include/private/soci-cstrtoi.h

0001 //
0002 // Copyright (C) 2020 Vadim Zeitlin.
0003 // Distributed under the Boost Software License, Version 1.0.
0004 // (See accompanying file LICENSE_1_0.txt or copy at
0005 // http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007
0008 #ifndef SOCI_PRIVATE_SOCI_CSTRTOI_H_INCLUDED
0009 #define SOCI_PRIVATE_SOCI_CSTRTOI_H_INCLUDED
0010
0011 #include "soci/error.h"
0012
0013 #include <cstdlib>
0014 #include <limits>
0015
0016 namespace soci
0017 {
0018
0019 namespace details
0020 {
0021
0022 // Convert string to a signed value of the given type, checking for overflow.
0023 //
0024 // Fill the provided result parameter and return true on success or false on
0025 // error, e.g. if the string couldn't be converted at all, if anything remains
0026 // in the string after conversion or if the value is out of range.
0027 template <typename T>
0028 bool cstring_to_integer(T& result, char const* buf)
0029 {
0030     char * end;
0031
0032     // No strtoll() on MSVC versions prior to Visual Studio 2013
0033 #if !defined (_MSC_VER) || (_MSC_VER >= 1800)
0034     long long t = strtoll(buf, &end, 10);
0035 #else
0036     long long t = _strtoi64(buf, &end, 10);
0037 #endif
0038
0039     if (end == buf || *end != '\0')
0040         return false;
0041
0042     // successfully converted to long long
0043     // and no other characters were found in the buffer
0044
0045     const T max = (std::numeric_limits<T>::max)();
0046     const T min = (std::numeric_limits<T>::min)();
0047     if (t > static_cast<long long>(max) || t < static_cast<long long>(min))
0048         return false;
0049
0050     result = static_cast<T>(t);
0051
0052     return true;
0053 }
0054
0055 // Similar to the above, but for the unsigned integral types.
0056 template <typename T>
0057 bool cstring_to_unsigned(T& result, char const* buf)
0058 {
0059     char * end;
0060
0061     // No strtoll() on MSVC versions prior to Visual Studio 2013
0062 #if !defined (_MSC_VER) || (_MSC_VER >= 1800)
0063     unsigned long long t = strtoull(buf, &end, 10);
0064 #else
0065     unsigned long long t = _strtoui64(buf, &end, 10);
0066 #endif
0067
0068     if (end == buf || *end != '\0')
0069         return false;
0070
0071     // successfully converted to unsigned long long
0072     // and no other characters were found in the buffer
0073
0074     const T max = (std::numeric_limits<T>::max)();
0075     if (t > static_cast<unsigned long long>(max))
0076         return false;
0077
0078     result = static_cast<T>(t);
0079
0080     return true;
0081 }
0082
0083 } // namespace details
0084
0085 } // namespace soci
0086
0087 #endif // SOCI_PRIVATE_SOCI_CSTRTOI_H_INCLUDED