conversion.cpp

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#include "yaml-cpp-pm/conversion.h"
#include <algorithm>

// Specializations for converting a string to specific types

namespace
{
        // we're not gonna mess with the mess that is all the isupper/etc. functions
        bool IsLower(char ch) { return 'a' <= ch && ch <= 'z'; }
        bool IsUpper(char ch) { return 'A' <= ch && ch <= 'Z'; }
        char ToLower(char ch) { return IsUpper(ch) ? ch + 'a' - 'A' : ch; }

        std::string tolower(const std::string& str)
        {
                std::string s(str);
                std::transform(s.begin(), s.end(), s.begin(), ToLower);
                return s;
        }

        template <typename T>
        bool IsEntirely(const std::string& str, T func)
        {
                for(std::size_t i=0;i<str.size();i++)
                        if(!func(str[i]))
                                return false;

                return true;
        }

        // IsFlexibleCase
        // . Returns true if 'str' is:
        //   . UPPERCASE
        //   . lowercase
        //   . Capitalized
        bool IsFlexibleCase(const std::string& str)
        {
                if(str.empty())
                        return true;

                if(IsEntirely(str, IsLower))
                        return true;

                bool firstcaps = IsUpper(str[0]);
                std::string rest = str.substr(1);
                return firstcaps && (IsEntirely(rest, IsLower) || IsEntirely(rest, IsUpper));
        }
}

namespace YAML_PM
{
        bool Convert(const std::string& input, bool& b)
        {
                // we can't use iostream bool extraction operators as they don't
                // recognize all possible values in the table below (taken from
                // http://yaml.org/type/bool.html)
                static const struct {
                        std::string truename, falsename;
                } names[] = {
                        { "y", "n" },
                        { "yes", "no" },
                        { "true", "false" },
                        { "on", "off" },
                };

                if(!IsFlexibleCase(input))
                        return false;

                for(unsigned i=0;i<sizeof(names)/sizeof(names[0]);i++) {
                        if(names[i].truename == tolower(input)) {
                                b = true;
                                return true;
                        }

                        if(names[i].falsename == tolower(input)) {
                                b = false;
                                return true;
                        }
                }

                return false;
        }
        
        bool Convert(const std::string& input, _Null& /*output*/)
        {
                return input.empty() || input == "~" || input == "null" || input == "Null" || input == "NULL";
        }
}