225 lines
6.0 KiB
C++
225 lines
6.0 KiB
C++
// inspect.cpp
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// Copyright (c) 2006 Johan Rade
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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//-------------------------------------
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#include <cstring>
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#include <iomanip>
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#include <iostream>
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#include <limits>
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#include <boost/detail/endian.hpp>
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//------------------------------------------------------------------------------
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bool is_big_endian()
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{
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float x = 1.0f;
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unsigned char first_byte;
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memcpy(&first_byte, &x, 1);
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return first_byte != 0;
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}
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//------------------------------------------------------------------------------
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void print_processor();
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void print_endianness();
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template<class T> void print_table();
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template<class T> void print_row(const char* name, T val, bool ok = true);
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//------------------------------------------------------------------------------
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int main()
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{
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std::cout << '\n';
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print_processor();
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print_endianness();
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std::cout << "---------- float --------------------\n\n";
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print_table<float>();
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std::cout << "---------- double -------------------\n\n";
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print_table<double>();
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std::cout << "---------- long double --------------\n\n";
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print_table<long double>();
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return 0;
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}
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//------------------------------------------------------------------------------
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void print_processor()
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{
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#if defined(__i386) || defined(__i386__) || defined(_M_IX86) \
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|| defined(__amd64) || defined(__amd64__) || defined(_M_AMD64) \
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|| defined(__x86_64) || defined(__x86_64__) || defined(_M_X64)
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std::cout << "Processor: x86 or x64\n\n";
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#elif defined(__ia64) || defined(__ia64__) || defined(_M_IA64)
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std::cout << "Processor: ia64\n\n";
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#elif defined(__powerpc) || defined(__powerpc__) || defined(__POWERPC__) \
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|| defined(__ppc) || defined(__ppc__) || defined(__PPC__)
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std::cout << "Processor: PowerPC\n\n";
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#elif defined(__m68k) || defined(__m68k__) \
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|| defined(__mc68000) || defined(__mc68000__) \
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std::cout << "Processor: Motorola 68K\n\n";
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#else
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std::cout << "Processor: Unknown\n\n";
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#endif
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}
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void print_endianness()
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{
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if(is_big_endian())
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std::cout << "This platform is big-endian.\n";
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else
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std::cout << "This platform is little-endian.\n";
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#ifdef BOOST_BIG_ENDIAN
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std::cout << "BOOST_BIG_ENDIAN is defined.\n\n";
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#endif
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#if defined BOOST_LITTLE_ENDIAN
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std::cout << "BOOST_LITTTLE_ENDIAN is defined.\n\n";
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#endif
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}
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//..............................................................................
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template<class T> void print_table()
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{
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print_row("0", (T)0);
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print_row("sn.min", std::numeric_limits<T>::denorm_min(),
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std::numeric_limits<T>::has_denorm);
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print_row("-sn.min", -std::numeric_limits<T>::denorm_min(),
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std::numeric_limits<T>::has_denorm);
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print_row("n.min/256", (std::numeric_limits<T>::min)()/256);
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print_row("n.min/2", (std::numeric_limits<T>::min)()/2);
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print_row("-n.min/2", -(std::numeric_limits<T>::min)()/2);
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print_row("n.min", (std::numeric_limits<T>::min)());
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print_row("1", (T)1);
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print_row("3/4", (T)3/(T)4);
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print_row("4/3", (T)4/(T)3);
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print_row("max", (std::numeric_limits<T>::max)());
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print_row("inf", std::numeric_limits<T>::infinity(),
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std::numeric_limits<T>::has_infinity);
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print_row("q.nan", std::numeric_limits<T>::quiet_NaN(),
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std::numeric_limits<T>::has_quiet_NaN);
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print_row("s.nan", std::numeric_limits<T>::signaling_NaN(),
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std::numeric_limits<T>::has_signaling_NaN);
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std::cout << "\n\n";
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}
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template<class T>
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void print_row(const char* name, T val, bool ok)
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{
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std::cout << std::left << std::setw(10) << name << std::right;
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std::cout << std::hex << std::setfill('0');
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if(ok) {
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if(is_big_endian()) {
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for(size_t i = 0; i < sizeof(T); ++i) {
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unsigned char c = *(reinterpret_cast<unsigned char*>(&val) + i);
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std::cout << std::setw(2)
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<< static_cast<unsigned int>(c) << ' ';
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}
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}
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else {
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for(size_t i = sizeof(T) - 1; i < sizeof(T); --i) {
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unsigned char c = *(reinterpret_cast<unsigned char*>(&val) + i);
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std::cout << std::setw(2)
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<< static_cast<unsigned int>(c) << ' ';
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}
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}
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}
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else {
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for(size_t i = 0; i < sizeof(T); ++i)
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std::cout << "-- ";
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}
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std::cout << '\n';
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std::cout << std::dec << std::setfill(' ');
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}
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/*
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Sample output on an AMD Quadcore running MSVC 10
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Processor: x86 or x64
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This platform is little-endian.
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BOOST_LITTTLE_ENDIAN is defined.
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---------- float --------------------
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0 00 00 00 00
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sn.min 00 00 00 01
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-sn.min 80 00 00 01
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n.min/256 00 00 80 00
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n.min/2 00 40 00 00
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-n.min/2 80 40 00 00
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n.min 00 80 00 00
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1 3f 80 00 00
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3/4 3f 40 00 00
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4/3 3f aa aa ab
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max 7f 7f ff ff
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inf 7f 80 00 00
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q.nan 7f c0 00 00
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s.nan 7f c0 00 01
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---------- double -------------------
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0 00 00 00 00 00 00 00 00
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sn.min 00 00 00 00 00 00 00 01
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-sn.min 80 00 00 00 00 00 00 01
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n.min/256 00 00 10 00 00 00 00 00
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n.min/2 00 08 00 00 00 00 00 00
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-n.min/2 80 08 00 00 00 00 00 00
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n.min 00 10 00 00 00 00 00 00
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1 3f f0 00 00 00 00 00 00
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3/4 3f e8 00 00 00 00 00 00
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4/3 3f f5 55 55 55 55 55 55
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max 7f ef ff ff ff ff ff ff
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inf 7f f0 00 00 00 00 00 00
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q.nan 7f f8 00 00 00 00 00 00
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s.nan 7f f8 00 00 00 00 00 01
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---------- long double --------------
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0 00 00 00 00 00 00 00 00
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sn.min 00 00 00 00 00 00 00 01
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-sn.min 80 00 00 00 00 00 00 01
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n.min/256 00 00 10 00 00 00 00 00
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n.min/2 00 08 00 00 00 00 00 00
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-n.min/2 80 08 00 00 00 00 00 00
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n.min 00 10 00 00 00 00 00 00
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1 3f f0 00 00 00 00 00 00
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3/4 3f e8 00 00 00 00 00 00
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4/3 3f f5 55 55 55 55 55 55
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max 7f ef ff ff ff ff ff ff
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inf 7f f0 00 00 00 00 00 00
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q.nan 7f f8 00 00 00 00 00 00
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s.nan 7f f8 00 00 00 00 00 01
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*/
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