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      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 #define __BIONIC_LP32_USE_LONG_DOUBLE
     30 
     31 #include <wchar.h>
     32 
     33 #include <stdlib.h>
     34 #include <string.h>
     35 
     36 #include "local.h"
     37 
     38 /// Performs wide-character string to floating point conversion.
     39 template <typename float_type>
     40 float_type wcstod(const wchar_t* str, wchar_t** end, float_type strtod_fn(const char*, char**)) {
     41   const wchar_t* original_str = str;
     42   while (iswspace(*str)) {
     43     str++;
     44   }
     45 
     46   // What's the longest span of the input that might be part of the float?
     47   size_t max_len = wcsspn(str, L"-+0123456789.xXeEpP()nNaAiIfFtTyY");
     48 
     49   // We know the only valid characters are ASCII, so convert them by brute force.
     50   char* ascii_str = new char[max_len + 1];
     51   if (!ascii_str) return float_type();
     52   for (size_t i = 0; i < max_len; ++i) {
     53     ascii_str[i] = str[i] & 0xff;
     54   }
     55   ascii_str[max_len] = 0;
     56 
     57   // Set up a fake FILE that points to those ASCII characters, for `parsefloat`.
     58   FILE f;
     59   __sfileext fext;
     60   _FILEEXT_SETUP(&f, &fext);
     61   f._flags = __SRD;
     62   f._bf._base = f._p = reinterpret_cast<unsigned char*>(ascii_str);
     63   f._bf._size = f._r = max_len;
     64   f._read = [](void*, char*, int) { return 0; }; // aka `eofread`, aka "no more data".
     65   f._lb._base = nullptr;
     66 
     67   // Ask `parsefloat` to look at the same data more carefully.
     68 
     69   // We can't just do this straight away because we can't construct a suitable FILE*
     70   // in the absence of any `fwmemopen` analogous to `fmemopen`. And we don't want to
     71   // duplicate the `parsefloat` logic. We also don't want to actually have to have wchar_t
     72   // implementations of the ASCII `strtod` logic (though if you were designing a libc
     73   // from scratch, you'd probably want to just make that more generic and lose all the
     74   // cruft on top).
     75   size_t actual_len = parsefloat(&f, ascii_str, ascii_str + max_len);
     76 
     77   // Finally let the ASCII conversion function do the work.
     78   char* ascii_end;
     79   float_type result = strtod_fn(ascii_str, &ascii_end);
     80   if (ascii_end != ascii_str + actual_len) abort();
     81 
     82   if (end) {
     83     if (actual_len == 0) {
     84       // There was an error. We need to set the end pointer back to the original string, not the
     85       // one we advanced past the leading whitespace.
     86       *end = const_cast<wchar_t*>(original_str);
     87     } else {
     88       *end = const_cast<wchar_t*>(str) + actual_len;
     89     }
     90   }
     91 
     92   delete[] ascii_str;
     93   return result;
     94 }
     95 
     96 float wcstof(const wchar_t* s, wchar_t** end) {
     97   return wcstod<float>(s, end, strtof);
     98 }
     99 
    100 double wcstod(const wchar_t* s, wchar_t** end) {
    101   return wcstod<double>(s, end, strtod);
    102 }
    103 
    104 long double wcstold(const wchar_t* s, wchar_t** end) {
    105   return wcstod<long double>(s, end, strtold);
    106 }
    107