small performance improvements0.12.1

For the most part, this switches write_record to write_byte_record where
possible, and also moves some uses of the `byte_records` iterator to the
manual `read_byte_record` method, which permits us to amortize
allocation.

This also removes the use of normal selection for `xsv search`, which
was causing a huge slow down.

Also, bump to csv 1.0.0.beta.3.

15 files changed, 86 insertions, 78 deletions

diff --git a/BENCHMARKS.md b/BENCHMARKS.md
index 7326a49..e8bfbad 100644
--- a/BENCHMARKS.md
+++ b/BENCHMARKS.md
@@ -10,23 +10,25 @@ These benchmarks were run on an Intel i7-6900K (8 CPUs, 16 threads) with 64GB
 of memory.
 
 ```
-count                   0.11  seconds  413.76   MB/sec
-flatten                 4.54  seconds  10.02    MB/sec
-flatten_condensed       4.45  seconds  10.22    MB/sec
-frequency               1.82  seconds  25.00    MB/sec
-index                   0.12  seconds  379.28   MB/sec
-sample_10               0.18  seconds  252.85   MB/sec
-sample_1000             0.18  seconds  252.85   MB/sec
-sample_100000           0.29  seconds  156.94   MB/sec
-search                  0.27  seconds  168.56   MB/sec
-select                  0.14  seconds  325.09   MB/sec
-sort                    2.18  seconds  20.87    MB/sec
-slice_one_middle        0.08  seconds  568.92   MB/sec
-slice_one_middle_index  0.01  seconds  4551.36  MB/sec
-stats                   1.09  seconds  41.75    MB/sec
-stats_index             0.15  seconds  303.42   MB/sec
-stats_everything        1.94  seconds  23.46    MB/sec
-stats_everything_index  0.93  seconds  48.93    MB/sec
+count                   0.11 seconds   413.76  MB/sec
+flatten                 4.54 seconds   10.02   MB/sec
+flatten_condensed       4.45 seconds   10.22   MB/sec
+frequency               1.82 seconds   25.00   MB/sec
+index                   0.12 seconds   379.28  MB/sec
+sample_10               0.18 seconds   252.85  MB/sec
+sample_1000             0.18 seconds   252.85  MB/sec
+sample_100000           0.29 seconds   156.94  MB/sec
+search                  0.27 seconds   168.56  MB/sec
+select                  0.14 seconds   325.09  MB/sec
+search                  0.13 seconds   350.10  MB/sec
+select                  0.13 seconds   350.10  MB/sec
+sort                    2.18 seconds   20.87   MB/sec
+slice_one_middle        0.08 seconds   568.92  MB/sec
+slice_one_middle_index  0.01 seconds   4551.36 MB/sec
+stats                   1.09 seconds   41.75   MB/sec
+stats_index             0.15 seconds   303.42  MB/sec
+stats_everything        1.94 seconds   23.46   MB/sec
+stats_everything_index  0.93 seconds   48.93   MB/sec
 ```
 
 ### Details
diff --git a/Cargo.lock b/Cargo.lock
index 78154df..4bc2439 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,18 +4,18 @@ version = "0.12.0"
 dependencies = [
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "chan 0.1.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "csv 1.0.0-beta.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "csv-index 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "csv 1.0.0-beta.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "csv-index 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "docopt 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "filetime 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickcheck 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "streaming-stats 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "tabwriter 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "threadpool 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -44,16 +44,16 @@ dependencies = [
 
 [[package]]
 name = "csv"
-version = "1.0.0-beta.1"
+version = "1.0.0-beta.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "csv-core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "csv-core 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "csv-core"
-version = "0.1.0"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "memchr 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -61,12 +61,12 @@ dependencies = [
 
