Fix the damn text file loading function

rendering.h

@@ -25,20 +25,32 @@ void checkShader(unsigned int shader, int statusFlag, char* actionName) {
     }
 }
 
-char* loadText(char* path) {
-    char* buffer = NULL;
-    long length;
-    FILE* f = fopen(path, "rb");
-    if (f) {
-        fseek(f, 0, SEEK_END);
-        length = ftell(f);
-        fseek(f, 0, SEEK_SET);
-        buffer = calloc(length, sizeof(char));
-        if (buffer) {
-            fread(buffer, 1, length, f);
-        }
-        fclose(f);
+char *loadText(char* path) {
+    char *buffer = NULL;
+    FILE *f = fopen(path, "r");
+    if (f == NULL) {
+        return NULL;
     }
+    if (fseek(f, 0, SEEK_END) != 0) {
+        return NULL;
+    }
+
+    i16 length = ftell(f);
+    if (length == -1) {
+        return NULL;
+    }
+    buffer = malloc((length + 1) * sizeof(char));
+    if (fseek(f, 0, SEEK_SET) != 0) {
+        return NULL;
+    }
+    usize newLen = fread(buffer, sizeof(char), length, f);
+    if (ferror(f) != 0) {
+        return NULL;
+    } else {
+        buffer[newLen] = '\0';
+    }
+
+    fclose(f);
     return buffer;
 }