1 // Boost CRC library crc.hpp header file -----------------------------------//
3 // Copyright 2001 Daryle Walker. Use, modification, and distribution are
4 // subject to the Boost Software License, Version 1.0. (See accompanying file
5 // LICENSE_1_0.txt or a copy at <http://www.boost.org/LICENSE_1_0.txt>.)
7 // See <http://www.boost.org/libs/crc/> for the library's home page.
12 #include <boost/config.hpp> // for BOOST_STATIC_CONSTANT, etc.
13 #include <boost/integer.hpp> // for boost::uint_t
15 #include <climits> // for CHAR_BIT, etc.
16 #include <cstddef> // for std::size_t
18 #include <boost/limits.hpp> // for std::numeric_limits
21 // The type of CRC parameters that can go in a template should be related
22 // on the CRC's bit count. This macro expresses that type in a compact
23 // form, but also allows an alternate type for compilers that don't support
24 // dependent types (in template value-parameters).
25 #if !(defined(BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS) || (defined(BOOST_MSVC) && (BOOST_MSVC <= 1300)))
26 #define BOOST_CRC_PARM_TYPE typename ::boost::uint_t<Bits>::fast
28 #define BOOST_CRC_PARM_TYPE unsigned long
31 // Some compilers [MS VC++ 6] cannot correctly set up several versions of a
32 // function template unless every template argument can be unambiguously
33 // deduced from the function arguments. (The bug is hidden if only one version
34 // is needed.) Since all of the CRC function templates have this problem, the
35 // workaround is to make up a dummy function argument that encodes the template
36 // arguments. Calls to such template functions need all their template
37 // arguments explicitly specified. At least one compiler that needs this
38 // workaround also needs the default value for the dummy argument to be
39 // specified in the definition.
40 #if defined(__GNUC__) || !defined(BOOST_NO_EXPLICIT_FUNCTION_TEMPLATE_ARGUMENTS)
41 #define BOOST_CRC_DUMMY_PARM_TYPE
42 #define BOOST_CRC_DUMMY_INIT
43 #define BOOST_ACRC_DUMMY_PARM_TYPE
44 #define BOOST_ACRC_DUMMY_INIT
46 namespace boost { namespace detail {
47 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
48 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
49 bool ReflectIn, bool ReflectRem >
50 struct dummy_crc_argument { };
52 #define BOOST_CRC_DUMMY_PARM_TYPE , detail::dummy_crc_argument<Bits, \
53 TruncPoly, InitRem, FinalXor, ReflectIn, ReflectRem> *p_
54 #define BOOST_CRC_DUMMY_INIT BOOST_CRC_DUMMY_PARM_TYPE = 0
55 #define BOOST_ACRC_DUMMY_PARM_TYPE , detail::dummy_crc_argument<Bits, \
56 TruncPoly, 0, 0, false, false> *p_
57 #define BOOST_ACRC_DUMMY_INIT BOOST_ACRC_DUMMY_PARM_TYPE = 0
65 // Forward declarations ----------------------------------------------------//
67 template < std::size_t Bits >
70 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly = 0u,
71 BOOST_CRC_PARM_TYPE InitRem = 0u,
72 BOOST_CRC_PARM_TYPE FinalXor = 0u, bool ReflectIn = false,
73 bool ReflectRem = false >
76 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
77 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
78 bool ReflectIn, bool ReflectRem >
79 typename uint_t<Bits>::fast crc( void const *buffer,
80 std::size_t byte_count
81 BOOST_CRC_DUMMY_PARM_TYPE );
83 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly >
84 typename uint_t<Bits>::fast augmented_crc( void const *buffer,
85 std::size_t byte_count, typename uint_t<Bits>::fast initial_remainder
86 BOOST_ACRC_DUMMY_PARM_TYPE );
88 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly >
89 typename uint_t<Bits>::fast augmented_crc( void const *buffer,
90 std::size_t byte_count
91 BOOST_ACRC_DUMMY_PARM_TYPE );
93 typedef crc_optimal<16, 0x8005, 0, 0, true, true> crc_16_type;
94 typedef crc_optimal<16, 0x1021, 0xFFFF, 0, false, false> crc_ccitt_type;
95 typedef crc_optimal<16, 0x8408, 0, 0, true, true> crc_xmodem_type;
