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Copyright (C) 1999-2007 The Botan Project. All rights reserved.
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Redistribution and use in source and binary forms, for any use, with or without
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modification, is permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice, this
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list of conditions, and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) "AS IS" AND ANY EXPRESS OR IMPLIED
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WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.
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IN NO EVENT SHALL THE AUTHOR(S) OR CONTRIBUTOR(S) BE LIABLE FOR ANY DIRECT,
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INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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namespace QCA { // WRAPNS_LINE
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/*************************************************
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* Bit/Word Operations Source File *
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* (C) 1999-2007 The Botan Project *
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*************************************************/
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#include <botan/bit_ops.h>
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namespace QCA { // WRAPNS_LINE
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/*************************************************
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* XOR arrays together *
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*************************************************/
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void xor_buf(byte data[], const byte mask[], u32bit length)
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data[0] ^= mask[0]; data[1] ^= mask[1];
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data[2] ^= mask[2]; data[3] ^= mask[3];
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data[4] ^= mask[4]; data[5] ^= mask[5];
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data[6] ^= mask[6]; data[7] ^= mask[7];
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data += 8; mask += 8; length -= 8;
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for(u32bit j = 0; j != length; ++j)
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void xor_buf(byte out[], const byte in[], const byte mask[], u32bit length)
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out[0] = in[0] ^ mask[0]; out[1] = in[1] ^ mask[1];
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out[2] = in[2] ^ mask[2]; out[3] = in[3] ^ mask[3];
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out[4] = in[4] ^ mask[4]; out[5] = in[5] ^ mask[5];
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out[6] = in[6] ^ mask[6]; out[7] = in[7] ^ mask[7];
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in += 8; out += 8; mask += 8; length -= 8;
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for(u32bit j = 0; j != length; ++j)
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out[j] = in[j] ^ mask[j];
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/*************************************************
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* Return true iff arg is 2**n for some n > 0 *
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*************************************************/
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bool power_of_2(u64bit arg)
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if(arg == 0 || arg == 1)
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if((arg & (arg-1)) == 0)
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/*************************************************
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* Return the index of the highest set bit *
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*************************************************/
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u32bit high_bit(u64bit n)
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for(u32bit count = 64; count > 0; --count)
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if((n >> (count - 1)) & 0x01)
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/*************************************************
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* Return the index of the lowest set bit *
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*************************************************/
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u32bit low_bit(u64bit n)
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for(u32bit count = 0; count != 64; ++count)
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if((n >> count) & 0x01)
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/*************************************************
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* Return the number of significant bytes in n *
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*************************************************/
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u32bit significant_bytes(u64bit n)
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for(u32bit j = 0; j != 8; ++j)
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/*************************************************
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* Return the Hamming weight of n *
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*************************************************/
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u32bit hamming_weight(u64bit n)
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for(u32bit j = 0; j != 64; ++j)