common/parity.h

   1 //-----------------------------------------------------------------------------
   2 // Copyright (C) Proxmark3 contributors. See AUTHORS.md for details.
   3 //
   4 // This program is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // See LICENSE.txt for the text of the license.
  15 //-----------------------------------------------------------------------------
  16 // Parity functions
  17 //-----------------------------------------------------------------------------
  18
  19 // all functions defined in header file by purpose. Allows compiler optimizations.
  20
  21 #ifndef __PARITY_H
  22 #define __PARITY_H
  23
  24 #include "common.h"
  25
  26 static const uint8_t g_odd_byte_parity[256] = {
  27     1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
  28     0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
  29     0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
  30     1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
  31     0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
  32     1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
  33     1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
  34     0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
  35     0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
  36     1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
  37     1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
  38     0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
  39     1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
  40     0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
  41     0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
  42     1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
  43 };
  44
  45 #define ODD_PARITY8(x)   g_odd_byte_parity[x]
  46 #define EVEN_PARITY8(x)  !g_odd_byte_parity[x]
  47
  48 static inline uint8_t oddparity8(const uint8_t x) {
  49     return g_odd_byte_parity[x];
  50 }
  51
  52 static inline uint8_t evenparity8(const uint8_t x) {
  53     return !g_odd_byte_parity[x];
  54 }
  55
  56 static inline uint8_t evenparity16(uint16_t x) {
  57 #if !defined __GNUC__
  58     x ^= x >> 8;
  59     return EVEN_PARITY8(x) ;
  60 #else
  61     return __builtin_parity(x);
  62 #endif
  63 }
  64
  65 static inline uint8_t oddparity16(uint16_t x) {
  66 #if !defined __GNUC__
  67     x ^= x >> 8;
  68     return ODD_PARITY8(x);
  69 #else
  70     return !__builtin_parity(x);
  71 #endif
  72 }
  73
  74 static inline uint8_t evenparity32(uint32_t x) {
  75 #if !defined __GNUC__
  76     x ^= x >> 16;
  77     x ^= x >> 8;
  78     return EVEN_PARITY8(x) ;
  79 #else
  80     return __builtin_parity(x);
  81 #endif
  82 }
  83
  84 static inline uint8_t oddparity32(uint32_t x) {
  85 #if !defined __GNUC__
  86     x ^= x >> 16;
  87     x ^= x >> 8;
  88     return ODD_PARITY8(x);
  89 #else
  90     return !__builtin_parity(x);
  91 #endif
  92 }
  93
  94 #endif /* __PARITY_H */