97 typedef crc_optimal<32, 0x04C11DB7, 0xFFFFFFFF, 0xFFFFFFFF, true, true>
101 // Forward declarations for implementation detail stuff --------------------//
102 // (Just for the stuff that will be needed for the next two sections)
106 template < std::size_t Bits >
110 struct mask_uint_t< std::numeric_limits<unsigned char>::digits >;
112 #if USHRT_MAX > UCHAR_MAX
114 struct mask_uint_t< std::numeric_limits<unsigned short>::digits >;
117 #if UINT_MAX > USHRT_MAX
119 struct mask_uint_t< std::numeric_limits<unsigned int>::digits >;
122 #if ULONG_MAX > UINT_MAX
124 struct mask_uint_t< std::numeric_limits<unsigned long>::digits >;
127 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly, bool Reflect >
130 template < std::size_t Bits, bool DoReflect >
133 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
134 template < std::size_t Bits >
135 class crc_helper< Bits, false >;
138 } // namespace detail
141 // Simple cyclic redundancy code (CRC) class declaration -------------------//
143 template < std::size_t Bits >
146 // Implementation type
147 typedef detail::mask_uint_t<Bits> masking_type;
151 typedef typename masking_type::least value_type;
153 // Constant for the template parameter
154 BOOST_STATIC_CONSTANT( std::size_t, bit_count = Bits );
157 explicit crc_basic( value_type truncated_polynominal,
158 value_type initial_remainder = 0, value_type final_xor_value = 0,
159 bool reflect_input = false, bool reflect_remainder = false );
161 // Internal Operations
162 value_type get_truncated_polynominal() const;
163 value_type get_initial_remainder() const;
164 value_type get_final_xor_value() const;
165 bool get_reflect_input() const;
166 bool get_reflect_remainder() const;
168 value_type get_interim_remainder() const;
169 void reset( value_type new_rem );
172 // External Operations
173 void process_bit( bool bit );
174 void process_bits( unsigned char bits, std::size_t bit_count );
175 void process_byte( unsigned char byte );
176 void process_block( void const *bytes_begin, void const *bytes_end );
177 void process_bytes( void const *buffer, std::size_t byte_count );
179 value_type checksum() const;
184 value_type poly_, init_, final_; // non-const to allow assignability
185 bool rft_in_, rft_out_; // non-const to allow assignability
187 }; // boost::crc_basic
190 // Optimized cyclic redundancy code (CRC) class declaration ----------------//
192 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
193 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
194 bool ReflectIn, bool ReflectRem >
197 // Implementation type
198 typedef detail::mask_uint_t<Bits> masking_type;
202 typedef typename masking_type::fast value_type;
204 // Constants for the template parameters
205 BOOST_STATIC_CONSTANT( std::size_t, bit_count = Bits );
206 BOOST_STATIC_CONSTANT( value_type, truncated_polynominal = TruncPoly );
207 BOOST_STATIC_CONSTANT( value_type, initial_remainder = InitRem );
208 BOOST_STATIC_CONSTANT( value_type, final_xor_value = FinalXor );
209 BOOST_STATIC_CONSTANT( bool, reflect_input = ReflectIn );
210 BOOST_STATIC_CONSTANT( bool, reflect_remainder = ReflectRem );
213 explicit crc_optimal( value_type init_rem = InitRem );
215 // Internal Operations
216 value_type get_truncated_polynominal() const;
217 value_type get_initial_remainder() const;
218 value_type get_final_xor_value() const;
219 bool get_reflect_input() const;
220 bool get_reflect_remainder() const;
222 value_type get_interim_remainder() const;
223 void reset( value_type new_rem = InitRem );
225 // External Operations
226 void process_byte( unsigned char byte );
227 void process_block( void const *bytes_begin, void const *bytes_end );
228 void process_bytes( void const *buffer, std::size_t byte_count );
230 value_type checksum() const;
233 void operator ()( unsigned char byte );
234 value_type operator ()() const;
237 // The implementation of output reflection depends on both reflect states.
