strtod.c 2.71 KB
Newer Older
1 2 3 4
/*
 * C99-compatible strtod() implementation
 * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
 *
5
 * This file is part of FFmpeg.
6
 *
7
 * FFmpeg is free software; you can redistribute it and/or
8 9 10 11
 * 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.
 *
12
 * FFmpeg is distributed in the hope that it will be useful,
13 14 15 16 17
 * 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
18
 * License along with FFmpeg; if not, write to the Free Software
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
 * 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 char *check_nan_suffix(char *s)
{
    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)
{
    char *end;
    double res;

    /* Skip leading spaces */
51
    while (av_isspace(*nptr))
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93
        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, &end, 16);
    } else {
        res = strtod(nptr, &end);
    }

    if (endptr)
        *endptr = end;

    return res;
}