1 files changed, 33 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/blender.c b/source/blender/blenkernel/intern/blender.c
index aca51e56c6e..1fe6447752e 100644
--- a/source/blender/blenkernel/intern/blender.c
+++ b/source/blender/blenkernel/intern/blender.c
@@ -525,6 +525,7 @@ typedef struct UndoElem {
 	char str[FILE_MAXDIR+FILE_MAXFILE];
 	char name[MAXUNDONAME];
 	MemFile memfile;
+	uintptr_t undosize;
 } UndoElem;
 
 static ListBase undobase={NULL, NULL};
@@ -555,6 +556,7 @@ static int read_undosave(UndoElem *uel)
 /* name can be a dynamic string */
 void BKE_write_undo(char *name)
 {
+	uintptr_t maxmem, totmem, memused;
 	int nr, success;
 	UndoElem *uel;
 	
@@ -616,8 +618,36 @@ void BKE_write_undo(char *name)
 		
 		if(curundo->prev) prevfile= &(curundo->prev->memfile);
 		
+		memused= MEM_get_memory_in_use();
 		success= BLO_write_file_mem(prevfile, &curundo->memfile, G.fileflags, &err);
-		
+		curundo->undosize= MEM_get_memory_in_use() - memused;
+	}
+
+	if(U.undomemory != 0) {
+		/* limit to maximum memory (afterwards, we can't know in advance) */
+		totmem= 0;
+		maxmem= ((uintptr_t)U.undomemory)*1024*1024;
+
+		/* keep at least two (original + other) */
+		uel= undobase.last;
+		while(uel && uel->prev) {
+			totmem+= uel->undosize;
+			if(totmem>maxmem) break;
+			uel= uel->prev;
+		}
+
+		if(uel) {
+			if(uel->prev && uel->prev->prev)
+				uel= uel->prev;
+
+			while(undobase.first!=uel) {
+				UndoElem *first= undobase.first;
+				BLI_remlink(&undobase, first);
+				/* the merge is because of compression */
+				BLO_merge_memfile(&first->memfile, &first->next->memfile);
+				MEM_freeN(first);
+			}
+		}
 	}
 }
 
@@ -683,14 +713,14 @@ char *BKE_undo_menu_string(void)
 	UndoElem *uel;
 	DynStr *ds= BLI_dynstr_new();
 	char *menu;
-	
+
 	BLI_dynstr_append(ds, "Global Undo History %t");
 	
 	for(uel= undobase.first; uel; uel= uel->next) {
 		BLI_dynstr_append(ds, "|");
 		BLI_dynstr_append(ds, uel->name);
 	}
-	
+
 	menu= BLI_dynstr_get_cstring(ds);
 	BLI_dynstr_free(ds);