As you know the format of the message, you can safely jump over the null terminators without the fear of overflowing the buffer or getting garbage data.
PHP Code:
new type = Sdata[4]
decl String:hostname[32]
strcopy(hostname,sizeof hostname, Sdata[6])
decl String:map[32], String:moddir[16], String:desc[64]
new len = strcopy(map,sizeof map, Sdata[7]) + 7
len += strcopy(moddir,sizeof moddir, Sdata[len + 1]) + 1
len += strcopy(desc,sizeof desc, Sdata[len + 1]) + 1
new playercount = Sdata[len + 2] //skip the null terminator and steam appid
new maxplayers = Sdata[len + 3]
new bool:password = Sdata[len + 7] ? true : false
...