73 lines
1.6 KiB
C++
73 lines
1.6 KiB
C++
// misc.cpp - written and placed in the public domain by Wei Dai
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#include "pch.h"
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#include "misc.h"
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#include "words.h"
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void xorbuf(byte *buf, const byte *mask, unsigned int count)
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{
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if (((ptr_size_type)buf | (ptr_size_type)mask | count) % WORD_SIZE == 0)
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XorWords((word *)buf, (const word *)mask, count/WORD_SIZE);
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else
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{
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for (unsigned int i=0; i<count; i++)
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buf[i] ^= mask[i];
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}
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}
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void xorbuf(byte *output, const byte *input, const byte *mask, unsigned int count)
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{
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if (((ptr_size_type)output | (ptr_size_type)input | (ptr_size_type)mask | count) % WORD_SIZE == 0)
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XorWords((word *)output, (const word *)input, (const word *)mask, count/WORD_SIZE);
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else
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{
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for (unsigned int i=0; i<count; i++)
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output[i] = input[i] ^ mask[i];
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}
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}
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unsigned int Parity(unsigned long value)
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{
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for (unsigned int i=8*sizeof(value)/2; i>0; i/=2)
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value ^= value >> i;
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return (unsigned int)value&1;
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}
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unsigned int BytePrecision(unsigned long value)
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{
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unsigned int i;
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for (i=sizeof(value); i; --i)
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if (value >> (i-1)*8)
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break;
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return i;
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}
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unsigned int BitPrecision(unsigned long value)
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{
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if (!value)
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return 0;
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unsigned int l=0, h=8*sizeof(value);
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while (h-l > 1)
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{
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unsigned int t = (l+h)/2;
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if (value >> t)
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l = t;
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else
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h = t;
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}
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return h;
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}
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unsigned long Crop(unsigned long value, int size)
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{
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if (size < 8*(int)sizeof(value))
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return (value & ((1L << size) - 1));
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else
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return value;
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}
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