digxel.hpp

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/*
  DIGXEL.hpp  -  grid aligned and fixed format time specifications
 
   Copyright (C)
     2010,            Hermann Vosseler <Ichthyostega@web.de>
 
 **Lumiera** is free software; you can redistribute it and/or modify it
 under the terms of the GNU General Public License as published by the
 Free Software Foundation; either version 2 of the License, or (at your
 option) any later version. See the file COPYING for further details.
 
*/
 
 
#ifndef LIB_TIME_DIGXEL_H
#define LIB_TIME_DIGXEL_H
 
#include "lib/error.hpp"
#include "lib/symbol.hpp"
#include "lib/util.hpp"
 
#include <boost/lexical_cast.hpp>
#include <functional>
#include <string>
#include <cstdio>
#include <cmath>
 
using std::string;
 
 
namespace lib {
namespace time {
  
  namespace digxel {
    
    using lib::Literal;
    using boost::lexical_cast;
    
    using CBuf = CStr;
    
    
    template<typename NUM, size_t len>
    class PrintfFormatter
      {
        enum{ bufsiz = len+1 };
        
        char printbuffer_[bufsiz];
        Literal formatSpec_;
        
      public:
        PrintfFormatter (Literal fmt)
          : printbuffer_()
          , formatSpec_(fmt)
          {
            clear();
          }
        
        void clear() { printbuffer_[0] = '\0'; }
        bool empty() { return '\0' == *printbuffer_; }
        
        size_t
        maxlen()  const
          {
            return len;
          }
        
        CBuf
        show (NUM val)
          {
            if (empty())
              {
                size_t space = std::snprintf (printbuffer_, bufsiz, formatSpec_, val);
                REQUIRE (space < bufsiz, "Digxel value exceeded available buffer size. "
                                         "For showing %s, %zu+1 chars instead of just %zu+1 would be required."
                                       , cStr(lexical_cast<string>(val)), space, len);               
              }
            ENSURE (!empty());
            return printbuffer_;
          }
      };
    
    
    template<typename NUM>
    struct Formatter;
    
    template<>
    struct Formatter<int>
      : PrintfFormatter<int, 9>
      {
        Formatter() : PrintfFormatter<int,9>("%3d") { }
      };
    
    template<>
    struct Formatter<double>
      : PrintfFormatter<double, 7>
      {
        Formatter() : PrintfFormatter<double,7>("%06.3f") { }
      };
    
    /* == other specialised Formatters == */
    struct SexaFormatter
      : PrintfFormatter<int, 4>
      {
        SexaFormatter() : PrintfFormatter<int,4>("%02d") { }
      };
    
    struct HexaFormatter
      : PrintfFormatter<uint, 2>
      {
        HexaFormatter() : PrintfFormatter<uint,2>("%02X") { }
      };
    
    struct CountFormatter
      : PrintfFormatter<long, 20>
      {
        CountFormatter() : PrintfFormatter<long,20>("%04ld") { }
      };
    
    struct HourFormatter
      : PrintfFormatter<int, 9>
      {
        HourFormatter() : PrintfFormatter<int,9>("%2d") { }
      };
    
    
    struct SignFormatter
      {
        void clear()          {  }
        size_t maxlen() const { return 1; }
        CBuf show (int val)   { return val<0? "-":" "; }
      };
    
  } //(End) digxel configuration namespace
  
  
  
  
  
  using std::bind;
  using std::function;
  using std::placeholders::_1;
  
  
    template< typename NUM
            , class FMT  = digxel::Formatter<NUM>
            >
  class Digxel
    {
      mutable
      FMT buffer_;
      NUM value_;
      
      typedef Digxel<NUM,FMT>      _Digxel;
      typedef function<void(NUM)> _Mutator;
      
      
      _Mutator mutator; 
 
    public:
      template<typename FUN, class THIS>
      void
      installMutator (FUN mutate, THIS& self)
        {
          mutator = bind (mutate, &self, _1 );
        }
      
      
      Digxel ()
        : buffer_()
        , value_ ()
        , mutator()
        { }
      
      // using the standard copy operations
      
      operator NUM()    const { return value_; }
      operator string() const { return show(); }
      
      size_t maxlen()   const { return buffer_.maxlen(); }
      
      
      digxel::CBuf
      show()  const
        {
          return buffer_.show (value_);
        }
      
      
      void
      operator= (NUM n)
        {
          if (n == value_) return;
          if (mutator)
            mutator (n);
          else
            setValueRaw (n);
        }
      
      void
      setValueRaw (NUM newVal)
        {
          if (newVal != value_)
            {
              value_ = newVal;
              buffer_.clear();
            }
        }
      
      
      
      //---Supporting-increments--------------
      Digxel& operator+=  (NUM inc)  { *this = value_ + inc; return *this; }
      Digxel& operator-=  (NUM dec)  { *this = value_ - dec; return *this; }
      Digxel& operator++  ()         { *this = value_ + 1;   return *this; }
      Digxel& operator--  ()         { *this = value_ - 1;   return *this; }
      NUM     operator++  (int)      { NUM p(value_); *this =p+1; return p;}
      NUM     operator--  (int)      { NUM p(value_); *this =p-1; return p;}
      
      //---Supporting-total-ordering----------
      auto operator<=>(Digxel const& o)  const { return value_ <=> NUM(o); }
      bool operator== (Digxel const& o)  const { return value_ ==  NUM(o); }
    };
  
  
  
  /* == predefined Digxel configurations == */
  using SexaDigit = Digxel< int, digxel::SexaFormatter>;  
  using HexaDigit = Digxel<uint, digxel::HexaFormatter>;  
  using HourDigit = Digxel< int, digxel::HourFormatter>;  
  
  using FrameCnt = int64_t;
  using CountVal = Digxel<FrameCnt, digxel::CountFormatter>;  
  
  
  class Signum
    : public Digxel<int,digxel::SignFormatter>
    {
      typedef Digxel<int, digxel::SignFormatter> _Par;
      
      void
      storeSign (int val)
        {
          setValueRaw (val<0? -1:+1);
        }
      
    public:
      Signum()
        {
          setValueRaw(1);
          installMutator (&Signum::storeSign, *this);
        }
      
      using _Par::operator=;
      
      friend int operator*= (Signum& s, int c) { s = c*s; return s; }
    };
  
  
}} // lib::time
#endif