From aacb9a0d949960db28984f9047f59daedac5a83e Mon Sep 17 00:00:00 2001
From: Marcus Holland-Moritz <github@mhxnet.de>
Date: Sun, 13 Aug 2023 22:29:13 +0200
Subject: [PATCH] add segmenter_factory

---
 CMakeLists.txt                      |   1 +
 include/dwarfs/categorized_option.h |  48 +++++++++++++
 include/dwarfs/options.h            |  22 +-----
 include/dwarfs/scanner.h            |   5 +-
 include/dwarfs/segmenter.h          |   5 +-
 include/dwarfs/segmenter_factory.h  |  66 +++++++++++++++++
 src/dwarfs/scanner.cpp              |  45 ++++++------
 src/dwarfs/segmenter.cpp            |   2 +-
 src/dwarfs/segmenter_factory.cpp    |  62 ++++++++++++++++
 src/mkdwarfs_main.cpp               | 105 +++++++++++++++-------------
 test/dwarfs.cpp                     |  18 ++++-
 test/dwarfs_benchmark.cpp           |  15 ++--
 12 files changed, 286 insertions(+), 108 deletions(-)
 create mode 100644 include/dwarfs/categorized_option.h
 create mode 100644 include/dwarfs/segmenter_factory.h
 create mode 100644 src/dwarfs/segmenter_factory.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 49c4381d..c938b328 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -399,6 +399,7 @@ list(
   src/dwarfs/safe_main.cpp
   src/dwarfs/scanner.cpp
   src/dwarfs/segmenter.cpp
+  src/dwarfs/segmenter_factory.cpp
   src/dwarfs/similarity.cpp
   src/dwarfs/similarity_ordering.cpp
   src/dwarfs/string_table.cpp
diff --git a/include/dwarfs/categorized_option.h b/include/dwarfs/categorized_option.h
new file mode 100644
index 00000000..dc6418b3
--- /dev/null
+++ b/include/dwarfs/categorized_option.h
@@ -0,0 +1,48 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/**
+ * \author     Marcus Holland-Moritz (github@mhxnet.de)
+ * \copyright  Copyright (c) Marcus Holland-Moritz
+ *
+ * This file is part of dwarfs.
+ *
+ * dwarfs is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * dwarfs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "dwarfs/contextual_option.h"
+#include "dwarfs/fragment_category.h"
+
+namespace dwarfs {
+
+namespace detail {
+
+template <typename T>
+struct categorized_option_policy {
+  using ContextArgumentType = fragment_category;
+  using ContextType = fragment_category::value_type;
+  using ValueType = T;
+
+  static ContextType context_from_arg(ContextArgumentType const& arg) {
+    return arg.value();
+  }
+};
+
+} // namespace detail
+
+template <typename ValueType>
+using categorized_option =
+    contextual_option<detail::categorized_option_policy<ValueType>>;
+
+} // namespace dwarfs
diff --git a/include/dwarfs/options.h b/include/dwarfs/options.h
index 4e5132c4..a6654c08 100644
--- a/include/dwarfs/options.h
+++ b/include/dwarfs/options.h
@@ -28,9 +28,8 @@
 #include <memory>
 #include <optional>
 
-#include "dwarfs/contextual_option.h"
+#include "dwarfs/categorized_option.h"
 #include "dwarfs/file_stat.h"
-#include "dwarfs/fragment_category.h"
 #include "dwarfs/types.h"
 
 namespace dwarfs {
@@ -38,25 +37,6 @@ namespace dwarfs {
 class categorizer_manager;
 class entry;
 
-namespace detail {
-
-template <typename T>
-struct categorized_option_policy {
-  using ContextArgumentType = fragment_category;
-  using ContextType = fragment_category::value_type;
-  using ValueType = T;
-
-  static ContextType context_from_arg(ContextArgumentType const& arg) {
-    return arg.value();
-  }
-};
-
-} // namespace detail
-
-template <typename ValueType>
-using categorized_option =
-    contextual_option<detail::categorized_option_policy<ValueType>>;
-
 enum class mlock_mode { NONE, TRY, MUST };
 
 enum class cache_tidy_strategy { NONE, EXPIRY_TIME, BLOCK_SWAPPED_OUT };
diff --git a/include/dwarfs/scanner.h b/include/dwarfs/scanner.h
index 5ee21405..44a34ef9 100644
--- a/include/dwarfs/scanner.h
+++ b/include/dwarfs/scanner.h
@@ -27,8 +27,6 @@
 #include <span>
 #include <string>
 
