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  1. /*
  2.  * C99-compatible strtod() implementation
  3.  * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg 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.  * FFmpeg 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 FFmpeg; 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. }
  94.