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/*
* 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 {
if (likely (frac <= MAX_FRACT / 10))
{
frac = frac * 10. + (fc - '0');
++frac_count;
}
}
action add_exp {
if (likely (exp * 10 + (fc - '0') <= MAX_EXP))
exp = exp * 10 + (fc - '0');
else
exp_overflow = true;
}
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))?
);
}%%
/* Works only for n < 512 */
static inline double
_pow10 (unsigned exponent)
{
static const double _powers_of_10[] =
{
1.0e+256,
1.0e+128,
1.0e+64,
1.0e+32,
1.0e+16,
1.0e+8,
10000.,
100.,
10.
};
unsigned mask = 1 << (ARRAY_LENGTH (_powers_of_10) - 1);
double result = 1;
for (const double *power = _powers_of_10; mask; ++power, mask >>= 1)
if (exponent & mask) result *= *power;
return result;
}
/* a variant of strtod that also gets end of buffer in its second argument */
static inline double
strtod_rl (const char *p, const char **end_ptr /* IN/OUT */)
{
double value = 0;
double frac = 0;
double frac_count = 0;
unsigned exp = 0;
bool neg = false, exp_neg = false, exp_overflow = false;
const unsigned long long MAX_FRACT = 0xFFFFFFFFFFFFFull; /* 2^52-1 */
const unsigned MAX_EXP = 0x7FFu; /* 2^11-1 */
const char *pe = *end_ptr;
while (p < pe && ISSPACE (*p))
p++;
int cs;
%%{
write init;
write exec;
}%%
*end_ptr = p;
if (frac_count) value += frac / _pow10 (frac_count);
if (neg) value *= -1.;
if (unlikely (exp_overflow))
{
if (value == 0) return value;
if (exp_neg) return neg ? -DBL_MIN : DBL_MIN;
else return neg ? -DBL_MAX : DBL_MAX;
}
if (exp)
{
if (exp_neg) value /= _pow10 (exp);
else value *= _pow10 (exp);
}
return value;
}
#endif /* HB_NUMBER_PARSER_HH */
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