sync

C/C2/shared/file_element.h

@@ -0,0 +1,66 @@
+#ifndef FILE_ELEMENT_H
+#define FILE_ELEMENT_H
+
+#include <stddef.h>
+
+#include "animal.h"
+
+int readAnimals(const char* filename, Animal* animalPtr, size_t nrAnimals);
+/* pre    : n.a.
+ * post   : If file contains enough Animals, nrAnimals Animals are read into
+ *          animalPtr. If less animals than nrAnimals exist, all animals from
+ *          the file are read into animalPtr.
+ * returns: Nr of animals written into animalPtr or -1 if an error occurs
+ */
+
+int writeAnimals(const char* filename, const Animal* animalPtr, size_t nrAnimals);
+/* pre    : n.a.
+ * post   : nrAnimals animals are written into a new file with data from
+ *          animalPtr
+ * returns: On succes: 0, on error (file could not be written, input pointers
+ *          are NULL): -1
+ */
+
+int getNrAnimalsInFile(const char* filename, size_t* nrAnimals);
+/* pre    : n.a.
+ * post   : get number of animals (Animal structures) in the file
+ * returns: on succes: 0, on error: -1
+ *
+ */
+
+
+int readAnimalFromFile(
+            const char* filename, size_t filePosition, Animal* animalPtr);
+/* pre    : n.a.
+ * post   : read the animal on filePosition (first animal is filePosition 0,
+ *          second animal is filePosition 1, ...) into animalPtr
+ * returns: On success: 0, on error: -1 (no data available on filePosition,
+ *          file could not be read, ...)
+ */
+
+int writeAnimalToFile(
+            const char* filename, size_t filePosition, const Animal* animalPtr);
+/* pre    :
+ * post   : write the animal in animalPtr to the file at position 'filePosition'
+ * returns: On success: 0, on error: -1
+ *
+ **** note: do not open the file in append mode (a or a+): in append mode you
+ ****       ALWAYS write to the end of the file. You cannot open the file in
+ ****       write mode either (w or w+), as this will truncate an existing file
+ ****       to 0 bytes. You MUST open the file in "r+" mode (means: r+w) and if
+ ****       that fails (could mean: file does not exist) retry in "w" mode.
+ */
+
+int renameAnimalInFile(
+            const char* filename, size_t filePosition, const char* animalSurname);
+/* pre	   :
+ * post    : change the animal name on the filePosition in this way:
+ *	         The new animal name will start with animalSurname, followed
+ *           by a space and followed by the original animal name
+ * Example : We have animal called "Max" on filePosition and animalSurname
+ *           "Verstappen". The new animal name will be "Verstappen Max".
+ *           The renamed animal will be written back to the file.
+ * returns : On success: 0, on error: -1
+ */
+
+#endif