Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/libelf/dl-hash.h b/libelf/dl-hash.h
new file mode 100644
index 0000000..6ee5d1a
--- /dev/null
+++ b/libelf/dl-hash.h
@@ -0,0 +1,75 @@
+/* Compute hash value for given string according to ELF standard.
+ Copyright (C) 1995-2015 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _DL_HASH_H
+#define _DL_HASH_H 1
+
+
+/* This is the hashing function specified by the ELF ABI. In the
+ first five operations no overflow is possible so we optimized it a
+ bit. */
+static unsigned int
+__attribute__ ((unused))
+_dl_elf_hash (const char *name_arg)
+{
+ const unsigned char *name = (const unsigned char *) name_arg;
+ unsigned long int hash = *name;
+ if (hash != 0 && name[1] != '\0')
+ {
+ hash = (hash << 4) + name[1];
+ if (name[2] != '\0')
+ {
+ hash = (hash << 4) + name[2];
+ if (name[3] != '\0')
+ {
+ hash = (hash << 4) + name[3];
+ if (name[4] != '\0')
+ {
+ hash = (hash << 4) + name[4];
+ name += 5;
+ while (*name != '\0')
+ {
+ unsigned long int hi;
+ hash = (hash << 4) + *name++;
+ hi = hash & 0xf0000000;
+
+ /* The algorithm specified in the ELF ABI is as
+ follows:
+
+ if (hi != 0)
+ hash ^= hi >> 24;
+
+ hash &= ~hi;
+
+ But the following is equivalent and a lot
+ faster, especially on modern processors. */
+
+ hash ^= hi >> 24;
+ }
+
+ /* Second part of the modified formula. This
+ operation can be lifted outside the loop. */
+ hash &= 0x0fffffff;
+ }
+ }
+ }
+ }
+ return hash;
+}
+
+#endif /* dl-hash.h */