diff --git a/CMakeLists.txt b/CMakeLists.txt
index 969d358..fe378c9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,6 +14,18 @@ include_directories(.)
 add_library(emory
     acl.cpp
     acl.hpp
+    emory/chunk/fwd.cpp
+    emory/chunk/fwd.hpp
+    emory/chunk/map.cpp
+    emory/chunk/map.hpp
+    emory/chunk/match.cpp
+    emory/chunk/match.hpp
+    emory/chunk/ostream.cpp
+    emory/chunk/ostream.hpp
+    emory/chunk/params.cpp
+    emory/chunk/params.hpp
+    emory/chunk/region.cpp
+    emory/chunk/region.hpp
 )
 
 
diff --git a/emory/chunk/fwd.cpp b/emory/chunk/fwd.cpp
new file mode 100644
index 0000000..81ecd09
--- /dev/null
+++ b/emory/chunk/fwd.cpp
@@ -0,0 +1,9 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "fwd.hpp"
diff --git a/emory/chunk/fwd.hpp b/emory/chunk/fwd.hpp
new file mode 100644
index 0000000..898ef15
--- /dev/null
+++ b/emory/chunk/fwd.hpp
@@ -0,0 +1,17 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#pragma once
+
+namespace emory::chunk {
+    struct params;
+    struct region;
+    struct map;
+
+    template <typename IdT> struct match;
+};
\ No newline at end of file
diff --git a/emory/chunk/map.cpp b/emory/chunk/map.cpp
new file mode 100644
index 0000000..261bddc
--- /dev/null
+++ b/emory/chunk/map.cpp
@@ -0,0 +1,50 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "map.hpp"
+
+#include "params.hpp"
+
+#include <cruft/util/hash/buzhash.hpp>
+
+using emory::chunk::map;
+
+
+///////////////////////////////////////////////////////////////////////////////
+map::map (cruft::view<u08 const *> data, const emory::chunk::params &p)
+{
+    using hash_type = cruft::hash::buzhash<u64>;
+    hash_type h (p.window, data);
+    auto remain = data.consume (p.window);
+
+    using digest_type = hash_type::digest_type ;
+    digest_type const mask = ~digest_type (0) >> (sizeof (digest_type) * 8 - p.bits);
+
+    for (u08 const *cursor = remain.begin (), *start = data.begin (); cursor != remain.end (); cursor++) {
+        auto const digest = h (cursor);
+
+        if (std::distance (start, cursor) < p.minimum)
+            continue;
+
+        if (unlikely (digest & mask))
+            continue;
+
+        cruft::view<u08 const*> const region { start, cursor };
+        start = cursor + 1;
+
+        elements.push_back ({
+            .offset = {
+                std::pair<std::size_t,std::size_t> {
+                    std::distance (data.begin (), region.begin ()),
+                    std::distance (data.begin (), region.end   ())
+                },
+            },
+            .digest = static_hash {} (region),
+        });
+    }
+}
diff --git a/emory/chunk/map.hpp b/emory/chunk/map.hpp
new file mode 100644
index 0000000..1c136ae
--- /dev/null
+++ b/emory/chunk/map.hpp
@@ -0,0 +1,25 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#pragma once
+
+#include "fwd.hpp"
+
+#include "region.hpp"
+
+#include <cruft/util/view.hpp>
+#include <cruft/util/std.hpp>
+
+#include <vector>
+
+namespace emory::chunk {
+    struct map {
+        map (cruft::view<u08 const*> data, params const&);
+        std::vector<region> elements;
+    };
+}
diff --git a/emory/chunk/match.cpp b/emory/chunk/match.cpp
new file mode 100644
index 0000000..0f8a3ff
--- /dev/null
+++ b/emory/chunk/match.cpp
@@ -0,0 +1,46 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "match.hpp"
+
+#include "map.hpp"
+
+std::vector<
+    emory::chunk::match<emory::chunk::map const*>
+>
+emory::chunk::common (map const &src, map const &dst)
+{
+    CHECK (std::is_sorted (src.elements.begin (), src.elements.end (), region::digest_ordering {}));
+    CHECK (std::is_sorted (dst.elements.begin (), dst.elements.end (), region::digest_ordering {}));
+
+    std::vector<match<map const*>> res;
+
+    for (auto src_cursor = src.elements.begin (), dst_cursor = dst.elements.begin ();
+         src_cursor != src.elements.end () && dst_cursor != dst.elements.end ();
+        /* nothing */)
+    {
+        if (src_cursor->digest < dst_cursor->digest) {
+            ++src_cursor;
+            continue;
+        }
+
+        if (dst_cursor->digest < src_cursor->digest) {
+            ++dst_cursor;
+            continue;
+        }
+
+        res.push_back ({
+            .src = { .id = &src, .data = *src_cursor },
+            .dst = { .id = &dst, .data = *dst_cursor },
+        });
+        ++src_cursor;
+        ++dst_cursor;
+    }
+
+    return res;
+}
diff --git a/emory/chunk/match.hpp b/emory/chunk/match.hpp
new file mode 100644
index 0000000..1af88d9
--- /dev/null
+++ b/emory/chunk/match.hpp
@@ -0,0 +1,56 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#pragma once
+
+#include "fwd.hpp"
+#include "region.hpp"
