Bug 61792

Summary:	Need to rework any code that iterates over chars
Product:	POI	Reporter:	PJ Fanning <fanningpj>
Component:	POI Overall	Assignee:	POI Developers List <dev>
Status:	RESOLVED CLOSED
Severity:	enhancement
Priority:	P2
Version:	3.17-FINAL
Target Milestone:	---
Hardware:	PC
OS:	Mac OS X 10.1

Description PJ Fanning 2017-11-20 22:48:24 UTC

If we need to iterate over chars, we should use codepoints (ints) instead of char primitives. Unicode surrogates need 2 java chars to represent one Unicode codepoint.
DrawTextParagraph.java has an example where we iterate over the chars of a String.
See https://stackoverflow.com/questions/1527856/how-can-i-iterate-through-the-unicode-codepoints-of-a-java-string

Comment 1 Javen O'Neal 2017-11-20 23:28:05 UTC

Is there any way to add this to forbidden-apis-check to find the issues and make sure it stays fixed?

Comment 2 PJ Fanning 2017-11-20 23:32:11 UTC

We should forbid:
Character toLowerCase() and toUpperCase() 
String toLowerCase() and toUpperCase() 

We should only use String toLowerCase(Locale) and toUpperCase(Locale)

Comment 3 Javen O'Neal 2017-11-21 05:14:26 UTC

https://svn.apache.org/viewvc/poi/trunk/src/resources/devtools/forbidden-signatures.txt?view=log

Comment 4 Dominik Stadler 2017-12-26 10:35:08 UTC

This seems to be mostly fixed now, is there still anything missing?

Comment 5 PJ Fanning 2017-12-26 11:13:18 UTC

Dominik, there are still a lot of places where the POI code iterates over chars. I suspect that it is best not to proceed with refactoring most of this code though. The risks of introducing new bugs needs to be weighed up against the likelihood that the code in question needs to be able to process Unicode surrogates correctly.