@Todd The input stream is not what needs to be saved. It is the result of *encoding* the stream that needs to be saved, which in the code is available as a string (since that is the final result required by the function). Unless you are going to use file handling primitives (Assign / ResetFile etc) you need something to provide the file handling to get that string onto disc in UTF8 form.
You *could* use a file stream for that but you would need to separately convert the string to a UTF8 buffer before Write()ing it to that stream, introducing multiple opportunities to aim the trigger at your own leg appendage. :) You *could* use a string stream. Interestingly though, as far as I can tell in this case you don't get a BOM in the output file and can't get one unless you explicitly write it there first yourself (adding much more complexity), so if you actually need/want a BOM this isn't easily adaptable to provide that. As I understand it, the BOM wasn't actually the problem in Robert's case, rather the assumption that there *wasn't* a BOM was the only problem. An encoded string stream is also a bit of a mess to get your head around. The encoding specified in the constructor determines the encoding of the bytes backing the storage of the "string". i.e. it isn't really a "StringStream" at all since this (to me) means a stream(able) "string", i.e. (in 2009+) UTF16. Before Delphi 2009 this is what it would have been, except in that case an ANSI string. Rather, as implemented, it's a "CharacterStream". A byte stream holding a sequence of characters in some arbitrary encoding. imho it would be more intuitive for a T*String*Stream to be a *stream* containing a *String *and instead of an Encoding property (unnecessary since it would always be UTF16 internally) have an Encoding parameter on the I/O methods etc. Just as a T*String*List is a *list* of *String*(s) which you Encode/Decode as necessary for any I/O. Even if you did use a string stream it wouldn't be any/much simpler than the string list version (and if that lack of BOM in any output file does actually cause a problem then it's a non-starter anyway). Which leaves... a stringlist as the simplest and most flexible option. You might choose one of the more complex options for a more robust implementation, but imho that would be overkill for a quick diagnostic facility. :) On 10 August 2016 at 09:31, Todd Martin <todd.martin...@gmail.com> wrote: > @Jolyon > The memory steam could have been simply copied to a TFilestream for that. > > Todd > > On 10 Aug 2016 8:38 a.m., "Jolyon Direnko-Smith" <jsm...@deltics.co.nz> > wrote: > >> @Todd - looking at the code I suspect that the stringlist is in there as >> a temporary facility to dump the encoded data to a file for >> inspection/diagnostics (the function returns the encoded string as it's >> result as well as writing it out to a file using a string list for >> convenience). >> >> I think in this case, the BOM behaviour of a string list has caused a bit >> of Heisenbergnostics - the thing observing the thing has changed the thing. >> :) >> >> Using a file/string stream to output the resulting string might have >> avoided introducing the BOM complication, but if this is a temporary >> diagnostic facility, and if it is the BOM which is the problem, then just >> turning off the BOM facility on the string list does the job just as nicely. >> >> :) >> >> On 9 August 2016 at 18:35, Todd Martin <todd.martin...@gmail.com> wrote: >> >>> Why are you using a TStringlist at all? >>> >>> If you're encoding to Base64, encoding to UTF8 is meaningless. >>> >>> Todd >>> >>> On 9 Aug 2016 5:54 p.m., "Peter Ingham" <ping_delphil...