238 BOOST_STATIC_CONSTANT( bool, reflect_output = (ReflectRem != ReflectIn) );
241 #define BOOST_CRC_REF_OUT_VAL reflect_output
243 typedef crc_optimal self_type;
244 #define BOOST_CRC_REF_OUT_VAL (self_type::reflect_output)
247 // More implementation types
248 typedef detail::crc_table_t<Bits, TruncPoly, ReflectIn> crc_table_type;
249 typedef detail::crc_helper<Bits, ReflectIn> helper_type;
250 typedef detail::crc_helper<Bits, BOOST_CRC_REF_OUT_VAL> reflect_out_type;
252 #undef BOOST_CRC_REF_OUT_VAL
257 }; // boost::crc_optimal
260 // Implementation detail stuff ---------------------------------------------//
264 // Forward declarations for more implementation details
265 template < std::size_t Bits >
268 template < std::size_t Bits >
272 // Traits class for mask; given the bit number
273 // (1-based), get the mask for that bit by itself.
274 template < std::size_t Bits >
276 : boost::uint_t< Bits >
278 typedef boost::uint_t<Bits> base_type;
279 typedef typename base_type::least least;
280 typedef typename base_type::fast fast;
282 #if defined(__EDG_VERSION__) && __EDG_VERSION__ <= 243
283 static const least high_bit = 1ul << ( Bits - 1u );
284 static const fast high_bit_fast = 1ul << ( Bits - 1u );
286 BOOST_STATIC_CONSTANT( least, high_bit = (least( 1u ) << ( Bits
288 BOOST_STATIC_CONSTANT( fast, high_bit_fast = (fast( 1u ) << ( Bits
292 }; // boost::detail::high_uint_t
295 // Reflection routine class wrapper
296 // (since MS VC++ 6 couldn't handle the unwrapped version)
297 template < std::size_t Bits >
300 typedef typename boost::uint_t<Bits>::fast value_type;
302 static value_type reflect( value_type x );
304 }; // boost::detail::reflector
306 // Function that reflects its argument
307 template < std::size_t Bits >
308 typename reflector<Bits>::value_type
309 reflector<Bits>::reflect
311 typename reflector<Bits>::value_type x
314 value_type reflection = 0;
315 value_type const one = 1;
317 for ( std::size_t i = 0 ; i < Bits ; ++i, x >>= 1 )
321 reflection |= ( one << (Bits - 1u - i) );
329 // Traits class for masks; given the bit number (1-based),
330 // get the mask for that bit and its lower bits.
331 template < std::size_t Bits >
333 : high_uint_t< Bits >
335 typedef high_uint_t<Bits> base_type;
336 typedef typename base_type::least least;
337 typedef typename base_type::fast fast;
340 using base_type::high_bit;
341 using base_type::high_bit_fast;
343 BOOST_STATIC_CONSTANT( least, high_bit = base_type::high_bit );
344 BOOST_STATIC_CONSTANT( fast, high_bit_fast = base_type::high_bit_fast );
347 #if defined(__EDG_VERSION__) && __EDG_VERSION__ <= 243
348 static const least sig_bits = (~( ~( 0ul ) << Bits )) ;
350 BOOST_STATIC_CONSTANT( least, sig_bits = (~( ~(least( 0u )) << Bits )) );
352 BOOST_STATIC_CONSTANT( fast, sig_bits_fast = fast(sig_bits) );
354 }; // boost::detail::mask_uint_t
357 struct mask_uint_t< std::numeric_limits<unsigned char>::digits >
358 : high_uint_t< std::numeric_limits<unsigned char>::digits >
360 typedef high_uint_t<std::numeric_limits<unsigned char>::digits>
362 typedef base_type::least least;
363 typedef base_type::fast fast;
366 using base_type::high_bit;
367 using base_type::high_bit_fast;
