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unicode: Write directly into std::string buffer

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This removes extra memory allocation.

Signed-off-by: Simon Rozman <simon@rozman.si>
This commit is contained in:
Simon Rozman 2024-01-05 22:37:11 +01:00
parent 114609274f
commit b42aa969dc
1 changed files with 16 additions and 12 deletions
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28
include/stdex/unicode.hpp
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@ -207,9 +207,10 @@ namespace stdex
if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) { if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
// Query the required output size. Allocate buffer. Then convert again. // Query the required output size. Allocate buffer. Then convert again.
cch = MultiByteToWideChar(static_cast<UINT>(m_from_wincp), dwFlagsMBWC, reinterpret_cast<LPCCH>(src), static_cast<int>(count_src), NULL, 0); cch = MultiByteToWideChar(static_cast<UINT>(m_from_wincp), dwFlagsMBWC, reinterpret_cast<LPCCH>(src), static_cast<int>(count_src), NULL, 0);
std::unique_ptr<WCHAR[]> szBuffer(new WCHAR[cch]); size_t offset = dst.size();
cch = MultiByteToWideChar(static_cast<UINT>(m_from_wincp), dwFlagsMBWC, reinterpret_cast<LPCCH>(src), static_cast<int>(count_src), szBuffer.get(), cch); dst.resize(offset + static_cast<size_t>(cch));
dst.append(reinterpret_cast<const T_to*>(szBuffer.get()), count_src != SIZE_MAX ? wcsnlen(szBuffer.get(), cch) : static_cast<size_t>(cch) - 1); cch = MultiByteToWideChar(static_cast<UINT>(m_from_wincp), dwFlagsMBWC, reinterpret_cast<LPCCH>(src), static_cast<int>(count_src), &dst[offset], cch);
dst.resize(offset + (count_src != SIZE_MAX ? wcsnlen(&dst[offset], cch) : static_cast<size_t>(cch) - 1));
return; return;
} }
throw std::system_error(GetLastError(), std::system_category(), "MultiByteToWideChar failed"); throw std::system_error(GetLastError(), std::system_category(), "MultiByteToWideChar failed");
@ -231,9 +232,10 @@ namespace stdex
if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) { if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
// Query the required output size. Allocate buffer. Then convert again. // Query the required output size. Allocate buffer. Then convert again.
cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, reinterpret_cast<LPCWCH>(src), static_cast<int>(count_src), NULL, 0, lpDefaultChar, NULL); cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, reinterpret_cast<LPCWCH>(src), static_cast<int>(count_src), NULL, 0, lpDefaultChar, NULL);
std::unique_ptr<CHAR[]> szBuffer(new CHAR[cch]); size_t offset = dst.size();
cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, reinterpret_cast<LPCWCH>(src), static_cast<int>(count_src), szBuffer.get(), cch, lpDefaultChar, NULL); dst.resize(offset + static_cast<size_t>(cch));
dst.append(reinterpret_cast<const T_to*>(szBuffer.get()), count_src != SIZE_MAX ? strnlen(szBuffer.get(), cch) : static_cast<size_t>(cch) - 1); cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, reinterpret_cast<LPCWCH>(src), static_cast<int>(count_src), &dst[offset], cch, lpDefaultChar, NULL);
dst.resize(offset + (count_src != SIZE_MAX ? strnlen(&dst[offset], cch) : static_cast<size_t>(cch) - 1));
return; return;
} }
throw std::system_error(GetLastError(), std::system_category(), "WideCharToMultiByte failed"); throw std::system_error(GetLastError(), std::system_category(), "WideCharToMultiByte failed");
@ -264,9 +266,10 @@ namespace stdex
if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) { if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
// Query the required output size. Allocate buffer. Then convert again. // Query the required output size. Allocate buffer. Then convert again.
cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, szStackBufferMBWC, static_cast<int>(count_inter), NULL, 0, lpDefaultChar, NULL); cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, szStackBufferMBWC, static_cast<int>(count_inter), NULL, 0, lpDefaultChar, NULL);
std::unique_ptr<CHAR[]> szBufferWCMB(new CHAR[cch]); size_t offset = dst.size();
cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, szStackBufferMBWC, static_cast<int>(count_inter), szBufferWCMB.get(), cch, lpDefaultChar, NULL); dst.resize(offset + cch);
dst.append(reinterpret_cast<const T_to*>(szBufferWCMB.get()), strnlen(szBufferWCMB.get(), cch)); cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, szStackBufferMBWC, static_cast<int>(count_inter), &dst[offset], cch, lpDefaultChar, NULL);
dst.resize(offset + strnlen(&dst[offset], cch));
return; return;
} }
throw std::system_error(GetLastError(), std::system_category(), "WideCharToMultiByte failed"); throw std::system_error(GetLastError(), std::system_category(), "WideCharToMultiByte failed");
@ -280,9 +283,10 @@ namespace stdex
// Query the required output size. Allocate buffer. Then convert again. // Query the required output size. Allocate buffer. Then convert again.
cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, szBufferMBWC.get(), static_cast<int>(count_inter), NULL, 0, lpDefaultChar, NULL); cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, szBufferMBWC.get(), static_cast<int>(count_inter), NULL, 0, lpDefaultChar, NULL);
std::unique_ptr<CHAR[]> szBufferWCMB(new CHAR[cch]); size_t offset = dst.size();
cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, szBufferMBWC.get(), static_cast<int>(count_inter), szBufferWCMB.get(), cch, lpDefaultChar, NULL); dst.resize(offset + cch);
dst.append(reinterpret_cast<const T_to*>(szBufferWCMB.get()), strnlen(szBufferWCMB.get(), cch)); cch = WideCharToMultiByte(static_cast<UINT>(m_to_wincp), dwFlagsWCMB, szBufferMBWC.get(), static_cast<int>(count_inter), &dst[offset], cch, lpDefaultChar, NULL);
dst.resize(offset + strnlen(&dst[offset], cch));
return; return;
} }
throw std::system_error(GetLastError(), std::system_category(), "MultiByteToWideChar failed"); throw std::system_error(GetLastError(), std::system_category(), "MultiByteToWideChar failed");