libmicrohttpd

HTTP/1.x server C library (MHD 1.x, stable)
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mhd_tool_str_to_uint.h (1990B)

      1 /*
      2   This file is part of GNU libmicrohttpd
      3   Copyright (C) 2023 Evgeny Grin (Karlson2k)
      4 
      5   This library is free software; you can redistribute it and/or
      6   modify it under the terms of the GNU Lesser General Public
      7   License as published by the Free Software Foundation; either
      8   version 2.1 of the License, or (at your option) any later version.
      9 
     10   This library is distributed in the hope that it will be useful,
     11   but WITHOUT ANY WARRANTY; without even the implied warranty of
     12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13   Lesser General Public License for more details.
     14 
     15   You should have received a copy of the GNU Lesser General Public
     16   License along with this library; if not, write to the Free Software
     17   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     18  */
     19 
     20 /**
     21  * @file tools/mhd_tool_str_to_uint.h
     22  * @brief  Function to decode the value of decimal string number.
     23  * @author Karlson2k (Evgeny Grin)
     24  */
     25 
     26 #ifndef MHD_TOOL_STR_TO_UINT_H_
     27 #define MHD_TOOL_STR_TO_UINT_H_ 1
     28 
     29 #include <stddef.h>
     30 
     31 /**
     32  * Convert decimal string to unsigned int.
     33  * Function stops at the end of the string or on first non-digit character.
     34  * @param str the string to convert
     35  * @param[out] value the pointer to put the result
     36  * @return return the number of digits converted or
     37  *         zero if no digits found or result would overflow the output
     38  *         variable (the output set to UINT_MAX in this case).
     39  */
     40 static size_t
     41 mhd_tool_str_to_uint (const char *str, unsigned int *value)
     42 {
     43   size_t i;
     44   unsigned int v = 0;
     45   *value = 0;
     46 
     47   for (i = 0; 0 != str[i]; ++i)
     48   {
     49     const char chr = str[i];
     50     unsigned int digit;
     51     if (('0' > chr) || ('9' < chr))
     52       break;
     53     digit = (unsigned char) (chr - '0');
     54     if ((((0U - 1) / 10) < v) || ((v * 10 + digit) < v))
     55     {
     56       /* Overflow */
     57       *value = 0U - 1;
     58       return 0;
     59     }
     60     v *= 10;
     61     v += digit;
     62   }
     63   *value = v;
     64   return i;
     65 }
     66 
     67 
     68 #endif /* MHD_TOOL_STR_TO_UINT_H_ */