So, falls es jemanden interessiert:
ich habe die float2hex-function gefunden und sie funktioniert auch so wie gewünscht:
<?php
/** Complementary functions to CONVERT PHP FLOATING POINT NUMBERS or DECIMALS
* (IEEE 754 single-precision 32 bit) TO HEXADECIMAL AND BACK.
*
* @author NSTIAC (Jorge D. Baigorri Salas) <http://www.nstiac.com> <http://www.n2works.com>
* @created on 28/Jan/2010 / time spent: 2hours approx.
* @special thanks to Thomas Finley's article "Floating Point"
* <http://tfinley.net/notes/cps104/floating.html>
*
* These functions allow to convert any php floating point numbers with the
* notation 1.234 (or fixed point numbers) into their corresponding 8 digits
* hexadecimal notation. (i.e.- 1557897.40 -> 49BE2C4B <- 1557897.40) by
* disregarding their implicit format and treating them at will as either
* integer, decimals, binary numbers, hexadecimal values, or plain text.
*
**/
/** FLOAT2HEX32n
* (Convert php float numbers or decimals (single-precision 32bits) to 8 digit Hexadecimal)
* Accepts only fixed point notation decimal numbers or fractions on a string (i.e.- "1.23456")
* @usage:
* float2hex32n("-1557897.13"); returns "c9be2c49"
**/
function float2hex32n($number) {
//Convert non-decimal to decimal.
$number=number_format($number,23,'.','');
//Get the integer portion of $number
if ($number>0) {
$intnumber=substr($number,0,strpos($number,"."));
} else {
//Check whether is a negative number to remove - sign.
$intnumber=substr($number,1,strpos($number,"."));
}
//Convert integer to binary
$binint=decbin($intnumber);
//Get the decimal fraction of the number
$pointnumber=substr($number,strpos($number,"."));
//Add a 0 to treat as single decimal fraction
$pointnumber="0".$pointnumber;
//Convert decimal values to base 2
$tmppoint=number_format($pointnumber*2,23,'.','');
for ($i=0; $i<23; $i++) {
$binpoint.=substr((string)$tmppoint,0,1);
$tmppoint=substr((string)$tmppoint,1);
$tmppoint=number_format($tmppoint*2,23,'.','');
}
//Gather both values to get base 2 binary fraction
$scibin=$binint.".".$binpoint;
//Find fraction separator "." position
$exp=strpos($scibin,".");
//Transform to scientific notation (1.x^exp)
$scibin=substr($binint,0,1).".".substr($binint,1).$binpoint;
//Create mantissa
if ($scibin>1) {
$mantissa=substr($scibin,2);
} else {
$mantissa=substr($scibin,1);
}
//Fill mantissa to 23 bit value
$fill23=23-strlen($mantissa);
for ($i=0; $i<$fill23; $i++) {
$mantissa.="0";
}
//Convert fraction separator position to exponent value
if ($exp>0) { $exp--; }
//Adjust to binary notation exponent value
$exp+=127;
//Convert to 8 bit binary
$exp=decbin($exp);
//Find 1 bit sign value
if ($number>0) { $sign=0; } else { $sign=1; }
//Compose final binary value
$binfinal=$sign.$exp.$mantissa;
//Reorganizae number into 4digit/bits packets and
//finally convert to decimal value and to hex.
$hexfinal.=dechex(bindec(substr($binfinal,0,4)));
$hexfinal.=dechex(bindec(substr($binfinal,4,4)));
$hexfinal.=dechex(bindec(substr($binfinal,8,4)));
$hexfinal.=dechex(bindec(substr($binfinal,12,4)));
$hexfinal.=dechex(bindec(substr($binfinal,16,4)));
$hexfinal.=dechex(bindec(substr($binfinal,20,4)));
$hexfinal.=dechex(bindec(substr($binfinal,24,4)));
$hexfinal.=dechex(bindec(substr($binfinal,28,4)));
return $hexfinal;
}
/** Using either function will return a value which can be used on the other function
* to return the original input. (Hope it helps =)
**/
?>
Jetzt heisst es „nur“ noch den string zur Ausgabe per udp zu generieren und da die erzeugten Werte einsetzen. D.h. ich habe einen festen Teil des Strings (2F 31 2F 62 6C 75 65 00 2C 66 00 00) und danach müsste ich die erzeugten 4 variablen Hex-Werte anfügen. Wenn jemand dazu einen Denkanstoss hat, wäre ich sehr dankbar. Ansonsten nimmt die ganze Geschichte so langsam Gestalt an.
Vielen Dank für eure Mitarbeit
Viele Grüße
Thilo
