/************************************************* * Adler32 Source File * * (C) 1999-2007 Jack Lloyd * *************************************************/ #include #include 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(); } }