3c3
< # $File: jpeg,v 1.19 2013/02/04 15:50:03 christos Exp $
---
> # $File: jpeg,v 1.21 2014/09/12 20:47:00 christos Exp $
25,28c25,30
< #>>13 byte 0 \b, aspect ratio
< #>>13 byte 1 \b, resolution (DPI)
< #>>13 byte 2 \b, resolution (DPCM)
< #>>4 beshort x \b, segment length %d
---
> >>13 byte 0 \b, aspect ratio
> >>13 byte 1 \b, resolution (DPI)
> >>13 byte 2 \b, resolution (DPCM)
> >>14 beshort x \b, density %dx
> >>16 beshort x \b%d
> >>4 beshort x \b, segment length %d
124,150d125
< # Here things get sticky. We can do ONE MORE marker segment with
< # indirect addressing, and that's all. It would be great if we could
< # do pointer arithemetic like in an assembler language. Christos?
< # And if there was some sort of looping construct to do searches, plus a few
< # named accumulators, it would be even more effective...
< # At least we can show a comment if no other segments got inserted before:
< >(4.S+5) byte 0xFE \b, comment:
< >>(4.S+6) pstring/HJ x "%s"
< # Or, we can show the encoding type (I've included only the three most common)
< # and image dimensions if we are lucky and the SOFn (image segment) is here:
< >(4.S+5) byte 0xC0 \b, baseline
< >>(4.S+6) byte x \b, precision %d
< >>(4.S+7) beshort x \b, %dx
< >>(4.S+9) beshort x \b%d
< >(4.S+5) byte 0xC1 \b, extended sequential
< >>(4.S+6) byte x \b, precision %d
< >>(4.S+7) beshort x \b, %dx
< >>(4.S+9) beshort x \b%d
< >(4.S+5) byte 0xC2 \b, progressive
< >>(4.S+6) byte x \b, precision %d
< >>(4.S+7) beshort x \b, %dx
< >>(4.S+9) beshort x \b%d
< # I've commented-out quantisation table reporting. I doubt anyone cares yet.
< #>(4.S+5) byte 0xDB \b, quantisation table
< #>>(4.S+6) beshort x \b length=%d
< #>14 beshort x \b, %d x
< #>16 beshort x \b %d
151a127,172
> # Jump to the first segment
> >(4.S+4) use jpeg_segment
>
> # This uses recursion...
> 0 name jpeg_segment
> >0 beshort 0xFFFE
> >>(2.S+2) use jpeg_segment
> >>2 pstring/HJ x \b, comment: "%s"
>
> >0 beshort 0xFFC0
> >>(2.S+2) use jpeg_segment
> >>4 byte x \b, baseline, precision %d
> >>7 beshort x \b, %dx
> >>5 beshort x \b%d
> >>9 byte x \b, frames %d
>
> >0 beshort 0xFFC1
> >>(2.S+2) use jpeg_segment
> >>4 byte x \b, extended sequential, precision %d
> >>7 beshort x \b, %dx
> >>5 beshort x \b%d
> >>9 byte x \b, frames %d
>
> >0 beshort 0xFFC2
> >>(2.S+2) use jpeg_segment
> >>4 byte x \b, progressive, precision %d
> >>7 beshort x \b, %dx
> >>5 beshort x \b%d
> >>9 byte x \b, frames %d
>
> # Define Huffman Tables
> >0 beshort 0xFFC4
> >>(2.S+2) use jpeg_segment
>
> # Application specific markers
> >0 beshort&0xFFE0 =0xFFE0
> >>(2.S+2) use jpeg_segment
>
> # DB: Define Quantization tables
> # DD: Define Restart interval [XXX: wrong here, it is 4 bytes]
> # D8: Start of image
> # D9: End of image
> # Dn: Restart
> >0 beshort&0xFFD0 =0xFFD0
> >>(2.S+2) use jpeg_segment
>