[英]C++ Reading UTF-8 file OK, converting to UTF-16 OK, writing back to file NOT OK
[英]Reading UTF-16 file in c++
我正在尝试读取具有BOM的UTF-16LE编码的文件。 我试过这段代码
#include <iostream>
#include <fstream>
#include <locale>
#include <codecvt>
int main() {
std::wifstream fin("/home/asutp/test");
fin.imbue(std::locale(fin.getloc(), new std::codecvt_utf16<wchar_t, 0x10ffff, std::consume_header>));
if (!fin) {
std::cout << "!fin" << std::endl;
return 1;
}
if (fin.eof()) {
std::cout << "fin.eof()" << std::endl;
return 1;
}
std::wstring wstr;
getline(fin, wstr);
std::wcout << wstr << std::endl;
if (wstr.find(L"Test") != std::string::npos) {
std::cout << "Found" << std::endl;
} else {
std::cout << "Not found" << std::endl;
}
return 0;
}
该文件可以包含拉丁文和西里尔文。 我用字符串“Testтест”创建了该文件。 这段代码还给我了
/home/asutp/CLionProjects/untitled/cmake-build-debug/untitled
Not found
Process finished with exit code 0
我在Linux Mint 18.3 x64,Clion 2018.1上
试着
理想情况下,您应该以UTF8保存文件,因为Window具有更好的UTF8支持(除了在控制台窗口中显示Unicode),而POSIX具有有限的UTF16支持。 甚至微软的产品都支持使用UTF8来保存Windows中的文件。
作为替代方案,您可以将UTF16文件读入缓冲区并将其转换为UTF8
std::ifstream fin("utf16.txt", std::ios::binary);
fin.seekg(0, ios::end);
size_t size = (size_t)fin.tellg();
//skip BOM
fin.seekg(2, ios::beg);
size -= 2;
std::u16string u16((size / 2) + 1, '\0');
fin.read((char*)&u16[0], size);
std::string utf8 = std::wstring_convert<
std::codecvt_utf8_utf16<char16_t>, char16_t>{}.to_bytes(u16);
std::ifstream fin("utf16.txt", std::ios::binary); //skip BOM fin.seekg(2); //read as raw bytes std::stringstream ss; ss << fin.rdbuf(); std::string bytes = ss.str(); //make sure len is divisible by 2 int len = bytes.size(); if(len % 2) len--; std::wstring sw; for(size_t i = 0; i < len;) { //little-endian int lo = bytes[i++] & 0xFF; int hi = bytes[i++] & 0xFF; sw.push_back(hi << 8 | lo); } std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> convert; std::string utf8 = convert.to_bytes(sw);
替换为 - std::wstring::npos
(不是std::string::npos
) - ,并且您的代码必须工作:
...
//std::wcout << wstr << std::endl;
if (wstr.find(L"Test") == std::wstring::npos) {
std::cout << "Not Found" << std::endl;
} else {
std::cout << "found" << std::endl;
}
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