added ImageInput

Startcode/imageInput.c

@@ -7,16 +7,147 @@
 #define FILE_HEADER_STRING "__info2_image_file_format__"
 
 // TODO Implementieren Sie geeignete Hilfsfunktionen für das Lesen der Bildserie aus einer Datei
+//Hilfsfunktion zum Einlesen eines einzigen Bildes
+static int read_single_image(FILE *file, unsigned short width, unsigned short height, GrayScaleImage *img, unsigned char *out_label)
+{
+    size_t pixels_to_read = (size_t)width * height;
+
+    img->width = width; //save width and height read from file in struct
+    img->height = height;
+
+    img->buffer = malloc(pixels_to_read * sizeof(GrayScalePixelType)); //allocating needed memory for pixel-buffer 
+    if(img->buffer == NULL) //Error case
+    {
+        printf("%s", "Fehler bei der Speicherreservierung!\n");
+        return 0;
+    }
+
+    
+    if(fread(img->buffer, sizeof(GrayScalePixelType), pixels_to_read, file) != pixels_to_read) //read all pixels one after another
+    {
+        free(img->buffer); //Error case: free allocated memory
+        return 0;
+    }
+    
+    
+    if(fread(out_label, sizeof(unsigned char), 1, file) != 1) //read label
+    {
+        free(img->buffer); //Error case: free allocated memory
+        return 0;
+    }
+
+    return 1; 
+}
+
+
 
 // TODO Vervollständigen Sie die Funktion readImages unter Benutzung Ihrer Hilfsfunktionen
 GrayScaleImageSeries *readImages(const char *path)
 {
-    GrayScaleImageSeries *series = NULL;
+    char buffer[BUFFER_SIZE];
+    unsigned short num_images;
+    unsigned short width;
+    unsigned short height;
+
     
+    
+    FILE *file = fopen(path, "rb"); 
+    
+    if(file == NULL) //file can not be opened 
+    {
+        return NULL;        
+    }
+
+    /*********************************************************************************
+     * VERIFY IF HEADER FILE IS INCLUDED
+     ********************************************************************************/
+    fread(buffer, sizeof(buffer[0]), strlen(FILE_HEADER_STRING), file);
+    buffer[strlen(FILE_HEADER_STRING)] = '\0';
+
+    if(strcmp(buffer, FILE_HEADER_STRING) != 0) //file does not include file header
+    {
+        fclose(file);
+        return NULL;
+    }
+
+    /*********************************************************************************
+     * READ AMOUNT, WIDTH, HEIGHT 
+     ********************************************************************************/
+    fread(&num_images, sizeof(num_images), 1, file);
+    fread(&width, sizeof(width), 1, file);
+    fread(&height, sizeof(height), 1, file);
+
+
+    /*********************************************************************************
+     * MEMORY ALLOCATION FOR SERIES
+     ********************************************************************************/
+    GrayScaleImageSeries *series = malloc(sizeof(GrayScaleImageSeries));
+    if(series == NULL) //Error: memory cannot be allocated; close file
+    {
+        fclose(file);
+        return NULL;
+    }
+
+    series->count = num_images; //save number of images in struct 
+    series->images = malloc(num_images * sizeof(GrayScaleImage)); //allocate memory for all images
+    series->labels = malloc(num_images * sizeof(unsigned char)); //allocate memory for all labels
+
+    if(series->images == NULL || series->labels == NULL) //Error: memory cannot be allocated: free every memory
+    {
+        free(series->images);
+        free(series->labels);
+        free(series);
+        
+        fclose(file);
+        return NULL;
+    }
+
+
+    /*********************************************************************************
+     * READ IMAGES
+     ********************************************************************************/
+
+    for(int i = 0; i < num_images; i++)
+    {
+        if(read_single_image(file, width, height, &series->images[i], &series->labels[i]) != 1)
+        {
+            series->count = i;
+
+            clearSeries(series); //free all allocated memory
+            
+            fclose(file); //Error case: close file 
+            return NULL;
+        }
+    }
+    
+    fclose(file);
+    
+
+
     return series;
 }
 
 // TODO Vervollständigen Sie die Funktion clearSeries, welche eine Bildserie vollständig aus dem Speicher freigibt
 void clearSeries(GrayScaleImageSeries *series)
 {
+    if(series == NULL) //pointer points to nothing; nothing to clear
+    {
+        return;
+    }
+
+    if(series->images != NULL) //check if image pointer is valid
+    {
+        for(int i = 0; i < series->count; i++) //free memory allocated for all images until error occured
+        {
+            free(series->images[i].buffer); 
+        }
+        free(series->images); //free memory allocated for image array
+    }
+
+    if(series->labels != NULL) //check if label pointer is valid
+    {
+        free(series->labels); //free memory allocated for label array
+    }
+
+    free(series); //free memory allocated for series 
 }