From 841234684b5cba03459c5e30f38c2d15d9eee5bc Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Fri, 24 May 2024 19:06:33 +0200
Subject: [PATCH] Library: verify further simple allocations and alignment

---
 tests/library/allocation-cluster-test.cpp | 52 +++++++++++++++--------
 wiki/thinkPad.ichthyo.mm                  | 10 +++--
 2 files changed, 40 insertions(+), 22 deletions(-)

diff --git a/tests/library/allocation-cluster-test.cpp b/tests/library/allocation-cluster-test.cpp
index 19d10f270..00914384d 100644
--- a/tests/library/allocation-cluster-test.cpp
+++ b/tests/library/allocation-cluster-test.cpp
@@ -202,49 +202,65 @@ namespace test {
           CHECK (0==checksum);
           {
             AllocationCluster clu;
+            // no allocation happened yet
             CHECK (0 == clu.numExtents());
             CHECK (0 == clu.numBytes());
-            
-SHOW_EXPR(clu.storage_.rest);
-SHOW_EXPR(size_t(clu.storage_.pos));
             CHECK (nullptr == clu.storage_.pos);
             CHECK (      0 == clu.storage_.rest);
-
+            
+            // build a simple object
             auto& i1 = clu.create<uint16_t> (1 + uint16_t(rand()));
             CHECK (i1 > 0);
             CHECK (1 == clu.numExtents());
-SHOW_EXPR(clu.numBytes())
             CHECK (2 == clu.numBytes());
-SHOW_EXPR(clu.storage_.rest);
-SHOW_EXPR(size_t(clu.storage_.pos));
             CHECK (clu.storage_.pos != nullptr);
+            CHECK (clu.storage_.pos == (& i1) + 1 ); // points directly behind the allocated integer
             CHECK (clu.storage_.rest == BLOCKSIZ - (2*sizeof(void*) +  sizeof(uint16_t)));
             
+            // Demonstration: how to reconstruct the start of the current extent
             byte* blk = static_cast<std::byte*>(clu.storage_.pos);
-SHOW_EXPR(size_t(blk));
             blk += clu.storage_.rest - BLOCKSIZ;
-SHOW_EXPR(size_t(blk));
-SHOW_EXPR((size_t*)blk);
             CHECK(size_t(blk) < size_t(clu.storage_.pos));
-            
+
+            // some abbreviations for navigating the raw storage blocks...
             auto currBlock = [&]{
                                   byte* blk = static_cast<std::byte*>(clu.storage_.pos);
                                   blk += clu.storage_.rest - BLOCKSIZ;
                                   return blk;
                                 };
+            auto posOffset = [&]{
+                                  return size_t(clu.storage_.pos) - size_t(currBlock()); 
+                                };
             auto slot = [&](size_t i)
                                 {
                                   size_t* slot = reinterpret_cast<size_t*> (currBlock());
                                   return slot[i];
                                 };
-            auto posOffset = [&]{
-                                  return size_t(clu.storage_.pos) - size_t(currBlock()); 
-                                };
-SHOW_EXPR(size_t(currBlock()))
-SHOW_EXPR(slot(0))
-SHOW_EXPR(slot(1))
-SHOW_EXPR(size_t(clu.storage_.pos) - size_t(currBlock()))
+            
+            CHECK (blk == currBlock());
+            // current storage pos: 2 »slots« of admin overhead plus the first allocated element 
             CHECK (posOffset() == 2 * sizeof(void*) + sizeof(uint16_t));
+            CHECK (slot(0) == 0); // only one extent, thus next-* is NULL
+            
+            // allocate another one
+            uint16_t i1pre = i1;
+            auto& i2 = clu.create<uint16_t> (55555);
+            CHECK (posOffset() == 2 * sizeof(void*) + 2 * sizeof(uint16_t));
+            CHECK (clu.storage_.rest == BLOCKSIZ - posOffset());
+            // existing storage unaffected
+            CHECK (i1 == i1pre);
+            CHECK (i2 == 55555);
+            CHECK (slot(0) == 0);
+            
+            // alignment is handled properly
+            char& c1 = clu.create<char> ('X');
+            CHECK (posOffset() == 2 * sizeof(void*) + 2 * sizeof(uint16_t) + sizeof(char));
+            auto& i3 = clu.create<int32_t> (42);
+            CHECK (posOffset() == 2 * sizeof(void*) + 2 * sizeof(uint16_t) + sizeof(char) + 3*sizeof(byte) + sizeof(int32_t));
+            CHECK (i1 == i1pre);
+            CHECK (i2 == 55555);
+            CHECK (c1 == 'X');
+            CHECK (i3 == 42);
             CHECK (slot(0) == 0);
           }
           CHECK (0==checksum);
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 7502101bb..9320e04b0 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -81708,8 +81708,7 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
       mu&#223; hier leider eine schecklicke low-level-Trickserei machen; das ist die Konsequenz der Entscheidung, mit dem absolut minimalen Storage-Overhead zu arbeiten, und au&#223;erdem mu&#223; ich auch noch das Non-Copyable <i>aushebeln...</i>
     </p>
   </body>
-</html>
-</richcontent>
+</html></richcontent>
 <icon BUILTIN="button_ok"/>
 </node>
 <node COLOR="#338800" CREATED="1715820289221" ID="ID_1541316374" MODIFIED="1716130701433" TEXT="&#xdc;berlauf: neuen Block belegen">
@@ -81912,14 +81911,17 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
 <node COLOR="#338800" CREATED="1716552160019" ID="ID_146077309" MODIFIED="1716566510566" TEXT="die Mechanik &#xfc;berhaupt erst mal zum Laufen bekommen">
 <icon BUILTIN="button_ok"/>
 </node>
-<node BACKGROUND_COLOR="#eef0c5" COLOR="#990000" CREATED="1716552180480" ID="ID_1382140920" MODIFIED="1716566512774" TEXT="eine Allokation im bestehenden Extent">
-<icon BUILTIN="pencil"/>
+<node COLOR="#338800" CREATED="1716552180480" ID="ID_1382140920" MODIFIED="1716570347935" TEXT="eine Allokation im bestehenden Extent">
+<icon BUILTIN="button_ok"/>
 <node COLOR="#338800" CREATED="1716566627518" ID="ID_874153150" MODIFIED="1716566633607" TEXT="sieht erst mal gut aus">
 <icon BUILTIN="button_ok"/>
 </node>
 <node COLOR="#338800" CREATED="1716566635117" ID="ID_674171131" MODIFIED="1716566656562" TEXT="lokale abk&#xfc;rzungs-&#x3bb; im Test">
 <icon BUILTIN="button_ok"/>
 </node>
+<node COLOR="#338800" CREATED="1716570349907" ID="ID_1594023993" MODIFIED="1716570356962" TEXT="Alignment wird ber&#xfc;cksichtigt">
+<icon BUILTIN="button_ok"/>
+</node>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1716552190584" ID="ID_1042988047" MODIFIED="1716552206544" TEXT="einen &#xdc;berlauf provozieren">
 <icon BUILTIN="flag-yellow"/>