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1 files changed, 61 insertions, 0 deletions

diff --git a/lib/bumpalloc.h b/lib/bumpalloc.h
new file mode 100644
index 000000000..ce37d1c68
--- /dev/null
+++ b/lib/bumpalloc.h
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+/* BUMP_ALLOC macro - increase table allocation by one element.
+   Copyright (C) 1990, 1991, 1993 Free Software Foundation, Inc.
+   François Pinard <pinard@iro.umontreal.ca>, 1990.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/*-------------------------------------------------------------------------.
+| Bump the allocation of the array pointed to by TABLE whenever required.  |
+| The table already has already COUNT elements in it, this macro ensure it |
+| has enough space to accommodate at least one more element.  Space is	   |
+| allocated (2 ^ EXPONENT) elements at a time.  Each element of the array  |
+| is of type TYPE.							   |
+`-------------------------------------------------------------------------*/
+
+/* Routines `xmalloc' and `xrealloc' are called to do the actual memory
+   management.  This implies that the program will abort with an `Memory
+   exhausted!' error if any problem arise.
+   
+   To work correctly, at least EXPONENT and TYPE should always be the
+   same for all uses of this macro for any given TABLE.  A secure way to
+   achieve this is to never use this macro directly, but use it to define
+   other macros, which would then be TABLE-specific.
+   
+   The first time through, COUNT is usually zero.  Note that COUNT is not
+   updated by this macro, but it should be update elsewhere, later.  This
+   is convenient, because it allows TABLE[COUNT] to refer to the new
+   element at the end.  Once its construction is completed, COUNT++ will
+   record it in the table.  Calling this macro several times in a row
+   without updating COUNT is a bad thing to do.  */
+
+#define BUMP_ALLOC(Table, Count, Exponent, Type) \
+  BUMP_ALLOC_WITH_SIZE ((Table), (Count), (Exponent), Type, sizeof (Type))
+
+/* In cases `sizeof TYPE' would not always yield the correct value for
+   the size of each element entry, this macro accepts a supplementary
+   SIZE argument.  The EXPONENT, TYPE and SIZE parameters should still
+   have the same value for all macro calls related to a specific TABLE.  */
+
+#define BUMP_ALLOC_WITH_SIZE(Table, Count, Exponent, Type, Size) \
+  do									\
+    {									\
+      if (((Count) & (~(~0 << (Exponent)))) == 0)			\
+	if ((Count) == 0)						\
+	  (Table) = (Type *) xmalloc ((1 << (Exponent)) * (Size));	\
+	else								\
+	  (Table) = (Type *)						\
+	    xrealloc ((Table), ((Count) + (1 << (Exponent))) * (Size));	\
+    }									\
+  while (0)