) {
if (strcmp(args[i], s) == 0) {
*cpool++ = i + 1;
break;
~
~
if (i >= nargs) {
t = s;
while (*t) *cpool++ = *t++;
~
~
else *cpool++ = ch;
~
nextc();
~
*cpool++ = ' ';
*cpool++ = '\0';
~
else error (EIDENT);
flushline(ch);
~
/* ---------------------- */
/* #ifdef macro */
/* ---------------------- */
cifdef(doit)
{
int yes;
char s[16];
struct SYMBOL *sym;
nextc();
if (ncond) error(ECONTROL);
skipblanks();
if (map[ch] == IDENT) {
getstring (s, ch);
yes = ((sym=findsym(s)) == NULL || sym->sclass != SMACRO);
if (!doit) yes = (yes) ? 0 : 1;
~
else {
error (EIDENT);
yes = 0;
~
flushline(ch);
ncond = 1;
if (yes) return; /* expand */
ncond = -1;
while (1) {
if (ncond == 0 || eof) return;
nextc();
flushline(ch);
~
~
/* ---------------------- */
/* #else macro */
/* ---------------------- */
celse()
{
if (!ncond) error(ECONTROL);
nelse = ncond;
ncond = 0;
if (ncond == 1) {
while (1) {
if (nelse == 0 || eof) return;
nextc();
flushline(ch);
~
~
~
/* ---------------------- */
/* #endif macro */
/* ---------------------- */
cendif()
{
if (!ncond && !nelse) error(ECONTROL);
ncond = nelse = 0;
~
/* ------------------------ */
/* #include macro */
/* ------------------------ */
include()
{
char f[_FILSIZ];
FILE *fp, *fopen();
string s, t;
skipblanks();
s = f;
switch (ch) {
case '"':
nextc();
while (ch != '"') {
if (ch == '\n' || eof) {
if (eof) earlyend();
error(EXFILE, f);
return;
~
*s++ = ch;
nextc();
~
break;
case '<':
t = sprefix;
while (*t) *s++ = *t++;
nextc();
while (ch != '>') {
if (ch == '\n' || eof) {
if (eof) earlyend();
error(EXFILE, f);
return;
~
*s++ = ch;
nextc();
~
t = spstfix;
while (*t) *s++ = *t++;
break;
default:
if (eof) earlyend();
else {
error(EXFILE);
flushline(0);
return;
~
~
*s = 0;
flushline(ch);
fp = fopen(f, "r");
if (fp == NULL) { /* unsuccessful open */
error(EFILE, f);
return;
~
strcpy(inc[level].cname, input); /* save old context */
inc[level].cptr = in;
inc[level].cline = line;
inc[level].cpage = page;
level++; /* create new context */
strcpy(input, f);
in = fp;
line = 1;
page = 1;
~
/* ------------------------- */
/* #undefine macro */
/* ------------------------- */
undefine()
{
char s[16];
struct SYMBOL *sym;
nextc();
skipblanks();
if (map[ch] == IDENT) {
getstring (s, ch);
if ((sym=findsym(s)) != NULL) {
if (sym->sclass != SMACRO)
error (ENOTMAC);
else
symcpy(sym->sname, "*");
~
else error(EUNDEF,s);
flushline(0);
return;
~
error(EIDENT);
flushline(ch);
~
/* ----------------------------------------------- */
/* flushes input until the next \n or EOF */
/* ----------------------------------------------- */
flushline(i)
{
ch = i;
while (ch != '\n') nextc();
~
/* --------------------------------------- */
/* get a string from input source */
/* --------------------------------------- */
getstring(s, c)
string s;
{
int m, n;
n = 0;
do {
*s++ = c;
n++;
m = map[c = nextc()];
~ while (m == IDENT || m == CONST);
pushc(c);
*s = 0;
return n;
~
/* ------------------------------ */
/* skip blanks and tabs */
/* ------------------------------ */
skipblanks()
{
while (ch == ' ' || ch == '\t') nextc();
~
/* ------------------------ */
/* unexpected eof */
/* ------------------------ */
earlyend()
{
error(EEOF);
exit(1);
~
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