From 1b1fca8138485920590d04b04ba699e78a418934 Mon Sep 17 00:00:00 2001
From: Harald Eilertsen <haraldei@anduin.net>
Date: Wed, 25 Nov 2020 14:14:45 +0100
Subject: Refactor parsing of ARCH chunks and add docs.

---
 src/main.rs | 54 ++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 38 insertions(+), 16 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 52a8d3f..7546df8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,6 +16,7 @@
  */
 
 use nom::{
+    branch::alt,
     bytes::complete::*,
     multi::{count, length_data, many0},
     number::complete::*,
@@ -101,7 +102,6 @@ fn bytevec<'a>(data: &'a[u8]) -> IResult<&'a [u8], &'a [u8]> {
 /// Version information about the app that created the file.
 #[derive(Debug)]
 struct PAppVersion<'a> {
-    num1: u32,
     appname: &'a str,
     appversion: &'a str,
     appdate: &'a str,
@@ -113,11 +113,10 @@ struct PAppVersion<'a> {
 }
 
 fn p_appversion<'a>(data: &'a [u8]) -> IResult<&'a [u8], PAppVersion<'a>> {
-    let (r, (num1, appname, appversion, appdate, num2, apparch, num3, appencoding, applocale)) =
-        tuple((be_u32, cmstring, cmstring, cmstring, be_u32, cmstring, be_u32, cmstring, cmstring))(&data)?;
+    let (r, (appname, appversion, appdate, num2, apparch, num3, appencoding, applocale)) =
+        tuple((cmstring, cmstring, cmstring, be_u32, cmstring, be_u32, cmstring, cmstring))(&data)?;
 
     Ok((r, PAppVersion {
-        num1,
         appname,
         appversion,
         appdate,
@@ -271,20 +270,35 @@ fn root_chunk<'a>(data: &'a [u8]) -> IResult<&'a [u8], ()> {
     Ok((rest, ()))
 }
 
-fn arch_chunk<'a>(data: &'a [u8]) -> IResult<&'a [u8], ()> {
-    let (rest, (nt, t, x)) = tuple((nodetype, cmstring, be_u16))(data)?;
-    println!("    {:?}: {}, {}", nt, t, x);
 
-    match nt {
-        NodeType::Container => {
-            arch_chunk(rest)?;
-        },
-        NodeType::Leaf => {
-            let (_, nodeval) = node_value(t, rest)?;
-            println!("      {:?}", nodeval);
-        }
-    };
+/**
+ * A container node does not contain any data of it's own, but contains
+ * one or more sub elements. These can be either other containers, or
+ * object/leaf nodes.
+ */
+fn container_node<'a>(data: &'a [u8]) -> IResult<&'a [u8], ()> {
+    let (r, (_, name, num)) = tuple((tag(b"\xff\xff\xff\xfe"), cmstring, be_u16))(data)?;
+    println!("     Container: {}, {}", name, num);
+    Ok((r, ()))
+}
+
+/**
+ * An object node contains serialized structured data.
+ *
+ * It has a size, as well as a payload containing the actual serialized data.
+ */
+fn object_node<'a>(data: &'a [u8]) -> IResult<&'a [u8], ()> {
+    let (r, (_, name, num, payload)) = tuple((tag(b"\xff\xff\xff\xff"), cmstring, be_u16, length_data(be_u32)))(data)?;
+    println!("       Object: {}, {}, {}", name, num, payload.len());
+    Ok((r, ()))
+}
 
+/**
+ * ARCH chunks contains one or more structured data elements that can be
+ * either container nodes or object/leaf nodes..
+ */
+fn arch_chunk<'a>(data: &'a [u8]) -> IResult<&'a [u8], ()> {
+    let (rest, _nodes) = many0(alt((container_node, object_node)))(data)?;
     Ok((rest, ()))
 }
 
@@ -302,6 +316,14 @@ fn chunk<'a>(data: &'a [u8]) -> IResult<&'a [u8], ()> {
     Ok((rest, ()))
 }
 
+/**
+ * Parse the Cubase project file header.
+ *
+ * A Cubase project file is almost a standard RIFF file, with the exception of an
+ * extra fourcc (NUND) following the global RIFF header. The extra (NUND) fourcc
+ * is _not_ followed by the length of the chunk, but rather immediately followed by
+ * the next chunk.
+ */
 fn file_hdr<'a>(data: &'a [u8]) -> IResult<&'a [u8], ()> {
     let (rest, (_, len, _)) = tuple((tag("RIFF"), be_u32, tag("NUND")))(data)?;
     println!("RIFF: {}, NUND", len);
-- 
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