feat: add support for compressed NBT

this switches from hematite_nbt to fastnbt.

sercon-backends/Cargo.toml

@@ -12,7 +12,8 @@ serde = "1.0"
 serde-value = "0.7"
 
 ciborium = "0.2.0"
-hematite-nbt = "0.5.2"
+fastnbt = "2.1.0"
+flate2 = "1.0.23"
 ron = "0.7.0"
 serde-lexpr = "0.1.2"
 serde-xml-rs = "0.5.1"

sercon-backends/src/backends/nbt.rs

@@ -1,5 +1,10 @@
 use std::io::{Read, Write};
 
+use flate2::{
+    bufread::{GzDecoder, ZlibDecoder},
+    write::GzEncoder,
+    Compression,
+};
 use miette::{Context, IntoDiagnostic};
 use sercon_base::Backend;
 use serde_value::Value;
@@ -9,16 +14,53 @@ pub struct NbtBackend;
 
 impl Backend for NbtBackend {
     fn serialize(&self, out: &mut dyn Write, data: Value) -> miette::Result<()> {
-        nbt::to_writer(out, &data, None)
+        let gz = GzEncoder::new(out, Compression::new(5));
+        fastnbt::to_writer(gz, &data)
             .into_diagnostic()
-            .wrap_err("NBT serialization error")
+            .wrap_err("failed to serialize NBT data")?;
+
+        Ok(())
     }
 
     fn deserialize(&self, data: &mut dyn Read) -> miette::Result<Value> {
-        nbt::from_reader(data)
+        let mut vec = vec![];
+        data.read_to_end(&mut vec).into_diagnostic()?;
+
+        let compression = vec
+            .get(0..2)
+            .map(|m| match m {
+                [0x1f, 0x8b] => CompressionType::Gzip,
+                [0x78, 0x01] | [0x78, 0x9C] | [0x78, 0xDA] => CompressionType::Zlib,
+                _ => CompressionType::None,
+            })
+            .unwrap_or(CompressionType::None);
+        let mut decomp = vec![];
+        match compression {
+            CompressionType::Gzip => {
+                GzDecoder::new(&vec[..])
+                    .read_to_end(&mut decomp)
+                    .into_diagnostic()
+                    .wrap_err("data gz decompression failed")?;
+            },
+            CompressionType::Zlib => {
+                ZlibDecoder::new(&vec[..])
+                    .read_to_end(&mut decomp)
+                    .into_diagnostic()
+                    .wrap_err("data zlib decompression failed")?;
+            },
+            CompressionType::None => decomp.copy_from_slice(&vec),
+        }
+
+        fastnbt::from_bytes(&decomp)
             .into_diagnostic()
-            .wrap_err("NBT deserialization error")
+            .wrap_err("NBT deserialization failed")
     }
 }
 
 impl_filetype_backend!(NbtBackend, ["nbt"]);
+
+enum CompressionType {
+    Gzip,
+    Zlib,
+    None,
+}