-#include "dwarfs/segmenter.h"
-
 namespace dwarfs {
 
 struct scanner_options;
@@ -39,11 +37,12 @@ class logger;
 class os_access;
 class progress;
 class script;
+class segmenter_factory;
 class worker_group;
 
 class scanner {
  public:
-  scanner(logger& lgr, worker_group& wg, const segmenter::config& cfg,
+  scanner(logger& lgr, worker_group& wg, std::shared_ptr<segmenter_factory> sf,
           std::shared_ptr<entry_factory> ef, std::shared_ptr<os_access> os,
           std::shared_ptr<script> scr, const scanner_options& options);
 
diff --git a/include/dwarfs/segmenter.h b/include/dwarfs/segmenter.h
index 41cbabdf..f3fb54f5 100644
--- a/include/dwarfs/segmenter.h
+++ b/include/dwarfs/segmenter.h
@@ -38,12 +38,11 @@ class progress;
 class segmenter {
  public:
   struct config {
-    unsigned blockhash_window_size;
+    unsigned blockhash_window_size{12};
     unsigned window_increment_shift{1};
     size_t max_active_blocks{1};
-    size_t memory_limit{256 << 20};
-    unsigned block_size_bits{22};
     unsigned bloom_filter_size{4};
+    unsigned block_size_bits{22};
   };
 
   using block_ready_cb = folly::Function<size_t(std::shared_ptr<block_data>)>;
diff --git a/include/dwarfs/segmenter_factory.h b/include/dwarfs/segmenter_factory.h
new file mode 100644
index 00000000..77d342a8
--- /dev/null
+++ b/include/dwarfs/segmenter_factory.h
@@ -0,0 +1,66 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/**
+ * \author     Marcus Holland-Moritz (github@mhxnet.de)
+ * \copyright  Copyright (c) Marcus Holland-Moritz
+ *
+ * This file is part of dwarfs.
+ *
+ * dwarfs is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * dwarfs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <memory>
+
+#include "dwarfs/categorized_option.h"
+#include "dwarfs/segmenter.h"
+
+namespace dwarfs {
+
+class logger;
+class progress;
+
+class segmenter_factory {
+ public:
+  struct config {
+    categorized_option<unsigned> blockhash_window_size;
+    categorized_option<unsigned> window_increment_shift;
+    categorized_option<size_t> max_active_blocks;
+    categorized_option<unsigned> bloom_filter_size;
+    unsigned block_size_bits{22};
+  };
+
+  segmenter_factory(logger& lgr, progress& prog, config const& cfg);
+
+  segmenter create(fragment_category cat, std::shared_ptr<block_manager> blkmgr,
+                   segmenter::block_ready_cb block_ready) const {
+    return impl_->create(cat, std::move(blkmgr), std::move(block_ready));
+  }
+
+  size_t get_block_size() const { return impl_->get_block_size(); }
+
+  class impl {
+   public:
+    virtual ~impl() = default;
+
+    virtual segmenter
+    create(fragment_category cat, std::shared_ptr<block_manager> blkmgr,
+           segmenter::block_ready_cb block_ready) const = 0;
+    virtual size_t get_block_size() const = 0;
+  };
+
+ private:
+  std::unique_ptr<impl> impl_;
+};
+} // namespace dwarfs
diff --git a/src/dwarfs/scanner.cpp b/src/dwarfs/scanner.cpp
index ecd1bb59..1318f917 100644
--- a/src/dwarfs/scanner.cpp
+++ b/src/dwarfs/scanner.cpp
@@ -57,6 +57,7 @@
 #include "dwarfs/progress.h"
 #include "dwarfs/scanner.h"
 #include "dwarfs/script.h"
+#include "dwarfs/segmenter_factory.h"
 #include "dwarfs/string_table.h"
 #include "dwarfs/util.h"
 #include "dwarfs/version.h"
@@ -273,7 +274,7 @@ std::string status_string(progress const& p, size_t width) {
 template <typename LoggerPolicy>
 class scanner_ final : public scanner::impl {
  public:
-  scanner_(logger& lgr, worker_group& wg, const segmenter::config& config,
+  scanner_(logger& lgr, worker_group& wg, std::shared_ptr<segmenter_factory> sf,
            std::shared_ptr<entry_factory> ef, std::shared_ptr<os_access> os,
            std::shared_ptr<script> scr, const scanner_options& options);
 
