From 0892f3f0b30ea489a905e0d0513c0317cf1be528 Mon Sep 17 00:00:00 2001
From: Vern Paxson <vern@ee.lbl.gov>
Date: Tue, 7 Dec 1993 11:10:49 +0000
Subject: [PATCH] Fixed nasty 8-bit bugs

---
 flex.skl |  7 +++++++
 gen.c    | 35 ++++++++++++++++++-----------------
 2 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/flex.skl b/flex.skl
index 336fdec..244a930 100644
--- a/flex.skl
+++ b/flex.skl
@@ -65,6 +65,13 @@ class istream;
 /* Returned upon end-of-file. */
 #define YY_NULL 0
 
+/* Promotes a possibly negative, possibly signed char to an unsigned
+ * integer for use as an array index.  If the signed char is negative,
+ * we want to instead treat it as an 8-bit unsigned char, hence the
+ * double cast.
+ */
+#define YY_SC_TO_UI(c) ((unsigned int) (unsigned char) c)
+
 /* Enter a start condition.  This macro really ought to take a parameter,
  * but we do it the disgusting crufty way forced on us by the ()-less
  * definition of BEGIN.
diff --git a/gen.c b/gen.c
index c12849c..e25160d 100644
--- a/gen.c
+++ b/gen.c
@@ -48,6 +48,7 @@ static int indent_level = 0; /* each level is 8 spaces */
 /* *Everything* is done in terms of arrays starting at 1, so provide
  * a null entry for the zero element of all C arrays.
  */
+static char C_int_decl[] = "static const int %s[%d] =\n    {   0,\n";
 static char C_short_decl[] = "static const short int %s[%d] =\n    {   0,\n";
 static char C_long_decl[] = "static const long int %s[%d] =\n    {   0,\n";
 static char C_state_decl[] =
@@ -225,15 +226,10 @@ void genctbl()
 void genecs()
 	{
 	Char clower();
-	static char C_char_decl[] = "static const %s %s[%d] =\n    {   0,\n";
-					/* } so vi doesn't get confused */
 	register int i, j;
 	int numrows;
 
-	if ( numecs < csize )
-		printf( C_char_decl, "YY_CHAR", "yy_ec", csize );
-	else
-		printf( C_char_decl, "short", "yy_ec", csize );
+	printf( C_int_decl, "yy_ec", csize );
 
 	for ( i = 1; i < csize; ++i )
 		{
@@ -477,14 +473,18 @@ void gen_next_match()
 	/* NOTE - changes in here should be reflected in gen_next_state() and
 	 * gen_NUL_trans().
 	 */
-	char *char_map = useecs ? "yy_ec[(unsigned int) *yy_cp]" : "*yy_cp";
-	char *char_map_2 =
-		useecs ? "yy_ec[(unsigned int) *++yy_cp]" : "*++yy_cp";
+	char *char_map = useecs ?
+				"yy_ec[YY_SC_TO_UI(*yy_cp)]" :
+				"YY_SC_TO_UI(*yy_cp)";
+
+	char *char_map_2 = useecs ?
+				"yy_ec[YY_SC_TO_UI(*++yy_cp)]" :
+				"YY_SC_TO_UI(*++yy_cp)";
 
 	if ( fulltbl )
 		{
 		indent_put2s(
-"while ( (yy_current_state = yy_nxt[yy_current_state][(unsigned int)%s]) > 0 )",
+	"while ( (yy_current_state = yy_nxt[yy_current_state][%s]) > 0 )",
 				char_map );
 
 		indent_up();
@@ -586,16 +586,17 @@ int worry_about_NULs;
 		{
 		if ( useecs )
 			(void) sprintf( char_map,
-				"(*yy_cp ? yy_ec[(unsigned int) *yy_cp] : %d)",
+				"(*yy_cp ? yy_ec[YY_SC_TO_UI(*yy_cp)] : %d)",
 					NUL_ec );
 		else
 			(void) sprintf( char_map,
-				"(*yy_cp ? *yy_cp : %d)", NUL_ec );
+				"(*yy_cp ? YY_SC_TO_UI(*yy_cp) : %d)", NUL_ec );
 		}
 
 	else
-		yy_strcpy( char_map,
-			useecs ? "yy_ec[(unsigned int) *yy_cp]" : "*yy_cp" );
+		yy_strcpy( char_map, useecs ?
+					"yy_ec[YY_SC_TO_UI(*yy_cp)]" :
+					"YY_SC_TO_UI(*yy_cp)" );
 
 	if ( worry_about_NULs && nultrans )
 		{
@@ -610,12 +611,12 @@ int worry_about_NULs;
 
 	if ( fulltbl )
 		indent_put2s(
-	"yy_current_state = yy_nxt[yy_current_state][(unsigned int) %s];", 
+			"yy_current_state = yy_nxt[yy_current_state][%s];", 
 				char_map );
 
 	else if ( fullspd )
 		indent_put2s(
-	"yy_current_state += yy_current_state[(unsigned int) %s].yy_nxt;",
+			"yy_current_state += yy_current_state[%s].yy_nxt;",
 				char_map );
 
 	else
@@ -904,7 +905,7 @@ void gentabs()
 		if ( trace )
 			fputs( "\n\nMeta-Equivalence Classes:\n", stderr );
 
-		printf( C_char_decl, "yy_meta", numecs + 1 );
+		printf( C_int_decl, "yy_meta", numecs + 1 );
 
 		for ( i = 1; i <= numecs; ++i )
 			{
-- 
2.40.0