On Apr 9, 2015, at 4:15 PM, Maciek Sokolewicz wrote:
On 10 April 2015 at 00:59, Jeffry Killen <jekillen@xxxxxxxxxxx> wrote:
>
>
> On Apr 9, 2015, at 3:41 PM, Maciek Sokolewicz wrote:
>
>> On 9-4-2015 21:48, Jeffry Killen wrote:
>>>
>>> Hello;
>>>
>>> Is there a reference to explanations of the meanings of the
>>> flags here I have marked with ??:
>>> ZIPARCHIVE::OVERWRITE (I presume this means to remove existing
content
>>> and start fresh)
>>> ZIPARCHIVE::CREATE
>>>
>>> ZIPARCHIVE::EXCL ?? (EXCL == exclude(?))
>>>
>>> ZIPARCHIVE::CHECKCONS ??
>>>
>>> There is no explanation in my copy of the manual
>>>
>>> accept what is obvious in the examples given.
>>>
>>> Thanks
>>>
>>> JK
>>
>>
>> Read the only up-to-date version of the manual: http://www.php.net/manual/en/zip.constants.php
>> (and yes, they're class constants)
>>
>> - Tul
>>
>
> Thank you; very helpful.
>
> It would be nice if there was a full manual on using this alone. I
could google using zip compression or something similar.
>
> So; as I understand it a constant will have an integer associated
> and might be used in a lookup array to get the string value?
>
> I will play around with this to get a feel for it.
>
> Thanks for time and attention
> JK
>
Please reply to the list as well.
The manual actually fully explains how to use them. It states that
you need to supply one of the flags in various functions/methods to
get some desired effect.
For instance:
http://www.php.net/manual/en/ziparchive.open.php
When using ZipArchive::open() it requires up to 2 parameters:
a filename, and an optional flag, which may be one of the following
constants: ZipArchive::OVERWRITE, ZipArchive::CREATE,
ZipArchive::EXCL or ZipArchive::CHECKCONS. Each constant has an
integer value. What this value is exactly, you shouldn't care.
Internally, the method wants to receive an integer; but for you (the
developer), it's much easier to figure out what's going on by using
a clear name; so instead you use a constant.
So when the following is used:
$filename = './archive.zip';
ZipArchive::open($filename, ZipArchive::CREATE);
PHP translates it to:
ZipArchive::open('./archive.zip', 1); // since the value of
ZipArchive::CREATE is some number, for example 1 (I don't know for
sure what it is, this is just for example purposes)
good guess... it is 1 according to my probing.
Now, you could of course just write things like:
ZipArchive::open('./archive.zip', 1);
ZipArchive::open('./archive.zip', 3);
but do you now immediately know what's going on here? And what each
flag does? Of course not. So instead we use constants which have a
clear name that tells us what the flag means, and have the
corresponding value (integer):
ZipArchive::open('./archive.zip', ZipArchive::CREATE);
ZipArchive::open('./archive.zip', ZipArchive::OVERWRITE);
The manual itself shows you a ton of examples: http://www.php.net/manual/en/zip.examples.php
and the entire ZipArchive chapter (http://www.php.net/manual/en/book.zip.php
) also contains a ton of info. No need to google anything, just RTFM
(online!).
- Tul
OK:
I thank you for pointers on where to find info in the manual on line.
I have trouble navigating the manual to find these things myself.
What I was wondering about most is the ZipArchive::CM... constants,
Where are they important and how would one use them?
for instance there is a ZipArchive constant CM_BZIP2: where and how
would I specify this algorythm?
And as well; comments, index, and name: What do these apply to?
Or suppose I wanted to remove an element from a zip archive file
without overwriting the whole thing? Is that possible? How would I do
that?
I am thinking along the lines of an O'Reilly or Apress text on the
subject. That is what I would google for.
I am in the process of compiling look up arrays to associate a string
with each of the constant values
I came across two oddities: mind you the version I am using is php
v5.3.26
//ZipArchive::CM_REDUCE_4: also shows 5
$_constCM[5] = 'ZipArchive::CM_REDUCE_3: reduced with factor 3';
-1 won't fit into an indexed array:
// ZipArchive::CM_DEFAULT gives -1: better of deflate or store
$_constCM_DEF = array(); // CM ??
$_constCM_DEF['code'] = -1;
$_constCM_DEF['means'] = "better of deflate or store";
I have just begun the ER constants.
Additionally, this is the first time I have payed any attention to the
inner workings of compression software.
As always thanks for time and attention:
JK
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