libmicrohttpd2

HTTP server C library (MHD 2.x, alpha)
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mhdtl_str_to_uint.h (3028B)

      1 /* SPDX-License-Identifier: LGPL-2.1-or-later OR (GPL-2.0-or-later WITH eCos-exception-2.0) */
      2 /*
      3   This file is part of GNU libmicrohttpd.
      4   Copyright (C) 2023-2025 Evgeny Grin (Karlson2k)
      5 
      6   GNU libmicrohttpd is free software; you can redistribute it and/or
      7   modify it under the terms of the GNU Lesser General Public
      8   License as published by the Free Software Foundation; either
      9   version 2.1 of the License, or (at your option) any later version.
     10 
     11   GNU libmicrohttpd is distributed in the hope that it will be useful,
     12   but WITHOUT ANY WARRANTY; without even the implied warranty of
     13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     14   Lesser General Public License for more details.
     15 
     16   Alternatively, you can redistribute GNU libmicrohttpd and/or
     17   modify it under the terms of the GNU General Public License as
     18   published by the Free Software Foundation; either version 2 of
     19   the License, or (at your option) any later version, together
     20   with the eCos exception, as follows:
     21 
     22     As a special exception, if other files instantiate templates or
     23     use macros or inline functions from this file, or you compile this
     24     file and link it with other works to produce a work based on this
     25     file, this file does not by itself cause the resulting work to be
     26     covered by the GNU General Public License. However the source code
     27     for this file must still be made available in accordance with
     28     section (3) of the GNU General Public License v2.
     29 
     30     This exception does not invalidate any other reasons why a work
     31     based on this file might be covered by the GNU General Public
     32     License.
     33 
     34   You should have received copies of the GNU Lesser General Public
     35   License and the GNU General Public License along with this library;
     36   if not, see <https://www.gnu.org/licenses/>.
     37 */
     38 
     39 /**
     40  * @file src/tools/mhdtl_str_to_uint.h
     41  * @brief  Function to decode the value of decimal string number.
     42  * @author Karlson2k (Evgeny Grin)
     43  */
     44 
     45 #ifndef MHDTL_STR_TO_UINT_H_
     46 #define MHDTL_STR_TO_UINT_H_ 1
     47 
     48 #include <stddef.h>
     49 
     50 /**
     51  * Convert decimal string to unsigned int.
     52  * Function stops at the end of the string or on first non-digit character.
     53  * @param str the string to convert
     54  * @param[out] value the pointer to put the result
     55  * @return return the number of digits converted or
     56  *         zero if no digits found or result would overflow the output
     57  *         variable (the output set to UINT_MAX in this case).
     58  */
     59 static inline size_t
     60 mhdtl_str_to_uint (const char *str, unsigned int *value)
     61 {
     62   size_t i;
     63   unsigned int v = 0;
     64 
     65   for (i = 0; 0 != str[i]; ++i)
     66   {
     67     const char chr = str[i];
     68     unsigned int digit;
     69     unsigned int prev_v;
     70     if (('0' > chr) || ('9' < chr))
     71       break;
     72     digit = (unsigned char) (chr - '0');
     73     prev_v = v;
     74     v *= 10;
     75     if (v / 10 == prev_v)
     76     {
     77       prev_v = v;
     78       v += digit;
     79       if (v >= prev_v)
     80         continue;
     81     }
     82     /* Overflow */
     83     *value = 0U - 1;
     84     return 0;
     85   }
     86   *value = v;
     87   return i;
     88 }
     89 
     90 
     91 #endif /* MHDTL_STR_TO_UINT_H_ */