read datas

shen-nbt5/src/lib.rs

@@ -1,44 +1,70 @@
-
+// pub enum Endian {
+//     Big,
+//     Little,
+// }
 
 /// 用于读取 NBT 数据
 pub struct NbtReader<'data> {
-    data: &'data [u8],
-    cursor: usize,
+    /// NBT 数据
+    pub data: &'data [u8],
+    /// 当前读取的位置
+    pub cursor: usize,
+    // be/le
+    // pub endian: Endian,
 }
 
+macro_rules! read {
+    ($name:ident, $ty:ty, $size:literal) => {
+        #[doc = concat!("读取 ", stringify!($ty), " 类型 ", $size, " 长度的数据")]
+        pub fn $name(&mut self) -> $ty {
+            unsafe {
+                let value = *(self.data[self.cursor..].as_ptr() as *const $ty);
+                self.cursor += std::mem::size_of::<$ty>();
+                value.to_be()
+            }
+        }
+    };
+    ($name:ident, $ty:ty, $size:literal, false) => {
+        #[doc = concat!("读取 ", stringify!($ty), " 类型 ", $size, " 长度的数据")]
+        pub fn $name(&mut self) -> $ty {
+            unsafe {
+                let value = *(self.data[self.cursor..].as_ptr() as *const $ty);
+                self.cursor += std::mem::size_of::<$ty>();
+                value
+            }
+        }
+    };
+}
 impl NbtReader<'_> {
     pub fn new(data: &[u8]) -> NbtReader {
         NbtReader {
             data,
             cursor: 0,
+            // endian: Endian::Big,
         }
     }
-    
     pub fn read_i8(&mut self) -> i8 {
         let value = self.data[self.cursor] as i8;
         self.cursor += 1;
         value
     }
-    pub fn read_i16(&mut self) -> i16 {
-        unsafe {
-            let value = *(self.data[self.cursor..].as_ptr() as *const i16);
-            self.cursor += 2;
-            value.to_be()
-        }
-    }
-    pub fn read_i32(&mut self) -> i32 {
-        unsafe {
-            let value = *(self.data[self.cursor..].as_ptr() as *const i32);
-            self.cursor += 4;
-            value.to_be()
-        }
-    }
-    pub fn read_i64(&mut self) -> i64 {
-        unsafe {
-            let value = *(self.data[self.cursor..].as_ptr() as *const i64);
-            self.cursor += 8;
-            value.to_be()
+    pub fn read_u8(&mut self) -> u8 {
+        let value = self.data[self.cursor];
+        self.cursor += 1;
+        value
     }
+    read!(read_i16, i16, 2);
+    read!(read_u16, u16, 2);
+    read!(read_i32, i32, 4);
+    read!(read_u32, u32, 4);
+    read!(read_i64, i64, 8);
+    read!(read_u64, u64, 8);
+    read!(read_f32, f32, 4, false);
+    read!(read_f64, f64, 8, false);
+    pub fn read_bytes(&mut self, len: usize) -> &[u8] {
+        let value = &self.data[self.cursor..self.cursor + len];
+        self.cursor += len;
+        value
     }
 }
 
@@ -71,4 +97,3 @@ pub enum NbtValue<'value> {
     /// 12
     LongArray(Vec<i64>),
 }
-