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-rw-r--r--src/lib/hash/checksum/adler32/adler32.cpp83
1 files changed, 83 insertions, 0 deletions
diff --git a/src/lib/hash/checksum/adler32/adler32.cpp b/src/lib/hash/checksum/adler32/adler32.cpp
new file mode 100644
index 000000000..f2385c5b8
--- /dev/null
+++ b/src/lib/hash/checksum/adler32/adler32.cpp
@@ -0,0 +1,83 @@
+/*
+* Adler32
+* (C) 1999-2007 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/hash_utils.h>
+#include <botan/adler32.h>
+
+namespace Botan {
+
+BOTAN_REGISTER_HASH_NOARGS(Adler32);
+
+namespace {
+
+void adler32_update(const byte input[], size_t length,
+ u16bit& S1, u16bit& S2)
+ {
+ u32bit S1x = S1;
+ u32bit 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(size_t j = 0; j != length; ++j)
+ {
+ S1x += input[j];
+ S2x += S1x;
+ }
+
+ S1 = S1x % 65521;
+ S2 = S2x % 65521;
+ }
+
+}
+
+/*
+* Update an Adler32 Checksum
+*/
+void Adler32::add_data(const byte input[], size_t length)
+ {
+ const size_t PROCESS_AMOUNT = 5552;
+
+ while(length >= PROCESS_AMOUNT)
+ {
+ adler32_update(input, PROCESS_AMOUNT, S1, S2);
+ input += PROCESS_AMOUNT;
+ length -= PROCESS_AMOUNT;
+ }
+
+ adler32_update(input, length, S1, S2);
+ }
+
+/*
+* Finalize an Adler32 Checksum
+*/
+void Adler32::final_result(byte output[])
+ {
+ store_be(output, S2, S1);
+ clear();
+ }
+
+}