1 files changed, 71 insertions, 0 deletions
diff --git a/libvoltronic/voltronic_crc.h b/libvoltronic/voltronic_crc.h
new file mode 100644
index 0000000..750f048
--- /dev/null
+++ b/libvoltronic/voltronic_crc.h
@@ -0,0 +1,71 @@
+/**
+ * Copyright (C) 2019  Johan van der Vyver
+ *
+ * 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/>.
+ */
+
+#ifndef __VOLTRONIC__CRC__H__
+#define __VOLTRONIC__CRC__H__
+
+  #include <stddef.h>
+
+  /**
+   * The underlying numeric type used to store the CRC
+   */
+  #if defined(_WIN32) || defined(WIN32)
+    #include "windows.h"
+
+    typedef unsigned __int16 voltronic_crc_t;
+  #else
+    #include <stdint.h>
+
+    typedef uint16_t voltronic_crc_t;
+  #endif
+
+  /**
+   * Write a voltronic_crc_t to a buffer
+   *
+   * crc - CRC to write
+   * buffer - Buffer to write CRC to or NULL/0
+   *
+   * Returns the size of the CRC
+   */
+  int write_voltronic_crc(
+    const voltronic_crc_t crc,
+    char* buffer);
+
+  /**
+   * Read a voltronic_crc_t from a buffer
+   *
+   * buffer - Buffer to read CRC from;
+   *          If the buffer is smaller than the size
+   *          returned by write_voltronic_crc behavoir is undefined
+   *
+   * Returns the CRC read from the buffer
+   */
+  voltronic_crc_t read_voltronic_crc(const char* buffer);
+
+  /**
+   * Calculate the Voltronic CRC by reading a buffer and calculating the CRC from the bytes
+   *
+   * buffer - Buffer to read from
+   * buffer_length - Number of bytes in the buffer
+   *
+   * Returns the CRC created from the bytes in the buffer
+   */
+  voltronic_crc_t calculate_voltronic_crc(
+    const char* buffer,
+    size_t buffer_length);
+
+#endif