Add asserts

File.c

@@ -1,8 +1,11 @@
 #include "CgeFile.h"
+#include <assert.h>
 
 int CgeFileError(CgeFile *file) {
     int flags;
 
+    assert(file != NULL);
+
     CgeFileFlags(file, &flags);
     return flags & CGE_FILE_ERROR;
 }
@@ -10,6 +13,8 @@ int CgeFileError(CgeFile *file) {
 int CgeFileEndOfFile(CgeFile *file) {
     int flags;
 
+    assert(file != NULL);
+
     CgeFileFlags(file, &flags);
     return flags & CGE_FILE_EOF;
 }
@@ -18,6 +23,9 @@ int CgeFilePeek(CgeFile *file, void *buffer, size_t size, size_t *actual) {
     int64_t pos;
     size_t n = 0;
 
+    assert(file != NULL);
+    assert(buffer != NULL);
+
     if (CgeFileError(file) || CgeFileEndOfFile(file))
         return 0;
 
@@ -26,6 +34,7 @@ int CgeFilePeek(CgeFile *file, void *buffer, size_t size, size_t *actual) {
         !CgeFileSeek(file, pos, CGE_FILE_SET))
         return 0;
 
-    if (actual) *actual = n;
+    if (actual)
+        *actual = n;
     return 1;
 }