[M3devel] files larger than 2gig

[Jay]

Hm, here is another approach -- leave more code alone, like don't attempt to let FileRd/FileWr work on files larger than 2gig on a 32bit system for example. But do fix the lowest level status record to have either LONGINT or LONGREAL, preferable LONGREAL for the sake of NT386 (much as I dislike floating point..). 
That is, an intermediate goal would be: 
 - browing to a directory with large files with the Trestle file picker should not crash 
 - 32bit Modula-3 code may or may not be able to read/write such files 
 
 - Jay



----------------------------------------
> From: jay.krell at cornell.edu
> To: m3devel at elegosoft.com
> Subject: RE: [M3devel] files larger than 2gig
> Date: Mon, 22 Jun 2009 13:05:13 +0000
>
>
> Hm..I'm not sure.
> Integers have certain properties, like dividing an integer by an integer yields an integer,
> that floating point doesn't. Integer division tends toward zero faster than floating point division.
> I can try getting it all to compile with LONGINT maybe instead.
> The current behavior is pretty lame.
>
> - Jay
>
> ----------------------------------------
>> From: jay.krell at cornell.edu
>> To: m3devel at elegosoft.com
>> Date: Mon, 22 Jun 2009 12:58:17 +0000
>> Subject: [M3devel] files larger than 2gig
>>
>>
>> C:\dev2\cm3.2\m3-libs\libm3\src\os\Common\File.i3
>>
>>
>> TYPE
>> Status = RECORD
>> type: Type;
>> modificationTime: Time.T;
>> size: INTEGER;
>> END;
>>
>>
>> size: INTEGER causes exceptions when you use the Modula-3 gui
>> and browse to a directory with files larger than 2 gig.
>>
>>
>> I suggest size be changed to LONGREAL, which generally has a 53 bit mantissa
>> (out 64 bits total) and thus can represent integers very much larger than INTEGER.
>>
>>
>> LONGINT is a tempting option but doesn't help on the current NT386 platform,
>> and I think 53 bits will last a very long time.
>>
>>
>> I'm just trying out such a change and I can see it is not source compatible:
>>
>>
>> "../src/rw/FileRd.m3", line 73: incompatible argument types: MIN
>> "../src/rw/FileRd.m3", line 140: types are not assignable
>> 2 errors encountered
>> "../src/rw/FileWr.m3", line 87: incompatible argument types: MIN
>> "../src/rw/FileWr.m3", line 103: incompatible argument types: MAX
>> 2 errors encountered
>>
>>
>> Nevertheless I think it should be done, probably even for this release.
>>
>>
>> - Jay