From cd7724351e009fd5ec0d7209502a3f1b20378e28 Mon Sep 17 00:00:00 2001
From: deadwood <deadwood@fb15a70f-31f2-0310-bbcc-cdcc74a49acc>
Date: Sun, 31 Mar 2013 15:36:58 +0000
Subject: [PATCH] exec.library: look for best candidates downwards from direct
 match index

git-svn-id: https://svn.aros.org/svn/aros/trunk/AROS@47122 fb15a70f-31f2-0310-bbcc-cdcc74a49acc
---
 rom/exec/memory.c | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/rom/exec/memory.c b/rom/exec/memory.c
index e0f89bfec6..164d12ef5b 100644
--- a/rom/exec/memory.c
+++ b/rom/exec/memory.c
@@ -222,6 +222,18 @@ void mhac_MemChunkClaimed(struct MemChunk * mc, struct MemHeaderAllocatorCtx * m
     }
 }
 
+static LONG mhac_CalcIndex(LONG size, ULONG indexsize)
+{
+    LONG r = 0;
+    size >>= FIRSTPOTBIT;
+    while (size >>= 1)
+        r++;
+
+    if (r > indexsize - 1) r = indexsize - 1;
+
+    return r;
+}
+
 void mhac_MemChunkCreated(struct MemChunk * mc, struct MemChunk *mcprev, struct MemHeaderAllocatorCtx * mhac)
 {
     LONG i, v = FIRSTPOT;
@@ -244,7 +256,6 @@ void mhac_MemChunkCreated(struct MemChunk * mc, struct MemChunk *mcprev, struct
             mhac->mhac_PrevChunks[i] = mcprev;
         }
     }
-
 }
 
 /* General idea:
@@ -263,15 +274,21 @@ struct MemChunk * mhac_GetBetterPrevMemChunk(struct MemChunk * prev, IPTR size,
 
     if (mhac)
     {
-        LONG i, v = FIRSTPOT;
+        LONG i;
+        LONG ii = mhac_CalcIndex(size, mhac->mhac_IndexSize);
 
-        for (i = 0; i < mhac->mhac_IndexSize; i++, v = v << POTSTEP)
+        if (mhac->mhac_PrevChunks[ii] != NULL)
+            _return = mhac->mhac_PrevChunks[ii];
+        else
         {
-            if (size < v)
-                return _return; /* This index is bigger than requester size */
-
-            if (mhac->mhac_PrevChunks[i] != NULL)
-                _return = mhac->mhac_PrevChunks[i];
+            for (i = ii - 1; i >= 0; i--)
+            {
+                if (mhac->mhac_PrevChunks[i] != NULL)
+                {
+                    _return = mhac->mhac_PrevChunks[i];
+                    break;
+                }
+            }
         }
     }
 
-- 
2.11.4.GIT