1 files changed, 76 insertions, 0 deletions
diff --git a/grub-core/lib/crc.c b/grub-core/lib/crc.c
new file mode 100644
index 0000000..bf97cc6
--- /dev/null
+++ b/grub-core/lib/crc.c
@@ -0,0 +1,76 @@
+/* crc.c - crc function  */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2008  Free Software Foundation, Inc.
+ *
+ *  GRUB 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 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/types.h>
+#include <grub/lib/crc.h>
+
+static grub_uint32_t crc32c_table [256];
+
+/* Helper for init_crc32c_table.  */
+static grub_uint32_t
+reflect (grub_uint32_t ref, int len)
+{
+  grub_uint32_t result = 0;
+  int i;
+
+  for (i = 1; i <= len; i++)
+    {
+      if (ref & 1)
+	result |= 1 << (len - i);
+      ref >>= 1;
+    }
+
+  return result;
+}
+
+static void
+init_crc32c_table (void)
+{
+  grub_uint32_t polynomial = 0x1edc6f41;
+  int i, j;
+
+  for(i = 0; i < 256; i++)
+    {
+      crc32c_table[i] = reflect(i, 8) << 24;
+      for (j = 0; j < 8; j++)
+        crc32c_table[i] = (crc32c_table[i] << 1) ^
+            (crc32c_table[i] & (1 << 31) ? polynomial : 0);
+      crc32c_table[i] = reflect(crc32c_table[i], 32);
+    }
+}
+
+grub_uint32_t
+grub_getcrc32c (grub_uint32_t crc, const void *buf, int size)
+{
+  int i;
+  const grub_uint8_t *data = buf;
+
+  if (! crc32c_table[1])
+    init_crc32c_table ();
+
+  crc^= 0xffffffff;
+
+  for (i = 0; i < size; i++)
+    {
+      crc = (crc >> 8) ^ crc32c_table[(crc & 0xFF) ^ *data];
+      data++;
+    }
+
+  return crc ^ 0xffffffff;
+}