busted, but really must move along...

ex17.c

@@ -15,9 +15,10 @@ struct Address {
 };
 
 struct Database {
+    size_t size;
     int max_data;
     int max_rows;
-    struct Address rows[];
+    struct Address *rows;
 };
 
 struct Connection {
@@ -48,11 +49,19 @@ void Address_print(struct Address *addr)
 
 void Database_load(struct Connection *conn)
 {
-    int rc = fread(conn->db, sizeof(struct Database), 1, conn->file);
+    rewind(conn->file);
-    if(rc != 1) die("Failed to load database.", conn);
+
+    int rc = fread(&conn->db->max_rows, sizeof(int), 1, conn->file);
+    if(rc != 1) die("Failed to load database max_rows.", conn);
+
+    rc = fread(&conn->db->max_data, sizeof(int), 1, conn->file);
+    if(rc != 1) die("Failed to load database max_data.", conn);
+
+    rc = fread(conn->db->rows, sizeof(struct Address), conn->db->max_rows, conn->file);
+    if(rc != 1) die("Failed to load database rows.", conn);
 }
 
-struct Connection* Database_open(const char *filename, char mode)
+struct Connection* Database_open(const char *filename, char mode, int max_rows)
 {
     struct Connection *conn = malloc(sizeof(struct Connection));
     if(!conn) die("Memory error", conn);
@@ -60,6 +69,11 @@ struct Connection* Database_open(const char *filename, char mode)
     conn->db = malloc(sizeof(struct Database));
     if(!conn->db) die("Memory error", conn);
 
+    size_t rowsize = max_rows * sizeof(struct Address);
+    conn->db->size = rowsize;
+    conn->db->rows = malloc(rowsize);
+    if(!conn->db->rows) die("Memory error", conn);
+
     if(mode == 'c') {
         conn->file = fopen(filename, "w");
     } else {
@@ -88,8 +102,17 @@ void Database_write(struct Connection *conn)
 {
     rewind(conn->file);
 
-    int rc = fwrite(conn->db, sizeof(struct Database), 1, conn->file);
+    int rc = fwrite(&conn->db->size, sizeof(size_t), 1, conn->file);
-    if(rc != 1) die("Failed to write database.", conn);
+    if(rc != 1) die("Failed to write database size.", conn);
+
+    rc = fwrite(&conn->db->max_rows, sizeof(int), 1, conn->file);
+    if(rc != 1) die("Failed to write database max_rows.", conn);
+
+    rc = fwrite(&conn->db->max_data, sizeof(int), 1, conn->file);
+    if(rc != 1) die("Failed to write database max_data.", conn);
+
+    rc = fwrite(conn->db->rows, conn->db->size, 1, conn->file);
+    if(rc != 1) die("Failed to write database rows.", conn);
 
     rc = fflush(conn->file);
     if(rc == -1) die("Cannot flush database.", conn);
@@ -170,7 +193,7 @@ int main(int argc, char *argv[])
         sscanf(argv[2], "%c:%d,%d", &action, &max_data, &max_rows);
     }
 
-    struct Connection *conn = Database_open(filename, action);
+    struct Connection *conn = Database_open(filename, action, max_rows);
     int id = 0;
 
     if(argc > 3) id = atoi(argv[3]);