369 BOOST_STATIC_CONSTANT( least, high_bit = base_type::high_bit );
370 BOOST_STATIC_CONSTANT( fast, high_bit_fast = base_type::high_bit_fast );
373 BOOST_STATIC_CONSTANT( least, sig_bits = (~( least(0u) )) );
374 BOOST_STATIC_CONSTANT( fast, sig_bits_fast = fast(sig_bits) );
376 }; // boost::detail::mask_uint_t
378 #if USHRT_MAX > UCHAR_MAX
380 struct mask_uint_t< std::numeric_limits<unsigned short>::digits >
381 : high_uint_t< std::numeric_limits<unsigned short>::digits >
383 typedef high_uint_t<std::numeric_limits<unsigned short>::digits>
385 typedef base_type::least least;
386 typedef base_type::fast fast;
389 using base_type::high_bit;
390 using base_type::high_bit_fast;
392 BOOST_STATIC_CONSTANT( least, high_bit = base_type::high_bit );
393 BOOST_STATIC_CONSTANT( fast, high_bit_fast = base_type::high_bit_fast );
396 BOOST_STATIC_CONSTANT( least, sig_bits = (~( least(0u) )) );
397 BOOST_STATIC_CONSTANT( fast, sig_bits_fast = fast(sig_bits) );
399 }; // boost::detail::mask_uint_t
402 #if UINT_MAX > USHRT_MAX
404 struct mask_uint_t< std::numeric_limits<unsigned int>::digits >
405 : high_uint_t< std::numeric_limits<unsigned int>::digits >
407 typedef high_uint_t<std::numeric_limits<unsigned int>::digits>
409 typedef base_type::least least;
410 typedef base_type::fast fast;
413 using base_type::high_bit;
414 using base_type::high_bit_fast;
416 BOOST_STATIC_CONSTANT( least, high_bit = base_type::high_bit );
417 BOOST_STATIC_CONSTANT( fast, high_bit_fast = base_type::high_bit_fast );
420 BOOST_STATIC_CONSTANT( least, sig_bits = (~( least(0u) )) );
421 BOOST_STATIC_CONSTANT( fast, sig_bits_fast = fast(sig_bits) );
423 }; // boost::detail::mask_uint_t
426 #if ULONG_MAX > UINT_MAX
428 struct mask_uint_t< std::numeric_limits<unsigned long>::digits >
429 : high_uint_t< std::numeric_limits<unsigned long>::digits >
431 typedef high_uint_t<std::numeric_limits<unsigned long>::digits>
433 typedef base_type::least least;
434 typedef base_type::fast fast;
437 using base_type::high_bit;
438 using base_type::high_bit_fast;
440 BOOST_STATIC_CONSTANT( least, high_bit = base_type::high_bit );
441 BOOST_STATIC_CONSTANT( fast, high_bit_fast = base_type::high_bit_fast );
444 BOOST_STATIC_CONSTANT( least, sig_bits = (~( least(0u) )) );
445 BOOST_STATIC_CONSTANT( fast, sig_bits_fast = fast(sig_bits) );
447 }; // boost::detail::mask_uint_t
451 // CRC table generator
452 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly, bool Reflect >
455 BOOST_STATIC_CONSTANT( std::size_t, byte_combos = (1ul << CHAR_BIT) );
457 typedef mask_uint_t<Bits> masking_type;
458 typedef typename masking_type::fast value_type;
459 #if defined(__BORLANDC__) && defined(_M_IX86) && (__BORLANDC__ == 0x560)
460 // for some reason Borland's command line compiler (version 0x560)
461 // chokes over this unless we do the calculation for it:
462 typedef value_type table_type[ 0x100 ];
464 typedef value_type table_type[ byte_combos ];
467 static void init_table();
469 static table_type table_;
471 }; // boost::detail::crc_table_t
473 // CRC table generator static data member definition
474 // (Some compilers [Borland C++] require the initializer to be present.)
