Implementation in PostScript

[zzo38]

I made a implementation of multicodec in PostScript (it will work on 64-bit Ghostscript). This file is public domain, and you must append the contents of the CSV immediately on the next line after the last line that says } bind exec.

/multicodec.dict << >> def

/multicodec.split {  %( str -- int str )
  0 0 1 8 {
    2 index 1 index get
    dup 16#7F and 2 index 7 mul bitshift 4 -1 roll or 3 1 roll
    128 ge {pop} {1 add exit} ifelse
  } for
  3 -1 roll exch
  1 index length 1 index sub getinterval
} bind def

/multicodec.make {  %( int str -- str )
  exch dup 2 64 string cvrs length 6 add 7 idiv
  dup 3 index length add string
  dup 3 -1 roll 5 -1 roll putinterval
  exch 0 1 8 {
    1 index 0 eq {pop pop exit} if
    2 index exch 2 index
    dup 128 ge {16#80 or 16#FF and} {16#7F and} ifelse put
    -7 bitshift
  } for
} bind def

<< /Q 256 string >> begin {
  end
  currentfile //Q readline pop pop  % discard header line
  {
    currentfile //Q readline
    not {pop exit} if
    ( 0x) search pop exch 0 (16#) putinterval
    exch (,) search pop length 3 add exch pop exch pop
    //Q exch 2 index length exch getinterval cvi
    exch (,) search pop exch pop exch pop cvn
    //multicodec.dict 3 1 roll 3 copy exch put put
  } loop
} bind exec

[BigLep]

Thanks for sharing.
Feel free to put it on github somewhere, and we're happy to link to it. We're going to close the issue since there isn't anything else actionable for the repo maintainers to do here.