kc3-lang/harfbuzz/src/hb-number-parser.rl

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• Hash : 47d82713
  Author :
  Date : 2019-09-06T20:33:10
  

  Replace strtod with a ragel implementation
  
  Use a ragel based number parser when strtod_l couldn't be found
  as libc's strtod may is locale sensetivity which we need to not.
  

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• src/hb-number-parser.rl

• /*
   * Copyright © 2019  Ebrahim Byagowi
   *
   *  This is part of HarfBuzz, a text shaping library.
   *
   * Permission is hereby granted, without written agreement and without
   * license or royalty fees, to use, copy, modify, and distribute this
   * software and its documentation for any purpose, provided that the
   * above copyright notice and the following two paragraphs appear in
   * all copies of this software.
   *
   * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
   * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
   * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
   * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *
   * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
   * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
   * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
   * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
   *
   */
  
  #ifndef HB_NUMBER_PARSER_HH
  #define HB_NUMBER_PARSER_HH
  
  #include "hb.hh"
  
  %%{
  
  machine double_parser;
  alphtype unsigned char;
  write data;
  
  action see_neg { neg = true; }
  action see_exp_neg { exp_neg = true; }
  
  action add_int  { value = value * 10. + (fc - '0'); }
  action add_frac { frac = frac * 10. + (fc - '0'); ++frac_count; }
  action add_exp  { exp = exp * 10 + (fc - '0'); }
  
  num = [0-9]+;
  
  main := (
  	(
  		(('+'|'-'@see_neg)? num @add_int) ('.' num @add_frac)?
  		|
  		(('+'|'-'@see_neg)? '.' num @add_frac)
  	)
  	(('e'|'E') (('+'|'-'@see_exp_neg)? num @add_exp))?
  );
  
  }%%
  
  constexpr double _pow2 (double x) { return x * x; }
  constexpr double _pow10_of_2i (unsigned int n)
  { return n == 1 ? 10. : _pow2 (_pow10_of_2i (n >> 1)); }
  
  static const double _powers_of_10[] =
  {
    _pow10_of_2i (0x100),
    _pow10_of_2i (0x80),
    _pow10_of_2i (0x40),
    _pow10_of_2i (0x20),
    _pow10_of_2i (0x10),
    _pow10_of_2i (0x8),
    _pow10_of_2i (0x4),
    _pow10_of_2i (0x2),
    _pow10_of_2i (0x1),
  };
  
  /* Works only for n < 512 */
  inline double
  _pow10 (unsigned int exponent)
  {
    unsigned int mask = 0x100; /* Should be same with the first element  */
    double result = 1;
    for (const double *power = _powers_of_10; mask; ++power, mask >>= 1)
      if (exponent & mask) result *= *power;
    return result;
  }
  
  inline double
  strtod_rl (const char *buf, char **end_ptr)
  {
    const char *p, *pe;
    double value = 0;
    double frac = 0;
    double frac_count = 0;
    unsigned int exp = 0;
    bool neg = false, exp_neg = false;
    p = buf;
    pe = p + strlen (p);
  
    while (p < pe && ISSPACE (*p))
      p++;
  
    int cs;
    %%{
      write init;
      write exec;
    }%%
  
    *end_ptr = (char *) p;
  
    if (frac_count) value += frac / _pow10 (frac_count);
    if (neg) value *= -1.;
  
    if (exp)
    {
      if (exp_neg)
        value /= _pow10 (exp);
      else
        value *= _pow10 (exp);
    }
  
    return value;
  }
  
  #endif /* HB_NUMBER_PARSER_HH */
  

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