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// Silence MSVC sprintf unsafe warnings
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <sstream>
#include <iomanip>
#include <limits>
#include <string>
#include <type_traits>
#include <algorithm>
#include <functional>
#include <ctype.h>
#include "libdivide.h"
#include "type_mappings.h"
inline std::string to_lower(std::string str) {
std::transform(str.begin(), str.end(), str.begin(),
[](unsigned char c){ return (char)::tolower(c); });
return str;
}
inline std::string to_upper(std::string str) {
std::transform(str.begin(), str.end(), str.begin(),
[](unsigned char c){ return (char)::toupper(c); });
return str;
}
template <typename _IntT>
void generator(std::function<void(_IntT)> pGen) {
// We're dealing with integer division. For any denominator:
// if (numerator<denominator) numerator/denominator==0
// if (numerator==denominator) numerator/denominator==1
// Compilers know this. So there's no point in generating constants > MAX/2.
for (_IntT denom = std::numeric_limits<_IntT>::min()/2;
denom<std::numeric_limits<_IntT>::max()/2;
++denom ) {
if (denom!=0) {
pGen(denom);
}
}
}
template <typename _IntT>
static std::string const_macro_name(_IntT denom) {
std::string name(to_upper(type_tag<_IntT>::get_tag()));
name += "LD_DENOM_";
if (denom<0) {
name += "MINUS_";
denom = -denom;
}
name += std::to_string(denom);
return name;
}
template <typename _IntT>
static std::string magic_tostr(_IntT magic) {
// Don't use hex representation here. Some hex literals are considered unsigned, so
// will cause a warning when cast to unsigned
std::stringstream stream;
stream << "(" << type_name<_IntT>::get_name() << ")" << magic;
return stream.str();
}
static std::string more_tostr(uint8_t more) {
std::stringstream stream;
stream << "(uint8_t)" << (uint16_t)more;
return stream.str();
}
template <typename _IntT>
void generate_constant_macro(_IntT denom) {
auto magic = libdivide_gen(denom);
std::cout << "#define " << const_macro_name(denom)+"_MAGIC" << " " << magic_tostr(magic.magic) << "\n";
std::cout << "#define " << const_macro_name(denom)+"_MORE" << " " << more_tostr(magic.more) << "\n";
}
template <typename _IntT>
void generate_specialized_template(_IntT denom) {
std::cout << "template<> struct libdivide_constants"
<< "<" << type_name<_IntT>::get_name() << "," << denom << "> "
<< "{ "
<< "static constexpr " << struct_selector<_IntT>::get_name() << " libdivide = { "
<< ".magic = " << const_macro_name(denom)+"_MAGIC, "
<< ".more = " << const_macro_name(denom)+"_MORE};"
<< "};\n";
}
template <typename _IntT>
void generate_ternary_primary(_IntT denom, const char *varName) {
std::cout << varName << "==" << denom << " ? "
<< struct_selector<_IntT>::get_name() << " { "
<< ".magic = " << const_macro_name(denom)+"_MAGIC, "
<< ".more = " << const_macro_name(denom)+"_MORE} :\n";
}
template <typename _IntT>
void generate_const_func() {
const char param_name[] = "v";
std::cout << "LIBDIVIDE_INLINE constexpr " << struct_selector<_IntT>::get_name()
<< " get_divider_" << type_tag<_IntT>::get_tag()
<< "(" << type_name<_IntT>::get_name() << " " << param_name << ") {\n"
<< "\treturn\n";
generator<_IntT>([param_name](_IntT denom) {
std::cout << "\t";
generate_ternary_primary<_IntT>(denom, param_name);
});
std:: cout << "\t" << struct_selector<_IntT>::get_name() << " { 0, 0 }; // Unreachable\n"
<< "}";
}
enum style {
macro,
cpp_template,
const_func,
};
template <typename _IntT>
void generate(style gen_style) {
switch (gen_style)
{
case style::macro:
generator<_IntT>(&generate_constant_macro<_IntT>);
break;
case style::cpp_template:
generator<_IntT>(&generate_specialized_template<_IntT>);
break;
case style::const_func:
generate_const_func<_IntT>();
break;
default:
break;
}
}
void print_disclaimer()
{
std::cout << "// This file is machine generated\n"
<< "// Do not make changes to it.\n"
<< "// See " << __FILE__ << "\n";
}
extern "C" int main(int argc, char *argv[]) {
if (argc!=3) {
std::cout
<< "Usage: fast_div_generator [DATATYPE] [STYLE]\n"
"\n"
"[DATATYPE] in [s16, u16]\n"
"[STYLE] in [MACRO, TEMPLATE, CONST_FUNC]"
<< std::endl;
exit(1);
}
print_disclaimer();
std::string data_type(to_lower(argv[1]));
std::string style_param(to_lower(argv[2]));
style generate_template = "template"==style_param ? style::cpp_template
: "macro"==style_param ? style::macro
: style::const_func;
if (data_type == type_tag<int16_t>::get_tag()) {
generate<int16_t>(generate_template);
} else if (data_type == type_tag<uint16_t>::get_tag()) {
generate<uint16_t>(generate_template);
}
}
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