From 3bc82898feb8c5da7b44f922a975df2e1e0e84dc Mon Sep 17 00:00:00 2001
From: Cristy <urban-warrior@imagemagick.org>
Date: Sat, 29 Dec 2018 08:18:13 -0500
Subject: [PATCH] 
 https://imagemagick.org/discourse-server/viewtopic.php?f=3&t=34906

---
 MagickCore/cache.c    | 25 ++++++++++--------------
 MagickCore/geometry.c | 44 +++++++++++++++++++++++++++++++++++--------
 2 files changed, 46 insertions(+), 23 deletions(-)

diff --git a/MagickCore/cache.c b/MagickCore/cache.c
index cd6853502..d73d4dd78 100644
--- a/MagickCore/cache.c
+++ b/MagickCore/cache.c
@@ -4997,12 +4997,15 @@ static inline MagickBooleanType AcquireCacheNexusPixels(
 static inline void PrefetchPixelCacheNexusPixels(const NexusInfo *nexus_info,
   const MapMode mode)
 {
+  if (nexus_info->length < CACHE_LINE_SIZE)
+    return;
   if (mode == ReadMode)
     {
-      MagickCachePrefetch((unsigned char *) nexus_info->pixels,0,1);
+      MagickCachePrefetch((unsigned char *) nexus_info->pixels+CACHE_LINE_SIZE,
+        0,1);
       return;
     }
-  MagickCachePrefetch((unsigned char *) nexus_info->pixels,1,1);
+  MagickCachePrefetch((unsigned char *) nexus_info->pixels+CACHE_LINE_SIZE,1,1);
 }
 
 static Quantum *SetPixelCacheNexusPixels(const CacheInfo *cache_info,
@@ -5021,6 +5024,7 @@ static Quantum *SetPixelCacheNexusPixels(const CacheInfo *cache_info,
   assert(cache_info->signature == MagickCoreSignature);
   if (cache_info->type == UndefinedCache)
     return((Quantum *) NULL);
+  (void) memset(&nexus_info->region,0,sizeof(nexus_info->region));
   if (((cache_info->type == MemoryCache) || (cache_info->type == MapCache)) &&
       (buffered == MagickFalse))
     {
@@ -5062,26 +5066,17 @@ static Quantum *SetPixelCacheNexusPixels(const CacheInfo *cache_info,
     cache_info->number_channels*sizeof(*nexus_info->pixels);
   if (cache_info->metacontent_extent != 0)
     length+=number_pixels*cache_info->metacontent_extent;
+  status=MagickTrue;
   if (nexus_info->cache == (Quantum *) NULL)
-    {
-      status=AcquireCacheNexusPixels(cache_info,length,nexus_info,exception);
-      if (status == MagickFalse)
-        {
-          (void) memset(&nexus_info->region,0,sizeof(nexus_info->region));
-          return((Quantum *) NULL);
-        }
-    }
+    status=AcquireCacheNexusPixels(cache_info,length,nexus_info,exception);
   else
     if (nexus_info->length < length)
       {
         RelinquishCacheNexusPixels(nexus_info);
         status=AcquireCacheNexusPixels(cache_info,length,nexus_info,exception);
-        if (status == MagickFalse)
-          {
-            (void) memset(&nexus_info->region,0,sizeof(nexus_info->region));
-            return((Quantum *) NULL);
-          }
       }
+  if (status == MagickFalse)
+    return((Quantum *) NULL);
   nexus_info->pixels=nexus_info->cache;
   nexus_info->metacontent=(void *) NULL;
   if (cache_info->metacontent_extent != 0)
diff --git a/MagickCore/geometry.c b/MagickCore/geometry.c
index 1b3d49fb6..a32600d14 100644
--- a/MagickCore/geometry.c
+++ b/MagickCore/geometry.c
@@ -1132,15 +1132,43 @@ MagickExport MagickStatusType ParseGeometry(const char *geometry,
         geometry_info->sigma=2.0;
     }
   if (((flags & SigmaValue) == 0) && ((flags & XiValue) != 0) &&
-      ((flags & PsiValue) == 0))
+      ((flags & XiNegative) != 0))
     {
-      /*
-        Support negative height values (e.g. 30x-20).
-      */
-      geometry_info->sigma=geometry_info->xi;
-      geometry_info->xi=0.0;
-      flags|=SigmaValue;
-      flags&=(~XiValue);
+      if ((flags & PsiValue) == 0)
+        {
+          /*
+            Support negative height values (e.g. 30x-20).
+          */
+          geometry_info->sigma=geometry_info->xi;
+          geometry_info->xi=0.0;
+          flags|=SigmaValue;
+          flags&=(~XiValue);
+        }
+      else
+        if ((flags & ChiValue) == 0)
+          {
+            /*
+              Support negative height values (e.g. 30x-20+10).
+            */
+            geometry_info->sigma=geometry_info->xi;
+            geometry_info->xi=geometry_info->psi;
+            flags|=SigmaValue;
+            flags|=XiValue;
+            flags&=(~PsiValue);
+          }
+        else
+          {
+            /*
+              Support negative height values (e.g. 30x-20+10+10).
+            */
+            geometry_info->sigma=geometry_info->xi;
+            geometry_info->xi=geometry_info->psi;
+            geometry_info->psi=geometry_info->chi;
+            flags|=SigmaValue;
+            flags|=XiValue;
+            flags|=PsiValue;
+            flags&=(~ChiValue);
+          }
     }
   if ((flags & PercentValue) != 0)
     {
-- 
2.40.0