make cutil work without stdlib via CMake option NOSTDLIB=ON, using internal implementations

CMakeLists.txt

@@ -24,5 +24,11 @@ add_library(cutil STATIC ${SOURCES} ${HEADERS}
     "arch/${CMAKE_SYSTEM_PROCESSOR}.S"
 )
 
+option(NOSTDLIB "compile cutil without stdlib" ON)
+if (NOSTDLIB)
+    target_compile_definitions(cutil PRIVATE CUTIL_NOSTDLIB)
+    target_compile_options(cutil PRIVATE -nostdlib)
+endif()
+
 add_executable(test test.c)
 target_link_libraries(test cutil)

cutil.c

@@ -1,24 +1,28 @@
 #include "cutil.h"
 #include "endian.h"
-#include <string.h>
 
-void* (*cu_malloc)(size_t);
-void* (*cu_realloc)(void*, size_t);
-void (*cu_free)(void*) = CUTIL_FREE;
-void* (*cu_memset)(void*,int,size_t);
-void* (*cu_memcpy)(void*,const void*,size_t);
-void* (*cu_memmove)(void*,const void*,size_t);
+#ifdef CUTIL_NOSTDLIB
+void* (*cu_malloc)(size_t) = NULL;
+void* (*cu_realloc)(void*, size_t) = NULL;
+void (*cu_free)(void*) = NULL;
+void* (*cu_memset)(void*,int,size_t) = _cu_memset;
+void* (*cu_memcpy)(void*,const void*,size_t) = _cu_memcpy;
+void* (*cu_memmove)(void*,const void*,size_t) = _cu_memmove;
+#else
+#   include <stdlib.h>
+#   include <string.h>
+
+void* (*cu_malloc)(size_t) = malloc;
+void* (*cu_realloc)(void*, size_t) = realloc;
+void (*cu_free)(void*) = free;
+void* (*cu_memset)(void*,int,size_t) = memset;
+void* (*cu_memcpy)(void*,const void*,size_t) = memcpy;
+void* (*cu_memmove)(void*,const void*,size_t) = memmove;
+#endif
 
 void cutil_init()
 {
     cu_endian_init();
-
-    cu_malloc = CUTIL_MALLOC;
-    cu_realloc = CUTIL_REALLOC;
-    cu_free = CUTIL_FREE;
-    cu_memset = CUTIL_MEMSET;
-    cu_memcpy = CUTIL_MEMCPY;
-    cu_memmove = CUTIL_MEMMOVE;
 }
 
 void cutil_exit()

cutil.h

@@ -2,20 +2,13 @@
 #define __CUTIL_H
 
 #include "cutypes.h"
-#include <stdlib.h>
+
 
 extern void* _cu_memset(void* dst, int val, size_t size);
 extern void* _cu_memcpy(void* dst, const void* src, size_t size);
-extern void* _cu_memmove(void* dst, void* src, size_t size);
+extern void* _cu_memmove(void* dst, const void* src, size_t size);
 void __cu_memmove(void* dst, void* src, size_t size);
 
-#define CUTIL_MALLOC malloc
-#define CUTIL_REALLOC realloc
-#define CUTIL_FREE free
-#define CUTIL_MEMSET memset
-#define CUTIL_MEMCPY memcpy
-#define CUTIL_MEMMOVE memmove
-
 extern void* (*cu_malloc)(size_t);
 extern void* (*cu_realloc)(void*, size_t);
 extern void (*cu_free)(void*);

cutypes.h

@@ -128,4 +128,11 @@ typedef void* cu_ptr;
 
 #define cu_align(value, align) (((value / align) + !!(value % align))*align)
 
+#ifdef CUTIL_NOSTDLIB
+#   define NULL (void*)0
+#   define ZERO 0
+typedef uword size_t;
+typedef iword ssize_t;
+#endif
+
 #endif

test.c

@@ -48,6 +48,10 @@ void va_test(int fixed, ...)
 
 int main()
 {
+    cu_malloc = malloc;
+    cu_realloc = realloc;
+    cu_free = free;
+
     cutil_init();
     printf("[list]\n");
     list_t list;