475 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly, bool Reflect >
476 typename crc_table_t<Bits, TruncPoly, Reflect>::table_type
477 crc_table_t<Bits, TruncPoly, Reflect>::table_
480 // Populate CRC lookup table
481 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly, bool Reflect >
483 crc_table_t<Bits, TruncPoly, Reflect>::init_table
487 // compute table only on the first run
488 static bool did_init = false;
489 if ( did_init ) return;
491 // factor-out constants to avoid recalculation
492 value_type const fast_hi_bit = masking_type::high_bit_fast;
493 unsigned char const byte_hi_bit = 1u << (CHAR_BIT - 1u);
495 // loop over every possible dividend value
496 unsigned char dividend = 0;
499 value_type remainder = 0;
501 // go through all the dividend's bits
502 for ( unsigned char mask = byte_hi_bit ; mask ; mask >>= 1 )
504 // check if divisor fits
505 if ( dividend & mask )
507 remainder ^= fast_hi_bit;
510 // do polynominal division
511 if ( remainder & fast_hi_bit )
514 remainder ^= TruncPoly;
522 table_[ crc_helper<CHAR_BIT, Reflect>::reflect(dividend) ]
523 = crc_helper<Bits, Reflect>::reflect( remainder );
525 while ( ++dividend );
531 // CRC helper routines
532 template < std::size_t Bits, bool DoReflect >
537 typedef typename uint_t<Bits>::fast value_type;
539 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
540 // Possibly reflect a remainder
541 static value_type reflect( value_type x )
542 { return detail::reflector<Bits>::reflect( x ); }
544 // Compare a byte to the remainder's highest byte
545 static unsigned char index( value_type rem, unsigned char x )
548 // Shift out the remainder's highest byte
549 static value_type shift( value_type rem )
550 { return rem >> CHAR_BIT; }
552 // Possibly reflect a remainder
553 static value_type reflect( value_type x )
554 { return DoReflect ? detail::reflector<Bits>::reflect( x ) : x; }
556 // Compare a byte to the remainder's highest byte
557 static unsigned char index( value_type rem, unsigned char x )
558 { return x ^ ( rem >> (DoReflect ? 0u : Bits - CHAR_BIT) ); }
560 // Shift out the remainder's highest byte
561 static value_type shift( value_type rem )
562 { return DoReflect ? rem >> CHAR_BIT : rem << CHAR_BIT; }
565 }; // boost::detail::crc_helper
567 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
568 template < std::size_t Bits >
569 class crc_helper<Bits, false>
573 typedef typename uint_t<Bits>::fast value_type;
575 // Possibly reflect a remainder
576 static value_type reflect( value_type x )
579 // Compare a byte to the remainder's highest byte
580 static unsigned char index( value_type rem, unsigned char x )
581 { return x ^ ( rem >> (Bits - CHAR_BIT) ); }
583 // Shift out the remainder's highest byte
584 static value_type shift( value_type rem )
585 { return rem << CHAR_BIT; }
587 }; // boost::detail::crc_helper
591 } // namespace detail
594 // Simple CRC class function definitions -----------------------------------//
596 template < std::size_t Bits >
598 crc_basic<Bits>::crc_basic
600 typename crc_basic<Bits>::value_type truncated_polynominal,
601 typename crc_basic<Bits>::value_type initial_remainder, // = 0
602 typename crc_basic<Bits>::value_type final_xor_value, // = 0
603 bool reflect_input, // = false
604 bool reflect_remainder // = false
606 : rem_( initial_remainder ), poly_( truncated_polynominal )
607 , init_( initial_remainder ), final_( final_xor_value )
608 , rft_in_( reflect_input ), rft_out_( reflect_remainder )
612 template < std::size_t Bits >
614 typename crc_basic<Bits>::value_type
615 crc_basic<Bits>::get_truncated_polynominal
622 template < std::size_t Bits >
624 typename crc_basic<Bits>::value_type
625 crc_basic<Bits>::get_initial_remainder
632 template < std::size_t Bits >
634 typename crc_basic<Bits>::value_type
635 crc_basic<Bits>::get_final_xor_value
642 template < std::size_t Bits >
645 crc_basic<Bits>::get_reflect_input
652 template < std::size_t Bits >
655 crc_basic<Bits>::get_reflect_remainder
662 template < std::size_t Bits >
664 typename crc_basic<Bits>::value_type
