PHP RFC: base_convert changes

• Version: 0.1
• Date: 2019-05-15
• Author: Scott Dutton,php@exussum.co.uk
• Status: Draft
• First Published at: https://wiki.php.net/rfc/base_convert_improvements

the base_convert family of functions(base_convert, binhex, hexbin etc) are very accepting with their input arguments, you can pass any string to to them and they give a best effort of converting it.

For example base_convert(“hello world”, 16, 10); will return 237 with no warnings. What this does internally is base_convert(“ed”, 16, 10);

Also negative numbers simply do not work, eg base_convert(“-ff”, 16, 10); will return 255. (similar to above the “-” gets silently ignored)

other functions effected by this decbin() - Decimal to binary bindec() - Binary to decimal decoct() - Decimal to octal octdec() - Octal to decimal dechex() - Decimal to hexadecimal hexdec() - Hexadecimal to decimal

I propose two changes to the base_convert family of functions.

When passed arguments that base_convert will ignore, also give a warning to the user informing them their input was incorrect. There is an exception in place for the second char, if base is 16 'x' is allowed eg “0xff”, base 2 allows b and base 8 allows o. this fits in with common formats for these numbers

This can be raised to a full exception for a later PHP version (eg PHP 8)

Negative numbers should be allowed to be passed to the base_convert family of functions. for example base_convert('-ff', 16', 10); should return -255. Currently users need to make an exception in this case

No BC breaks for a warning, in the case of an exception there will be a BC break - Would suggest PHP 8 for this.

base_convert currently in the backend has a zend_ulong as its representation. We would need a zend_long. This will change the behavior of numbers in the range 9223372036854775807 - 18446744073709551615 but will allow negative numbers.

This currently breaks a fair amount of unit tests that I will need to update if this change is accepted. The unit tests are around extreme values.

This issue has been worked around in userland PHP for example https://stackoverflow.com/a/7051224/1281385

This change will break these work arounds

PHP 7.4 for warnings PHP 8.0 for negative arguments and exceptions

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Make sure there are no open issues when the vote starts!

Only the base_convert family of functions will be changed

N/A

Include these so readers know where you are heading and can discuss the proposed voting options.

https://github.com/php/php-src/pull/3911

After the project is implemented, this section should contain

1. the version(s) it was merged into
2. a link to the git commit(s)
3. a link to the PHP manual entry for the feature
4. a link to the language specification section (if any)

https://bugs.php.net/bug.php?id=61740 https://bugs.php.net/bug.php?id=55393

Keep this updated with features that were discussed on the mail lists.