 [[package]]
 name = "csv-index"
-version = "0.1.0"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "csv 1.0.0-beta.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "csv-core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "csv 1.0.0-beta.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "csv-core 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -109,7 +109,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "log"
-version = "0.3.7"
+version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -239,22 +239,22 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "serde"
-version = "1.0.7"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "serde_derive"
-version = "1.0.7"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive_internals 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive_internals 0.15.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "serde_derive_internals"
-version = "0.15.0"
+version = "0.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -365,15 +365,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum aho-corasick 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "500909c4f87a9e52355b26626d890833e9e1d53ac566db76c36faa984b889699"
 "checksum byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c40977b0ee6b9885c9013cd41d9feffdd22deb3bb4dc3a71d901cc7a77de18c8"
 "checksum chan 0.1.19 (registry+https://github.com/rust-lang/crates.io-index)" = "f93bfe971116428a9066c1c3c69a09ae3ef69432f8418be28ab50f96783e6a50"
-"checksum csv 1.0.0-beta.1 (registry+https://github.com/rust-lang/crates.io-index)" = "81675dd89651e2aa0989e6a5249dc5c5bcfc13772baec7f9652208e7691e0955"
-"checksum csv-core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6a11ab3094dd197341f9d66753789a5cdf29ce35450a7d6e7968024e2d44519c"
-"checksum csv-index 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7405ccdb151a01a4844b2cf851e2806dca2bdec892537057bf0719f4a7504c60"
+"checksum csv 1.0.0-beta.3 (registry+https://github.com/rust-lang/crates.io-index)" = "158edc15f3da84af2ae2689ab84157f7f94a21dff3dec455320cf44be8963433"
+"checksum csv-core 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "ed4919aaefb12f555bb4e34aa6415b5db7e20e01e517427f13c2bde286ae9b53"
+"checksum csv-index 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "22fe847d4629c76b667e11da543f7e0da336e9aa39487ecd3e3a1f9517a06c47"
 "checksum docopt 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ab32ea6e284d87987066f21a9e809a73c14720571ef34516f0890b3d355ccfd8"
 "checksum filetime 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "5363ab8e4139b8568a6237db5248646e5a8a2f89bd5ccb02092182b11fd3e922"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "3b37545ab726dd833ec6420aaba8231c5b320814b9029ad585555d2a03e94fbf"
 "checksum libc 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)" = "e7eb6b826bfc1fdea7935d46556250d1799b7fe2d9f7951071f4291710665e3e"
-"checksum log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "5141eca02775a762cc6cd564d8d2c50f67c0ea3a372cbf1c51592b3e029e10ad"
+"checksum log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "880f77541efa6e5cc74e76910c9884d9859683118839d6a1dc3b11e63512565b"
 "checksum memchr 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1dbccc0e46f1ea47b9f17e6d67c5a96bd27030519c519c9c91327e31275a47b4"
 "checksum num 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "98b15ba84e910ea7a1973bccd3df7b31ae282bf9d8bd2897779950c9b8303d40"
 "checksum num-bigint 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "ba6d838b16e56da1b6c383d065ff1ec3c7d7797f65a3e8f6ba7092fd87820bac"
@@ -389,9 +389,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1731164734096285ec2a5ec7fea5248ae2f5485b3feeb0115af4fda2183b2d1b"
 "checksum regex-syntax 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ad890a5eef7953f55427c50575c680c42841653abd2b028b68cd223d157f62db"
 "checksum rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)" = "dcf128d1287d2ea9d80910b5f1120d0b8eede3fbf1abe91c40d39ea7d51e6fda"
-"checksum serde 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "c0c3d79316a6051231925504f6ef893d45088e8823c77a8331a3dcf427ee9087"
-"checksum serde_derive 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "0019cd5b9f0529a1a0e145a912e9a2d60c325c58f7f260fc36c71976e9d76aee"
-"checksum serde_derive_internals 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)" = "021c338d22c7e30f957a6ab7e388cb6098499dda9fd4ba1661ee074ca7a180d1"
+"checksum serde 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)" = "c2f530d36fb84ec48fb7146936881f026cdbf4892028835fd9398475f82c1bb4"
+"checksum serde_derive 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)" = "10552fad5500771f3902d0c5ba187c5881942b811b7ba0d8fbbfbf84d80806d3"
+"checksum serde_derive_internals 0.15.1 (registry+https://github.com/rust-lang/crates.io-index)" = "37aee4e0da52d801acfbc0cc219eb1eda7142112339726e427926a6f6ee65d3a"
 "checksum streaming-stats 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)" = "f13d0cd680e11a62c5e125d9799debfb39fcfff9a2ef416336ce748f65018b89"
 "checksum strsim 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b4d15c810519a91cf877e7e36e63fe068815c678181439f2f29e2562147c3694"
 "checksum syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d3b891b9015c88c576343b9b3e41c2c11a51c219ef067b264bd9c8aa9b441dad"
diff --git a/Cargo.toml b/Cargo.toml
index b9e386d..c4fe495 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,6 +21,7 @@ name = "tests"
 
 [profile.release]
 opt-level = 3
+debug = true
 
 [profile.test]
 opt-level = 3
@@ -28,8 +29,8 @@ opt-level = 3
 [dependencies]
 byteorder = "1"
 chan = "0.1"
-csv = "1.0.0-beta.1"
-csv-index = "0.1"
+csv = "1.0.0-beta.3"
+csv-index = "0.1.2"
 docopt = "0.7"
 filetime = "0.1"
 num_cpus = "1.4"
diff --git a/src/cmd/cat.rs b/src/cmd/cat.rs
index 7e7c1f3..9c838bf 100644
--- a/src/cmd/cat.rs
+++ b/src/cmd/cat.rs
@@ -69,14 +69,15 @@ impl Args {
     }
 
