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[#391] string_length: Remove use of strnlen and use consistent length type.

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* Removes reference to strnlen as per #391

* Use ptrdiff for string_length interfaces for #391
This commit is contained in:
Josaphat Valdivia 2016-10-17 15:41:24 -04:00 committed by Neil MacIntosh
parent 1287e624cd
commit a14f27474f
1 changed files with 18 additions and 30 deletions
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48
gsl/string_span
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@ -56,10 +56,6 @@
#endif // _MSC_VER <= 1800 #endif // _MSC_VER <= 1800
#endif // _MSC_VER #endif // _MSC_VER
#ifndef __CYGWIN__
#define GSL_PLATFORM_HAS_STRNLEN
#endif
// In order to test the library, we need it to throw exceptions that we can catch // In order to test the library, we need it to throw exceptions that we can catch
#ifdef GSL_THROW_ON_CONTRACT_VIOLATION #ifdef GSL_THROW_ON_CONTRACT_VIOLATION
@ -101,40 +97,32 @@ using wzstring = basic_zstring<wchar_t, Extent>;
namespace details namespace details
{ {
inline std::size_t string_length(const char *str, std::size_t n) inline std::ptrdiff_t string_length(const char *str, std::ptrdiff_t n)
{ {
#ifdef GSL_PLATFORM_HAS_STRNLEN if (str == nullptr || n <= 0)
return strnlen(str, n);
#else
if (str == nullptr || n == 0)
return 0; return 0;
std::size_t len = 0;
span<const char> str_span{str, n}; span<const char> str_span{str, n};
std::ptrdiff_t len = 0;
while (len < n && str_span[len]) while (len < n && str_span[len])
len++; len++;
return len; return len;
#endif
} }
inline std::size_t wstring_length(const wchar_t *str, std::size_t n) inline std::ptrdiff_t wstring_length(const wchar_t *str, std::ptrdiff_t n)
{ {
#ifdef GSL_PLATFORM_HAS_STRNLEN if (str == nullptr || n <= 0)
return wcsnlen(str, n);
#else
if (str == nullptr || n == 0)
return 0; return 0;
std::size_t len = 0;
span<const wchar_t> str_span{str, n}; span<const wchar_t> str_span{str, n};
std::ptrdiff_t len = 0;
while (len < n && str_span[len]) while (len < n && str_span[len])
len++; len++;
return len; return len;
#endif
} }
} }
@ -170,30 +158,30 @@ inline span<T, dynamic_extent> ensure_z(T* const& sz, std::ptrdiff_t max = PTRDI
// overloads to share an implementation // overloads to share an implementation
inline span<char, dynamic_extent> ensure_z(char* const& sz, std::ptrdiff_t max) inline span<char, dynamic_extent> ensure_z(char* const& sz, std::ptrdiff_t max)
{ {
auto len = details::string_length(sz, narrow_cast<size_t>(max)); auto len = details::string_length(sz, max);
Ensures(sz[len] == 0); Ensures(sz[len] == 0);
return {sz, static_cast<std::ptrdiff_t>(len)}; return {sz, len};
} }
inline span<const char, dynamic_extent> ensure_z(const char* const& sz, std::ptrdiff_t max) inline span<const char, dynamic_extent> ensure_z(const char* const& sz, std::ptrdiff_t max)
{ {
auto len = details::string_length(sz, narrow_cast<size_t>(max)); auto len = details::string_length(sz, max);
Ensures(sz[len] == 0); Ensures(sz[len] == 0);
return {sz, static_cast<std::ptrdiff_t>(len)}; return {sz, len};
} }
inline span<wchar_t, dynamic_extent> ensure_z(wchar_t* const& sz, std::ptrdiff_t max) inline span<wchar_t, dynamic_extent> ensure_z(wchar_t* const& sz, std::ptrdiff_t max)
{ {
auto len = details::wstring_length(sz, narrow_cast<size_t>(max)); auto len = details::wstring_length(sz, max);
Ensures(sz[len] == 0); Ensures(sz[len] == 0);
return {sz, static_cast<std::ptrdiff_t>(len)}; return {sz, len};
} }
inline span<const wchar_t, dynamic_extent> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max) inline span<const wchar_t, dynamic_extent> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max)
{ {
auto len = details::wstring_length(sz, narrow_cast<size_t>(max)); auto len = details::wstring_length(sz, max);
Ensures(sz[len] == 0); Ensures(sz[len] == 0);
return {sz, static_cast<std::ptrdiff_t>(len)}; return {sz, len};
} }
template <typename T, size_t N> template <typename T, size_t N>
@ -239,7 +227,7 @@ namespace details
{ {
std::ptrdiff_t operator()(char* const ptr, std::ptrdiff_t length) noexcept std::ptrdiff_t operator()(char* const ptr, std::ptrdiff_t length) noexcept
{ {
return narrow_cast<std::ptrdiff_t>(details::string_length(ptr, narrow_cast<size_t>(length))); return details::string_length(ptr, length);
} }
}; };
@ -248,7 +236,7 @@ namespace details
{ {
std::ptrdiff_t operator()(wchar_t* const ptr, std::ptrdiff_t length) noexcept std::ptrdiff_t operator()(wchar_t* const ptr, std::ptrdiff_t length) noexcept
{ {
return narrow_cast<std::ptrdiff_t>(details::wstring_length(ptr, narrow_cast<size_t>(length))); return details::wstring_length(ptr, length);
} }
}; };
@ -257,7 +245,7 @@ namespace details
{ {
std::ptrdiff_t operator()(const char* const ptr, std::ptrdiff_t length) noexcept std::ptrdiff_t operator()(const char* const ptr, std::ptrdiff_t length) noexcept
{ {
return narrow_cast<std::ptrdiff_t>(details::string_length(ptr, narrow_cast<size_t>(length))); return details::string_length(ptr, length);
} }
}; };
@ -266,7 +254,7 @@ namespace details
{ {
std::ptrdiff_t operator()(const wchar_t* const ptr, std::ptrdiff_t length) noexcept std::ptrdiff_t operator()(const wchar_t* const ptr, std::ptrdiff_t length) noexcept
{ {
return narrow_cast<std::ptrdiff_t>(details::wstring_length(ptr, narrow_cast<size_t>(length))); return details::wstring_length(ptr, length);
} }
}; };
} }