Refactoring with API improvements (#8)

Cargo.toml

@@ -15,6 +15,3 @@ byteorder = "1.3"
 named-binary-tag = "0.3"
 bitvec = "0.17"
 log = "0.4.11"
-
-[dev-dependencies]
-tempfile = "3.1"

README.md

@@ -20,11 +20,22 @@ anvil-region = "0.4"
 #### Read
 
 ```rust
-use anvil_region::AnvilChunkProvider;
+use anvil_region::provider::{FolderRegionProvider, RegionProvider};
 
-let chunk_provider = AnvilChunkProvider::new("test/region");
+let provider = FolderRegionProvider::new("test/region");
 
-let chunk_compound_tag = chunk_provider.load_chunk(4, 2).unwrap();
+let chunk_x = 4;
+let chunk_z = 2;
+
+let region_x = chunk_x >> 31;
+let region_z = chunk_z >> 31;
+
+let region_chunk_x = (chunk_x & 31) as u8;
+let region_chunk_z = (chunk_z & 31) as u8;
+
+let mut region = provider.get_region(region_x, region_z).unwrap();
+
+let chunk_compound_tag = region.read_chunk(region_chunk_x, region_chunk_z).unwrap();
 let level_compound_tag = chunk_compound_tag.get_compound_tag("Level").unwrap();
 
 assert_eq!(level_compound_tag.get_i32("xPos").unwrap(), 4);
@@ -34,10 +45,22 @@ assert_eq!(level_compound_tag.get_i32("zPos").unwrap(), 2);
 #### Write
 
 ```rust
-use anvil_region::AnvilChunkProvider;
+use anvil_region::provider::{FolderRegionProvider, RegionProvider};
 use nbt::CompoundTag;
 
-let chunk_provider = AnvilChunkProvider::new("test/region");
+let provider = FolderRegionProvider::new("test/region");
+
+let chunk_x = 31;
+let chunk_z = 16;
+
+let region_x = chunk_x >> 31;
+let region_z = chunk_z >> 31;
+
+let region_chunk_x = (chunk_x & 31) as u8;
+let region_chunk_z = (chunk_z & 31) as u8;
+
+let mut region = provider.get_region(region_x, region_z).unwrap();
+
 let mut chunk_compound_tag = CompoundTag::new();
 let mut level_compound_tag = CompoundTag::new();
 
@@ -48,5 +71,5 @@ level_compound_tag.insert_i32("zPos", 16);
 
 chunk_compound_tag.insert_compound_tag("Level", level_compound_tag);
 
-chunk_provider.save_chunk(31, 16, chunk_compound_tag);
+region.write_chunk(region_chunk_x, region_chunk_z, chunk_compound_tag);
 ```

src/error.rs

@@ -0,0 +1,72 @@
+use nbt::decode::TagDecodeError;
+use std::io;
+
+/// Possible errors while loading the chunk.
+#[derive(Debug)]
+pub enum ChunkReadError {
+    /// Chunk at specified coordinates inside region not found.
+    ChunkNotFound {
+        region_chunk_x: u8,
+        region_chunk_z: u8,
+    },
+    /// Chunk length overlaps declared maximum.
+    ///
+    /// This should not occur under normal conditions.
+    ///
+    /// Region file are corrupted.
+    LengthExceedsMaximum {
+        /// Chunk length.
+        length: u32,
+        /// Chunk maximum expected length.
+        maximum_length: u32,
+    },
+    /// Currently are only 2 types of compression: Gzip and Zlib.
+    ///
+    /// This should not occur under normal conditions.
+    ///
+    /// Region file are corrupted or was introduced new compression type.
+    UnsupportedCompressionScheme {
+        /// Compression scheme type id.
+        compression_scheme: u8,
+    },
+    /// I/O Error which happened while were reading chunk data from region file.
+    IOError { io_error: io::Error },
+    /// Error while decoding binary data to NBT tag.
+    ///
+    /// This should not occur under normal conditions.
+    ///
+    /// Region file are corrupted or a developer error in the NBT library.
+    TagDecodeError { tag_decode_error: TagDecodeError },
+}
+
+impl From<io::Error> for ChunkReadError {
+    fn from(io_error: io::Error) -> Self {
+        ChunkReadError::IOError { io_error }
+    }
+}
+
+impl From<TagDecodeError> for ChunkReadError {
+    fn from(tag_decode_error: TagDecodeError) -> Self {
+        ChunkReadError::TagDecodeError { tag_decode_error }
+    }
+}
+
+/// Possible errors while saving the chunk.
+#[derive(Debug)]
+pub enum ChunkWriteError {
+    /// Chunk length exceeds 1 MB.
+    ///
+    /// This should not occur under normal conditions.
+    LengthExceedsMaximum {
+        /// Chunk length.
+        length: u32,
+    },
+    /// I/O Error which happened while were writing chunk data to region.
+    IOError { io_error: io::Error },
+}
+
+impl From<io::Error> for ChunkWriteError {
+    fn from(io_error: io::Error) -> Self {
+        ChunkWriteError::IOError { io_error }
+    }
+}