Add read_labels

src/preview_mnist.c

@@ -10,6 +10,10 @@ uint32_t swap_endian(uint32_t val) {
 }
 
 
+// Prévisualise un chiffre écrit à la main
+// de taille width x height
+// commencant à l'adresse mémoire start
+// dans le fichier pointé par ptr
 void print_image(unsigned int width, unsigned int height, FILE* ptr, int start) {
     unsigned char buffer[width*height+start];
 
@@ -27,9 +31,10 @@ void print_image(unsigned int width, unsigned int height, FILE* ptr, int start)
     }
 }
 
-
-void read_mnist_images(char* filename) {
-    unsigned char buffer[4];
+// Lit un set de données images de la base de données MNIST
+// dans le fichier situé à filename, les
+// images comportant comme labels 'labels'
+void read_mnist_images(char* filename, unsigned char* labels) {
     FILE *ptr;
     
     ptr = fopen(filename, "rb");
@@ -61,17 +66,49 @@ void read_mnist_images(char* filename) {
     //printf("%u x %u\n\n", width, height);
 
     for (int i=0; i < number_of_images; i++) {
-        printf("--- Number %d ---\n", i);
+        printf("--- Number %d : %u ---\n", i, labels[i]);
         print_image(width, height, ptr, (i*width*height));
     }
 }
 
 
+unsigned char* read_mnist_labels(char* filename) {
+    FILE* ptr;
+
+    ptr = fopen(filename, "rb");
+
+    uint32_t magic_number;
+    uint32_t number_of_items;
+
+    fread(&magic_number, sizeof(uint32_t), 1, ptr);
+    magic_number = swap_endian(magic_number);
+
+    if (magic_number != 2049) {
+        printf("Incorrect magic number !\n");
+        exit(1);
+    }
+
+    fread(&number_of_items, sizeof(uint32_t), 1, ptr);
+    number_of_items = swap_endian(number_of_items);
+
+    printf("number of items: %" PRIu32 "\n", number_of_items);
+
+    unsigned char* labels = malloc(sizeof(unsigned char)*number_of_items); 
+    unsigned char tmp;
+    for (int i=0; i< number_of_items; i++) {
+        fread(&tmp, sizeof(unsigned char), 1, ptr);
+        labels[i] = tmp;
+    }
+    return labels;
+}
+
 int main(int argc, char *argv[]) {
-    if (argc == 1) {
-        printf("Utilisation: %s [FILE]\n", argv[0]);
+    if (argc < 3) {
+        printf("Utilisation: %s [IMAGES FILE] [LABELS FILE]\n", argv[0]);
         return 1;
     }
-    read_mnist_images(argv[1]);
+    unsigned char* labels = read_mnist_labels(argv[2]);
+    read_mnist_images(argv[1], labels);
+    free(labels);
     return 0;
 }