Directory recursive walking

[dog2002]

On Thursday, 14 January 2021 at 22:28:19 UTC, Paul Backus wrote:
> On Thursday, 14 January 2021 at 20:23:37 UTC, dog2002 wrote:
>> About 1000 large files.
>>
>> I want to replace several first bytes in all the files, so I 
>> just copy the remaining bytes into a new file. Might this be 
>> the reason for high memory consumption? If so, is there a way 
>> not to copy the entire file, just delete first bytes and write 
>> the replaced bytes into the beginning of the file?
>>
>> I use Windows x64.
>
> What code are you using to copy the bytes? If you're reading 
> the whole file into memory at once, that will consume a lot of 
> memory.

void func(string inputFile, string outFile, uint chunk_size) {
	try {
		File _inputFile = File(inputFile, "r");
		File _outputFile = File(outFile, "w");
		
		ubyte[] tempBuffer = _inputFile.rawRead(new ubyte[](512));
	
                 //doing some operations with the tempBuffer	

		_outputFile.rawWrite(tempBuffer);
		
		_inputFile.seek(tempBuffer.length, SEEK_SET);
		
		
		foreach(_buffer; _inputFile.byChunk(chunk_size)) {
			_outputFile.rawWrite(_buffer);
		}
		_inputFile.close();
		_outputFile.close();
	}
	catch (Throwable) {}

}