ffmpeg/compat/strtod.c

94 lines
2.8 KiB
C
Raw Normal View History

/*
* C99-compatible strtod() implementation
* Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <limits.h>
#include <stdlib.h>
#include "libavutil/avstring.h"
#include "libavutil/mathematics.h"
static const char *check_nan_suffix(const char *s)
{
const char *start = s;
if (*s++ != '(')
return start;
while ((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
(*s >= '0' && *s <= '9') || *s == '_')
s++;
return *s == ')' ? s + 1 : start;
}
#undef strtod
double strtod(const char *, char **);
double avpriv_strtod(const char *nptr, char **endptr)
{
const char *end;
double res;
/* Skip leading spaces */
while (av_isspace(*nptr))
nptr++;
if (!av_strncasecmp(nptr, "infinity", 8)) {
end = nptr + 8;
res = INFINITY;
} else if (!av_strncasecmp(nptr, "inf", 3)) {
end = nptr + 3;
res = INFINITY;
} else if (!av_strncasecmp(nptr, "+infinity", 9)) {
end = nptr + 9;
res = INFINITY;
} else if (!av_strncasecmp(nptr, "+inf", 4)) {
end = nptr + 4;
res = INFINITY;
} else if (!av_strncasecmp(nptr, "-infinity", 9)) {
end = nptr + 9;
res = -INFINITY;
} else if (!av_strncasecmp(nptr, "-inf", 4)) {
end = nptr + 4;
res = -INFINITY;
} else if (!av_strncasecmp(nptr, "nan", 3)) {
end = check_nan_suffix(nptr + 3);
res = NAN;
} else if (!av_strncasecmp(nptr, "+nan", 4) ||
!av_strncasecmp(nptr, "-nan", 4)) {
end = check_nan_suffix(nptr + 4);
res = NAN;
} else if (!av_strncasecmp(nptr, "0x", 2) ||
!av_strncasecmp(nptr, "-0x", 3) ||
!av_strncasecmp(nptr, "+0x", 3)) {
/* FIXME this doesn't handle exponents, non-integers (float/double)
* and numbers too large for long long */
res = strtoll(nptr, (char **)&end, 16);
} else {
res = strtod(nptr, (char **)&end);
}
if (endptr)
*endptr = (char *)end;
return res;
}