From 754f9ce45deb20c9bc780ccb7ac79993e0352d2d Mon Sep 17 00:00:00 2001
From: ceriel <none@none>
Date: Thu, 20 Aug 1987 18:12:31 +0000
Subject: [PATCH] fixed a problem with the ifdef-stack

---
 util/cpp/domacro.c   | 12 ++++++++----
 util/cpp/file_info.h |  2 --
 util/cpp/input.c     |  6 +++++-
 util/cpp/main.c      |  1 -
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/util/cpp/domacro.c b/util/cpp/domacro.c
index 665233e2f..aa8cd716f 100644
--- a/util/cpp/domacro.c
+++ b/util/cpp/domacro.c
@@ -30,6 +30,10 @@ PRIVATE char ifstack[IFDEPTH];	/* if-stack: the content of an entry is	*/
 				/* 1 if a corresponding ELSE has been	*/
 				/* encountered.				*/
 
+int nestlevel = -1;
+int svnestlevel[30] = {-1};
+int nestcount;
+
 PRIVATE char *
 GetIdentifier()
 {
@@ -261,7 +265,7 @@ do_include()
 		}
 		else {
 			WorkingDir = getwdir(result);
-			nestlevel = -1;
+			svnestlevel[++nestcount] = nestlevel;
 			FileName = result;
 			LineNumber = 1;
 		}
@@ -331,7 +335,7 @@ push_if()
 PRIVATE
 do_elif()
 {
-	if (nestlevel < 0 || (ifstack[nestlevel])) {
+	if (nestlevel <= svnestlevel[nestcount] || (ifstack[nestlevel])) {
 		error("#elif without corresponding #if");
 		PushBack();
 		skipline();
@@ -348,7 +352,7 @@ do_else()
 {
 	PushBack();
 	skipline();
-	if (nestlevel < 0 || (ifstack[nestlevel]))
+	if (nestlevel <= svnestlevel[nestcount] || (ifstack[nestlevel]))
 		error("#else without corresponding #if");
 	else {	/* mark this level as else-d		*/
 		++(ifstack[nestlevel]);
@@ -361,7 +365,7 @@ do_endif()
 {
 	PushBack();
 	skipline();
-	if (nestlevel-- < 0)
+	if (nestlevel-- <= svnestlevel[nestcount])
 		error("#endif without corresponding #if");
 }
 
diff --git a/util/cpp/file_info.h b/util/cpp/file_info.h
index cc6c663ce..241c8de6b 100644
--- a/util/cpp/file_info.h
+++ b/util/cpp/file_info.h
@@ -9,12 +9,10 @@ struct file_info {
 	unsigned int	fil_lino;
 	char		*fil_name;
 	char		*fil_wdir;
-	int		fil_nestlevel;
 };
 
 #define LineNumber	finfo.fil_lino
 #define FileName	finfo.fil_name
 #define WorkingDir	finfo.fil_wdir
-#define nestlevel	finfo.fil_nestlevel
 
 extern struct file_info finfo;	/* input.c */
diff --git a/util/cpp/input.c b/util/cpp/input.c
index 78aca5b6a..55789caed 100644
--- a/util/cpp/input.c
+++ b/util/cpp/input.c
@@ -47,8 +47,12 @@ AtEoIT()
 
 AtEoIF()
 {
+	extern int nestlevel;
+	extern int nestcount;
+	extern int svnestlevel[];
 
-	if (nestlevel != -1) warning("missing #endif");
+	if (nestlevel > svnestlevel[nestcount]) warning("missing #endif");
 	else if (NoUnstack) warning("unexpected EOF");
+	nestlevel = svnestlevel[nestcount--];
 	return 0;
 }
diff --git a/util/cpp/main.c b/util/cpp/main.c
index ac04bca59..e9585cf9c 100644
--- a/util/cpp/main.c
+++ b/util/cpp/main.c
@@ -78,6 +78,5 @@ compile(argc, argv)
 		fatal("%s: no source file %s\n", prog_name, 
 			source ? source : "stdin");
 	if (source) WorkingDir = getwdir(dummy);
-	nestlevel = -1;
 	preprocess(source);
 }
-- 
2.34.1