From ea35ab7829ae1aaae2b24408a7281ee94ce90478 Mon Sep 17 00:00:00 2001
From: Mike Frysinger <vapier@gentoo.org>
Date: Thu, 5 Jan 2006 23:48:49 +0000
Subject: import the extend_alloca() macro from glibc

---
 include/libc-internal.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'include/libc-internal.h')

diff --git a/include/libc-internal.h b/include/libc-internal.h
index 2e372267f..6cd4feb53 100644
--- a/include/libc-internal.h
+++ b/include/libc-internal.h
@@ -322,6 +322,36 @@ extern int __sprintf (char *__restrict __s,
 #define fopen64 __fopen64
 #endif
 
+/* #include <alloca.h> */
+#include <bits/stackinfo.h>
+#if _STACK_GROWS_DOWN
+# define extend_alloca(buf, len, newlen) \
+  (__typeof (buf)) ({ size_t __newlen = (newlen);			      \
+		      char *__newbuf = alloca (__newlen);		      \
+		      if (__newbuf + __newlen == (char *) buf)		      \
+			len += __newlen;				      \
+		      else						      \
+			len = __newlen;					      \
+		      __newbuf; })
+#elif _STACK_GROWS_UP
+# define extend_alloca(buf, len, newlen) \
+  (__typeof (buf)) ({ size_t __newlen = (newlen);			      \
+		      char *__newbuf = alloca (__newlen);		      \
+		      char *__buf = (buf);				      \
+		      if (__buf + __newlen == __newbuf)			      \
+			{						      \
+			  len += __newlen;				      \
+			  __newbuf = __buf;				      \
+			}						      \
+		      else						      \
+			len = __newlen;					      \
+		      __newbuf; })
+#else
+# warning unknown stack
+# define extend_alloca(buf, len, newlen) \
+  alloca (((len) = (newlen)))
+#endif
+
 /* #include <stdlib.h> */
 extern char *__getenv (__const char *__name) attribute_hidden;
 extern void __exit (int __status) __THROW __attribute__ ((__noreturn__)) attribute_hidden;
-- 
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