2 // This file contains a slimmed down version of read_real().
3 // It does not pull in all the generic real number code.
6 #include "base/cl_sysdep.h"
9 #include "cln/float_io.h"
15 #include "cln/input.h"
16 #include "cln/integer.h"
17 #include "integer/cl_I.h"
18 #include "float/cl_F.h"
22 #define floor cln_floor
26 // Step forward over all digits, to the end of string or to the next non-digit.
27 static const char * skip_digits (const char * ptr, const char * string_limit, unsigned int base)
29 for ( ; ptr != string_limit; ptr++) {
31 if ((ch >= '0') && (ch <= '9'))
32 if (ch < '0' + (int)base)
39 if (((ch >= 'A') && (ch < 'A'-10+(int)base))
40 || ((ch >= 'a') && (ch < 'a'-10+(int)base))
50 #define at_end_of_parse(ptr) \
52 { *end_of_parse = (ptr); } \
54 { if ((ptr) != string_limit) { throw read_number_junk_exception((ptr),string,string_limit); } }
56 const cl_F read_float (const cl_read_flags& flags, const char * string, const char * string_limit, const char * * end_of_parse)
58 ASSERT((flags.syntax & ~(syntax_float|syntax_maybe_bad)) == 0);
59 // If no string_limit is given, it defaults to the end of the string.
61 string_limit = string + ::strlen(string);
62 if (flags.syntax & syntax_float) {
63 // Check for floating-point number syntax:
64 // {'+'|'-'|} {digit}+ {'.' {digit}* | } expo {'+'|'-'|} {digit}+
65 // {'+'|'-'|} {digit}* '.' {digit}+ expo {'+'|'-'|} {digit}+
66 // {'+'|'-'|} {digit}* '.' {digit}+
67 var const char * ptr = string;
68 var const unsigned int float_base = 10;
69 var cl_signean sign = 0;
70 if (ptr == string_limit) goto not_float_syntax;
72 case '-': sign = ~sign; // fallthrough
76 var const char * ptr_after_sign = ptr;
77 var const char * ptr_after_intpart = skip_digits(ptr_after_sign,string_limit,float_base);
78 var const char * ptr_before_fracpart = ptr_after_intpart;
79 var const char * ptr_after_fracpart = ptr_after_intpart;
80 ptr = ptr_after_intpart;
81 if (ptr != string_limit)
83 ptr_before_fracpart = ptr+1;
84 ptr_after_fracpart = skip_digits(ptr_before_fracpart,string_limit,float_base);
86 ptr = ptr_after_fracpart;
87 var char exponent_marker;
88 var bool have_exponent;
89 var const char * ptr_in_exponent = ptr;
90 var const char * ptr_after_exponent = ptr;
91 if ((ptr == string_limit) || !(((*ptr >= '0') && (*ptr <= '9')) || ((*ptr >= 'A') && (*ptr <= 'Z') && (*ptr != 'I')) || ((*ptr >= 'a') && (*ptr <= 'z') && (*ptr != 'i')) || (*ptr == '.') || (*ptr == '/'))) {
93 have_exponent = false;
94 // Must have at least one fractional part digit.
95 if (ptr_after_fracpart == ptr_before_fracpart) goto not_float_syntax;
96 exponent_marker = 'E';
99 // Must have at least one digit.
100 if (ptr_after_sign == ptr_after_intpart)
101 if (ptr_after_fracpart == ptr_before_fracpart)
102 goto not_float_syntax;
103 exponent_marker = ((*ptr >= 'a') && (*ptr <= 'z') ? *ptr - 'a' + 'A' : *ptr);
104 switch (exponent_marker) {
106 case 'S': case 'F': case 'D': case 'L':
109 goto not_float_syntax;
114 if (ptr == string_limit) goto not_float_syntax;
120 ptr_in_exponent = ptr;
121 ptr_after_exponent = skip_digits(ptr_in_exponent,string_limit,10);
122 if (ptr_after_exponent == ptr_in_exponent) goto not_float_syntax;
124 ptr = ptr_after_exponent;
125 var const char * ptr_after_prec = ptr;
126 var float_format_t prec;
127 if ((ptr != string_limit) && (*ptr == '_')) {
129 ptr_after_prec = skip_digits(ptr,string_limit,10);
130 if (ptr_after_prec == ptr) goto not_float_syntax;
131 var cl_I prec1 = digits_to_I(ptr,ptr_after_prec-ptr,10);
132 var uintC prec2 = cl_I_to_UC(prec1);
133 prec = (float_base==10 ? float_format(prec2)
134 : (float_format_t)((uintC)((1+prec2)*::log((double)float_base)*1.442695041)+1)
137 switch (exponent_marker) {
138 case 'S': prec = float_format_sfloat; break;
139 case 'F': prec = float_format_ffloat; break;
140 case 'D': prec = float_format_dfloat; break;
141 case 'L': prec = flags.float_flags.default_lfloat_format; break;
142 case 'E': prec = flags.float_flags.default_float_format; break;
145 if (flags.float_flags.mantissa_dependent_float_format) {
146 // Count the number of significant digits.
147 ptr = ptr_after_sign;
148 while (ptr < ptr_after_fracpart && (*ptr == '0' || *ptr == '.')) ptr++;
149 var uintC num_significant_digits =
150 (ptr_after_fracpart - ptr) - (ptr_before_fracpart > ptr ? 1 : 0);
151 var uintC prec2 = (num_significant_digits>=2 ? num_significant_digits-2 : 0);
152 var float_format_t precx =
153 (float_base==10 ? float_format(prec2)
154 : (float_format_t)((uintC)((1+prec2)*::log((double)float_base)*1.442695041)+1)
156 if ((uintE)precx > (uintE)prec)
161 , if (!(flags.syntax & syntax_sfloat)) goto not_float_syntax;
162 , if (!(flags.syntax & syntax_ffloat)) goto not_float_syntax;
163 , if (!(flags.syntax & syntax_dfloat)) goto not_float_syntax;
165 if (!(flags.syntax & syntax_lfloat)) goto not_float_syntax;
167 at_end_of_parse(ptr_after_prec);
168 return read_float(float_base,prec,sign,ptr_after_sign,0,ptr_after_fracpart-ptr_after_sign,ptr_after_exponent-ptr_after_sign,ptr_before_fracpart-ptr_after_sign);
171 if (flags.syntax & syntax_maybe_bad) {
172 ASSERT(end_of_parse);
173 *end_of_parse = string;
174 return cl_F(); // dummy return
176 throw read_number_bad_syntax_exception(string,string_limit);