Add Readme; determine endianness function and a test for it

.gitignore

@@ -1,2 +1,4 @@
 build/
 bin/
+testing/test
+auxilib

README.md

@@ -0,0 +1,16 @@
+# AUXILIB
+## A collection of various drop-in helper functions; AKA auxiliary C/С++ library
+
+# Build
+`make lib` or, if you don't have make or don't use gcc - translate the "lib" recipe into what works best for you, ie:
+`gcc -Wall -Werror -O2 -shared src/*/*.c -o auxilib`
+
+# Use
+Either
+- Compile the library as a whole separately and use that
+or
+- Copy file(s) with needed functionality to your project
+
+# License
+Currently auxilib uses MIT license.
+You're free to do anything you want, just don't forget to include a notice !

src/endian/endian.c

@@ -12,6 +12,19 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I
 
 #include <stdint.h>
 
+// Determine this machine's endianness. Returns 0 in case it is of Big-Endian type, 1 - Little-Endian
+int endianness() {
+    // 00000000 00000001
+    int16_t n = 1;
+    if (*(uint8_t*) &n == 1) {
+        // 00000001
+        return 1;
+    } else {
+        // 00000000
+        return 0;
+    }
+}
+
 uint16_t swap_endian16(uint16_t num) {
     return (uint16_t) 
     (

testing/test.c

@@ -75,6 +75,12 @@ int test_img() {
 }
 
 int test_endian() {
+    if (endianness() == 0) {
+        printf("[INFO] This machine is determined to be of Big-Endian type; Test's failed if that's not the case\n");
+    } else {
+        printf("[INFO] This machine is determined to be of Little-Endian type; Test's failed if that's not the case\n");
+    }
+
     // 01100001 10101000
     const uint16_t test_num16 = 25000;
     // 10101000 01100001