From 50c17f33d9cbda6ab36098eaa14eaceb698b104f Mon Sep 17 00:00:00 2001
From: mykola2312 <49044616+mykola2312@users.noreply.github.com>
Date: Thu, 28 Apr 2022 18:26:15 +0300
Subject: [PATCH] implement endiannes run-time detection

---
 CMakeLists.txt |  2 ++
 cutil.c        |  3 +++
 cutypes.h      |  2 +-
 endian.c       | 27 +++++++++++++++++++++++++++
 endian.h       | 17 +++++++++++++++++
 test.c         |  2 ++
 6 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 endian.c
 create mode 100644 endian.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4cdf5ff..198451e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,6 +7,7 @@ set(HEADERS
     list.h
     array.h
     bitmap.h
+    endian.h
 )
 
 set(SOURCES
@@ -14,6 +15,7 @@ set(SOURCES
     list.c
     array.c
     bitmap.c
+    endian.c
 )
 
 add_library(cutil STATIC ${SOURCES} ${HEADERS})
diff --git a/cutil.c b/cutil.c
index 534c606..88ee079 100644
--- a/cutil.c
+++ b/cutil.c
@@ -1,4 +1,5 @@
 #include "cutil.h"
+#include "endian.h"
 #include <string.h>
 
 void* (*cu_malloc)(size_t);
@@ -10,6 +11,8 @@ void* (*cu_memmove)(void*,const void*,size_t);
 
 void cutil_init()
 {
+    cu_endian_init();
+
     cu_malloc = CUTIL_MALLOC;
     cu_realloc = CUTIL_REALLOC;
     cu_free = CUTIL_FREE;
diff --git a/cutypes.h b/cutypes.h
index e283b52..a8e7277 100644
--- a/cutypes.h
+++ b/cutypes.h
@@ -89,7 +89,7 @@ typedef int64_t iword;
 typedef uint32_t uword;
 typedef int32_t iword;
 #else
-#   warning "define CU_32BIT or CU_64BIT"
+#   warning "unknown bus width for arch " CU_ARCH
 #endif
 
 typedef uint32_t uint;
diff --git a/endian.c b/endian.c
new file mode 100644
index 0000000..0e9bde6
--- /dev/null
+++ b/endian.c
@@ -0,0 +1,27 @@
+#include "endian.h"
+
+enum cu_endian_e cu_endian;
+
+static const union {
+    uint8_t bytes[4];
+    uint32_t value;
+} host_order = {
+    {0, 1, 2, 3}
+};
+
+#define ORDER_LITTLE_ENDIAN     0x03020100
+#define ORDER_BIG_ENDIAN        0x00010203
+#define ORDER_PDP_ENDIAN        0x01000302
+#define ORDER_HONEYWELL_ENDIAN  0x02030001
+
+void cu_endian_init()
+{
+    if (host_order.value == ORDER_LITTLE_ENDIAN)
+        cu_endian = LittleEndian;
+    else if (host_order.value == ORDER_BIG_ENDIAN)
+        cu_endian = BigEndian;
+    else if (host_order.value == ORDER_PDP_ENDIAN)
+        cu_endian = PDPEndian;
+    else if (host_order.value == ORDER_HONEYWELL_ENDIAN)
+        cu_endian = HoneywellEndian;
+}
diff --git a/endian.h b/endian.h
new file mode 100644
index 0000000..6fdff4f
--- /dev/null
+++ b/endian.h
@@ -0,0 +1,17 @@
+#ifndef __ENDIAN_H
+#define __ENDIAN_H
+
+#include "cutypes.h"
+
+enum cu_endian_e {
+    LittleEndian,
+    BigEndian,
+    PDPEndian,
+    HoneywellEndian
+};
+
+extern enum cu_endian_e cu_endian;
+
+void cu_endian_init();
+
+#endif
\ No newline at end of file
diff --git a/test.c b/test.c
index 4b37af9..9a28daf 100644
--- a/test.c
+++ b/test.c
@@ -5,6 +5,7 @@
 #include "list.h"
 #include "array.h"
 #include "bitmap.h"
+#include "endian.h"
 
 int main()
 {
@@ -76,6 +77,7 @@ int main()
 
     printf("[cutil]\n");
     printf("cutil_arch\t%u\n", CU_ARCH);
+    printf("cutil_endian\t%u\n", cu_endian);
 
     cutil_exit();
     return 0;