add note to docs/DEBUG
diff --git a/docs/DEBUG b/docs/DEBUG
index 3d6acd3..a427613 100644
--- a/docs/DEBUG
+++ b/docs/DEBUG
@@ -187,9 +187,41 @@
If it is undefined, or if its value is not strictly positive, then
no allocation bounds are checked at runtime.
+
+ FT2_ALLOC_CUR_MAX_SITE
+
+ This variable is ignored if FT2_DEBUG_MEMORY is not defined. It
+ allows you to specify a maximum size of the memory buffer allocated
+ at the specific site in the source code of FreeType. The variable is
+ a list of the per-site limits, separated by the space. The per-site
+ limit is a pair of the site specification and the limiting value in
+ digits, separated by a comma. The site specification is a pair of
+ the path name of source code and the line number in digits, as the
+ summary report given by setting FT2_DEBUG_MEMORY.
+
+ Example:
+
+ FT2_ALLOC_CUR_MAX_SITE=/tmp/freetype2/src/base/ftobjs.c:302,300000 \
+ /tmp/freetype2/src/base/ftglyph.c:290,10000 \
+ ...
+
+ This is useful to check the recovery from an out of memory error at
+ the specific site of the source code. If it is undefined, or if its
+ value is negative, then no allocation bounds are checked at runtime.
+
+
+ FT2_ALLOC_TOTAL_MAX_SITE
+
+ This variable is almost same with FT2_ALLOC_CUR_MAX_SITE in above,
+ but it counts the summary of historical allocations at the specified
+ site of the source code. It does not care about whether the buffers
+ are freed. When the limiting value for a site is set to 1000 bytes
+ and repeating 100 bytes allocation and free it, the 11th allocation
+ will fail.
+
------------------------------------------------------------------------
-Copyright 2002, 2003, 2004, 2005, 2009 by
+Copyright 2002, 2003, 2004, 2005, 2009, 2011 by
David Turner, Robert Wilhelm, and Werner Lemberg.
This file is part of the FreeType project, and may only be used,