@@ -297,25 +298,25 @@ class scanner_ final : public scanner::impl {
 
   LOG_PROXY_DECL(LoggerPolicy);
   worker_group& wg_;
-  const segmenter::config& cfg_;
-  const scanner_options& options_;
-  std::shared_ptr<entry_factory> entry_;
+  scanner_options const& options_;
+  std::shared_ptr<segmenter_factory> segmenter_factory_;
+  std::shared_ptr<entry_factory> entry_factory_;
   std::shared_ptr<os_access> os_;
   std::shared_ptr<script> script_;
 };
 
 template <typename LoggerPolicy>
 scanner_<LoggerPolicy>::scanner_(logger& lgr, worker_group& wg,
-                                 const segmenter::config& cfg,
+                                 std::shared_ptr<segmenter_factory> sf,
                                  std::shared_ptr<entry_factory> ef,
                                  std::shared_ptr<os_access> os,
                                  std::shared_ptr<script> scr,
                                  const scanner_options& options)
     : LOG_PROXY_INIT(lgr)
-    , wg_(wg)
-    , cfg_(cfg)
-    , options_(options)
-    , entry_(std::move(ef))
+    , wg_{wg}
+    , options_{options}
+    , segmenter_factory_{std::move(sf)}
+    , entry_factory_{std::move(ef)}
     , os_(std::move(os))
     , script_(std::move(scr)) {}
 
@@ -325,7 +326,7 @@ scanner_<LoggerPolicy>::add_entry(std::filesystem::path const& name,
                                   std::shared_ptr<dir> parent, progress& prog,
                                   detail::file_scanner& fs, bool debug_filter) {
   try {
-    auto pe = entry_->create(*os_, name, parent);
+    auto pe = entry_factory_->create(*os_, name, parent);
     bool exclude = false;
 
     if (script_) {
@@ -429,7 +430,7 @@ template <typename LoggerPolicy>
 std::shared_ptr<entry>
 scanner_<LoggerPolicy>::scan_tree(std::filesystem::path const& path,
                                   progress& prog, detail::file_scanner& fs) {
-  auto root = entry_->create(*os_, path);
+  auto root = entry_factory_->create(*os_, path);
   bool const debug_filter = options_.debug_filter_function.has_value();
 
   if (root->type() != entry::E_DIR) {
@@ -489,7 +490,7 @@ scanner_<LoggerPolicy>::scan_list(std::filesystem::path const& path,
 
   auto ti = LOG_TIMED_INFO;
 
-  auto root = entry_->create(*os_, path);
+  auto root = entry_factory_->create(*os_, path);
 
   if (root->type() != entry::E_DIR) {
     DWARFS_THROW(runtime_error,
@@ -673,8 +674,6 @@ void scanner_<LoggerPolicy>::scan(
   //   which gets run on a worker groups; each batch keeps track of
   //   its CPU time and affects thread naming
 
-  // segmenter seg(LOG_GET_LOGGER, prog, cfg_, fsw);
-
   auto blockmgr = std::make_shared<block_manager>();
 
   {
@@ -695,12 +694,11 @@ void scanner_<LoggerPolicy>::scan(
         wg_blockify.add_job(
             [this, catmgr, blockmgr, category, meta, &prog, &fsw,
              span = im.ordered_span(category, wg_ordering)]() mutable {
-              // TODO: segmenter config per-category
-              segmenter seg(LOG_GET_LOGGER, prog, blockmgr, cfg_,
-                            [category, meta, &fsw](auto block) {
-                              return fsw.write_block(category.value(),
-                                                     std::move(block), meta);
-                            });
+              auto seg = segmenter_factory_->create(
+                  category, blockmgr, [category, meta, &fsw](auto block) {
+                    return fsw.write_block(category.value(), std::move(block),
+                                           meta);
+                  });
 
               for (auto ino : span) {
                 prog.current.store(ino.get());
@@ -844,7 +842,7 @@ void scanner_<LoggerPolicy>::scan(
   mv2.gids() = ge_data.get_gids();
   mv2.modes() = ge_data.get_modes();
   mv2.timestamp_base() = ge_data.get_timestamp_base();
-  mv2.block_size() = UINT32_C(1) << cfg_.block_size_bits;
+  mv2.block_size() = segmenter_factory_->get_block_size();
   mv2.total_fs_size() = prog.original_size;
   mv2.total_hardlink_size() = prog.hardlink_size;
   mv2.options() = fsopts;
@@ -870,12 +868,13 @@ void scanner_<LoggerPolicy>::scan(
            << ")";
 }
 
