3 This file is part of libmspstrings
4 Copyright © 2006-2008 Mikko Rasa
5 Distributed under the LGPL
10 #include "lexicalcast.h"
20 { enum { result = !(static_cast<T>(-1)>0) }; };
22 template<typename T, bool f = (sizeof(T)>sizeof(unsigned long))>
24 { typedef unsigned long Type; };
27 struct Temporary<T, true>
32 typedef unsigned long long Type;
36 /* Helper to avoid warnings about an unsigned type never being < 0 */
37 template<typename T, bool f = IsSigned<T>::result>
39 { static bool eval(T v) { return v<0; } };
42 struct IsNegative<T, false>
43 { static bool eval(T) { return false; } };
45 /* Helper to avoid errors about ambiguous function calls since there are no
46 overloads of abs for unsigned types */
47 template<typename T, bool f = IsSigned<T>::result>
49 { static T eval(T v) { return v<0 ? -v : v; } };
52 struct Absolute<T, false>
53 { static T eval(T v) { return v; } };
56 /*** Integer conversions ***/
58 const char udigits[] = "0123456789ABCDEF";
59 const char ldigits[] = "0123456789abcdef";
62 char *int_to_str(T v, const Fmt &f, char *end)
64 if(f.get_type()==Fmt::CHAR)
72 // Find out the base to use
73 unsigned base = f.get_base();
77 // Format the number, starting from the least significant digit
78 const char *digits = (f.get_uppercase() ? udigits : ldigits);
81 typename Temporary<T>::Type w = Absolute<T>::eval(v);
84 *--ptr = digits[w%base];
91 char sign = (IsNegative<T>::eval(v) ? '-' : f.get_showpos() ? '+' : 0);
94 /* Zero-fill, taking base/sign size into account. The expression is a
95 bit ugly, but saves having to write code for creating the prefix both
97 unsigned pfxsize = ((f.get_showbase() && base!=10) ? base==8 ? 1 : 2 : 0) + (sign!=0);
98 for(unsigned i=(end-ptr)+pfxsize; i<f.get_width(); ++i)
102 if(f.get_showbase() && v!=0)
104 // Add base indicator
106 *--ptr = (f.get_uppercase() ? 'B' : 'b');
108 *--ptr = (f.get_uppercase() ? 'X' : 'x');
120 string int_to_str(T v, const Fmt &f)
122 unsigned size = max(f.get_width(), max<unsigned>(f.get_precision(), sizeof(T)*8+3));
123 char *buf = new char[size];
124 string result(int_to_str(v, f, buf+size), buf+size);
130 T str_to_int(const std::string &s, const Fmt &f)
133 throw LexicalError("Empty input in integer conversion");
135 std::string::const_iterator i = s.begin();
137 // See if the input starts with a sign
141 if(!IsSigned<T>::result)
142 throw LexicalError("Negative sign in unsigned integer conversion");
149 // Must have some digits to convert
151 throw LexicalError("Missing digits in integer conversion");
153 T base = f.get_base();
154 if(!base && i!=s.end())
156 // Automatic base detection requested, figure it out
157 if(*i=='0' && ++i!=s.end())
159 if(*i=='x' || *i=='X')
164 else if(*i=='b' || *i=='B')
178 for(; i!=s.end(); ++i)
181 if(*i>='0' && *i<='9')
183 else if(*i>='A' && *i<='F')
185 else if(*i>='a' && *i<='f')
188 throw LexicalError("Invalid digit in integer conversion");
189 T next = result*base+digit;
190 if(next/base!=result)
191 throw LexicalError("Overflow in integer conversion");
202 /*** Boolean conversions ***/
204 string bool_to_str(bool b, const Fmt &f)
206 if(f.get_type()==Fmt::STR)
207 return b ? "true" : "false";
209 return b ? "1" : "0";
212 bool str_to_bool(const string &s)
215 throw LexicalError("Empty input in boolean conversion");
217 if(s=="1" || s=="true" || s=="yes" || s=="on")
219 else if(s=="0" || s=="false" || s=="no" || s=="off")
222 throw LexicalError("Invalid input in boolean conversion");
226 /*** Floating-point conversions ***/
229 string flt_to_str(T v, const Fmt &f)