+
+
+namespace emory::chunk {
+    template <typename IdT>
+    struct match {
+        struct side {
+            IdT id;
+            region data;
+        };
+
+        side src, dst;
+
+
+        struct src_equality {
+            bool operator() (match const &a, match const &b) const
+            {
+                return a.src == b.src;
+            }
+        };
+
+
+        struct dst_equality {
+            bool operator() (match const &a, match const &b) const
+            {
+                return region::digest_equality {} (
+                    a.dst.data,
+                    b.dst.data
+                );
+            }
+        };
+
+
+        struct src_ordering {
+            bool operator() (match const &a, match const &b) const
+            {
+                return region::digest_ordering {} (a.src.data, b.src.data);
+            }
+        };
+    };
+
+
+    std::vector<match<map const*>>
+    common (map const &a, map const &b);
+}
diff --git a/emory/chunk/ostream.cpp b/emory/chunk/ostream.cpp
new file mode 100644
index 0000000..1856fb4
--- /dev/null
+++ b/emory/chunk/ostream.cpp
@@ -0,0 +1,39 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "ostream.hpp"
+
+#include "region.hpp"
+#include "match.hpp"
+
+#include <ostream>
+#include <iomanip>
+
+///////////////////////////////////////////////////////////////////////////////
+std::ostream&
+emory::chunk::operator<< (std::ostream &os, region const &val)
+{
+    return os << "{ first: 0x"  << std::setw (8) << std::setfill ('0') << std::hex << val.offset.first
+              << ", second: 0x" << std::setw (8) << std::setfill ('0') << std::hex << val.offset.second
+              << " }" << std::dec;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+template <typename IdT>
+std::ostream&
+emory::chunk::operator<< (std::ostream &os, match<IdT> const &val)
+{
+    return os << "{ src: { id: " << val.src.id << ", data: " << val.src.data << " }"
+              << ", dst: { id: " << val.dst.id << ", data: " << val.dst.data << " }"
+              << " }";
+}
+
+
+//-----------------------------------------------------------------------------
+template std::ostream& emory::chunk::operator<< (std::ostream&, match<int> const&);
diff --git a/emory/chunk/ostream.hpp b/emory/chunk/ostream.hpp
new file mode 100644
index 0000000..93f5316
--- /dev/null
+++ b/emory/chunk/ostream.hpp
@@ -0,0 +1,23 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#pragma once
+
+#include "fwd.hpp"
+
+#include <iosfwd>
+
+
+namespace emory::chunk {
+    std::ostream& operator<< (std::ostream &, region const &);
+
+
+    template <typename IdT>
+    std::ostream&
+    operator<< (std::ostream &, match<IdT> const &);
+}
diff --git a/emory/chunk/params.cpp b/emory/chunk/params.cpp
new file mode 100644
index 0000000..bcace08
--- /dev/null
+++ b/emory/chunk/params.cpp
@@ -0,0 +1,9 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "params.hpp"
\ No newline at end of file
diff --git a/emory/chunk/params.hpp b/emory/chunk/params.hpp
new file mode 100644
index 0000000..2a970ca
--- /dev/null
+++ b/emory/chunk/params.hpp
@@ -0,0 +1,19 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#pragma once
+
+#include <cstddef>
+
+namespace emory::chunk {
+    struct params {
+        std::size_t bits;
+        std::size_t window;
+        std::ptrdiff_t minimum;
+    };
+}
diff --git a/emory/chunk/region.cpp b/emory/chunk/region.cpp
new file mode 100644
index 0000000..e701cff
--- /dev/null
+++ b/emory/chunk/region.cpp
@@ -0,0 +1,9 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "region.hpp"
diff --git a/emory/chunk/region.hpp b/emory/chunk/region.hpp
new file mode 100644
index 0000000..956c0df
--- /dev/null
+++ b/emory/chunk/region.hpp
@@ -0,0 +1,38 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#pragma once
+
+#include <cruft/crypto/hash/sha1.hpp>
+
+#include <utility>
+
+namespace emory::chunk {
+    using static_hash = cruft::crypto::hash::SHA1;
+
+
+    struct region {
+        std::pair<off64_t, off64_t> offset;
+        static_hash::digest_t digest;
+
+        struct digest_equality {
+            bool operator() (region const &a, region const &b) const
+            {
+                return a.digest == b.digest;
+            }
+        };
+
+
+        struct digest_ordering {
+            bool operator() (region const &a, region const &b) const
+            {
+                return a.digest < b.digest;
+            }
+        };
+    };
+}
diff --git a/tools/compare.cpp b/tools/compare.cpp
index 8001f41..b8de046 100644
--- a/tools/compare.cpp
+++ b/tools/compare.cpp
@@ -6,182 +6,16 @@
  * Copyright 2013 Danny Robson <danny@nerdcruft.net>
  */
 
