compat/strtod.c

   1 /*
   2  * C99-compatible strtod() implementation
   3  * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <limits.h>
  23 #include <stdlib.h>
  24
  25 #include "libavutil/avstring.h"
  26 #include "libavutil/mathematics.h"
  27
  28 static char *check_nan_suffix(char *s)
  29 {
  30     char *start = s;
  31
  32     if (*s++ != '(')
  33         return start;
  34
  35     while ((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
  36            (*s >= '0' && *s <= '9') ||  *s == '_')
  37         s++;
  38
  39     return *s == ')' ? s + 1 : start;
  40 }
  41
  42 #undef strtod
  43 double strtod(const char *, char **);
  44
  45 double avpriv_strtod(const char *nptr, char **endptr)
  46 {
  47     char *end;
  48     double res;
  49
  50     /* Skip leading spaces */
  51     while (av_isspace(*nptr))
  52         nptr++;
  53
  54     if (!av_strncasecmp(nptr, "infinity", 8)) {
  55         end = nptr + 8;
  56         res = INFINITY;
  57     } else if (!av_strncasecmp(nptr, "inf", 3)) {
  58         end = nptr + 3;
  59         res = INFINITY;
  60     } else if (!av_strncasecmp(nptr, "+infinity", 9)) {
  61         end = nptr + 9;
  62         res = INFINITY;
  63     } else if (!av_strncasecmp(nptr, "+inf", 4)) {
  64         end = nptr + 4;
  65         res = INFINITY;
  66     } else if (!av_strncasecmp(nptr, "-infinity", 9)) {
  67         end = nptr + 9;
  68         res = -INFINITY;
  69     } else if (!av_strncasecmp(nptr, "-inf", 4)) {
  70         end = nptr + 4;
  71         res = -INFINITY;
  72     } else if (!av_strncasecmp(nptr, "nan", 3)) {
  73         end = check_nan_suffix(nptr + 3);
  74         res = NAN;
  75     } else if (!av_strncasecmp(nptr, "+nan", 4) ||
  76                !av_strncasecmp(nptr, "-nan", 4)) {
  77         end = check_nan_suffix(nptr + 4);
  78         res = NAN;
  79     } else if (!av_strncasecmp(nptr, "0x", 2) ||
  80                !av_strncasecmp(nptr, "-0x", 3) ||
  81                !av_strncasecmp(nptr, "+0x", 3)) {
  82         /* FIXME this doesn't handle exponents, non-integers (float/double)
  83          * and numbers too large for long long */
  84         res = strtoll(nptr, &end, 16);
  85     } else {
  86         res = strtod(nptr, &end);
  87     }
  88
  89     if (endptr)
  90         *endptr = end;
  91
  92     return res;
  93 }