RFC - Zend Stdlib Environment

h1. Overview
This RFC contains a proposal for a class detecting basic environment capabilities. The class should only contain detections which are often used on several components and/or user land code *AND* are tricky to detect with PHP itself.

The main goal is to have a single point of detection that is good tested and re-usable to minimize code duplications and possible issues.

*UPDATE:*
After some discussion I prefer to add a class BinaryUtils contains helper methods to work with binary string incl. mbstring.func_overload workarounds, a class {{StringUtils}} contains helper methods to work with strings of different character sets (based on iconv/mbstring) incl. pcre unicode check
and the class Environment contains other detections like the type of the operating system.

On method naming of {{StringUtils/BinaryUtils}} I avoided the name "string" because of confusions on BinaryUtils vs. StringUtils but to use the same method names on both.

*NOTE:* System-Memory detections should be completely removed from ZF because it's not possible to work well on all installations and it's not required on other components.

h2. Justification
* unified way to detect OS, PHP version, extension compatibility, PCRE unicode compatibility, machine byte order and other valuable eviromental parameters. Current ZF code has:
** OS detection: 22 usages
** PHP version check: 3 usages
** extension detection: 70 usages
** PCRE unicode support: 18 usages

* unified way to detect memory and disk capacity
_Questionable. there is no clear portable way to detect systemmemory (see notes above)_

Many components use own unicode support functions. There is no clear way what extension should be used for multibyte, some components use iconv some mbstring.

* byteorder
Many components need byteorder dependent way to work with binary data. Right now custom functions are in: {{Pdf/BinaryParser}}, {{Serializer}}, {{Amf/Util/BinaryStream}}, {{Filter/Compress}}, and many others.

* machine byteorder dependent behaviour of {{pack/unpack()}}
From PHP manual: "PHP internally stores integral values as signed. If you unpack a large unsigned long and it is of the same size as PHP internally stored values the result will be a negative number even though unsigned unpacking was specified."
BinUtils could address that with wrapper function.

* unified way to get int/float from binary representation
Right now custom functions for this are in: {{Pdf/BinaryParser}}, {{Serializer}}

* unified way to perform bitwise operations on binary data
functions like {{setBit}}, {{clearBit}}, {{testBit}}

h2. Prototype
[https://github.com/marc-mabe/zf2/tree/env/library/Zend/Stdlib]
{code}
namespace Zend\Stdlib;

class Enviroment
{
public static function is32Bit();
public static function is64Bit();

public static function isWindows();
/*
public static function isUnix();
public static function isLinux();
public static function isBsd();
public static function isSolaris();
public static function isDarwin();
public static function isCygwin()
...
*/
}

class StringUtils
{
public static function hasMbString();
public static function hasIconv();
public static function isPcreUnicodeAware();

public static function isSingleByteCharset($charset);

public static function length($input, $charset = 'utf-8');
public static function indexOf($haystack, $needle, $offset = 0, $charset = 'utf-8');
public static function lastIndexOf($haystack, $needle, $offset = 0, $charset = 'utf-8');
public static function subset($input, $offset, $length = 0, $charset = 'utf-8');

// moved from Zend\Text\MultiByte
public static function wordWrap($string, $width = 75, $break = "\n", $cut = false, $charset = 'utf-8');
public static function strPad($input, $padLength, $padString = ' ', $padType = STR_PAD_RIGHT, $charset = 'utf-8');
}

class BinaryUtils
{
const BYTEORDER_MACHINE = 0;
const BYTEORDER_LE = 1;
const BYTEORDER_BE = 2;

public static function isLittleEndian();
public static function isBigEndian();

public static function length($input);
public static function indexOf($haystack, $needle, $offset = 0);
public static function lastIndexOf($haystack, $needle, $offset = 0);
public static function subset($input, $offset, $length = 0);
}

{code}