/**
* Generate a HexBlock from the current position in the file stream.
*
* The pointer will be returned to the initial position when done, essentially leaving the file stream untouched.
*
* @param resource|string $data a resource handle or a string.
* @param int $bytes number of bytes to print. -1 will dump the entirety of the file.
* @param bool $encodeHTML Encode the special characters that may occur on the right panel.
*
* @return string The generated Hex Block.
*/
public static function createBlock($data, $bytes, $encodeHTML = true)
{
$out = "";
/** @var resource $handle */
$handle = null;
$isLocalHandle = false;
if (is_string($data)) {
$handle = DebugHelpers::str2resource($data);
$isLocalHandle = true;
} else {
if (is_resource($data)) {
$handle = $data;
} else {
return $out;
}
}
$stat = fstat($handle);
$length = $stat['size'];
$pos = ftell($handle);
if ($bytes === -1) {
$bytes = $length - $pos;
}
$endPos = $pos + $bytes;
$realPos = $pos & 0xfffffff0;
fseek($handle, $realPos, SEEK_SET);
$isRangeOverreached = $pos + $bytes > $length;
$rDigits = strlen(dechex($isRangeOverreached ? $length : $pos + $bytes));
$rDigits += $rDigits % 2;
if ($rDigits < 2) {
$rDigits = 2;
}
$lDigits = strlen(dechex($bytes));
$lDigits += $lDigits % 2;
if ($lDigits < 2) {
$lDigits = 2;
}
$out .= "Start: 0x" . str_pad(strtoupper(dechex($pos)), $rDigits, "0", STR_PAD_LEFT);
$out .= "; Length: " . $bytes . " (0x" . str_pad(strtoupper(dechex($bytes)), $lDigits, "0", STR_PAD_LEFT) . ")\n";
if ($isRangeOverreached) {
$or = $pos + $bytes - $length;
$out .= "* Requested length overreach by " . $or . " bytes, only " . ($bytes - $or) . " available in stream.\n";
if ($bytes - $or <= 0) {
fseek($handle, $pos, SEEK_SET);
return $out;
}
}
while (ftell($handle) < $endPos && !(feof($handle) || ftell($handle) === $length)) {
$lsp = ftell($handle);
$out .= str_pad(strtoupper(dechex($lsp)), $rDigits, "0", STR_PAD_LEFT) . ": ";
$rp = "| ";
for ($j = 0; $j < 16; $j++) {
if ($j == 8) {
$rp .= " ";
$out .= " ";
}
if ($lsp + $j < $pos) {
$rp .= "-";
$out .= "-- ";
fread($handle, 1);
} elseif ($lsp + $j >= $endPos || (feof($handle) || ftell($handle) === $length)) {
$rp .= "-";
$out .= "-- ";
} else {
$d = fread($handle, 1);
$out .= bin2hex($d) . " ";
$od = ord($d);
if ($od < 0x20 || $od >= 0x7f) {
$d = '.';
}
$rp .= $encodeHTML ? htmlspecialchars($d) : $d;
}
}
$out .= $rp . "\n";
}
$out .= "\n";
if ($isLocalHandle) {
fclose($handle);
} else {
fseek($handle, $pos, SEEK_SET);
}
return $out;
}
