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Groups > microsoft.public.scripting.vbscript > #12255

Re: file.ReadAll - another quirk

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Mayayana,

> But the former will stop at the first null when I try to read

I'm not sure what you mean with "when I try to read" there.   The whole file 
gets processed, as is proven by the last bytes of the resulting malformed 
string matching the last bytes of the file.

> If I ReadAll a GIF or Read(filelen) a GIF I apparently get the same bytes.

That fully depends on the size of the file.  The readall code internally 
works in increments of 260 bytes.  Take a file of at least that size and the 
corruption will take place.

> But the former will stop at the first null when I try to read it
> while the latter will not.

Again, /it doesn't stop/.

> I don't understand what you mean by "copying after reallocating".

The "readall" method goes (simplified) like this:

- while not at EOF
- try to read 260 bytes of data
- convert from utf-8 to widestring
- allocate a new blob of memory the size of the old one  plus the size of 
the wide string
- copy the contents of the old blob into the new blob   <=== !!
- copy the widestring into the new blob (at an offset equal to the old blobs 
size)
- wend
- return contents of the "new blob"

It goes wrong at the "copy the contents of the old blob into the new blob" 
point.  That copy routine stops at the first zero (leaving the remainder of 
the "new blob" undefined) when it should just have copied the whole 
specified block (copy X bytes from Y to Z).

Regards,
Rudy Wieser

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file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-20 12:54 +0100
  Re: file.ReadAll - another quirk "Mayayana" <mayayana@invalid.nospam> - 2019-11-20 08:39 -0500
  Re: file.ReadAll - another quirk JJ <jj4public@vfemail.net> - 2019-11-22 00:00 +0700
    Re: file.ReadAll - another quirk "Mayayana" <mayayana@invalid.nospam> - 2019-11-21 12:50 -0500
    Re: file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-21 20:39 +0100
      Re: file.ReadAll - another quirk "Mayayana" <mayayana@invalid.nospam> - 2019-11-21 15:04 -0500
        Re: file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-21 21:46 +0100
          Re: file.ReadAll - another quirk "Mayayana" <mayayana@invalid.nospam> - 2019-11-21 16:31 -0500
            Re: file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-22 09:23 +0100
              Re: file.ReadAll - another quirk "Mayayana" <mayayana@invalid.nospam> - 2019-11-22 09:14 -0500
                Re: file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-22 15:58 +0100
          Re: file.ReadAll - another quirk JJ <jj4public@vfemail.net> - 2019-11-22 19:13 +0700
            Re: file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-22 15:47 +0100
              Re: file.ReadAll - another quirk "Mayayana" <mayayana@invalid.nospam> - 2019-11-22 10:10 -0500
                Re: file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-22 18:37 +0100
                Re: file.ReadAll - another quirk "Mayayana" <mayayana@invalid.nospam> - 2019-11-22 18:40 -0500
                Re: file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-23 09:19 +0100
                Re: file.ReadAll - another quirk "Mayayana" <mayayana@invalid.nospam> - 2019-11-23 10:09 -0500
                Re: file.ReadAll - another quirk "R.Wieser" <address@not.available> - 2019-11-23 17:36 +0100
      Re: file.ReadAll - another quirk JJ <jj4public@vfemail.net> - 2019-11-22 19:10 +0700

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