diff options
Diffstat (limited to 'ml/dlib/dlib/byte_orderer/byte_orderer_kernel_1.h')
| -rw-r--r-- | ml/dlib/dlib/byte_orderer/byte_orderer_kernel_1.h | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/ml/dlib/dlib/byte_orderer/byte_orderer_kernel_1.h b/ml/dlib/dlib/byte_orderer/byte_orderer_kernel_1.h new file mode 100644 index 000000000..9f8e8342f --- /dev/null +++ b/ml/dlib/dlib/byte_orderer/byte_orderer_kernel_1.h @@ -0,0 +1,176 @@ +// Copyright (C) 2006 Davis E. King (davis@dlib.net) +// License: Boost Software License See LICENSE.txt for the full license. +#ifndef DLIB_BYTE_ORDEREr_KERNEL_1_ +#define DLIB_BYTE_ORDEREr_KERNEL_1_ + +#include "byte_orderer_kernel_abstract.h" +#include "../algs.h" +#include "../assert.h" + +namespace dlib +{ + + class byte_orderer + { + /*! + INITIAL VALUE + - if (this machine is little endian) then + - little_endian == true + - else + - little_endian == false + + CONVENTION + - host_is_big_endian() == !little_endian + - host_is_little_endian() == little_endian + + - if (this machine is little endian) then + - little_endian == true + - else + - little_endian == false + + + !*/ + + + public: + + // this is here for backwards compatibility with older versions of dlib. + typedef byte_orderer kernel_1a; + + byte_orderer ( + ) + { + // This will probably never be false but if it is then it means chars are not 8bits + // on this system. Which is a problem for this object. + COMPILE_TIME_ASSERT(sizeof(short) >= 2); + + unsigned long temp = 1; + unsigned char* ptr = reinterpret_cast<unsigned char*>(&temp); + if (*ptr == 1) + little_endian = true; + else + little_endian = false; + } + + virtual ~byte_orderer ( + ){} + + bool host_is_big_endian ( + ) const { return !little_endian; } + + bool host_is_little_endian ( + ) const { return little_endian; } + + template < + typename T + > + inline void host_to_network ( + T& item + ) const + { if (little_endian) flip(item); } + + template < + typename T + > + inline void network_to_host ( + T& item + ) const { if (little_endian) flip(item); } + + template < + typename T + > + void host_to_big ( + T& item + ) const { if (little_endian) flip(item); } + + template < + typename T + > + void big_to_host ( + T& item + ) const { if (little_endian) flip(item); } + + template < + typename T + > + void host_to_little ( + T& item + ) const { if (!little_endian) flip(item); } + + template < + typename T + > + void little_to_host ( + T& item + ) const { if (!little_endian) flip(item); } + + + private: + + template < + typename T, + size_t size + > + inline void flip ( + T (&array)[size] + ) const + /*! + ensures + - flips the bytes in every element of this array + !*/ + { + for (size_t i = 0; i < size; ++i) + { + flip(array[i]); + } + } + + template < + typename T + > + inline void flip ( + T& item + ) const + /*! + ensures + - reverses the byte ordering in item + !*/ + { + DLIB_ASSERT_HAS_STANDARD_LAYOUT(T); + + T value; + + // If you are getting this as an error then you are probably using + // this object wrong. If you think you aren't then send me (Davis) an + // email and I'll either set you straight or change/remove this check so + // your stuff works :) + COMPILE_TIME_ASSERT(sizeof(T) <= sizeof(long double)); + + // If you are getting a compile error on this line then it means T is + // a pointer type. It doesn't make any sense to byte swap pointers + // since they have no meaning outside the context of their own process. + // So you probably just forgot to dereference that pointer before passing + // it to this function :) + COMPILE_TIME_ASSERT(is_pointer_type<T>::value == false); + + + const size_t size = sizeof(T); + unsigned char* const ptr = reinterpret_cast<unsigned char*>(&item); + unsigned char* const ptr_temp = reinterpret_cast<unsigned char*>(&value); + for (size_t i = 0; i < size; ++i) + ptr_temp[size-i-1] = ptr[i]; + + item = value; + } + + bool little_endian; + }; + + // make flip not do anything at all for chars + template <> inline void byte_orderer::flip<char> ( char& ) const {} + template <> inline void byte_orderer::flip<unsigned char> ( unsigned char& ) const {} + template <> inline void byte_orderer::flip<signed char> ( signed char& ) const {} +} + +#endif // DLIB_BYTE_ORDEREr_KERNEL_1_ + |