1/* 2 * Copyright © 2019 Ebrahim Byagowi 3 * 4 * This is part of HarfBuzz, a text shaping library. 5 * 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. 11 * 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 16 * DAMAGE. 17 * 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. 23 * 24 */ 25 26#ifndef HB_NUMBER_PARSER_HH 27#define HB_NUMBER_PARSER_HH 28 29#include "hb.hh" 30 31%%{ 32 33machine double_parser; 34alphtype unsigned char; 35write data; 36 37action see_neg { neg = true; } 38action see_exp_neg { exp_neg = true; } 39 40action add_int { 41 value = value * 10. + (fc - '0'); 42} 43action add_frac { 44 if (likely (frac <= MAX_FRACT / 10)) 45 { 46 frac = frac * 10. + (fc - '0'); 47 ++frac_count; 48 } 49} 50action add_exp { 51 if (likely (exp * 10 + (fc - '0') <= MAX_EXP)) 52 exp = exp * 10 + (fc - '0'); 53 else 54 exp_overflow = true; 55} 56 57num = [0-9]+; 58 59main := ( 60 ( 61 (('+'|'-'@see_neg)? num @add_int) ('.' num @add_frac)? 62 | 63 (('+'|'-'@see_neg)? '.' num @add_frac) 64 ) 65 (('e'|'E') (('+'|'-'@see_exp_neg)? num @add_exp))? 66); 67 68}%% 69 70/* Works only for n < 512 */ 71static inline double 72_pow10 (unsigned exponent) 73{ 74 static const double _powers_of_10[] = 75 { 76 1.0e+256, 77 1.0e+128, 78 1.0e+64, 79 1.0e+32, 80 1.0e+16, 81 1.0e+8, 82 10000., 83 100., 84 10. 85 }; 86 unsigned mask = 1 << (ARRAY_LENGTH (_powers_of_10) - 1); 87 double result = 1; 88 for (const double *power = _powers_of_10; mask; ++power, mask >>= 1) 89 if (exponent & mask) result *= *power; 90 return result; 91} 92 93/* a variant of strtod that also gets end of buffer in its second argument */ 94static inline double 95strtod_rl (const char *p, const char **end_ptr /* IN/OUT */) 96{ 97 double value = 0; 98 double frac = 0; 99 double frac_count = 0; 100 unsigned exp = 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 */ 104 105 const char *pe = *end_ptr; 106 while (p < pe && ISSPACE (*p)) 107 p++; 108 109 int cs; 110 %%{ 111 write init; 112 write exec; 113 }%% 114 115 *end_ptr = p; 116 117 if (frac_count) value += frac / _pow10 (frac_count); 118 if (neg) value *= -1.; 119 120 if (unlikely (exp_overflow)) 121 { 122 if (value == 0) return value; 123 if (exp_neg) return neg ? -DBL_MIN : DBL_MIN; 124 else return neg ? -DBL_MAX : DBL_MAX; 125 } 126 127 if (exp) 128 { 129 if (exp_neg) value /= _pow10 (exp); 130 else value *= _pow10 (exp); 131 } 132 133 return value; 134} 135 136#endif /* HB_NUMBER_PARSER_HH */ 137