Merge branch 'Temp' into 'Development'

Image.c

See merge request jastornig/c-net!4

image.c

@@ -1,39 +1,76 @@
-#pragma once
-
-#include <stdlib.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "image.h"
 #include "matrix.h"
 
-Img** import_images(char* image_file_string, char* label_file_string, int number_of_images) {
+int endian_swap(int input) {
+    return ((input >> 24) & 0xff) |      // move byte 3 to byte 0
+           ((input << 8) & 0xff0000) |   // move byte 1 to byte 2
+           ((input >> 8) & 0xff00) |     // move byte 2 to byte 1
+           ((input << 24) & 0xff000000); // byte 0 to byte 3
+}
+
+int validate_files(FILE* image_file, FILE* label_file) {
+
+    // read magic number from files
+    int magic_number_label, magic_number_images;
+    fread(&magic_number_label, 4, 1, label_file);
+    fread(&magic_number_images, 4, 1, image_file);
+
+    // compare magic numbers with pre-defined value
+    if(endian_swap(magic_number_label) != 2049 || endian_swap(magic_number_images) != 2051) {
+        return 0;
+    }
+
+    return 1;
+}
+
+Image** import_images(char* image_file_string, char* label_file_string, int number_of_images) {
 
     // create file pointer for the image and label data
-    FILE* image_file = fopen(image_file_string, 'r');
-    FILE* label_file = fopen(label_file_string, 'r');
+    FILE* image_file = fopen(image_file_string, "r");
+    FILE* label_file = fopen(label_file_string, "r");
 
     // check if the file could be opened
     if(image_file == NULL || label_file == NULL) {
-        printf("ERROR: File could not be opened! ()");
+        printf("ERROR: File could not be opened! (import_images)");
+        exit(1);
     }
 
+    // check magic number of the files
+    if(validate_files(image_file, label_file)) {
+        printf("ERROR: File validation failed! (validate_files)");
+        exit(1);
+    }
+
+
+    // Jakob Section
+
+
+    // allocate memory for the storage of images
+    Image** images = malloc(sizeof(Image) * number_of_images);
+
+    fclose(image_file);
+    fclose(label_file);
 }
 
-void img_print (Img* img) {
+void img_print (Image* img) {
+
     //print the image
     matrix_print(img->pixel_values);
     //print the number of the image
     printf("Number it is supposed to be: %d\n", img->image_label);
 }
 
-void img_free (Img* img) {
+void img_free (Image* img) {
     //frees the matrix of image (deep free)
     matrix_free(img->pixel_values);
     //frees the rest of img
     free(img);
 }
 
-void images_free (Img** images, int quantity){
+void images_free (Image** images, int quantity){
     //frees every single image
     for(int i=0;i<quantity;i++){
         img_free(images[i]);