-scanner::scanner(logger& lgr, worker_group& wg, const segmenter::config& cfg,
+scanner::scanner(logger& lgr, worker_group& wg,
+                 std::shared_ptr<segmenter_factory> sf,
                  std::shared_ptr<entry_factory> ef,
                  std::shared_ptr<os_access> os, std::shared_ptr<script> scr,
                  const scanner_options& options)
     : impl_(make_unique_logging_object<impl, scanner_, logger_policies>(
-          lgr, wg, cfg, std::move(ef), std::move(os), std::move(scr),
+          lgr, wg, std::move(sf), std::move(ef), std::move(os), std::move(scr),
           options)) {}
 
 } // namespace dwarfs
diff --git a/src/dwarfs/segmenter.cpp b/src/dwarfs/segmenter.cpp
index 64b409fb..4e251e1e 100644
--- a/src/dwarfs/segmenter.cpp
+++ b/src/dwarfs/segmenter.cpp
@@ -349,7 +349,7 @@ class segmenter_ final : public segmenter::impl {
   LOG_PROXY_DECL(LoggerPolicy);
   progress& prog_;
   std::shared_ptr<block_manager> blkmgr_;
-  const segmenter::config& cfg_;
+  segmenter::config const cfg_;
   segmenter::block_ready_cb block_ready_;
 
   size_t const window_size_;
diff --git a/src/dwarfs/segmenter_factory.cpp b/src/dwarfs/segmenter_factory.cpp
new file mode 100644
index 00000000..6a577b77
--- /dev/null
+++ b/src/dwarfs/segmenter_factory.cpp
@@ -0,0 +1,62 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/**
+ * \author     Marcus Holland-Moritz (github@mhxnet.de)
+ * \copyright  Copyright (c) Marcus Holland-Moritz
+ *
+ * This file is part of dwarfs.
+ *
+ * dwarfs is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * dwarfs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "dwarfs/segmenter_factory.h"
+
+namespace dwarfs {
+
+class segmenter_factory_ final : public segmenter_factory::impl {
+ public:
+  segmenter_factory_(logger& lgr, progress& prog,
+                     const segmenter_factory::config& cfg)
+      : lgr_{lgr}
+      , prog_{prog}
+      , cfg_{cfg} {}
+
+  segmenter create(fragment_category cat, std::shared_ptr<block_manager> blkmgr,
+                   segmenter::block_ready_cb block_ready) const override {
+    segmenter::config cfg;
+
+    cfg.blockhash_window_size = cfg_.blockhash_window_size.get(cat);
+    cfg.window_increment_shift = cfg_.window_increment_shift.get(cat);
+    cfg.max_active_blocks = cfg_.max_active_blocks.get(cat);
+    cfg.bloom_filter_size = cfg_.bloom_filter_size.get(cat);
+    cfg.block_size_bits = cfg_.block_size_bits;
+
+    return segmenter(lgr_, prog_, std::move(blkmgr), cfg,
+                     std::move(block_ready));
+  }
+
+  size_t get_block_size() const override {
+    return static_cast<size_t>(1) << cfg_.block_size_bits;
+  }
+
+ private:
+  logger& lgr_;
+  progress& prog_;
+  segmenter_factory::config cfg_;
+};
+
+segmenter_factory::segmenter_factory(logger& lgr, progress& prog,
+                                     config const& cfg)
+    : impl_(std::make_unique<segmenter_factory_>(lgr, prog, cfg)) {}
+
+} // namespace dwarfs
diff --git a/src/mkdwarfs_main.cpp b/src/mkdwarfs_main.cpp
index 760f8c9e..21d71e11 100644
--- a/src/mkdwarfs_main.cpp
+++ b/src/mkdwarfs_main.cpp
@@ -72,7 +72,7 @@
 #include "dwarfs/progress.h"
 #include "dwarfs/scanner.h"
 #include "dwarfs/script.h"
-#include "dwarfs/segmenter.h"
+#include "dwarfs/segmenter_factory.h"
 #include "dwarfs/terminal.h"
 #include "dwarfs/tool.h"
 #include "dwarfs/util.h"
@@ -274,7 +274,7 @@ int mkdwarfs_main(int argc, sys_char** argv) {
 
   const size_t num_cpu = std::max(folly::hardware_concurrency(), 1u);
 
