OK, declaring a few 'unsigned int' in BitBltSimulation suffices to make the
problem disappear on SqueakCogSpur64 MacOSX, I'll publish this evening.

2016-03-31 7:42 GMT+02:00 Nicolas Cellier <
nicolas.cellier.aka.nice at gmail.com>:

> I have a change where I massively decalred the bitblt operands as unsigned
> int.
> I did not push it so far, but I'll try to see if it solves the symptoms.
>
> 2016-03-31 3:16 GMT+02:00 Levente Uzonyi <leves at caesar.elte.hu>:
>
>> Hi Eliot,
>>
>> I made a snippet to read the source of the method as an array of integers
>> from the .mcz in the package cache:
>>
>> (MCMczReader versionFromFile: 'package-cache/Multilingual-ul.210.mcz')
>> snapshot definitions
>>         detect: [ :each |
>>                 each isMethodDefinition
>>                         and: [ each className = #JapaneseEnvironment
>>                                 and: [ each selector =
>> #flapTabTextFor:in: ] ] ]
>>         ifFound: [ :definition |
>>                 Array streamContents: [ :stream |
>>                         | source |
>>                         source := definition source.
>>                         1 to: source size do: [ :index |
>>                                 stream nextPut: (source basicAt: index) ]
>> ] ]
>>         ifNone: [ self error ]
>>
>> In MCMczReader >> #loadDefinitions, if you change this line
>>
>>                 [:m | [^definitions := (DataStream on: m contentStream)
>> next definitions]
>>
>> to this
>>
>>                 [:m | [ self error. ^definitions := (DataStream on: m
>> contentStream) next definitions]
>>
>> then the definition will be read from the sources instead of the binary
>> snapshot, and you'll get the correct source code.
>>
>> First I disabled all the ZipPlugin primitives to see if those are
>> responsible for this issue, but they turned out to be okay.
>> Then I dag into DataStream, and I came to the conclusion that the issue
>> is in BitBlt. The mangled characters appear when PositionableStream >>
>> #nextWordsInto: applies some BitBlt magic to convert the read bytes into a
>> WideString.
>>
>> Here's a snippet triggering the error:
>>
>> | wideString source pos blt expectedWideString |
>> source := #[1 64 255 14 1 64 48 251].
>> expectedWideString := WideString fromByteArray: source.
>> wideString := WideString new: source size // 4.
>> pos := 0.
>> blt := (BitBlt
>>         toForm: (Form new hackBits: wideString))
>>         sourceForm: (Form new hackBits: source).
>> blt
>>         combinationRule: Form over;
>>         sourceX: 0;
>>         sourceY: pos // 4;
>>         height: wideString byteSize // 4;
>>         width: 4;
>>         destX: 0;
>>         destY: 0;
>>         copyBits.
>> wideString restoreEndianness.
>> self assert: wideString = expectedWideString
>>
>> Levente
>>
>>
>
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