1.0.66 release

Vlnk/src/crc32.c

@@ -0,0 +1,77 @@
+/******************************************************************************
+ * crc32.c  ---- 
+ *
+ * Copyright (c) 2022, longpanda <admin@ventoy.net>
+ *
+ * This program 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.
+ * 
+ * This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include "vlnk.h"
+
+static uint32_t crc32c_table [256];
+
+/* Helper for init_crc32c_table.  */
+static uint32_t reflect (uint32_t ref, int len)
+{
+  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)
+{
+  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);
+    }
+}
+
+uint32_t ventoy_getcrc32c (uint32_t crc, const void *buf, int size)
+{
+  int i;
+  const 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;
+}
+