2 * Copyright © 2019 Ebrahim Byagowi
4 * This is part of HarfBuzz, a text shaping library.
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
26 #ifndef HB_NUMBER_PARSER_HH
27 #define HB_NUMBER_PARSER_HH
33 machine double_parser;
34 alphtype unsigned char;
37 action see_neg { neg = true; }
38 action see_exp_neg { exp_neg = true; }
41 value = value * 10. + (fc - '0');
44 if (likely (frac <= MAX_FRACT / 10))
46 frac = frac * 10. + (fc - '0');
51 if (likely (exp * 10 + (fc - '0') <= MAX_EXP))
52 exp = exp * 10 + (fc - '0');
61 (('+'|'-'@see_neg)? num @add_int) ('.' num @add_frac)?
63 (('+'|'-'@see_neg)? '.' num @add_frac)
65 (('e'|'E') (('+'|'-'@see_exp_neg)? num @add_exp))?
70 /* Works only for n < 512 */
72 _pow10 (unsigned exponent)
74 static const double _powers_of_10[] =
86 unsigned mask = 1 << (ARRAY_LENGTH (_powers_of_10) - 1);
88 for (const double *power = _powers_of_10; mask; ++power, mask >>= 1)
89 if (exponent & mask) result *= *power;
93 /* a variant of strtod that also gets end of buffer in its second argument */
95 strtod_rl (const char *p, const char **end_ptr /* IN/OUT */)
99 double frac_count = 0;
101 bool neg = false, exp_neg = false, exp_overflow = false;
102 const unsigned long long MAX_FRACT = 0xFFFFFFFFFFFFFull; /* 2^52-1 */
103 const unsigned MAX_EXP = 0x7FFu; /* 2^11-1 */
105 const char *pe = *end_ptr;
106 while (p < pe && ISSPACE (*p))
117 if (frac_count) value += frac / _pow10 (frac_count);
118 if (neg) value *= -1.;
120 if (unlikely (exp_overflow))
122 if (value == 0) return value;
123 if (exp_neg) return neg ? -DBL_MIN : DBL_MIN;
124 else return neg ? -DBL_MAX : DBL_MAX;
129 if (exp_neg) value /= _pow10 (exp);
130 else value *= _pow10 (exp);
136 #endif /* HB_NUMBER_PARSER_HH */