     fn cat_rows(&self) -> CliResult<()> {
+        let mut row = csv::ByteRecord::new();
         let mut wtr = Config::new(&self.flag_output).writer()?;
         for (i, conf) in self.configs()?.into_iter().enumerate() {
             let mut rdr = conf.reader()?;
             if i == 0 {
                 conf.write_headers(&mut rdr, &mut wtr)?;
             }
-            for r in rdr.byte_records() {
-                wtr.write_record(&r?)?;
+            while rdr.read_byte_record(&mut row)? {
+                wtr.write_byte_record(&row)?;
             }
         }
         wtr.flush().map_err(From::from)
@@ -124,7 +125,7 @@ impl Args {
             if num_done >= iters.len() {
                 break 'OUTER;
             }
-            wtr.write_record(&record)?;
+            wtr.write_byte_record(&record)?;
         }
         wtr.flush().map_err(From::from)
     }
diff --git a/src/cmd/fixlengths.rs b/src/cmd/fixlengths.rs
index eb176bb..feaed67 100644
--- a/src/cmd/fixlengths.rs
+++ b/src/cmd/fixlengths.rs
@@ -88,7 +88,7 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
         } else {
             r.truncate(length);
         }
-        wtr.write_record(&r)?;
+        wtr.write_byte_record(&r)?;
     }
     wtr.flush()?;
     Ok(())
diff --git a/src/cmd/fmt.rs b/src/cmd/fmt.rs
index 4bd7070..3878408 100644
--- a/src/cmd/fmt.rs
+++ b/src/cmd/fmt.rs
@@ -72,8 +72,9 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
 
     let mut rdr = rconfig.reader()?;
     let mut wtr = wconfig.writer()?;
-    for r in rdr.byte_records() {
-        wtr.write_record(&r?)?;
+    let mut r = csv::ByteRecord::new();
+    while rdr.read_byte_record(&mut r)? {
+        wtr.write_byte_record(&r)?;
     }
     wtr.flush()?;
     Ok(())
diff --git a/src/cmd/input.rs b/src/cmd/input.rs
index f16a712..17d9c44 100644
--- a/src/cmd/input.rs
+++ b/src/cmd/input.rs
@@ -1,3 +1,5 @@
+use csv;
+
 use CliResult;
 use config::{Config, Delimiter};
 use util;
@@ -48,8 +50,9 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
 
     let mut rdr = rconfig.reader()?;
     let mut wtr = wconfig.writer()?;
-    for r in rdr.byte_records() {
-        wtr.write_record(&r?)?;
+    let mut row = csv::ByteRecord::new();
+    while rdr.read_byte_record(&mut row)? {
+        wtr.write_record(&row)?;
     }
     wtr.flush()?;
     Ok(())
diff --git a/src/cmd/partition.rs b/src/cmd/partition.rs
index 687302c..224f3dd 100644
--- a/src/cmd/partition.rs
+++ b/src/cmd/partition.rs
@@ -96,9 +96,8 @@ impl Args {
 
         let mut writers: HashMap<Vec<u8>, BoxedWriter> =
             HashMap::new();
-        for row in rdr.byte_records() {
-            let row = row?;
-
+        let mut row = csv::ByteRecord::new();
+        while rdr.read_byte_record(&mut row)? {
             // Decide what file to put this in.
             let column = &row[key_col];
             let key = match self.flag_prefix_length {
@@ -118,7 +117,7 @@ impl Args {
                     vacant.insert(wtr)
                 }
             };
-            wtr.write_record(&row)?;
+            wtr.write_byte_record(&row)?;
         }
         Ok(())
     }
diff --git a/src/cmd/sample.rs b/src/cmd/sample.rs
index 20bef81..3e919d7 100644
--- a/src/cmd/sample.rs
+++ b/src/cmd/sample.rs
@@ -73,7 +73,7 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
         }
     };
     for row in sampled.into_iter() {
-        wtr.write_record(&row)?;
+        wtr.write_byte_record(&row)?;
     }
     Ok(wtr.flush()?)
 }
diff --git a/src/cmd/search.rs b/src/cmd/search.rs
index 7ebc506..78996dc 100644
--- a/src/cmd/search.rs
+++ b/src/cmd/search.rs
@@ -1,3 +1,4 @@
+use csv;
 use regex::bytes::RegexBuilder;
 
 use CliResult;
@@ -60,19 +61,19 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
     let mut wtr = Config::new(&args.flag_output).writer()?;
 
     let headers = rdr.byte_headers()?.clone();
-    let nsel = rconfig.normal_selection(&headers)?;
+    let sel = rconfig.selection(&headers)?;
 
