Y
wchar_t wird vom Stream gar nicht erst unterstützt. Ich habe mal einen Blick in die Implementierung geworfen und tatsächlich wird überall char bzw. string anstatt der templates verwendet.
Nun habe ich mir eine eigene Klasse geschrieben.
#pragma once
#include <windows.h>
#include <string>
#include <algorithm>
class FileReader{
private:
// File handle
HANDLE file;
// Read buffer
char buffer[4096];
char* buffer_start, *buffer_end = buffer_start;
public:
// Constructors
FileReader()
: file(INVALID_HANDLE_VALUE){}
FileReader(std::string& filename)
: file(CreateFileA(filename.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL)){}
FileReader(std::wstring& filename)
: file(CreateFileW(filename.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL)){}
FileReader(FileReader& reader)
: file(reader.file){
reader.file = INVALID_HANDLE_VALUE;
}
// Assign operator
FileReader& operator =(FileReader& reader){
if(this->file != INVALID_HANDLE_VALUE)
CloseHandle(this->file);
this->file = reader.file;
this->buffer_start = this->buffer_end;
reader.file = INVALID_HANDLE_VALUE;
return *this;
}
// Destructor
virtual ~FileReader(){
if(this->file != INVALID_HANDLE_VALUE)
CloseHandle(this->file);
}
// Check file state
operator bool(){
return this->file != INVALID_HANDLE_VALUE;
}
// Reset file pointer
void reset(){
if(this->file != INVALID_HANDLE_VALUE){
SetFilePointer(this->file, 0, 0, FILE_BEGIN);
this->buffer_start = this->buffer_end;
}
}
// Read one line from file
bool getline(std::string& line){
if(this->file != INVALID_HANDLE_VALUE){
// Clear old line content
line.clear();
// Fill line content
while(true){
// Check for buffer content
if(this->buffer_start == this->buffer_end){
// Fill buffer
DWORD read;
if(!ReadFile(this->file, this->buffer, sizeof(this->buffer), &read, NULL) || read == 0)
// Error or EOF
break;
this->buffer_start = this->buffer;
this->buffer_end = this->buffer + read;
}
// Search newline
char* newline = std::find(this->buffer_start, this->buffer_end, '\n');
// Assign content to line
if(newline == this->buffer_end){
line.append(this->buffer_start, this->buffer_end);
this->buffer_start = this->buffer_end;
}else{
line.append(this->buffer_start, newline);
this->buffer_start = newline + 1;
return true;
}
}
// Read anything?
return !line.empty();
}
// File handle invalid
return false;
}
};
Könnte nun wie folgt genutzt werden:
FileReader reader("ähm.txt");
if(reader){
string line;
while(reader.getline(line))
...
