I hereby relicense all my work on Sortix under the ISC license as below. All Sortix contributions by other people are already under this license, are not substantial enough to be copyrightable, or have been removed. All imported code from other projects is compatible with this license. All GPL licensed code from other projects had previously been removed. Copyright 2011-2016 Jonas 'Sortie' Termansen and contributors. Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
200 lines
4.7 KiB
C
200 lines
4.7 KiB
C
/*
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* Copyright (c) 2016 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* stdlib/strtof.c
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* Converts floating numbers represented as strings to binary representation.
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*/
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#ifndef STRTOF
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#define STRTOF_FLOAT float
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#define STRTOF strtof
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#define STRTOF_CHAR char
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#define STRTOF_CTYPE_CHAR unsigned char
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#define STRTOF_L(x) x
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#define STRTOF_ISSPACE isspace
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#define STRTOF_STRNCASECMP strncasecmp
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#define STRTOF_POW powf
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#endif
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#include <ctype.h>
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#include <errno.h>
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#include <math.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include <wchar.h>
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#include <wctype.h>
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// TODO: This is an imperfect implementation that doesn't try to minimize loss
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// and explicitly handle overflow conditions. It behaves well enough on
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// simple common inputs to do for now.
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#ifndef __is_sortix_libk
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static inline size_t nan_parameter(const STRTOF_CHAR* str)
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{
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size_t index = 0;
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if ( str[index++] != STRTOF_L('(') )
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return 0;
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// TODO: What exactly does digit and nondigit mean here in POSIX?
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if ( !str[index] || str[index] == STRTOF_L(')') )
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return 0;
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while ( str[index] && str[index] != STRTOF_L(')') )
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index++;
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if ( str[index++] != STRTOF_L(')') )
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return 0;
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return index;
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}
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static inline bool is_hexadecimal_float(const STRTOF_CHAR* str)
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{
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if ( *str++ != '0' )
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return false;
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if ( *str != 'x' && *str != 'X' )
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return false;
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str++;
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if ( *str == '.' )
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str++;
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return isxdigit((STRTOF_CTYPE_CHAR) *str);
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}
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static inline bool is_exponent(const STRTOF_CHAR* str,
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STRTOF_CHAR elc,
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STRTOF_CHAR euc)
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{
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if ( *str != elc && *str != euc )
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return false;
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str++;
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if ( *str == '-' || *str == '+' )
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str++;
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return STRTOF_L('0') <= *str && *str <= STRTOF_L('9');
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}
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static inline bool parse_digit(const STRTOF_CHAR* str,
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int base,
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STRTOF_FLOAT* out)
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{
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if ( STRTOF_L('0') <= *str && *str <= STRTOF_L('9') )
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return *out = *str - STRTOF_L('0') , true;
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if ( base == 16 )
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{
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if ( STRTOF_L('a') <= *str && *str <= STRTOF_L('f') )
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return *out = 10 + *str - STRTOF_L('a') , true;
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if ( STRTOF_L('A') <= *str && *str <= STRTOF_L('F') )
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return *out = 10 + *str - STRTOF_L('A') , true;
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}
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return false;
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}
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STRTOF_FLOAT STRTOF(const STRTOF_CHAR* str, STRTOF_CHAR** nptr)
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{
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if ( nptr )
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*nptr = (STRTOF_CHAR*) str;
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while ( *str && STRTOF_ISSPACE((STRTOF_CTYPE_CHAR) *str) )
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str++;
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if ( !STRTOF_STRNCASECMP(str, STRTOF_L("INF"), 3) )
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{
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str += 3;
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if ( !STRTOF_STRNCASECMP(str, STRTOF_L("INITY"), 5) )
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str += 5;
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if ( nptr )
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*nptr = (STRTOF_CHAR*) str;
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return INFINITY;
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}
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if ( !STRTOF_STRNCASECMP(str, STRTOF_L("NAN"), 3) )
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{
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str += 3;
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str += nan_parameter(str);
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if ( nptr )
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*nptr = (STRTOF_CHAR*) str;
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return NAN;
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}
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bool negative = *str == STRTOF_L('-');
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if ( *str == STRTOF_L('-') )
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str++;
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else if ( *str == STRTOF_L('+') )
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str++;
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int base = 10;
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STRTOF_CHAR elc = 'e';
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STRTOF_CHAR euc = 'E';
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if ( is_hexadecimal_float(str) )
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{
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str += 2;
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base = 16;
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elc = 'p';
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euc = 'P';
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}
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bool any_digits = false;
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STRTOF_FLOAT result = 0.0;
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STRTOF_FLOAT add;
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while ( parse_digit(str, base, &add) )
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{
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str++;
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result = base * result + add;
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any_digits = true;
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}
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if ( *str == STRTOF_L('.' ) )
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{
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str++;
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STRTOF_FLOAT magnitude = 1.0;
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while ( parse_digit(str, base, &add) )
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{
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str++;
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magnitude /= base;
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result += add * magnitude;
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any_digits = true;
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}
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}
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if ( !any_digits )
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return errno = EINVAL, 0;
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if ( is_exponent(str, elc, euc) )
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{
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str++;
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bool exponent_negative = *str == STRTOF_L('-');
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if ( *str == STRTOF_L('-') )
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str++;
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else if ( *str == STRTOF_L('+') )
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str++;
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STRTOF_FLOAT exponent = 0.0;
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while ( parse_digit(str, 10, &add) )
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{
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str++;
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exponent = 10.0 * exponent + add;
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any_digits = true;
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}
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if ( exponent_negative )
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exponent = -exponent;
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result *= STRTOF_POW(base == 16 ? 2 : base, exponent);
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}
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if ( negative )
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result = -result;
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if ( nptr )
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*nptr = (STRTOF_CHAR*) str;
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return result;
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}
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#endif
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