From bf00a2b1568abea6d2b1c773aafb41ecb781721e Mon Sep 17 00:00:00 2001
From: Dennis Schwerdel <schwerdel@googlemail.com>
Date: Wed, 19 Apr 2017 19:54:53 +0200
Subject: [PATCH] Added fixed chunker

---
 chunking/Cargo.lock   | 17 -----------------
 chunking/src/fixed.rs | 40 ++++++++++++++++++++++++++++++++++++++++
 chunking/src/lib.rs   |  2 ++
 src/chunker.rs        | 19 +++++++++++++------
 4 files changed, 55 insertions(+), 23 deletions(-)
 create mode 100644 chunking/src/fixed.rs

diff --git a/chunking/Cargo.lock b/chunking/Cargo.lock
index d4da0da..2457033 100644
--- a/chunking/Cargo.lock
+++ b/chunking/Cargo.lock
@@ -3,8 +3,6 @@ name = "chunking"
 version = "0.1.0"
 dependencies = [
  "quick-error 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 0.9.14 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_utils 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -12,20 +10,5 @@ name = "quick-error"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
-[[package]]
-name = "serde"
-version = "0.9.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "serde_utils"
-version = "0.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "serde 0.9.14 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [metadata]
 "checksum quick-error 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0aad603e8d7fb67da22dbdf1f4b826ce8829e406124109e73cf1b2454b93a71c"
-"checksum serde 0.9.14 (registry+https://github.com/rust-lang/crates.io-index)" = "a4c9a40d556f8431394def53446db659f796dc87a53ef67b7541f21057fbdd91"
-"checksum serde_utils 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b34a52969c7fc0254e214b82518c9a95dc88c84fc84cd847add314996a031be6"
diff --git a/chunking/src/fixed.rs b/chunking/src/fixed.rs
new file mode 100644
index 0000000..e738297
--- /dev/null
+++ b/chunking/src/fixed.rs
@@ -0,0 +1,40 @@
+use super::*;
+
+use std::cmp::min;
+
+
+pub struct FixedChunker {
+    buffer: [u8; 4096],
+    size: usize
+}
+
+impl FixedChunker {
+    pub fn new(avg_size: usize) -> FixedChunker {
+        FixedChunker{
+            buffer: [0; 4096],
+            size: avg_size,
+        }
+    }
+}
+
+impl Chunker for FixedChunker {
+    #[allow(unknown_lints,explicit_counter_loop)]
+    fn chunk(&mut self, r: &mut Read, mut w: &mut Write) -> Result<ChunkerStatus, ChunkerError> {
+        let mut todo = self.size;
+        loop {
+            // Fill the buffer, there might be some bytes still in there from last chunk
+            let max_read = min(todo, self.buffer.len());
+            let read = try!(r.read(&mut self.buffer[..max_read]).map_err(ChunkerError::Read));
+            // If nothing to do, finish
+            if read == 0 {
+                return Ok(ChunkerStatus::Finished)
+            }
+            // Write all bytes from this chunk out to sink and store rest for next chunk
+            try!(w.write_all(&self.buffer[..read]).map_err(ChunkerError::Write));
+            todo -= read;
+            if todo == 0 {
+                return Ok(ChunkerStatus::Continue)
+            }
+        }
+    }
+}
diff --git a/chunking/src/lib.rs b/chunking/src/lib.rs
index 4c1413f..d073ec5 100644
--- a/chunking/src/lib.rs
+++ b/chunking/src/lib.rs
@@ -2,10 +2,12 @@
 
 use std::io::{self, Write, Read};
 
+mod fixed;
 mod ae;
 mod rabin;
 mod fastcdc;
 
+pub use self::fixed::FixedChunker;
 pub use self::ae::AeChunker;
 pub use self::rabin::RabinChunker;
 pub use self::fastcdc::FastCdcChunker;
diff --git a/src/chunker.rs b/src/chunker.rs
index ac3d819..fce9507 100644
--- a/src/chunker.rs
+++ b/src/chunker.rs
@@ -7,12 +7,14 @@ use std::str::FromStr;
 pub enum ChunkerType {
     Ae(usize),
     Rabin((usize, u32)),
-    FastCdc((usize, u64))
+    FastCdc((usize, u64)),
+    Fixed(usize)
 }
 serde_impl!(ChunkerType(u64) {
     Ae(usize) => 1,
     Rabin((usize, u32)) => 2,
-    FastCdc((usize, u64)) => 3
+    FastCdc((usize, u64)) => 3,
+    Fixed(usize) => 4
 });
 
 
@@ -22,6 +24,7 @@ impl ChunkerType {
             "ae" => Ok(ChunkerType::Ae(avg_size)),
             "rabin" => Ok(ChunkerType::Rabin((avg_size, seed as u32))),
             "fastcdc" => Ok(ChunkerType::FastCdc((avg_size, seed))),
+            "fixed" => Ok(ChunkerType::Fixed(avg_size)),
             _ => Err("Unsupported chunker type")
         }
     }
@@ -43,7 +46,8 @@ impl ChunkerType {
         match *self {
             ChunkerType::Ae(size) => Box::new(AeChunker::new(size)),
             ChunkerType::Rabin((size, seed)) => Box::new(RabinChunker::new(size, seed)),
-            ChunkerType::FastCdc((size, seed)) => Box::new(FastCdcChunker::new(size, seed))
+            ChunkerType::FastCdc((size, seed)) => Box::new(FastCdcChunker::new(size, seed)),
+            ChunkerType::Fixed(size) => Box::new(FixedChunker::new(size)),
         }
     }
 
@@ -51,7 +55,8 @@ impl ChunkerType {
         match *self {
             ChunkerType::Ae(_size) => "ae",
             ChunkerType::Rabin((_size, _seed)) => "rabin",
-            ChunkerType::FastCdc((_size, _seed)) => "fastcdc"
+            ChunkerType::FastCdc((_size, _seed)) => "fastcdc",
+            ChunkerType::Fixed(_size) => "fixed",
         }
     }
 
@@ -59,7 +64,8 @@ impl ChunkerType {
         match *self {
             ChunkerType::Ae(size) => size,
             ChunkerType::Rabin((size, _seed)) => size,
-            ChunkerType::FastCdc((size, _seed)) => size
+            ChunkerType::FastCdc((size, _seed)) => size,
+            ChunkerType::Fixed(size) => size
         }
     }
 
@@ -71,7 +77,8 @@ impl ChunkerType {
         match *self {
             ChunkerType::Ae(_size) => 0,
             ChunkerType::Rabin((_size, seed)) => seed as u64,
-            ChunkerType::FastCdc((_size, seed)) => seed
+            ChunkerType::FastCdc((_size, seed)) => seed,
+            ChunkerType::Fixed(_size) => 0,
         }
     }
 }