Drop custom PtrCursor (#569)

* Drop custom PtrCursor

* Drop unused crate

* Fixup

---------

Co-authored-by: GG Bond <whatever@tagkong.com>

app/src/main/rust/Cargo.toml

@@ -14,7 +14,6 @@ quick-xml = { default-features = false, version = "0.31" }
 tl = "0.7"
 log = "0.4"
 android_logger = { default-features = false, version = "0.13" }
-apply = "0.3"
 once_cell = { default-features = false, version = "1.19" }
 serde_json = "1.0"
 serde = { version = "1.0", features = ["derive"] }

app/src/main/rust/src/lib.rs

@@ -1,7 +1,6 @@
 mod parser;
 
 extern crate android_logger;
-extern crate apply;
 extern crate jni;
 extern crate jni_fn;
 extern crate log;
@@ -18,9 +17,9 @@ use jni::JNIEnv;
 use log::LevelFilter;
 use serde::Serialize;
 use std::ffi::c_void;
-use std::io::Write;
+use std::io::Cursor;
 use std::panic::{catch_unwind, UnwindSafe};
-use std::ptr::slice_from_raw_parts;
+use std::ptr::{slice_from_raw_parts, slice_from_raw_parts_mut};
 use std::str::from_utf8_unchecked;
 use tl::{Bytes, Node, NodeHandle, Parser, VDom};
 
@@ -35,28 +34,6 @@ macro_rules! regex {
 const EHGT_PREFIX: &str = "https://ehgt.org/";
 const EX_PREFIX: &str = "https://s.exhentai.org/";
 
-struct PtrCursor {
-    ptr: *mut u8,
-    pos: i32,
-}
-
-impl Write for PtrCursor {
-    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
-        let len = buf.len();
-        unsafe {
-            self.ptr.copy_from(buf.as_ptr(), len);
-            self.ptr = self.ptr.add(len);
-            self.pos += len as i32;
-        }
-        Ok(len)
-    }
-
-    fn flush(&mut self) -> std::io::Result<()> {
-        // Nothing
-        Ok(())
-    }
-}
-
 fn check_html(str: &str) {
     if !str.contains('<') {
         panic!("{}", str)
@@ -110,9 +87,12 @@ where
             // Nothing to marshal
             None => 0,
             Some(value) => {
-                let mut cursor = PtrCursor { ptr, pos: 0 };
+                let mut cursor = unsafe {
+                    let slice = slice_from_raw_parts_mut(ptr, 0x80000);
+                    Cursor::new(&mut *slice)
+                };
                 serde_json::to_writer(&mut cursor, &value).unwrap();
-                cursor.pos
+                cursor.position() as i32
             }
         }
     };