1 files changed, 72 insertions, 0 deletions
diff --git a/modules/checksum/adler32/adler32.cpp b/modules/checksum/adler32/adler32.cpp
new file mode 100644
index 000000000..b808e3e67
--- /dev/null
+++ b/modules/checksum/adler32/adler32.cpp
@@ -0,0 +1,72 @@
+/*************************************************
+* Adler32 Source File                            *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/adler32.h>
+#include <botan/loadstor.h>
+
+namespace Botan {
+
+/*************************************************
+* Adler32 Checksum                               *
+*************************************************/
+void Adler32::hash(const byte input[], u32bit length)
+   {
+   u32bit S1x = S1, S2x = S2;
+   while(length >= 16)
+      {
+      S1x += input[ 0]; S2x += S1x;
+      S1x += input[ 1]; S2x += S1x;
+      S1x += input[ 2]; S2x += S1x;
+      S1x += input[ 3]; S2x += S1x;
+      S1x += input[ 4]; S2x += S1x;
+      S1x += input[ 5]; S2x += S1x;
+      S1x += input[ 6]; S2x += S1x;
+      S1x += input[ 7]; S2x += S1x;
+      S1x += input[ 8]; S2x += S1x;
+      S1x += input[ 9]; S2x += S1x;
+      S1x += input[10]; S2x += S1x;
+      S1x += input[11]; S2x += S1x;
+      S1x += input[12]; S2x += S1x;
+      S1x += input[13]; S2x += S1x;
+      S1x += input[14]; S2x += S1x;
+      S1x += input[15]; S2x += S1x;
+      input += 16;
+      length -= 16;
+      }
+   for(u32bit j = 0; j != length; ++j)
+      {
+      S1x += input[j]; S2x += S1x;
+      }
+   S1x %= 65521;
+   S2x %= 65521;
+   S1 = S1x;
+   S2 = S2x;
+   }
+
+/*************************************************
+* Update an Adler32 Checksum                     *
+*************************************************/
+void Adler32::add_data(const byte input[], u32bit length)
+   {
+   const u32bit PROCESS_AMOUNT = 5552;
+   while(length >= PROCESS_AMOUNT)
+      {
+      hash(input, PROCESS_AMOUNT);
+      input += PROCESS_AMOUNT;
+      length -= PROCESS_AMOUNT;
+      }
+   hash(input, length);
+   }
+
+/*************************************************
+* Finalize an Adler32 Checksum                   *
+*************************************************/
+void Adler32::final_result(byte output[])
+   {
+   store_be(output, S2, S1);
+   clear();
+   }
+
+}