I have an application, which unfortunately is written in Delphi 6, that allows the user to extract substrings / delete characters from input. The operator sees a TLabel, this is on purpose to avoid direct and incorrect input.
This works fine for English text. But sometimes, the text is mixed content (ANSI-encoded), I set the charset and the display works fine without modification.
One trivial example could be:
月123中
The string in hex is 8C 8E | 31 | 32 | 33 | 92 86 (split on characters for clarity)
But once modification starts, things go wrong. I know why - the standard StrLeft / StrRight / SubString works on single bytes - and once I remove a byte, the text renders meaningless.
Do I have to go through a WideString conversion and back every time I modify something? Or are there native libraries / functions in older Delphi versions to do what I need?
Something like this, in pseudocode:
mixedStringLength(content) = 5 // 5 characters visible
mixedStingLeft(content,2) = "月1" // actually the bytes 8C 8E 31
mixedStringDeleteCharsRight(content,1) = "月123" // actually deletes 2 bytes
As the string in question is used in many other places, and the project is large, it's not as trivial as just using TNT libraries, or switching over to a newer Delphi version.