-  segmenter::config cfg;
+  segmenter_factory::config sf_config;
   sys_string path_str, output_str;
   std::string memory_limit, script_arg, header, schema_compression,
       metadata_compression, log_level_str, timestamp, time_resolution,
@@ -283,7 +283,7 @@ int mkdwarfs_main(int argc, sys_char** argv) {
       categorizer_list_str;
   std::vector<sys_string> filter;
   std::vector<std::string> order, max_lookback_blocks, window_size, window_step,
-      compression;
+      bloom_filter_size, compression;
   size_t num_workers, num_scanner_workers;
   bool no_progress = false, remove_header = false, no_section_index = false,
        force_overwrite = false;
@@ -294,6 +294,7 @@ int mkdwarfs_main(int argc, sys_char** argv) {
   integral_value_parser<size_t> max_lookback_parser;
   integral_value_parser<unsigned> window_size_parser(6, 24);
   integral_value_parser<unsigned> window_step_parser(0, 8);
+  integral_value_parser<unsigned> bloom_filter_size_parser(0, 8);
   fragment_order_parser order_parser;
   block_compressor_parser compressor_parser;
 
@@ -353,7 +354,7 @@ int mkdwarfs_main(int argc, sys_char** argv) {
   po::options_description advanced_opts("Advanced options");
   advanced_opts.add_options()
     ("block-size-bits,S",
-        po::value<unsigned>(&cfg.block_size_bits),
+        po::value<unsigned>(&sf_config.block_size_bits),
         "block size bits (size = 2^arg bits)")
     ("num-workers,N",
         po::value<size_t>(&num_workers)->default_value(num_cpu),
@@ -426,7 +427,8 @@ int mkdwarfs_main(int argc, sys_char** argv) {
         po::value<std::vector<std::string>>(&window_step)->multitoken(),
         "window step (as right shift of size)")
     ("bloom-filter-size",
-        po::value<unsigned>(&cfg.bloom_filter_size)->default_value(4),
+        // po::value<unsigned>(&cfg.bloom_filter_size)->default_value(4), // TODO
+        po::value<std::vector<std::string>>(&bloom_filter_size)->multitoken(),
         "bloom filter size (2^N*values bits)")
     ;
 
@@ -601,7 +603,7 @@ int mkdwarfs_main(int argc, sys_char** argv) {
   auto const& defaults = levels[level];
 
   if (!vm.count("block-size-bits")) {
-    cfg.block_size_bits = defaults.block_size_bits;
+    sf_config.block_size_bits = defaults.block_size_bits;
   }
 
   if (!vm.count("compression")) {
@@ -617,22 +619,23 @@ int mkdwarfs_main(int argc, sys_char** argv) {
   }
 
   if (!vm.count("max-lookback-blocks")) {
-    cfg.max_active_blocks = 1; // TODO
     max_lookback_blocks.push_back(folly::to<std::string>(1));
   }
 
   if (!vm.count("window-size")) {
-    cfg.blockhash_window_size = defaults.window_size; // TODO
     window_size.push_back(folly::to<std::string>(defaults.window_size));
   }
 
   if (!vm.count("window-step")) {
-    cfg.window_increment_shift = defaults.window_step; // TODO
     window_step.push_back(folly::to<std::string>(defaults.window_step));
   }
 
-  if (cfg.block_size_bits < min_block_size_bits ||
-      cfg.block_size_bits > max_block_size_bits) {
+  if (!vm.count("bloom-filter-size")) {
+    bloom_filter_size.push_back(folly::to<std::string>(4));
+  }
+
+  if (sf_config.block_size_bits < min_block_size_bits ||
+      sf_config.block_size_bits > max_block_size_bits) {
     std::cerr << "error: block size must be between " << min_block_size_bits
               << " and " << max_block_size_bits << "\n";
     return 1;
@@ -923,13 +926,14 @@ int mkdwarfs_main(int argc, sys_char** argv) {
 
   progress prog(std::move(updater), interval_ms);
 
