* Improve Coverage for Sylk
I believe that both BaseReader and Sylk Reader are now 100% covered.
Documentation available for this format is sparse.
It was always incomplete, and in some cases inaccurate.
My goal was to use PhpSpreadsheet to load the test file,
save it as Xlsx, and visually compare the two, then add a test
loaded with assertions. Cell values and calculated values,
and border styles were generally handled pretty well without changes.
Other types of styling were not handled so well. I added a few cells
to exercise some previously uncovered code.
Sylk files must be ASCII. I have deprecated the use of the
setEncoding and getEncoding functions, which had no test cases.
File author erroneously assumed that backslash was used to escape
quotes in CSV; in fact, doubling the quote is used for escape.
The test still worked, but mainly because the content of the cell
with the escape wasn't tested. The file is now fixed, and
a new test added.
I believe that both CSV Reader and Writer are 100% covered now.
There were some errors uncovered during development.
The reader specifically permits encodings other than UTF-8 to be used.
However, fgetcsv will not properly handle other encodings.
I tried replacing it with fgets/iconv/strgetcsv, but that could not
handle line breaks within a cell, even for UTF-8.
This is, I'm sure, a very rare use case.
I eventually handled it by using php://memory to hold the translated
file contents for non-UTF8. There were no tests for this situation,
and now there are (probably too many).
"Contiguous" read was not handle correctly. There is a file
in samples which uses it. It was designed to read a large sheet,
and split it into three. The first sheet was corrrect, but the
second and third were almost entirely empty. This has been corrected,
and the sample code was adapted into a formal test with assertions
to confirm that it works as designed.
I made a minor documentation change. Unlike HTML, where you never
need a BOM because you can declare the encoding in the file,
a CSV with non-ASCII characters must explicitly include a BOM
for Excel to handle it correctly. This was explained in the Reading CSV
section, but was glossed over in the Writing CSV section, which I
have updated.
We now always trust the file extension to avoid false positive of mime
detection for most simple cases. But we still try to guess the mime type
if the file extension does not match or is missing.
Fixes#564
CSV reader used to accept any file without any kind of check. That made
users incorrectly believe that things were ok, even though there is no
way for CSV reader to read anything else that plain text files.
Fixes#167
Because even if it doesn't make a difference in practice, it is
technically more correct to call static methods statically. It
also better advertise that those methods can be used from any context.
Removed "unescape enclosure functionality", since the unescaping is already handled by fgetcsv,
and performing the unescaping again would actually result int the text from the cell being read wrong.
As an example try parsing the folowing CSV:
```
"<img alt="""" src=""http://example.com/image.jpg"" />"
```
With the additional unescaping it would have ended up as:
```
<img alt=" src="http://example.com/image.jpg" />
```
instead of the correct:
```
<img alt="" src="http://example.com/image.jpg" />
```
Fixes https://github.com/PHPOffice/PHPExcel/pull/1171
oleibman