665 crc_basic<Bits>::get_interim_remainder
669 return rem_ & masking_type::sig_bits;
672 template < std::size_t Bits >
675 crc_basic<Bits>::reset
677 typename crc_basic<Bits>::value_type new_rem
683 template < std::size_t Bits >
686 crc_basic<Bits>::reset
690 this->reset( this->get_initial_remainder() );
693 template < std::size_t Bits >
696 crc_basic<Bits>::process_bit
701 value_type const high_bit_mask = masking_type::high_bit;
703 // compare the new bit with the remainder's highest
704 rem_ ^= ( bit ? high_bit_mask : 0u );
706 // a full polynominal division step is done when the highest bit is one
707 bool const do_poly_div = static_cast<bool>( rem_ & high_bit_mask );
709 // shift out the highest bit
712 // carry out the division, if needed
719 template < std::size_t Bits >
721 crc_basic<Bits>::process_bits
724 std::size_t bit_count
727 // ignore the bits above the ones we want
728 bits <<= CHAR_BIT - bit_count;
730 // compute the CRC for each bit, starting with the upper ones
731 unsigned char const high_bit_mask = 1u << ( CHAR_BIT - 1u );
732 for ( std::size_t i = bit_count ; i > 0u ; --i, bits <<= 1u )
734 process_bit( static_cast<bool>(bits & high_bit_mask) );
738 template < std::size_t Bits >
741 crc_basic<Bits>::process_byte
746 process_bits( (rft_in_ ? detail::reflector<CHAR_BIT>::reflect(byte)
750 template < std::size_t Bits >
752 crc_basic<Bits>::process_block
754 void const * bytes_begin,
755 void const * bytes_end
758 for ( unsigned char const * p
759 = static_cast<unsigned char const *>(bytes_begin) ; p < bytes_end ; ++p )
765 template < std::size_t Bits >
768 crc_basic<Bits>::process_bytes
771 std::size_t byte_count
774 unsigned char const * const b = static_cast<unsigned char const *>(
777 process_block( b, b + byte_count );
780 template < std::size_t Bits >
782 typename crc_basic<Bits>::value_type
783 crc_basic<Bits>::checksum
787 return ( (rft_out_ ? detail::reflector<Bits>::reflect( rem_ ) : rem_)
788 ^ final_ ) & masking_type::sig_bits;
792 // Optimized CRC class function definitions --------------------------------//
794 // Macro to compact code
795 #define BOOST_CRC_OPTIMAL_NAME crc_optimal<Bits, TruncPoly, InitRem, \
796 FinalXor, ReflectIn, ReflectRem>
798 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
799 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
800 bool ReflectIn, bool ReflectRem >
802 BOOST_CRC_OPTIMAL_NAME::crc_optimal
804 typename BOOST_CRC_OPTIMAL_NAME::value_type init_rem // = InitRem
806 : rem_( helper_type::reflect(init_rem) )
808 crc_table_type::init_table();
811 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
812 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
813 bool ReflectIn, bool ReflectRem >
815 typename BOOST_CRC_OPTIMAL_NAME::value_type
816 BOOST_CRC_OPTIMAL_NAME::get_truncated_polynominal
823 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
824 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
825 bool ReflectIn, bool ReflectRem >
827 typename BOOST_CRC_OPTIMAL_NAME::value_type
828 BOOST_CRC_OPTIMAL_NAME::get_initial_remainder
835 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
836 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
837 bool ReflectIn, bool ReflectRem >
839 typename BOOST_CRC_OPTIMAL_NAME::value_type
840 BOOST_CRC_OPTIMAL_NAME::get_final_xor_value
847 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
848 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
849 bool ReflectIn, bool ReflectRem >
852 BOOST_CRC_OPTIMAL_NAME::get_reflect_input
859 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
860 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
861 bool ReflectIn, bool ReflectRem >
864 BOOST_CRC_OPTIMAL_NAME::get_reflect_remainder
871 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
872 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
873 bool ReflectIn, bool ReflectRem >
875 typename BOOST_CRC_OPTIMAL_NAME::value_type
876 BOOST_CRC_OPTIMAL_NAME::get_interim_remainder
880 // Interim remainder should be _un_-reflected, so we have to undo it.
