1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <wchar.h>
30
31 #include <stdlib.h>
32 #include <string.h>
33
34 #include "local.h"
35
36 /// Performs wide-character string to floating point conversion.
37 template <typename float_type>
wcstod(const wchar_t * str,wchar_t ** end,float_type strtod_fn (const char *,char **))38 float_type wcstod(const wchar_t* str, wchar_t** end, float_type strtod_fn(const char*, char**)) {
39 const wchar_t* original_str = str;
40 while (iswspace(*str)) {
41 str++;
42 }
43
44 // What's the longest span of the input that might be part of the float?
45 size_t max_len = wcsspn(str, L"-+0123456789.xXeEpP()nNaAiIfFtTyY");
46
47 // We know the only valid characters are ASCII, so convert them by brute force.
48 char* ascii_str = new char[max_len + 1];
49 if (!ascii_str) return float_type();
50 for (size_t i = 0; i < max_len; ++i) {
51 ascii_str[i] = str[i] & 0xff;
52 }
53 ascii_str[max_len] = 0;
54
55 // Set up a fake FILE that points to those ASCII characters, for `parsefloat`.
56 FILE f;
57 __sfileext fext;
58 _FILEEXT_SETUP(&f, &fext);
59 f._flags = __SRD;
60 f._bf._base = f._p = reinterpret_cast<unsigned char*>(ascii_str);
61 f._bf._size = f._r = max_len;
62 f._read = [](void*, char*, int) { return 0; }; // aka `eofread`, aka "no more data".
63 f._lb._base = nullptr;
64
65 // Ask `parsefloat` to look at the same data more carefully.
66
67 // We can't just do this straight away because we can't construct a suitable FILE*
68 // in the absence of any `fwmemopen` analogous to `fmemopen`. And we don't want to
69 // duplicate the `parsefloat` logic. We also don't want to actually have to have wchar_t
70 // implementations of the ASCII `strtod` logic (though if you were designing a libc
71 // from scratch, you'd probably want to just make that more generic and lose all the
72 // cruft on top).
73 size_t actual_len = parsefloat(&f, ascii_str, ascii_str + max_len);
74
75 // Finally let the ASCII conversion function do the work.
76 char* ascii_end;
77 float_type result = strtod_fn(ascii_str, &ascii_end);
78 if (ascii_end != ascii_str + actual_len) abort();
79
80 if (end) {
81 if (actual_len == 0) {
82 // There was an error. We need to set the end pointer back to the original string, not the
83 // one we advanced past the leading whitespace.
84 *end = const_cast<wchar_t*>(original_str);
85 } else {
86 *end = const_cast<wchar_t*>(str) + actual_len;
87 }
88 }
89
90 delete[] ascii_str;
91 return result;
92 }
93
wcstof(const wchar_t * s,wchar_t ** end)94 float wcstof(const wchar_t* s, wchar_t** end) {
95 return wcstod<float>(s, end, strtof);
96 }
97 __strong_alias(wcstof_l, wcstof);
98
wcstod(const wchar_t * s,wchar_t ** end)99 double wcstod(const wchar_t* s, wchar_t** end) {
100 return wcstod<double>(s, end, strtod);
101 }
102 __strong_alias(wcstod_l, wcstod);
103
wcstold(const wchar_t * s,wchar_t ** end)104 long double wcstold(const wchar_t* s, wchar_t** end) {
105 return wcstod<long double>(s, end, strtold);
106 }
107 __strong_alias(wcstold_l, wcstold);
108