Replace impl Read with Cursor<&[u8]> (#26)

* Start getting rid of Cursor

* try to make the tests pass and fail

* make the tests pass

* remove unused uses

* fix clippy warnings

* fix potential OOM exploits

* fix OOM in az-nbt

* fix nbt benchmark

* fix a test

* start replacing it with Cursor<Vec<u8>>

* wip

* fix all the issues

* fix all tests

* fix nbt benchmark

* fix warnings

1 files changed, 7 insertions, 9 deletions

diff --git a/azalea-core/src/position.rs b/azalea-core/src/position.rs
index d47072d4..d408d817 100644
--- a/azalea-core/src/position.rs
+++ b/azalea-core/src/position.rs
@@ -1,7 +1,7 @@
 use crate::ResourceLocation;
 use azalea_buf::{BufReadError, McBufReadable, McBufWritable};
 use std::{
-    io::{Read, Write},
+    io::{Cursor, Write},
     ops::{Add, Mul, Rem},
 };
 
@@ -301,7 +301,7 @@ const Z_OFFSET: u64 = PACKED_Y_LENGTH;
 const X_OFFSET: u64 = PACKED_Y_LENGTH + PACKED_Z_LENGTH;
 
 impl McBufReadable for BlockPos {
-    fn read_from(buf: &mut impl Read) -> Result<Self, BufReadError> {
+    fn read_from(buf: &mut Cursor<&[u8]>) -> Result<Self, BufReadError> {
         let val = i64::read_from(buf)?;
         let x = (val << (64 - X_OFFSET - PACKED_X_LENGTH) >> (64 - PACKED_X_LENGTH)) as i32;
         let y = (val << (64 - PACKED_Y_LENGTH) >> (64 - PACKED_Y_LENGTH)) as i32;
@@ -311,7 +311,7 @@ impl McBufReadable for BlockPos {
 }
 
 impl McBufReadable for GlobalPos {
-    fn read_from(buf: &mut impl Read) -> Result<Self, BufReadError> {
+    fn read_from(buf: &mut Cursor<&[u8]>) -> Result<Self, BufReadError> {
         Ok(GlobalPos {
             dimension: ResourceLocation::read_from(buf)?,
             pos: BlockPos::read_from(buf)?,
@@ -320,7 +320,7 @@ impl McBufReadable for GlobalPos {
 }
 
 impl McBufReadable for ChunkSectionPos {
-    fn read_from(buf: &mut impl Read) -> Result<Self, BufReadError> {
+    fn read_from(buf: &mut Cursor<&[u8]>) -> Result<Self, BufReadError> {
         let long = i64::read_from(buf)?;
         Ok(ChunkSectionPos {
             x: (long >> 42) as i32,
@@ -361,8 +361,6 @@ impl McBufWritable for ChunkSectionPos {
 
 #[cfg(test)]
 mod tests {
-    use std::io::Cursor;
-
     use super::*;
 
     #[test]
@@ -403,10 +401,10 @@ mod tests {
 
     #[test]
     fn test_read_blockpos_from() {
-        let mut buf = Cursor::new(Vec::new());
+        let mut buf = Vec::new();
         13743895338965u64.write_into(&mut buf).unwrap();
-        buf.set_position(0);
-        let block_pos = BlockPos::read_from(&mut buf).unwrap();
+        let buf = &mut &buf[..];
+        let block_pos = BlockPos::read_from(buf).unwrap();
         assert_eq!(block_pos, BlockPos::new(49, -43, -3));
     }
 }