misc.cpp
00001
00002
00003 #include "pch.h"
00004 #include "misc.h"
00005 #include "words.h"
00006
00007 NAMESPACE_BEGIN(CryptoPP)
00008
00009 byte OAEP_P_DEFAULT[1];
00010
00011 template<> void ByteReverse(word16 *, const word16 *, unsigned int);
00012 template<> void ByteReverse(word32 *, const word32 *, unsigned int);
00013 #ifdef WORD64_AVAILABLE
00014 template<> void ByteReverse(word64 *, const word64 *, unsigned int);
00015 #endif
00016
00017 void xorbuf(byte *buf, const byte *mask, unsigned int count)
00018 {
00019 if (((unsigned int)buf | (unsigned int)mask | count) % WORD_SIZE == 0)
00020 XorWords((word *)buf, (const word *)mask, count/WORD_SIZE);
00021 else
00022 {
00023 for (unsigned int i=0; i<count; i++)
00024 buf[i] ^= mask[i];
00025 }
00026 }
00027
00028 void xorbuf(byte *output, const byte *input, const byte *mask, unsigned int count)
00029 {
00030 if (((unsigned int)output | (unsigned int)input | (unsigned int)mask | count) % WORD_SIZE == 0)
00031 XorWords((word *)output, (const word *)input, (const word *)mask, count/WORD_SIZE);
00032 else
00033 {
00034 for (unsigned int i=0; i<count; i++)
00035 output[i] = input[i] ^ mask[i];
00036 }
00037 }
00038
00039 unsigned int Parity(unsigned long value)
00040 {
00041 for (unsigned int i=8*sizeof(value)/2; i>0; i/=2)
00042 value ^= value >> i;
00043 return (unsigned int)value&1;
00044 }
00045
00046 unsigned int BytePrecision(unsigned long value)
00047 {
00048 unsigned int i;
00049 for (i=sizeof(value); i; --i)
00050 if (value >> (i-1)*8)
00051 break;
00052
00053 return i;
00054 }
00055
00056 unsigned int BitPrecision(unsigned long value)
00057 {
00058 if (!value)
00059 return 0;
00060
00061 unsigned int l=0, h=8*sizeof(value);
00062
00063 while (h-l > 1)
00064 {
00065 unsigned int t = (l+h)/2;
00066 if (value >> t)
00067 l = t;
00068 else
00069 h = t;
00070 }
00071
00072 return h;
00073 }
00074
00075 unsigned long Crop(unsigned long value, unsigned int size)
00076 {
00077 if (size < 8*sizeof(value))
00078 return (value & ((1L << size) - 1));
00079 else
00080 return value;
00081 }
00082
00083 NAMESPACE_END
Generated on Wed Jul 28 08:07:08 2004 for Crypto++ by
1.3.7