// Boost CRC library crc.hpp header file -----------------------------------//
-// Copyright 2001 Daryle Walker. Use, modification, and distribution are
+// Copyright 2001, 2004 Daryle Walker. Use, modification, and distribution are
// subject to the Boost Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or a copy at <http://www.boost.org/LICENSE_1_0.txt>.)
#else
BOOST_STATIC_CONSTANT( least, sig_bits = (~( ~(least( 0u )) << Bits )) );
#endif
+#if defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ == 0 && __GNUC_PATCHLEVEL__ == 2
+ // Work around a weird bug that ICEs the compiler in build_c_cast
+ BOOST_STATIC_CONSTANT( fast, sig_bits_fast = static_cast<fast>(sig_bits) );
+#else
BOOST_STATIC_CONSTANT( fast, sig_bits_fast = fast(sig_bits) );
-
+#endif
}; // boost::detail::mask_uint_t
template < >
typedef typename masking_type::fast value_type;
#if defined(__BORLANDC__) && defined(_M_IX86) && (__BORLANDC__ == 0x560)
// for some reason Borland's command line compiler (version 0x560)
- // chokes over this unless we do the calculation for it:
+ // chokes over this unless we do the calculation for it:
typedef value_type table_type[ 0x100 ];
+#elif defined(__GNUC__)
+ // old versions of GCC (before 4.0.2) choke on using byte_combos
+ // as a constant expression when compiling with -pedantic.
+ typedef value_type table_type[1ul << CHAR_BIT];
#else
typedef value_type table_type[ byte_combos ];
#endif
did_init = true;
}
+ #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
+ // Align the msb of the remainder to a byte
+ template < std::size_t Bits, bool RightShift >
+ class remainder
+ {
+ public:
+ typedef typename uint_t<Bits>::fast value_type;
+
+ static unsigned char align_msb( value_type rem )
+ { return rem >> (Bits - CHAR_BIT); }
+ };
+
+ // Specialization for the case that the remainder has less
+ // bits than a byte: align the remainder msb to the byte msb
+ template < std::size_t Bits >
+ class remainder< Bits, false >
+ {
+ public:
+ typedef typename uint_t<Bits>::fast value_type;
+
+ static unsigned char align_msb( value_type rem )
+ { return rem << (CHAR_BIT - Bits); }
+ };
+ #endif
// CRC helper routines
template < std::size_t Bits, bool DoReflect >
// Compare a byte to the remainder's highest byte
static unsigned char index( value_type rem, unsigned char x )
- { return x ^ ( rem >> (DoReflect ? 0u : Bits - CHAR_BIT) ); }
+ { return x ^ ( DoReflect ? rem :
+ ((Bits>CHAR_BIT)?( rem >> (Bits - CHAR_BIT) ) :
+ ( rem << (CHAR_BIT - Bits) ))); }
// Shift out the remainder's highest byte
static value_type shift( value_type rem )
// Compare a byte to the remainder's highest byte
static unsigned char index( value_type rem, unsigned char x )
- { return x ^ ( rem >> (Bits - CHAR_BIT) ); }
+ { return x ^ remainder<Bits,(Bits>CHAR_BIT)>::align_msb( rem ); }
// Shift out the remainder's highest byte
static value_type shift( value_type rem )
// a full polynominal division step is done when the highest bit is one
bool const do_poly_div = static_cast<bool>( rem_ & high_bit_mask );
- // shift out the highest bit
+ // shift out the highest bit
rem_ <<= 1;
// carry out the division, if needed