1 files changed, 58 insertions, 0 deletions
diff --git a/wsutil/adler32.c b/wsutil/adler32.c
new file mode 100644
index 00000000..2830eab4
--- /dev/null
+++ b/wsutil/adler32.c
@@ -0,0 +1,58 @@
+/* adler32.c
+ * Compute the Adler32 checksum (RFC 1950)
+ * 2003 Tomas Kukosa
+ * Based on code from RFC 1950 (Chapter 9. Appendix: Sample code)
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <wsutil/adler32.h>
+
+#include <string.h>
+
+#define BASE 65521 /* largest prime smaller than 65536 */
+
+/*--- update_adler32 --------------------------------------------------------*/
+uint32_t update_adler32(uint32_t adler, const uint8_t *buf, size_t len)
+{
+  uint32_t s1 = adler & 0xffff;
+  uint32_t s2 = (adler >> 16) & 0xffff;
+  size_t n;
+
+  for (n = 0; n < len; n++) {
+    s1 = (s1 + buf[n]) % BASE;
+    s2 = (s2 + s1)     % BASE;
+  }
+  return (s2 << 16) + s1;
+}
+
+/*--- adler32 ---------------------------------------------------------------*/
+uint32_t adler32_bytes(const uint8_t *buf, size_t len)
+{
+  return update_adler32(1, buf, len);
+}
+
+/*--- adler32_str -----------------------------------------------------------*/
+uint32_t adler32_str(const char *buf)
+{
+  return update_adler32(1, (const uint8_t*)buf, strlen(buf));
+}
+
+/*---------------------------------------------------------------------------*/
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local Variables:
+ * c-basic-offset: 2
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set shiftwidth=2 tabstop=8 expandtab:
+ * :indentSize=2:tabSize=8:noTabs=true:
+ */