Class: AutoC::Hasher

Inherits:
Object
  • Object
show all
Includes:
Entity, STD, Singleton
Defined in:
lib/autoc/hashers.rb

Overview

Basic xor-shift incremental hasher

Constant Summary

Constants included from Entity

Entity::ReferenceSet

Constants included from STD

STD::ASSERT_H, STD::BOOL, STD::CHAR, STD::COMPLEX, STD::COMPLEX_H, STD::DOUBLE, STD::DOUBLE_COMPLEX, STD::DOUBLE_T, STD::FLOAT, STD::FLOAT_COMPLEX, STD::FLOAT_T, STD::INT, STD::INTMAX_T, STD::INTPTR_T, STD::INTTYPES_H, STD::LONG, STD::LONG_DOUBLE, STD::LONG_DOUBLE_COMPLEX, STD::LONG_LONG, STD::MALLOC_H, STD::MATH_H, STD::PTRDIFF_T, STD::SHORT, STD::SIGNED_CHAR, STD::SIZE_T, STD::STDBOOL_H, STD::STDDEF_H, STD::STDLIB_H, STD::STRING_H, STD::UINTMAX_T, STD::UINTPTR_T, STD::UNSIGNED, STD::UNSIGNED_CHAR, STD::UNSIGNED_LONG, STD::UNSIGNED_LONG_LONG, STD::UNSIGNED_SHORT, STD::WCHAR_T

Instance Method Summary collapse

Methods included from Entity

#<=>, #complexity, #dependencies, #forward_declarations, #implementation, #interface, #position, #references, #total_dependencies, #total_references

Constructor Details

#initialize ⇒ Hasher

Returns a new instance of Hasher.



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# File 'lib/autoc/hashers.rb', line 28

def initialize = dependencies << STDLIB_H

Instance Method Details

#create(hasher) ⇒ Object 



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# File 'lib/autoc/hashers.rb', line 20

def create(hasher) = "#{hasher} = AUTOC_HASHER_SEED"

#destroy(hasher) ⇒ Object 



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# File 'lib/autoc/hashers.rb', line 22

def destroy(hasher) = nil

#render_forward_declarations(stream) ⇒ Object 



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# File 'lib/autoc/hashers.rb', line 30

def render_forward_declarations(stream)
  stream << %{
    #include <limits.h>
    #include <stddef.h>
    #ifndef AUTOC_HASHER_SEED /* no seed is specified, using randomly generated one */
      #define _AUTOC_RANDOMIZE_SEED
      #define AUTOC_HASHER_SEED _autoc_hasher_seed
      AUTOC_EXTERN void
      #ifdef __POCC__
        __cdecl
      #endif
      _autoc_hasher_randomize_seed(void); /* invoke default seed randomizer */
      AUTOC_EXTERN size_t _autoc_hasher_seed;
    #elif ~(~AUTOC_HASHER_SEED + 1) == 1 /* if macro value is unspecified on the command line it is implicitly set to 1 */
      #undef AUTOC_HASHER_SEED
      #define AUTOC_HASHER_SEED 0 /* set seed's default value */
    #endif
  }
end

#render_implementation(stream) ⇒ Object 



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# File 'lib/autoc/hashers.rb', line 50

def render_implementation(stream)
  # Predefined C compiler macros datasheet: https://sourceforge.net/p/predef/wiki/Compilers/
  stream << %{
    #ifdef _AUTOC_RANDOMIZE_SEED
      size_t _autoc_hasher_seed = 0; /* fallback default until _autoc_hasher_randomize_seed() is called */
      #if defined(__cplusplus)
        extern "C" void _autoc_hasher_randomize_seed(void);
      #elif defined(__GNUC__) || defined(__clang__)
        void _autoc_hasher_randomize_seed(void) __attribute__((__constructor__));
      #elif defined(__POCC__)
        #pragma startup _autoc_hasher_randomize_seed
      #elif defined(_MSC_VER) || defined(__POCC__)
        #pragma message("WARNING: _autoc_hasher_randomize_seed() will not be called automatically; either call it manually or compile this source as C++ in order to actually yield random seed")
      #else
        #warning _autoc_hasher_randomize_seed() will not be be called automatically; either call it manually or compile this source as C++ in order to actually yield random seed
      #endif
      #include <time.h>
      #ifdef __POCC__
        #include <stdlib.h>
      #endif
      void
      #ifdef __POCC__
        __cdecl
      #endif
      _autoc_hasher_randomize_seed(void) {
        #if defined(__POCC__)
          /* Pelles C check comes first as it might set _MSC_VER as well */
          unsigned r;
          _rand_s(&r);
          _autoc_hasher_seed = r;
        #elif defined(_MSC_VER)
          unsigned r;
          rand_s(&r);
          _autoc_hasher_seed = r;
        #else
          srand(time(NULL));
          _autoc_hasher_seed = rand();
        #endif
      }
      #ifdef __cplusplus
        static struct _hasher {
          _hasher() {_autoc_hasher_randomize_seed();}
        } _hasher;
      #endif

    #endif
  }
end

#result(hasher) ⇒ Object 



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# File 'lib/autoc/hashers.rb', line 26

def result(hasher) = hasher

#to_s ⇒ Object 



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# File 'lib/autoc/hashers.rb', line 18

def to_s = :size_t

#update(hasher, value) ⇒ Object 



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# File 'lib/autoc/hashers.rb', line 24

def update(hasher, value) = "#{hasher} = ((#{hasher} << 1) | (#{hasher} >> (sizeof(#{hasher})*CHAR_BIT - 1))) ^ (#{value})"