-  auto min_memory_req = num_workers * (UINT64_C(1) << cfg.block_size_bits);
+  auto min_memory_req =
+      num_workers * (UINT64_C(1) << sf_config.block_size_bits);
 
   // TODO:
   if (mem_limit < min_memory_req /* && compression != "null" */) {
     LOG_WARN << "low memory limit (" << size_with_unit(mem_limit) << "), need "
              << size_with_unit(min_memory_req) << " to efficiently compress "
-             << size_with_unit(UINT64_C(1) << cfg.block_size_bits)
+             << size_with_unit(UINT64_C(1) << sf_config.block_size_bits)
              << " blocks with " << num_workers << " threads";
   }
 
@@ -976,44 +980,45 @@ int mkdwarfs_main(int argc, sys_char** argv) {
   category_parser cp(options.inode.categorizer_mgr);
 
   try {
-    contextual_option_parser cop("--order", options.inode.fragment_order, cp,
-                                 order_parser);
-    cop.parse(defaults.order);
-    cop.parse(order);
-    LOG_DEBUG << cop.as_string();
-  } catch (std::exception const& e) {
-    LOG_ERROR << e.what();
-    return 1;
-  }
+    {
+      contextual_option_parser cop("--order", options.inode.fragment_order, cp,
+                                   order_parser);
+      cop.parse(defaults.order);
+      cop.parse(order);
+      LOG_DEBUG << cop.as_string();
+    }
 
-  try {
-    categorized_option<size_t> max_lookback_opt;
-    contextual_option_parser cop("--max-lookback-blocks", max_lookback_opt, cp,
-                                 max_lookback_parser);
-    cop.parse(max_lookback_blocks);
-    LOG_DEBUG << cop.as_string();
-  } catch (std::exception const& e) {
-    LOG_ERROR << e.what();
-    return 1;
-  }
+    {
+      contextual_option_parser cop("--max-lookback-blocks",
+                                   sf_config.max_active_blocks, cp,
+                                   max_lookback_parser);
+      cop.parse(max_lookback_blocks);
+      LOG_DEBUG << cop.as_string();
+    }
 
-  try {
-    categorized_option<unsigned> window_size_opt;
-    contextual_option_parser cop("--window-size", window_size_opt, cp,
-                                 window_size_parser);
-    cop.parse(window_size);
-    LOG_DEBUG << cop.as_string();
-  } catch (std::exception const& e) {
-    LOG_ERROR << e.what();
-    return 1;
-  }
+    {
+      contextual_option_parser cop("--window-size",
+                                   sf_config.blockhash_window_size, cp,
+                                   window_size_parser);
+      cop.parse(window_size);
+      LOG_DEBUG << cop.as_string();
+    }
 
-  try {
-    categorized_option<unsigned> window_step_opt;
-    contextual_option_parser cop("--window-step", window_step_opt, cp,
-                                 window_step_parser);
-    cop.parse(window_step);
-    LOG_DEBUG << cop.as_string();
+    {
+      contextual_option_parser cop("--window-step",
+                                   sf_config.window_increment_shift, cp,
+                                   window_step_parser);
+      cop.parse(window_step);
+      LOG_DEBUG << cop.as_string();
+    }
+
+    {
+      contextual_option_parser cop("--bloom-filter-size",
+                                   sf_config.bloom_filter_size, cp,
+                                   bloom_filter_size_parser);
+      cop.parse(bloom_filter_size);
+      LOG_DEBUG << cop.as_string();
+    }
   } catch (std::exception const& e) {
     LOG_ERROR << e.what();
     return 1;
@@ -1060,7 +1065,9 @@ int mkdwarfs_main(int argc, sys_char** argv) {
                              fsw, rw_opts);
       wg_compress.wait();
     } else {
-      scanner s(lgr, wg_scanner, cfg, entry_factory::create(),
+      auto sf = std::make_shared<segmenter_factory>(lgr, prog, sf_config);
+
+      scanner s(lgr, wg_scanner, sf, entry_factory::create(),
                 std::make_shared<os_access_generic>(), std::move(script),
                 options);
 
diff --git a/test/dwarfs.cpp b/test/dwarfs.cpp
index d32f5b0f..a104d496 100644
--- a/test/dwarfs.cpp
+++ b/test/dwarfs.cpp
@@ -44,6 +44,7 @@
 #include "dwarfs/options.h"
 #include "dwarfs/progress.h"
 #include "dwarfs/scanner.h"
+#include "dwarfs/segmenter_factory.h"
 #include "dwarfs/vfs_stat.h"
 
