We have identical constants defined in several places, and use literals in others. We aren't consistent in checking limits. This PR makes the use of the constants in Cell/AddressRange the "official" source, deprecates all other constants, and substitutes the constants wherever literals are used. A number of different edge case tests are added.
During testing, I discovered that `columnIndexFromString` correctly throws an exception for 4-character string, but allows `XFE` through `ZZZ`, all of which are also invalid. There are similar inconsistencies with related routines, and this PR attempts to make them operate consistently. One suprise is that throwing for `row=0` causes serious regression problems, so it continues to be permitted (but the high row limit is enforced).
Further, Reference Helper sometimes dips into negative numbers, resulting in totally unexpected results (-1 affects column Z, -2 column Y, etc.). It is changed to ignore rows and columns outside the limits.
While we might never be able to have 100% of our code strict, we can at
the very least do it for all of our tests. This ensures that our tests
are using our API with the types as intended by the test author, and not
silently be cast to what our API requires.
Column indexes are always based on 1 everywhere in PhpSpreadsheet.
This is consistent with rows starting at 1, as well as Excel
function `COLUMN()`. It should also make it easier to reason about
columns and rows and remove any doubts whether a specific method is
expecting 0 based or 1 based indexes.
Fixes#273
Fixes https://github.com/PHPOffice/PHPExcel/issues/307
Fixes https://github.com/PHPOffice/PHPExcel/issues/476
oleibman
Adrien Crivelli