231 if(f.get_type()==Fmt::CHAR)
232 throw LexicalError("Character format in floating-point conversion");
234 Fmt::FloatMode mode = f.get_floatmode();
235 long double w = abs(v);
236 char sign = (v<0 ? '-' : f.get_showpos() ? '+' : 0);
238 // Handle infinity and not-a-number as special cases
245 result += (f.get_uppercase() ? "NAN" : "nan");
247 result += (f.get_uppercase() ? "INF" : "inf");
248 if(result.size()<f.get_width())
249 result = string(f.get_width()-result.size(), ' ')+result;
253 /* Find out the base-10 exponent. Building up the multiplier / divisor
254 first helps with accuracy in some cases. */
266 else if(mode!=Fmt::FIXED && w<1 && w!=0)
277 // Decide how to format the number
280 bool showexp = false;
284 digits = point+f.get_precision();
286 else if(mode==Fmt::SCI)
288 digits = f.get_precision()+1;
293 digits = max(f.get_precision(), 1U);
294 if(exp<-4 || exp>=static_cast<int>(digits))
301 point = max(exp, 0)+1;
308 w += 5.0l/pow(10.0l, static_cast<long double>(digits));
311 // Rounding bumped us to the next exponent, deal with it
313 if(mode==Fmt::AUTOFLT && exp+1==static_cast<int>(digits))
327 // Create a buffer and start from the end
328 unsigned size = max(f.get_width(), digits+8);
329 char *buf = new char[size];
330 char *end = buf+size;
336 ptr = int_to_str(exp, Fmt().showpos().fill('0').width(3), ptr);
337 *--ptr = (f.get_uppercase() ? 'E' : 'e');
340 // Format mantissa left-to-right
342 ptr -= digits+(point<digits || f.get_showpoint());
344 for(unsigned i=0; i<digits; ++i)
348 if(showexp || static_cast<int>(i)>=-exp)
350 int digit = static_cast<int>(w);
358 if(f.get_showpoint())
360 // Radix point requested but not displayed yet, add it
364 else if(mode==Fmt::AUTOFLT && digits>point)
366 // Remove trailing zeroes from fraction and a lone radix point
379 // Add filling and sign
380 if(f.get_fill()=='0')
382 unsigned pfxlen = (sign!=0);
383 while(end-ptr+pfxlen<f.get_width())
389 string result(ptr, end);
395 T str_to_flt(const string &s, const Fmt &)
398 throw LexicalError("Empty input in floating-point conversion");
400 std::string::const_iterator i = s.begin();
402 // See if the input starts with a sign
412 // Must have some digits to convert
414 throw LexicalError("Missing digits in floating-point conversion");
420 bool point_seen = false;
421 for(; i!=s.end(); ++i)
426 throw LexicalError("Extra point in floating-point conversion");
429 else if(*i>='0' && *i<='9')
435 else if(*i=='e' || *i=='E')
437 // We have an exponent
440 exp += str_to_int<int>(string(i, s.end()), Fmt());
441 // str_to_int has eaten the rest of the input or thrown
445 throw LexicalError("Invalid digit in floating-point conversion");
448 // Scale and negate the result as needed
467 /*** String conversions ***/
469 string str_to_str(const string &s, const Fmt &f)
471 if(f.get_type()==Fmt::NUM)
472 throw LexicalError("Numeric format in string conversion");
480 void LexicalConverter::result(const string &s)
482 if(s.size()<fmt.get_width())
484 if(fmt.get_align()==Fmt::RIGHT)
485 buf = string(fmt.get_width()-s.size(), fmt.get_fill())+s;
487 buf = s+string(fmt.get_width()-s.size(), fmt.get_fill());
496 void operator<<(LexicalConverter &c, char v)
498 Fmt::Type type = c.get_fmt().get_type();
500 c.result(int_to_str(v, c.get_fmt()));
502 c.result(string(1, v));
505 void operator<<(LexicalConverter &c, signed char v)
506 { c.result(int_to_str(v, c.get_fmt())); }
508 void operator<<(LexicalConverter &c, short v)
509 { c.result(int_to_str(v, c.get_fmt())); }
511 void operator<<(LexicalConverter &c, int v)
