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Forum Index : Microcontroller and PC projects : Reading binary data from a file

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William Leue
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Joined: 03/07/2020
Location: United States
Posts: 410

Posted: 03:00pm 18 Apr 2026

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I am trying to read binary data from a file.

Although using:

open "foo.bmp" for input as #2
hdr$ = input$(#2, hdr$)

Does work, I would really like to read data into an integer array. I tried this:

dim hdr(1000)
load data "foo.bmp", peek(VARADDR, hdr())

but this gives me a syntax error on the 'load data' line.

Any clues?
-Bill

Martin H.

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Joined: 04/06/2022
Location: Germany
Posts: 1447

Posted: 03:04pm 18 Apr 2026

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I think your parameters are incorrect; here, for example, is how to read the width and height of a PNG file

open FN$ + ".png" for input as #1
s$ = INPUT$(24, #1)
' Read width
w=ASC(MID$(s$,17,1))*16777216
inc w,(ASC(MID$(s$,18,1))*65536)
inc w,(ASC(MID$(s$,19,1))*256)
inc w,ASC(MID$(s$,20,1))
' Read height
h=ASC(MID$(s$,21,1))*16777216
inc h,(ASC(MID$(s$,22,1))*65536)
inc h,(ASC(MID$(s$,23,1))*256)
inc h,ASC(MID$(s$,24,1))
close #1

so it is INPUT$(number of bytes, #Chanalno.)

'no comment

William Leue
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Joined: 03/07/2020
Location: United States
Posts: 410

Posted: 03:07pm 18 Apr 2026

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Thanks a lot, I had it backwards!
-Bill

Volhout
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Joined: 05/03/2018
Location: Netherlands
Posts: 5859

Posted: 05:05pm 18 Apr 2026

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In the newer pico basics, ASC(MID$ can be replaced by the faster BYTE command.

Volhout

PicomiteVGA PETSCII ROBOTS

William Leue
Guru

Joined: 03/07/2020
Location: United States
Posts: 410

Posted: 07:06pm 18 Apr 2026

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Has that change been added to Color Maximite version of MMBasic too, Volhout?

-Bill

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