From 82edc0b660ad0835db9bb962b5c387ddd79b9673 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Thu, 8 Jan 2026 18:34:31 -0500
Subject: [PATCH] xo-arena: DArenaHashMap: move detail::Group to dedicated file

---
 include/xo/arena/DArenaHashMap.hpp        | 63 +----------------
 include/xo/arena/hashmap/ControlGroup.hpp | 82 +++++++++++++++++++++++
 2 files changed, 83 insertions(+), 62 deletions(-)
 create mode 100644 include/xo/arena/hashmap/ControlGroup.hpp

diff --git a/include/xo/arena/DArenaHashMap.hpp b/include/xo/arena/DArenaHashMap.hpp
index 1623d33..e560bdb 100644
--- a/include/xo/arena/DArenaHashMap.hpp
+++ b/include/xo/arena/DArenaHashMap.hpp
@@ -7,6 +7,7 @@
 
 #include "DArenaVector.hpp"
 #include "hashmap/DArenaHashMapUtil.hpp"
+#include "hashmap/ControlGroup.hpp"
 #include <xo/indentlog/scope.hpp>
 #include <algorithm>
 #include <array>
@@ -62,68 +63,6 @@ namespace xo {
 #endif
 
         namespace detail {
-            /** @brief 16x 8-bit control bytes.
-             *
-             *  Support optimization using SIMD operations
-             **/
-            struct Group {
-                std::array<uint8_t, DArenaHashMapUtil::c_group_size> ctrl_;
-
-                explicit Group(uint8_t * lo) {
-                    ::memcpy(ctrl_.data(), lo, DArenaHashMapUtil::c_group_size);
-                }
-
-                /** find all exact matches in ctrl_[0..15] for @p h2.
-                 *  for each match set corresponding bit in return value.
-                 *  Bits {0x1, 0x2, 0x4, ...} set iff exact match on
-                 *  {ctrl_[0], ctrl_[1], ctrl_2[], ...} respectively
-                 **/
-                uint16_t all_matches(uint8_t h2) const {
-                    uint16_t retval = 0;
-                    uint16_t bit = 1;
-                    for (auto xi : ctrl_) {
-                        if (xi == h2)
-                            retval |= bit;
-                        bit = bit << 1;
-                    }
-
-                    return retval;
-                }
-
-                /** find all empty sentinels in ctrl_[0..15].
-                 *  for each empty, set corresponding bit in return value.
-                 *  Bits {0x1, 0x2, 0x4, ...} set iff empty spot
-                 *  {ctrl_[0], ctrl_[1], ctrl_[2], ...} respectively
-                 **/
-                uint16_t empty_matches() const {
-                    uint16_t retval = 0;
-                    uint16_t bit = 1;
-                    for (auto xi : ctrl_) {
-                        if (xi == DArenaHashMapUtil::c_empty_slot)
-                            retval |= bit;
-                        bit = bit << 1;
-                    }
-
-                    return retval;
-                }
-
-#ifdef NOT_YET
-                __m128i ctrl;  // 16 bytes loaded via SSE2
-
-                // Find all slots matching h2
-                uint16_t Match(uint8_t h2) const {
-                    __m128i pattern = _mm_set1_epi8(h2);
-                    __m128i result = _mm_cmpeq_epi8(ctrl, pattern);
-                    return _mm_movemask_epi8(result);  // 16-bit mask
-                }
-
-                // Find all empty slots (0xFF)
-                uint16_t MatchEmpty() const {
-                    return _mm_movemask_epi8(_mm_cmpeq_epi8(ctrl, _mm_set1_epi8(0xFF)));
-                }
-#endif
-            };
-
             template <typename Key,
                       typename Value>
             struct HashMapStore : DArenaHashMapUtil {
diff --git a/include/xo/arena/hashmap/ControlGroup.hpp b/include/xo/arena/hashmap/ControlGroup.hpp
new file mode 100644
index 0000000..2b60a79
--- /dev/null
+++ b/include/xo/arena/hashmap/ControlGroup.hpp
@@ -0,0 +1,82 @@
+/** @file ControlGroupo
+ *
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#pragma once
+
+#include "DArenaHashMapUtil.hpp"
+#include <array>
+#include <cstdint>
+#include <cstring>
+
+namespace xo {
+    namespace mm {
+        namespace detail {
+            /** @brief 16x 8-bit control bytes.
+             *
+             *  Support optimization using SIMD operations
+             **/
+            struct Group {
+                std::array<uint8_t, DArenaHashMapUtil::c_group_size> ctrl_;
+
+                explicit Group(uint8_t * lo) {
+                    ::memcpy(ctrl_.data(), lo, DArenaHashMapUtil::c_group_size);
+                }
+
+                /** find all exact matches in ctrl_[0..15] for @p h2.
+                 *  for each match set corresponding bit in return value.
+                 *  Bits {0x1, 0x2, 0x4, ...} set iff exact match on
+                 *  {ctrl_[0], ctrl_[1], ctrl_2[], ...} respectively
+                 **/
+                uint16_t all_matches(uint8_t h2) const {
+                    uint16_t retval = 0;
+                    uint16_t bit = 1;
+                    for (auto xi : ctrl_) {
+                        if (xi == h2)
+                            retval |= bit;
+                        bit = bit << 1;
+                    }
+
+                    return retval;
+                }
+
+                /** find all empty sentinels in ctrl_[0..15].
+                 *  for each empty, set corresponding bit in return value.
+                 *  Bits {0x1, 0x2, 0x4, ...} set iff empty spot
+                 *  {ctrl_[0], ctrl_[1], ctrl_[2], ...} respectively
+                 **/
+                uint16_t empty_matches() const {
+                    uint16_t retval = 0;
+                    uint16_t bit = 1;
+
+                    for (auto xi : ctrl_) {
+                        if (xi == DArenaHashMapUtil::c_empty_slot)
+                            retval |= bit;
+                        bit = bit << 1;
+                    }
+
+                    return retval;
+                }
+
+#ifdef NOT_YET
+                __m128i ctrl;  // 16 bytes loaded via SSE2
+
+                // Find all slots matching h2
+                uint16_t Match(uint8_t h2) const {
+                    __m128i pattern = _mm_set1_epi8(h2);
+                    __m128i result = _mm_cmpeq_epi8(ctrl, pattern);
+                    return _mm_movemask_epi8(result);  // 16-bit mask
+                }
+
+                // Find all empty slots (0xFF)
+                uint16_t MatchEmpty() const {
+                    return _mm_movemask_epi8(_mm_cmpeq_epi8(ctrl, _mm_set1_epi8(0xFF)));
+                }
+#endif
+            };
+        }
+    } /*namespace mm*/
+} /*namespace xo*/
+
+/* end ControlGroup.hpp */