 #include "filter_test_data.h"
@@ -71,15 +72,26 @@ build_dwarfs(logger& lgr, std::shared_ptr<test::os_access_mock> input,
   // force multithreading
   worker_group wg("worker", 4);
 
-  scanner s(lgr, wg, cfg, entry_factory::create(), input, scr, options);
-
-  std::ostringstream oss;
   std::unique_ptr<progress> local_prog;
   if (!prog) {
     local_prog = std::make_unique<progress>([](const progress&, bool) {}, 1000);
     prog = local_prog.get();
   }
 
+  // TODO: ugly hack :-)
+  segmenter_factory::config sf_cfg;
+  sf_cfg.block_size_bits = cfg.block_size_bits;
+  sf_cfg.blockhash_window_size.set_default(cfg.blockhash_window_size);
+  sf_cfg.window_increment_shift.set_default(cfg.window_increment_shift);
+  sf_cfg.max_active_blocks.set_default(cfg.max_active_blocks);
+  sf_cfg.bloom_filter_size.set_default(cfg.bloom_filter_size);
+
+  auto sf = std::make_shared<segmenter_factory>(lgr, *prog, sf_cfg);
+
+  scanner s(lgr, wg, sf, entry_factory::create(), input, scr, options);
+
+  std::ostringstream oss;
+
   block_compressor bc(compression);
   filesystem_writer fsw(oss, lgr, wg, *prog, bc, bc);
   fsw.add_default_compressor(bc);
diff --git a/test/dwarfs_benchmark.cpp b/test/dwarfs_benchmark.cpp
index 14fcbf3b..a5e23497 100644
--- a/test/dwarfs_benchmark.cpp
+++ b/test/dwarfs_benchmark.cpp
@@ -35,7 +35,7 @@
 #include "dwarfs/options.h"
 #include "dwarfs/progress.h"
 #include "dwarfs/scanner.h"
-#include "dwarfs/segmenter.h"
+#include "dwarfs/segmenter_factory.h"
 #include "dwarfs/string_table.h"
 #include "dwarfs/vfs_stat.h"
 #include "dwarfs/worker_group.h"
@@ -91,10 +91,13 @@ void PackParamsDirs(::benchmark::internal::Benchmark* b) {
 }
 
 std::string make_filesystem(::benchmark::State const& state) {
-  segmenter::config cfg;
+  segmenter_factory::config cfg;
   scanner_options options;
 
-  cfg.blockhash_window_size = 8;
+  cfg.blockhash_window_size.set_default(12);
+  cfg.window_increment_shift.set_default(1);
+  cfg.max_active_blocks.set_default(1);
+  cfg.bloom_filter_size.set_default(4);
   cfg.block_size_bits = 12;
 
   options.with_devices = true;
@@ -112,17 +115,19 @@ std::string make_filesystem(::benchmark::State const& state) {
   options.plain_symlinks_table = state.range(1);
 
   worker_group wg("writer", 4);
+  progress prog([](const progress&, bool) {}, 1000);
 
   std::ostringstream logss;
   stream_logger lgr(logss); // TODO: mock
   lgr.set_policy<prod_logger_policy>();
 
-  scanner s(lgr, wg, cfg, entry_factory::create(),
+  auto sf = std::make_shared<segmenter_factory>(lgr, prog, cfg);
+
+  scanner s(lgr, wg, sf, entry_factory::create(),
             test::os_access_mock::create_test_instance(),
             std::make_shared<test::script_mock>(), options);
 
   std::ostringstream oss;
-  progress prog([](const progress&, bool) {}, 1000);
 
   block_compressor bc("null");
   filesystem_writer fsw(oss, lgr, wg, prog, bc, bc);