From 1e810adafb91a62241ecaf4dcae76f417fdd545a Mon Sep 17 00:00:00 2001
From: Harald Eilertsen <haraldei@anduin.net>
Date: Mon, 7 Dec 2020 22:13:56 +0100
Subject: refactor: arch_chunk now takes sub parser as arg.

The sub parser is applied to the chunk payload, and the returned output
is the output of the sub parser.
---
 src/main.rs | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index c5f1e46..964635a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,12 +21,14 @@ use cubase_project::*;
 
 use nom::{
     bytes::complete::*,
-    combinator::map,
+    combinator::{map, rest},
+    error::ParseError,
     multi::{length_data, length_value, many1},
     number::complete::*,
     sequence::{preceded, terminated, tuple},
     Finish,
     IResult,
+    Parser,
 };
 use std::{
     error::Error,
@@ -110,10 +112,14 @@ fn root_chunk<'a>(input: &'a [u8]) -> IResult<&'a [u8], (&str, &str)> {
         length_value(be_u32, tuple((cmstring, cmstring))))(input)
 }
 
-fn arch_chunk<'a>(input: &'a [u8]) -> IResult<&'a [u8], &'a [u8]> {
+fn arch_chunk<'a, O, E, F>(subparser: F) -> impl FnMut(&'a [u8]) -> IResult<&'a [u8], O, E>
+where
+    E: ParseError<&'a [u8]>,
+    F: Parser<&'a [u8], O, E>,
+{
     preceded(
         tag(b"ARCH"),
-        length_data(be_u32))(input)
+        length_value(be_u32, subparser))
 }
 
 /**
@@ -152,18 +158,18 @@ fn cpr_file<'a>(input: &'a [u8]) -> IResult<&'a [u8], CubaseProject> {
 
         match k {
             "Version" => {
-                let (r2, v) = version_chunk(r)?;
+                let (r2, v) = arch_chunk(version_chunk)(r)?;
                 println!("[*] {:?}", v);
                 proj.app_version = v;
                 payload = r2;
             },
             "Arrangement1" => {
-                let (r2, a) = arrangement_chunk(r)?;
+                let (r2, a) = arch_chunk(arrangement_chunk)(r)?;
                 println!("[*] {:?}", a);
                 payload = r2;
             },
             _ => {
-                let (r2, _) = arch_chunk(r)?;
+                let (r2, _) = arch_chunk(rest)(r)?;
                 payload = r2;
             }
         }
@@ -196,9 +202,7 @@ fn cpr_file_header<'a>(input: &'a [u8]) -> IResult<&'a [u8], u32> {
 
 
 fn version_chunk<'a>(input: &'a [u8]) -> IResult<&'a [u8], PAppVersion> {
-    let (r, chunk) = arch_chunk(input)?;
-
-    let (odata, c) = container_node(chunk)?;
+    let (odata, c) = container_node(input)?;
     println!("[*] {:?}", c);
 
     let (r2, o) = object_node(odata)?;
@@ -208,13 +212,11 @@ fn version_chunk<'a>(input: &'a [u8]) -> IResult<&'a [u8], PAppVersion> {
     let (r2, v) = p_app_version(o.payload.unwrap())?;
     assert_eq!(r2.len(), 0);
 
-    Ok((r, v))
+    Ok((r2, v))
 }
 
 
 fn arrangement_chunk<'a>(input: &'a [u8]) -> IResult<&'a [u8], PArrangement> {
-    let (r, chunk) = arch_chunk(input)?;
-
     // It varies a bit how many levels deep the actual PArrangement object is.
     //
     // File created with Cubase 4.5.x (file version 310?) seems to have this
@@ -224,7 +226,7 @@ fn arrangement_chunk<'a>(input: &'a [u8]) -> IResult<&'a [u8], PArrangement> {
     //
     // While Cubase version 5.x (file version 400?) seems to have the CmObject
     // directly under the GDocument container.
-    let (odata, c) = many1(container_node)(chunk)?;
+    let (odata, c) = many1(container_node)(input)?;
     println!("[*] {:?}", c);
 
     // This is the actual PArrangeent object
@@ -235,7 +237,7 @@ fn arrangement_chunk<'a>(input: &'a [u8]) -> IResult<&'a [u8], PArrangement> {
     let (r2, v) = p_arrangement(o.payload.unwrap())?;
     // assert_eq!(r2.len(), 0);
 
-    Ok((r, PArrangement::default()))
+    Ok((r2, PArrangement::default()))
 }
 
 pub fn parse_cubase_project<P>(filename: P) -> Result<CubaseProject, Box<dyn Error>>
-- 
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