881 return helper_type::reflect( rem_ ) & masking_type::sig_bits_fast;
884 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
885 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
886 bool ReflectIn, bool ReflectRem >
889 BOOST_CRC_OPTIMAL_NAME::reset
891 typename BOOST_CRC_OPTIMAL_NAME::value_type new_rem // = InitRem
894 rem_ = helper_type::reflect( new_rem );
897 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
898 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
899 bool ReflectIn, bool ReflectRem >
902 BOOST_CRC_OPTIMAL_NAME::process_byte
907 process_bytes( &byte, sizeof(byte) );
910 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
911 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
912 bool ReflectIn, bool ReflectRem >
914 BOOST_CRC_OPTIMAL_NAME::process_block
916 void const * bytes_begin,
917 void const * bytes_end
920 // Recompute the CRC for each byte passed
921 for ( unsigned char const * p
922 = static_cast<unsigned char const *>(bytes_begin) ; p < bytes_end ; ++p )
924 // Compare the new byte with the remainder's higher bits to
925 // get the new bits, shift out the remainder's current higher
926 // bits, and update the remainder with the polynominal division
928 unsigned char const byte_index = helper_type::index( rem_, *p );
929 rem_ = helper_type::shift( rem_ );
930 rem_ ^= crc_table_type::table_[ byte_index ];
934 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
935 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
936 bool ReflectIn, bool ReflectRem >
939 BOOST_CRC_OPTIMAL_NAME::process_bytes
942 std::size_t byte_count
945 unsigned char const * const b = static_cast<unsigned char const *>(
947 process_block( b, b + byte_count );
950 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
951 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
952 bool ReflectIn, bool ReflectRem >
954 typename BOOST_CRC_OPTIMAL_NAME::value_type
955 BOOST_CRC_OPTIMAL_NAME::checksum
959 return ( reflect_out_type::reflect(rem_) ^ get_final_xor_value() )
960 & masking_type::sig_bits_fast;
963 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
964 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
965 bool ReflectIn, bool ReflectRem >
968 BOOST_CRC_OPTIMAL_NAME::operator ()
973 process_byte( byte );
976 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
977 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
978 bool ReflectIn, bool ReflectRem >
980 typename BOOST_CRC_OPTIMAL_NAME::value_type
981 BOOST_CRC_OPTIMAL_NAME::operator ()
989 // CRC computation function definition -------------------------------------//
991 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly,
992 BOOST_CRC_PARM_TYPE InitRem, BOOST_CRC_PARM_TYPE FinalXor,
993 bool ReflectIn, bool ReflectRem >
995 typename uint_t<Bits>::fast
999 std::size_t byte_count
1000 BOOST_CRC_DUMMY_INIT
1003 BOOST_CRC_OPTIMAL_NAME computer;
1004 computer.process_bytes( buffer, byte_count );
1005 return computer.checksum();
1009 // Augmented-message CRC computation function definitions ------------------//
1011 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly >
1012 typename uint_t<Bits>::fast
1015 void const * buffer,
1016 std::size_t byte_count,
1017 typename uint_t<Bits>::fast initial_remainder
1018 BOOST_ACRC_DUMMY_INIT
1021 typedef unsigned char byte_type;
1022 typedef detail::mask_uint_t<Bits> masking_type;
1023 typedef detail::crc_table_t<Bits, TruncPoly, false> crc_table_type;
1025 typename masking_type::fast rem = initial_remainder;
1026 byte_type const * const b = static_cast<byte_type const *>( buffer );
1027 byte_type const * const e = b + byte_count;
1029 crc_table_type::init_table();
1030 for ( byte_type const * p = b ; p < e ; ++p )
1032 // Use the current top byte as the table index to the next
1033 // "partial product." Shift out that top byte, shifting in
1034 // the next augmented-message byte. Complete the division.
1035 byte_type const byte_index = rem >> ( Bits - CHAR_BIT );
1038 rem ^= crc_table_type::table_[ byte_index ];
1041 return rem & masking_type::sig_bits_fast;
1044 template < std::size_t Bits, BOOST_CRC_PARM_TYPE TruncPoly >
1046 typename uint_t<Bits>::fast
1049 void const * buffer,
1050 std::size_t byte_count
1051 BOOST_ACRC_DUMMY_INIT
1054 // The last function argument has its type specified so the other version of
1055 // augmented_crc will be called. If the cast wasn't in place, and the
1056 // BOOST_ACRC_DUMMY_INIT added a third argument (for a workaround), the "0"
1057 // would match as that third argument, leading to infinite recursion.
1058 return augmented_crc<Bits, TruncPoly>( buffer, byte_count,
1059 static_cast<typename uint_t<Bits>::fast>(0) );
1063 } // namespace boost
1066 // Undo header-private macros
1067 #undef BOOST_CRC_OPTIMAL_NAME
1068 #undef BOOST_ACRC_DUMMY_INIT
1069 #undef BOOST_ACRC_DUMMY_PARM_TYPE
1070 #undef BOOST_CRC_DUMMY_INIT
1071 #undef BOOST_CRC_DUMMY_PARM_TYPE
1072 #undef BOOST_CRC_PARM_TYPE
1075 #endif // BOOST_CRC_HPP