PHP what is the best way to write data to middle of file without rewriting file

Question

I am working with large text files in php (1GB+), I am using

file_get_contents(\"file.txt\", NULL, NULL, 100000000,100); 

To get data from

Answer 1

To Overwrite Data :

$fp = fopen("file.txt", "rw+");
fseek($fp, 100000000); // move to the position
fwrite($fp, $string, 100); // Overwrite the data in this position 
fclose($fp);

To Inject Data

This is a tricky because you have to rewrite the file. It can be optimized with partial modificationfrom point of injection rather than the whole file

$string = "###INJECT THIS DATA ##### \n";
injectData("file.txt", $string, 100000000);

Function Used

function injectData($file, $data, $position) {
    $fpFile = fopen($file, "rw+");
    $fpTemp = fopen('php://temp', "rw+");

    $len = stream_copy_to_stream($fpFile, $fpTemp); // make a copy

    fseek($fpFile, $position); // move to the position
    fseek($fpTemp, $position); // move to the position

    fwrite($fpFile, $data); // Add the data

    stream_copy_to_stream($fpTemp, $fpFile); // @Jack

    fclose($fpFile); // close file
    fclose($fpTemp); // close tmp
}

Answer 2

A variant on Baba's answer, not sure if it would be more efficient when working with larger files:

function injectData($file, $data, $position) {
    $fpFile = fopen($file, "rw+");
    $fpTemp = fopen('php://temp', "rw+");
    stream_copy_to_stream($fpFile, $fpTemp, $position);
    fwrite($fpTemp, $data);
    stream_copy_to_stream($fpFile, $fpTemp, -1, $position);

    rewind($fpFile);
    rewind($fpTemp);
    stream_copy_to_stream($fpTemp, $fpFile);

    fclose($fpFile);
    fclose($fpTemp);
}

injectData('testFile.txt', 'JKL', 3);

Variant of my earlier method that eliminates one of the stream_copy_to_stream() calls, so should be a shade faster:

function injectData3($file, $data, $position) {
    $fpFile = fopen($file, "rw+");
    $fpTemp = fopen('php://temp', "rw+");
    stream_copy_to_stream($fpFile, $fpTemp, -1, $position);
    fseek($fpFile, $position);
    fwrite($fpFile, $data);
    rewind($fpTemp);
    stream_copy_to_stream($fpTemp, $fpFile);

    fclose($fpFile);
    fclose($fpTemp);
}

Answer 3

Another variant of the injectData() function:

function injectData($file, $data, $position) 
{
    $temp = fopen('php://temp', "rw+");
    $fd = fopen($file, 'r+b');

    fseek($fd, $position);
    stream_copy_to_stream($fd, $temp); // copy end

    fseek($fd, $position); // seek back
    fwrite($fd, $data); // write data

    rewind($temp);
    stream_copy_to_stream($temp, $fd); // stich end on again

    fclose($temp);
    fclose($fd);
}

It copies the end of file (from $position onwards) into a temporary file, seeks back to write the data and stitches everything back up.