From 3836e89df153ae4063ab55e9ea43e5820949a031 Mon Sep 17 00:00:00 2001
From: Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>
Date: Wed, 1 Dec 2010 01:22:55 +0100
Subject: [PATCH] Add crc32c for btrfs

---
 Makefile.util.def           |  1 +
 grub-core/Makefile.core.def |  1 +
 grub-core/lib/crc.c         | 75 +++++++++++++++++++++++++++++++++++++
 include/grub/lib/crc.h      | 25 +++++++++++++
 4 files changed, 102 insertions(+)
 create mode 100644 grub-core/lib/crc.c
 create mode 100644 include/grub/lib/crc.h

diff --git a/Makefile.util.def b/Makefile.util.def
index 3e8ae16f5..4d642a2b6 100644
--- a/Makefile.util.def
+++ b/Makefile.util.def
@@ -79,6 +79,7 @@ library = {
   common = grub-core/lib/LzFind.c;
   common = grub-core/lib/LzmaEnc.c;
   common = grub-core/lib/pbkdf2.c;
+  common = grub-core/lib/crc.c;
   common = grub-core/normal/datetime.c;
   common = grub-core/normal/misc.c;
   common = grub-core/partmap/acorn.c;
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index ce10ba372..c62d7d12f 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -905,6 +905,7 @@ module = {
 module = {
   name = btrfs;
   common = fs/btrfs.c;
+  common = lib/crc.c;
 };
 
 module = {
diff --git a/grub-core/lib/crc.c b/grub-core/lib/crc.c
new file mode 100644
index 000000000..ffc3ef3b5
--- /dev/null
+++ b/grub-core/lib/crc.c
@@ -0,0 +1,75 @@
+/* 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];
+
+static void
+init_crc32c_table (void)
+{
+  auto grub_uint32_t reflect (grub_uint32_t ref, int len);
+  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;
+    }
+
+  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;
+}
diff --git a/include/grub/lib/crc.h b/include/grub/lib/crc.h
new file mode 100644
index 000000000..c5098a8c3
--- /dev/null
+++ b/include/grub/lib/crc.h
@@ -0,0 +1,25 @@
+/* crc.h - prototypes for crc */
+/*
+ *  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/>.
+ */
+
+#ifndef GRUB_CRC_H
+#define GRUB_CRC_H	1
+
+grub_uint32_t grub_getcrc32c (grub_uint32_t crc, const void *buf, int size);
+
+#endif /* ! GRUB_CRC_H */