@3days.co.nz> >>> wrote: >>> >>>> If you look at the output file in a hex editor, what do you see? >>>> >>>> If the first 3 bytes are 0xEF,0xBB,0xBF, then that is a "Byte Order >>>> Mark". >>>> >>>> UTF-8 is a method for encoding UNICODE characters using 8-Bit Bytes. >>>> >>>> A file containing 7-Bit ASCII (high-order bit of every character zero), >>>> when converted to UTF-8 is likely to look very similar. For anything >>>> else, all bets are off. Treating them as universally equivalent is asking >>>> for trouble. >>>> >>>> Many text editors will look for Byte Order marks (of varying types) and >>>> use them without displaying them (e.g: see >>>> https://en.wikipedia.org/wiki/Byte_order_mark#UTF-8). >>>> >>>> >>>> Regards >>>> On 9/08/2016 5:01 p.m., Robert Martin wrote: >>>> >>>> Hi guys >>>> >>>> >>>> I have been struggling to get some basic Mime encoding working, I have >>>> the following code which I use to Mime64 Encode a picture contained in a >>>> TImage component.... >>>> >>>> Base64 := TMime64.create; >>>> try >>>> MemoryStream := TMemoryStream.Create; >>>> MemoryStream.Position := 0; >>>> Image.Picture.Graphic.SaveToStream(MemoryStream); >>>> >>>> ReportImage.ImageMime := >>>> Base64.Encode_New(MemoryStream); >>>> ..... >>>> >>>> Function shown below... >>>> >>>> >>>> >>>> function TMime64.Encode_New(aSourceStream: TMemoryStream): String; >>>> var >>>> IdEncoderMIME : TIdEncoderMIME; >>>> Sl : TStringList; >>>> begin >>>> Result := ''; >>>> try >>>> >>>> IdEncoderMIME := TIdEncoderMIME.Create(nil); >>>> sl := TStringList.Create; >>>> try >>>> aSourceStream.Position := 0; >>>> Result := IdEncoderMIME.EncodeStream(aSourceStream); >>>> >>>> sl.Text := Result; >>>> sl.SaveToFile('d:\d\a.txt', TEncoding.UTF8); >>>> finally >>>> IdEncoderMIME.Free; >>>> sl.Free; >>>> end; >>>> except >>>> on E : Exception do begin >>>> raise EMimeError.Create(E.Message); >>>> end; >>>> end; >>>> end; >>>> >>>> The issue is that when I try to save the results in a UTF8 formatted >>>> file (the destination is to be a UTF-8 formatted XML file), there are >>>> 'bad' characters in the file which are invisible in Notepad++ but are >>>> present. >>>> >>>> If I save without specifying the file encoding ( >>>> sl.SaveToFile('d:\d\a.txt') instead of sl.SaveToFile('d:\d\a.txt', >>>> TEncoding.UTF8) ) I have what appears to be a clean ASCII file. My >>>> understanding is that ASCII characters have the same byte value (0-127) >>>> in an ASCII formatted file or a UTF-8 formatted file so I don't >>>> understand why the values would change. >>>> >>>> Any suggestions. >>>> >>>> >>>> p.s. I have to be able to save the file as UTF-8 because that is what >>>> the destination XML is encoded in. Currently it is 'corrupt' because of >>>> the 'bad' characters. >>>> >>>> p.p.s TIdEncoderMIME.EncodeStream returns a String. I am using Delphi Xe2. >>>> >>>> p.p.p.s I know it is something stupid I am doing ! >>>> >>>> >>>> >>>> >>>> Thanks >>>> Rob >>>> >>>> >>>> _______________________________________________ >>>> NZ Borland Developers Group - Delphi mailing list >>>> Post: delphi@listserver.123.net.nz >>>> Admin: http://delphi.org.nz/mailman/listinfo/delphi >>>> Unsubscribe: send an email to delphi-requ...@listserver.123.net.nz with >>>> Subject: unsubscribe >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> NZ Borland Developers Group - Delphi mailing list >>>> Post: delphi@listserver.123.net.nz >>>> Admin: http://delphi.org.nz/mailman/listinfo/delphi >>>> Unsubscribe: send an email to delphi-requ...@listserver.123.net.nz >>>> with Subject: unsubscribe >>>> >>> >>> _______________________________________________ >>> NZ Borland Developers Group - Delphi mailing list >>> Post: delphi@listserver.123.net.nz >>> Admin: http://delphi.org.nz/mailman/listinfo/delphi >>> Unsubscribe: send an email to delphi-requ...@listserver.123.net.nz with >>> Subject: unsubscribe >>> >> >> >> _______________________________________________ >> NZ Borland Developers Group - Delphi mailing list >> Post: delphi@listserver.123.net.nz >> Admin: http://delphi.org.nz/mailman/listinfo/delphi >> Unsubscribe: send an email to delphi-requ...@listserver.123.net.nz with >> Subject: unsubscribe >> > > _______________________________________________ > NZ Borland Developers Group - Delphi mailing list > Post: delphi@listserver.123.net.nz > Admin: http://delphi.org.nz/mailman/listinfo/delphi > Unsubscribe: send an email to delphi-requ...@listserver.123.net.nz with > Subject: unsubscribe >
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