140 lines
3.1 KiB
Ragel
140 lines
3.1 KiB
Ragel
/*
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* Copyright © 2019 Ebrahim Byagowi
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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*/
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#ifndef HB_NUMBER_PARSER_HH
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#define HB_NUMBER_PARSER_HH
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#include "hb.hh"
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#include <float.h>
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%%{
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machine double_parser;
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alphtype unsigned char;
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write data;
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action see_neg { neg = true; }
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action see_exp_neg { exp_neg = true; }
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action add_int {
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value = value * 10. + (fc - '0');
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}
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action add_frac {
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if (likely (frac <= MAX_FRACT / 10))
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{
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frac = frac * 10. + (fc - '0');
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++frac_count;
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}
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}
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action add_exp {
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if (likely (exp * 10 + (fc - '0') <= MAX_EXP))
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exp = exp * 10 + (fc - '0');
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else
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exp_overflow = true;
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}
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num = [0-9]+;
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main := (
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(
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(('+'|'-'@see_neg)? num @add_int) ('.' num @add_frac)?
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(('+'|'-'@see_neg)? '.' num @add_frac)
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)
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(('e'|'E') (('+'|'-'@see_exp_neg)? num @add_exp))?
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);
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}%%
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/* Works only for n < 512 */
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static inline double
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_pow10 (unsigned int exponent)
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{
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static const double _powers_of_10[] =
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{
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1.0e+256,
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1.0e+128,
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1.0e+64,
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1.0e+32,
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1.0e+16,
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1.0e+8,
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10000.,
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100.,
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10.
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};
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unsigned int mask = 1 << (ARRAY_LENGTH (_powers_of_10) - 1);
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double result = 1;
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for (const double *power = _powers_of_10; mask; ++power, mask >>= 1)
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if (exponent & mask) result *= *power;
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return result;
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}
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static inline double
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strtod_rl (const char *buf, char **end_ptr)
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{
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const char *p, *pe;
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double value = 0;
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double frac = 0;
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double frac_count = 0;
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unsigned int exp = 0;
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bool neg = false, exp_neg = false, exp_overflow = false;
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const unsigned long long MAX_FRACT = 0xFFFFFFFFFFFFFull; /* 1^52-1 */
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const unsigned int MAX_EXP = 0x7FFu; /* 1^11-1 */
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p = buf;
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pe = p + strlen (p);
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while (p < pe && ISSPACE (*p))
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p++;
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int cs;
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%%{
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write init;
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write exec;
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}%%
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*end_ptr = (char *) p;
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if (frac_count) value += frac / _pow10 (frac_count);
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if (neg) value *= -1.;
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if (unlikely (exp_overflow))
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{
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if (value == 0) return value;
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if (exp_neg) return neg ? -DBL_MIN : DBL_MIN;
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else return neg ? -DBL_MAX : DBL_MAX;
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}
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if (exp)
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{
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if (exp_neg) value /= _pow10 (exp);
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else value *= _pow10 (exp);
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}
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return value;
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}
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#endif /* HB_NUMBER_PARSER_HH */
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