1 files changed, 107 insertions, 0 deletions
diff --git a/lib/crc32_file.c b/lib/crc32_file.c
new file mode 100644
index 0000000..5946df9
--- /dev/null
+++ b/lib/crc32_file.c
@@ -0,0 +1,107 @@
+/* Compute CRC32 checksum of file contents.
+   Copyright (C) 2006 Red Hat, Inc.
+   This file is part of Red Hat elfutils.
+
+   Red Hat elfutils 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; version 2 of the License.
+
+   Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
+
+   In addition, as a special exception, Red Hat, Inc. gives You the
+   additional right to link the code of Red Hat elfutils with code licensed
+   under an Open Source Initiative certified open source license
+   (http://www.opensource.org/licenses/index.php) and to distribute linked
+   combinations including the two.  Non-GPL Code permitted under this
+   exception must only link to the code of Red Hat elfutils through those
+   well defined interfaces identified in the file named EXCEPTION found in
+   the source code files (the "Approved Interfaces").  The files of Non-GPL
+   Code may instantiate templates or use macros or inline functions from
+   the Approved Interfaces without causing the resulting work to be covered
+   by the GNU General Public License.  Only Red Hat, Inc. may make changes
+   or additions to the list of Approved Interfaces.  Red Hat's grant of
+   this exception is conditioned upon your not adding any new exceptions.
+   If you wish to add a new Approved Interface or exception, please contact
+   Red Hat.  You must obey the GNU General Public License in all respects
+   for all of the Red Hat elfutils code and other code used in conjunction
+   with Red Hat elfutils except the Non-GPL Code covered by this exception.
+   If you modify this file, you may extend this exception to your version
+   of the file, but you are not obligated to do so.  If you do not wish to
+   provide this exception without modification, you must delete this
+   exception statement from your version and license this file solely under
+   the GPL without exception.
+
+   Red Hat elfutils is an included package of the Open Invention Network.
+   An included package of the Open Invention Network is a package for which
+   Open Invention Network licensees cross-license their patents.  No patent
+   license is granted, either expressly or impliedly, by designation as an
+   included package.  Should you wish to participate in the Open Invention
+   Network licensing program, please visit www.openinventionnetwork.com
+   <http://www.openinventionnetwork.com>.  */
+
+#include "system.h"
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+int
+crc32_file (int fd, uint32_t *resp)
+{
+  unsigned char buffer[1024 * 8];
+  uint32_t crc = 0;
+  off_t off = 0;
+  ssize_t count;
+
+  struct stat st;
+  if (fstat (fd, &st) == 0)
+    {
+      /* Try mapping in the file data.  */
+      size_t mapsize = st.st_size;
+      void *mapped = mmap (NULL, mapsize, PROT_READ, MAP_PRIVATE, fd, 0);
+      if (mapped == MAP_FAILED && errno == ENOMEM)
+	{
+	  const size_t pagesize = sysconf (_SC_PAGE_SIZE);
+	  mapsize = ((mapsize / 2) + pagesize - 1) & -pagesize;
+	  while (mapsize >= pagesize
+		 && (mapped = mmap (NULL, mapsize, PROT_READ, MAP_PRIVATE,
+				    fd, 0)) == MAP_FAILED && errno == ENOMEM)
+	    mapsize /= 2;
+	}
+      if (mapped != MAP_FAILED)
+	{
+	  do
+	    {
+	      if (st.st_size <= (off_t) mapsize)
+		{
+		  *resp = crc32 (crc, mapped, st.st_size);
+		  munmap (mapped, mapsize);
+		  return 0;
+		}
+	      crc = crc32 (crc, mapped, mapsize);
+	      off += mapsize;
+	      st.st_size -= mapsize;
+	    } while (mmap (mapped, mapsize, PROT_READ, MAP_FIXED|MAP_PRIVATE,
+			   fd, off) == mapped);
+	  munmap (mapped, mapsize);
+	}
+    }
+
+  while ((count = TEMP_FAILURE_RETRY (pread (fd, buffer, sizeof buffer,
+					     off))) > 0)
+    {
+      off += count;
+      crc = crc32 (crc, buffer, count);
+    }
+
+  *resp = crc;
+
+  return count == 0 ? 0 : -1;
+}