fixed parameter block offset

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "c3dio"
-version = "0.1.0"
+version = "0.2.0"
 authors = ["Claire V. Hammond <claire@biomech.dev>"]
 edition = "2021"
 categories = ["encoding", "filesystem", "parser-implementation", "motion-capture", "biomechanics"]

src/c3d.rs

@@ -32,13 +32,11 @@ impl C3d {
 
     /// Parses a C3D file from a byte slice.
     pub fn from_bytes(bytes: &[u8]) -> Result<C3d, C3dParseError> {
-        let c3d = C3d::new()?
+        Ok(C3d::new()?
             .parse_basic_info_from_bytes(bytes)?
             .parse_header()?
             .parse_parameters()?
-            .parse_data_from_bytes(bytes)?;
-
-        Ok(c3d)
+            .parse_data_from_bytes(bytes)?)
     }
 
     /// Parses a C3D file with just the header data.
@@ -148,7 +146,7 @@ impl C3d {
             return Err(C3dParseError::InsufficientBlocks("data".to_string()));
         }
 
-        self.bytes.parameter = bytes[512..(512 * (self.bytes.data_start_block_index))]
+        self.bytes.parameter = bytes[512..(512 * (self.bytes.data_start_block_index - 1))]
             .try_into()
             .unwrap();
 
@@ -203,7 +201,7 @@ impl C3d {
     }
 
     fn parse_data_from_bytes(mut self, bytes: &[u8]) -> Result<C3d, C3dParseError> {
-        let data_start_byte = 512 * (self.bytes.data_start_block_index);
+        let data_start_byte = 512 * (self.bytes.data_start_block_index - 1);
         if bytes.len() < data_start_byte {
             return Err(C3dParseError::InsufficientBlocks("data".to_string()));
         }

tests/test_byte_and_file_parity.rs

@@ -0,0 +1,19 @@
+use c3dio::C3d;
+use std::fs::File;
+use std::io::{BufReader, Read};
+
+#[test]
+fn compare_byte_to_file_load() {
+    let sample19_file = C3d::load("tests/data/short.c3d").unwrap();
+
+    let file = File::open("tests/data/short.c3d").unwrap();
+    let mut buffer = BufReader::new(file);
+    let mut bytes = Vec::new();
+    buffer.read_to_end(&mut bytes).unwrap();
+    let sample19_bytes = C3d::from_bytes(&bytes).unwrap();
+
+    assert_eq!(sample19_file.parameters, sample19_bytes.parameters);
+    assert_eq!(sample19_file.events, sample19_bytes.events);
+    assert_eq!(sample19_file.data, sample19_bytes.data);
+}
+