-#include <cruft/util/debug.hpp>
-#include <cruft/util/hash/buzhash.hpp>
+#include "emory/chunk/params.hpp"
+#include "emory/chunk/map.hpp"
+#include "emory/chunk/match.hpp"
+#include "emory/chunk/ostream.hpp"
+
 #include <cruft/util/io.hpp>
 #include <cruft/util/parse/value.hpp>
 
-#include <cruft/crypto/hash/sha1.hpp>
-
-#include <algorithm>
+#include <cstddef>
 #include <iostream>
-#include <iomanip>
-
-
-namespace emory {
-    using static_hash = cruft::crypto::hash::SHA1;
-
-    struct params {
-        std::size_t bits;
-        std::size_t window;
-        std::ptrdiff_t minimum;
-    };
-
-    struct chunk {
-        std::pair<off64_t, off64_t> offset;
-        static_hash::digest_t digest;
-
-        struct digest_equality {
-            bool operator() (chunk const &a, chunk const &b) const
-            {
-                return a.digest == b.digest;
-            }
-        };
-
-
-        struct digest_ordering {
-            bool operator() (chunk const &a, chunk const &b) const
-            {
-                return a.digest < b.digest;
-            }
-        };
-    };
-
-
-    template <typename IdT>
-    struct match {
-        struct side {
-            IdT id;
-            chunk data;
-        };
-
-        side src, dst;
-
-
-        struct src_equality {
-            bool operator() (match const &a, match const &b) const
-            {
-                return a.src == b.src;
-            }
-        };
-
-
-        struct dst_equality {
-            bool operator() (match const &a, match const &b) const
-            {
-                return chunk::digest_equality {} (
-                    a.dst.data,
-                    b.dst.data
-                );
-            }
-        };
-
-
-        struct src_ordering {
-            bool operator() (match const &a, match const &b) const
-            {
-                return chunk::digest_ordering {} (a.src.data, b.src.data);
-            }
-        };
-    };
-
-
-    std::ostream& operator<< (std::ostream &os, chunk const &val)
-    {
-        return os << "{ first: 0x"  << std::setw (8) << std::setfill ('0') << std::hex << val.offset.first
-                  << ", second: 0x" << std::setw (8) << std::setfill ('0') << std::hex << val.offset.second
-                  << " }" << std::dec;
-    }
-
-
-    struct map {
-        map (cruft::view<u08 const*> data, params const&);
-        std::vector<chunk> elements;
-    };
-
-
-    template <typename IdT>
-    std::ostream&
-    operator<< (std::ostream &os, match<IdT> const &val)
-    {
-        return os << "{ src: { id: " << val.src.id << ", data: " << val.src.data << " }"
-                  << ", dst: { id: " << val.dst.id << ", data: " << val.dst.data << " }"
-                  << " }";
-    }
-
-
-    std::vector<match<map const*>> common (map const &a, map const &b);
-}
-
-
-emory::map::map (cruft::view<u08 const *> data, const emory::params &p)
-{
-    using hash_type = cruft::hash::buzhash<u64>;
-    hash_type h (p.window, data);
-    auto remain = data.consume (p.window);
-
-    using digest_type = hash_type::digest_type ;
-    digest_type const mask = ~digest_type (0) >> (sizeof (digest_type) * 8 - p.bits);
-
-    for (u08 const *cursor = remain.begin (), *start = data.begin (); cursor != remain.end (); cursor++) {
-        auto const digest = h (cursor);
-
-        if (std::distance (start, cursor) < p.minimum)
-            continue;
-
-        if (unlikely (digest & mask))
-            continue;
-
-        cruft::view<u08 const*> const region { start, cursor };
-        start = cursor + 1;
-
-        elements.push_back ({
-            .offset = {
-                std::pair<std::size_t,std::size_t> {
-                    std::distance (data.begin (), region.begin ()),
-                    std::distance (data.begin (), region.end   ())
-                },
-            },
-            .digest = static_hash {} (region),
-        });
-    }
-}
-
-
-std::vector<
-    emory::match<emory::map const*>
->
-emory::common (emory::map const &src, emory::map const &dst)
-{
-    CHECK (std::is_sorted (src.elements.begin (), src.elements.end (), emory::chunk::digest_ordering {}));
-    CHECK (std::is_sorted (dst.elements.begin (), dst.elements.end (), emory::chunk::digest_ordering {}));
-
-    std::vector<emory::match<emory::map const*>> res;
-
-    for (auto src_cursor = src.elements.begin (), dst_cursor = dst.elements.begin ();
-         src_cursor != src.elements.end () && dst_cursor != dst.elements.end ();
-         /* nothing */)
-    {
-        if (src_cursor->digest < dst_cursor->digest) {
-            ++src_cursor;
-            continue;
-        }
-
-        if (dst_cursor->digest < src_cursor->digest) {
-            ++dst_cursor;
-            continue;
-        }
-
-        res.push_back ({
-            .src = { .id = &src, .data = *src_cursor },
-            .dst = { .id = &dst, .data = *dst_cursor },
-        });
-        ++src_cursor;
-        ++dst_cursor;
-    }
-
-    return res;
-}
 
