crc32

source/Core/BSP/Magic/crc32.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <stdint.h>
+
+#define DEFAULT_POLY 0x973afb51
+
+template <uint32_t polynomial = DEFAULT_POLY> struct CRC32Table {
+  constexpr CRC32Table() : table() {
+    for (uint32_t i = 0; i < 256; i++) {
+      uint32_t c = i;
+      for (auto j = 0; j < 8; j++) {
+        if (c & 1) {
+          c = polynomial ^ (c >> 1);
+        } else {
+          c >>= 1;
+        }
+      }
+      table[i] = c;
+    }
+  }
+  uint32_t table[256];
+  uint32_t computeCRC32(uint32_t initial, const uint8_t *buf, int len) {
+    uint32_t c = initial ^ 0xFFFFFFFF;
+    for (auto i = 0; i < len; ++i) {
+      c = table[(c ^ buf[i]) & 0xFF] ^ (c >> 8);
+    }
+    return c ^ 0xFFFFFFFF;
+  }
+};