     if !rconfig.no_headers {
         wtr.write_record(&headers)?;
     }
-    for row in rdr.byte_records() {
-        let row = row?;
-        let mut m = nsel.select(row.iter()).any(|f| pattern.is_match(f));
+    let mut record = csv::ByteRecord::new();
+    while rdr.read_byte_record(&mut record)? {
+        let mut m = sel.select(&record).any(|f| pattern.is_match(f));
         if args.flag_invert_match {
             m = !m;
         }
         if m {
-            wtr.write_record(&row)?;
+            wtr.write_byte_record(&record)?;
         }
     }
     Ok(wtr.flush()?)
diff --git a/src/cmd/slice.rs b/src/cmd/slice.rs
index 5a6e7e0..334b01b 100644
--- a/src/cmd/slice.rs
+++ b/src/cmd/slice.rs
@@ -69,7 +69,7 @@ impl Args {
 
         let (start, end) = self.range()?;
         for r in rdr.byte_records().skip(start).take(end - start) {
-            wtr.write_record(&r?)?;
+            wtr.write_byte_record(&r?)?;
         }
         Ok(wtr.flush()?)
     }
@@ -87,7 +87,7 @@ impl Args {
         }
         idx.seek(start as u64)?;
         for r in idx.byte_records().take(end - start) {
-            wtr.write_record(&r?)?;
+            wtr.write_byte_record(&r?)?;
         }
         wtr.flush()?;
         Ok(())
diff --git a/src/cmd/sort.rs b/src/cmd/sort.rs
index 0db828c..647fb3c 100644
--- a/src/cmd/sort.rs
+++ b/src/cmd/sort.rs
@@ -87,7 +87,7 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
 
     rconfig.write_headers(&mut rdr, &mut wtr)?;
     for r in all.into_iter() {
-        wtr.write_record(&r)?;
+        wtr.write_byte_record(&r)?;
     }
     Ok(wtr.flush()?)
 }
diff --git a/src/cmd/split.rs b/src/cmd/split.rs
index 01b90a5..b6b8c31 100644
--- a/src/cmd/split.rs
+++ b/src/cmd/split.rs
@@ -77,12 +77,15 @@ impl Args {
         let headers = rdr.byte_headers()?.clone();
 
         let mut wtr = self.new_writer(&headers, 0)?;
-        for (i, row) in rdr.byte_records().enumerate() {
+        let mut i = 0;
+        let mut row = csv::ByteRecord::new();
+        while rdr.read_byte_record(&mut row)? {
             if i > 0 && i % self.flag_size == 0 {
                 wtr.flush()?;
                 wtr = self.new_writer(&headers, i)?;
             }
-            wtr.write_record(&row?)?;
+            wtr.write_byte_record(&row)?;
+            i += 1;
         }
         wtr.flush()?;
         Ok(())
@@ -111,7 +114,7 @@ impl Args {
                 idx.seek((i * args.flag_size) as u64).unwrap();
                 for row in idx.byte_records().take(args.flag_size) {
                     let row = row.unwrap();
-                    wtr.write_record(row.into_iter()).unwrap();
+                    wtr.write_byte_record(&row).unwrap();
                 }
                 wtr.flush().unwrap();
                 wg.done();
diff --git a/src/config.rs b/src/config.rs
index 41cd9a7..063d2dc 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -11,7 +11,7 @@ use index::Indexed;
 use rustc_serialize::{Decodable, Decoder};
 
 use CliResult;
-use select::{SelectColumns, Selection, NormalSelection};
+use select::{SelectColumns, Selection};
 use util;
 
 
@@ -172,13 +172,6 @@ impl Config {
         }
     }
 
-    pub fn normal_selection(
-        &self,
-        first_record: &csv::ByteRecord,
-    ) -> Result<NormalSelection, String> {
-        self.selection(first_record).map(|sel| sel.normal())
-    }
-
     pub fn write_headers<R: io::Read, W: io::Write>
                         (&self, r: &mut csv::Reader<R>, w: &mut csv::Writer<W>)
                         -> csv::Result<()> {
@@ -301,6 +294,7 @@ impl Config {
             .quote_style(self.quote_style)
             .double_quote(self.double_quote)
             .escape(self.escape)
+            .buffer_capacity(32 * (1<<10))
             .from_writer(wtr)
     }
 }
diff --git a/src/main.rs b/src/main.rs
index ca0f5ce..f0d4d81 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -216,9 +216,12 @@ impl From<docopt::Error> for CliError {
 
 impl From<csv::Error> for CliError {
     fn from(err: csv::Error) -> CliError {
-        match err {
-            csv::Error::Io(v) => From::from(v),
-            v => CliError::Csv(v),
+        if !err.is_io_error() {
+            return CliError::Csv(err);
+        }
+        match err.into_kind() {
+            csv::ErrorKind::Io(v) => From::from(v),
+            _ => unreachable!(),
         }
     }
 }