From c6e34c57564dbe26e5d58d6a27fa0cdc2c3a75ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cyryl=20P=C5=82otnicki?= <cyplo@cyplo.net>
Date: Sat, 15 May 2021 20:10:26 +0100
Subject: [PATCH] wip on error correction

---
 .build.yml                         |  2 +-
 Cargo.lock                         | 19 ++++---------------
 Cargo.toml                         |  2 +-
 src/index/io.rs                    |  2 +-
 src/io/error_correcting_encoder.rs | 20 +++++++++-----------
 5 files changed, 16 insertions(+), 29 deletions(-)

diff --git a/.build.yml b/.build.yml
index 55108f4..b7be321 100644
--- a/.build.yml
+++ b/.build.yml
@@ -3,7 +3,7 @@ sources:
   - git@git.sr.ht:~cyplo/bakare
 
 secrets:
-  - b7161fff-05f4-4470-b4a1-57bd67dede23
+  - 6c23a8c1-7a30-4a7e-b3b7-0171e898a7d3
   - 996295b0-681c-49e8-8774-1be2f3e0bfe9
 
 environment:
diff --git a/Cargo.lock b/Cargo.lock
index a14b5ed..dd8dd98 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -41,7 +41,7 @@ dependencies = [
  "proptest",
  "rand 0.8.3",
  "rayon",
- "reed-solomon-erasure",
+ "reed-solomon",
  "rust-crypto",
  "serde",
  "serde_cbor",
@@ -642,15 +642,10 @@ dependencies = [
 ]
 
 [[package]]
-name = "reed-solomon-erasure"
-version = "4.0.2"
+name = "reed-solomon"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a415a013dd7c5d4221382329a5a3482566da675737494935cbbbcdec04662f9d"
-dependencies = [
- "cc",
- "libc",
- "smallvec",
-]
+checksum = "13de68c877a77f35885442ac72c8beb7c2f0b09380c43b734b9d63d1db69ee54"
 
 [[package]]
 name = "regex-syntax"
@@ -773,12 +768,6 @@ dependencies = [
  "opaque-debug",
 ]
 
-[[package]]
-name = "smallvec"
-version = "1.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
-
 [[package]]
 name = "syn"
 version = "1.0.60"
diff --git a/Cargo.toml b/Cargo.toml
index 5a6f17e..4a32b2d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,7 +19,7 @@ log = "0.4"
 nix = "0.19"
 rand = "0.8"
 rayon = "1.5"
-reed-solomon-erasure = { version = "4.0", features = ["simd-accel"] }
+reed-solomon = "0.2"
 rust-crypto = "0.2"
 serde = { version = "1.0", features = ["derive"] }
 serde_cbor = "0.11"
diff --git a/src/index/io.rs b/src/index/io.rs
index f5af465..77f2e0f 100644
--- a/src/index/io.rs
+++ b/src/index/io.rs
@@ -74,7 +74,7 @@ impl Index {
 
         {
             let mut file = index_file_path.create_file()?;
-            file.write_all(encoded).context("writing index to disk")?;
+            file.write_all(&encoded).context("writing index to disk")?;
             file.flush()?;
         }
 
diff --git a/src/io/error_correcting_encoder.rs b/src/io/error_correcting_encoder.rs
index 595899c..b09c502 100644
--- a/src/io/error_correcting_encoder.rs
+++ b/src/io/error_correcting_encoder.rs
@@ -1,18 +1,17 @@
+use std::io::Read;
+
 use anyhow::Result;
+use reed_solomon::Encoder;
 
-pub fn encode(bytes: &[u8]) -> Result<&[u8]> {
-    // find number of shards and parity blocks
-    // encode checksum with each block
-    // when decoding, remove blocks with invalid checksum
+const ECC_LENGTH: usize = 8;
 
-    Ok(bytes)
+pub fn encode(bytes: &[u8]) -> Result<Vec<u8>> {
+    let encoder = Encoder::new(ECC_LENGTH);
+    let encoded = encoder.encode(bytes);
+    Ok(encoded.bytes().collect::<Result<Vec<u8>, _>>()?)
 }
 
 pub fn decode(bytes: &[u8]) -> Result<&[u8]> {
-    // find number of shards and parity blocks
-    // encode checksum with each block
-    // when decoding, remove blocks with invalid checksum
-
     Ok(bytes)
 }
 
@@ -20,7 +19,6 @@ mod must {
 
     use anyhow::Result;
     use rand::{thread_rng, Rng, RngCore};
-    use vfs::{MemoryFS, VfsPath};
 
     use super::{decode, encode};
 
@@ -35,7 +33,7 @@ mod must {
         let corrupt_byte_index = rand::thread_rng().gen_range::<usize, _>(0..size);
 
         let mut corrupted: [u8; 32] = [0; 32];
-        corrupted.copy_from_slice(encoded);
+        corrupted.copy_from_slice(&encoded);
         corrupted[corrupt_byte_index] = rand::thread_rng().gen::<u8>();
 
         let decoded = decode(&corrupted)?;