From e9c442bbb6d129259d7489eb227dd289c8b3f67c Mon Sep 17 00:00:00 2001
From: Michael Gernoth <michael@gernoth.net>
Date: Sun, 13 Jan 2008 13:04:29 +0100
Subject: [PATCH] automatic byteorder detection

---
 src/sim/g_cam.c    | 48 ++++++++++++++++++++++++++--------------------
 src/sim/makefile   |  4 ++--
 src/sim/s_fileio.c | 19 ++++++++----------
 3 files changed, 37 insertions(+), 34 deletions(-)

diff --git a/src/sim/g_cam.c b/src/sim/g_cam.c
index c2f1b12..139da46 100644
--- a/src/sim/g_cam.c
+++ b/src/sim/g_cam.c
@@ -1083,39 +1083,45 @@ cam_load_rule(Cam *cam, char *filename)
   FILE *fp;
   QUAD magic, neighborhood, rule_size;
   Byte *rule;
+  int test = 1;
 
   if ((fp = fopen(filename, "r")) == NULL) {
     fprintf(stderr, "cam: Can't open rule file \"%s\"\n", filename);
     return;
   }
 
-/* XXX: Make this byte order independent!!! */
-
-#if defined(MSDOS) || defined(OSF1) || defined(IS_INTEL)
 
 #define SWAPQUAD(x) ((x = ((x <<24) & 0xff000000) | \
 			  ((x <<8)  & 0x00ff0000) | \
 			  ((x >>8)  & 0x0000ff00) | \
 			  ((x >>24) & 0x000000ff)), 0)
 
-#else
-
-#define SWAPQUAD(x) 0
-
-#endif
-
-  if ((fread(&magic, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
-      SWAPQUAD(magic) ||
-      (magic != 0xcac0cac0) ||
-      (fread(&neighborhood, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
-      SWAPQUAD(neighborhood) ||
-      (fread(&rule_size, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
-      SWAPQUAD(rule_size) ||
-      ((rule = (Byte *)malloc(rule_size)) == NULL) ||
-      (fread(rule, 1, rule_size, fp) != rule_size)) {
-    fprintf(stderr, "cam: Bad rule file \"%s\"\n", filename);
-    fclose(fp);
-    return;
+/* XXX: Make this byte order independent!!! */
+  if ((*(unsigned char*) (&test))) {
+    if ((fread(&magic, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
+        SWAPQUAD(magic) ||
+        (magic != 0xcac0cac0) ||
+        (fread(&neighborhood, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
+        SWAPQUAD(neighborhood) ||
+        (fread(&rule_size, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
+        SWAPQUAD(rule_size) ||
+        ((rule = (Byte *)malloc(rule_size)) == NULL) ||
+        (fread(rule, 1, rule_size, fp) != rule_size)) {
+      fprintf(stderr, "cam: Bad rule file \"%s\"\n", filename);
+      fclose(fp);
+      return;
+    }
+  } else {
+    if ((fread(&magic, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
+        (magic != 0xcac0cac0) ||
+        (fread(&neighborhood, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
+        (fread(&rule_size, 1, sizeof(QUAD), fp) != sizeof(QUAD)) ||
+        ((rule = (Byte *)malloc(rule_size)) == NULL) ||
+        (fread(rule, 1, rule_size, fp) != rule_size)) {
+      fprintf(stderr, "cam: Bad rule file \"%s\"\n", filename);
+      fclose(fp);
+      return;
+    }
   }
 
   fclose(fp);
diff --git a/src/sim/makefile b/src/sim/makefile
index e74f94e..bce5113 100644
--- a/src/sim/makefile
+++ b/src/sim/makefile
@@ -10,8 +10,8 @@ CC = gcc
 OPTFLAGS = -O3
 #OPTFLAGS = -g
 
-#DEFINES = -DIS_LINUX -DIS_INTEL -DCAM -DNET
-DEFINES = -DIS_LINUX -DIS_INTEL
+#DEFINES = -DIS_LINUX -DCAM -DNET
+DEFINES = -DIS_LINUX
 
 CFLAGS = $(OPTFLAGS) $(DEFINES)
 
diff --git a/src/sim/s_fileio.c b/src/sim/s_fileio.c
index 3768f01..37637f7 100644
--- a/src/sim/s_fileio.c
+++ b/src/sim/s_fileio.c
@@ -62,17 +62,19 @@
 #include "sim.h"
 
 
-#if defined(MSDOS) || defined(OSF1) || defined(IS_INTEL)
-
 #define SWAP_SHORTS(a,b)	_swap_shorts(a,b)
 #define SWAP_LONGS(a,b)		_swap_longs(a,b)
 #define HALF_SWAP_LONGS(a,b)	_half_swap_longs(a,b)
 
+#define NOOP_ON_BE	{ int test = 1; if (!(*(unsigned char*) (&test))) return; }
+
 static void
 _swap_shorts(short *buf, int len)
 {
   int i;
 
+  NOOP_ON_BE;
+
   /* Flip bytes in each short! */
   for (i = 0; i < len; i++) {	
     *buf = ((*buf & 0xFF) <<8) | ((*buf &0xFF00) >>8);
@@ -85,6 +87,8 @@ _swap_longs(long *buf, int len)
 {
   int i;
 
+  NOOP_ON_BE;
+
   /* Flip bytes in each long! */
   for (i = 0; i < len; i++) {	
     long l = *buf;
@@ -102,6 +106,8 @@ _half_swap_longs(long *buf, int len)
 {
   int i;
 
+  NOOP_ON_BE
+
   /* Flip bytes in each long! */
   for (i = 0; i < len; i++) {	
     long l = *buf;
@@ -112,15 +118,6 @@ _half_swap_longs(long *buf, int len)
   }
 }
 
-#else
-
-#define SWAP_SHORTS(a, b)
-#define SWAP_LONGS(a, b)
-#define HALF_SWAP_LONGS(a, b)
-
-#endif
-
-
 static int
 _load_short(short *buf, int len, FILE *f)
 {
-- 
2.39.5