From 96b3d72848b0326d690d72d6095dcfd17eb6a894 Mon Sep 17 00:00:00 2001
From: Pia Keil <piakeil@Mac.fritz.box>
Date: Fri, 21 Nov 2025 04:54:54 +0100
Subject: [PATCH] Implement header check helper function

---
 imageInput.c | 72 ++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 61 insertions(+), 11 deletions(-)

diff --git a/imageInput.c b/imageInput.c
index bb30de1..8875ad4 100644
--- a/imageInput.c
+++ b/imageInput.c
@@ -1,4 +1,4 @@
-#include <stdio.h>
+##include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "imageInput.h"
@@ -6,17 +6,67 @@
 #define BUFFER_SIZE 100
 #define FILE_HEADER_STRING "__info2_image_file_format__"
 
-// TODO Implementieren Sie geeignete Hilfsfunktionen für das Lesen der Bildserie aus einer Datei
 
-// TODO Vervollständigen Sie die Funktion readImages unter Benutzung Ihrer Hilfsfunktionen
-GrayScaleImageSeries *readImages(const char *path)
-{
-    GrayScaleImageSeries *series = NULL;
-    
-    return series;
+/*
+ * Hilfsfunktionen 
+ */
+
+
+static FILE *openImageFile(const char *path) // Checks if the given filename pointer is valid (not NULL).
+{  
+if (path == NULL)
+    {
+        return NULL;
+    }
+
+    return fopen(path, "rb");  //opening document in binear 
 }
 
-// TODO Vervollständigen Sie die Funktion clearSeries, welche eine Bildserie vollständig aus dem Speicher freigibt
-void clearSeries(GrayScaleImageSeries *series)
+static int readAndCheckHeader(FILE *file) // gets the length of the header text
 {
-}
\ No newline at end of file
+    size_t headerLength = strlen(FILE_HEADER_STRING);
+    char buffer[BUFFER_SIZE];
+
+    if (headerLength + 1 > BUFFER_SIZE) //checks if buffer is big enough for header size
+    {
+        return 0;
+    }
+
+    if (fread(buffer, 1, headerLength, file) != headerLength) // Checks if reading the expected number of header bytes from the file succeeded
+
+        return 0;
+    
+
+    buffer[headerLength] = '\0'; // add string terminator so the header becomes a valid C-string
+
+    if (strcmp(buffer, FILE_HEADER_STRING) != 0) // checks if the expected header matches the header read from the file
+
+    {
+        return 0;
+    }
+
+    return 1; /* Header ok */
+}
+
+
+
+
+static int readImageMetaData(FILE *file, // reads the metadata (count, width, height) from the file and stores them in the provided pointers
+                             unsigned short *count,
+                             unsigned short *width,
+                             unsigned short *height)
+{
+
+
+
+
+
+
+    /*
+    Hauptfunktion
+    */
+
+
+
+
+    
\ No newline at end of file