 
 enum {
@@ -203,24 +37,24 @@ int main (int argc, char const **argv)
         return EXIT_FAILURE;
     }
 
-    emory::params const p {
+    emory::chunk::params const p {
         .bits   = cruft::parse::from_string<std::size_t> (argv[ARG_BITS  ]),
         .window = cruft::parse::from_string<std::size_t> (argv[ARG_WINDOW]),
         .minimum = cruft::parse::from_string<std::ptrdiff_t> (argv[ARGS_MINIMUM]),
     };
 
     std::clog << "Hashing target\n";
-    emory::map target (cruft::mapped_file (argv[ARGS_TARGET]), p);
-    std::sort (target.elements.begin (), target.elements.end (), emory::chunk::digest_ordering {});
+    emory::chunk::map target (cruft::mapped_file (argv[ARGS_TARGET]), p);
+    std::sort (target.elements.begin (), target.elements.end (), emory::chunk::region::digest_ordering {});
     std::cout << "Found " << target.elements.size () << " chunks\n";
 
-    std::vector<emory::match<int>> found;
+    std::vector<emory::chunk::match<int>> found;
 
     for (int i = ARGS_SOURCE; i != argc; ++i) {
         auto const path = argv[i];
         std::clog << "Hashing source: " << path << '\n';
-        emory::map source (cruft::mapped_file (path), p);
-        std::sort (source.elements.begin (), source.elements.end (), emory::chunk::digest_ordering {});
+        emory::chunk::map source (cruft::mapped_file (path), p);
+        std::sort (source.elements.begin (), source.elements.end (), emory::chunk::region::digest_ordering {});
 
         std::clog << "Finding common\n";
         auto const &source_matches = common (target, source);
@@ -230,7 +64,7 @@ int main (int argc, char const **argv)
             std::begin (source_matches),
             std::end   (source_matches),
             std::back_inserter (found),
-            [&] (auto const &j) -> emory::match<int>
+            [&] (auto const &j) -> emory::chunk::match<int>
         {
             return {
                 .src = {           i, j.src.data },
@@ -241,14 +75,14 @@ int main (int argc, char const **argv)
         std::sort (
             std::begin (found),
             std::end   (found),
-            emory::match<int>::src_ordering {}
+            emory::chunk::match<int>::src_ordering {}
         );
 
         found.erase (
             std::unique (
                 std::begin (found),
                 std::end   (found),
-                emory::match<int>::dst_equality {}
+                emory::chunk::match<int>::dst_equality {}
             ),
             found.end ()
         );