512 { c.result(int_to_str(v, c.get_fmt())); }
514 void operator<<(LexicalConverter &c, long v)
515 { c.result(int_to_str(v, c.get_fmt())); }
517 void operator<<(LexicalConverter &c, unsigned char v)
518 { c.result(int_to_str(v, c.get_fmt())); }
520 void operator<<(LexicalConverter &c, unsigned short v)
521 { c.result(int_to_str(v, c.get_fmt())); }
523 void operator<<(LexicalConverter &c, unsigned v)
524 { c.result(int_to_str(v, c.get_fmt())); }
526 void operator<<(LexicalConverter &c, unsigned long v)
527 { c.result(int_to_str(v, c.get_fmt())); }
530 void operator<<(LexicalConverter &c, long long v)
531 { c.result(int_to_str(v, c.get_fmt())); }
533 void operator<<(LexicalConverter &c, unsigned long long v)
534 { c.result(int_to_str(v, c.get_fmt())); }
537 void operator<<(LexicalConverter &c, bool v)
538 { c.result(bool_to_str(v, c.get_fmt())); }
540 void operator<<(LexicalConverter &c, float v)
541 { c.result(flt_to_str(v, c.get_fmt())); }
543 void operator<<(LexicalConverter &c, double v)
544 { c.result(flt_to_str(v, c.get_fmt())); }
546 void operator<<(LexicalConverter &c, long double v)
547 { c.result(flt_to_str(v, c.get_fmt())); }
549 void operator<<(LexicalConverter &c, const string &s)
550 { c.result(str_to_str(s, c.get_fmt())); }
552 void operator<<(LexicalConverter &c, const char *s)
553 { c.result(str_to_str(s, c.get_fmt())); }
555 void operator<<(LexicalConverter &c, const void *p)
556 { c.result(int_to_str(reinterpret_cast<unsigned long>(p), c.get_fmt())); }
561 void operator>>(const LexicalConverter &c, char &v)
563 if(c.get_fmt().get_type()==Fmt::NUM)
564 v = str_to_int<char>(c.get(), c.get_fmt());
567 const std::string &s = c.get();
569 throw LexicalError("Empty input in character conversion");
571 throw LexicalError("Extra input in character conversion");
576 void operator>>(const LexicalConverter &c, signed char &v)
577 { v = str_to_int<signed char>(c.get(), c.get_fmt()); }
579 void operator>>(const LexicalConverter &c, short &v)
580 { v = str_to_int<short>(c.get(), c.get_fmt()); }
582 void operator>>(const LexicalConverter &c, int &v)
583 { v = str_to_int<int>(c.get(), c.get_fmt()); }
585 void operator>>(const LexicalConverter &c, long &v)
586 { v = str_to_int<long>(c.get(), c.get_fmt()); }
588 void operator>>(const LexicalConverter &c, unsigned char &v)
589 { v = str_to_int<unsigned char>(c.get(), c.get_fmt()); }
591 void operator>>(const LexicalConverter &c, unsigned short &v)
592 { v = str_to_int<unsigned short>(c.get(), c.get_fmt()); }
594 void operator>>(const LexicalConverter &c, unsigned int &v)
595 { v = str_to_int<unsigned int>(c.get(), c.get_fmt()); }
597 void operator>>(const LexicalConverter &c, unsigned long &v)
598 { v = str_to_int<unsigned long>(c.get(), c.get_fmt()); }
601 void operator>>(const LexicalConverter &c, long long &v)
602 { v = str_to_int<long long>(c.get(), c.get_fmt()); }
604 void operator>>(const LexicalConverter &c, unsigned long long &v)
605 { v = str_to_int<unsigned long long>(c.get(), c.get_fmt()); }
608 void operator>>(const LexicalConverter &c, bool &v)
609 { v = str_to_bool(c.get()); }
611 void operator>>(const LexicalConverter &c, float &v)
612 { v = str_to_flt<float>(c.get(), c.get_fmt()); }
614 void operator>>(const LexicalConverter &c, double &v)
615 { v = str_to_flt<double>(c.get(), c.get_fmt()); }
617 void operator>>(const LexicalConverter &c, long double &v)
618 { v = str_to_flt<long double>(c.get(), c.get_fmt()); }
620 void operator>>(const LexicalConverter &c, string &s)
621 { s = str_to_str(c.get(), c.get_fmt()); }