hem-hashes VS pg_hexedit

I am the author of a tool that generates wxHexEditor tags and annotations for Postgres relation files -- pg_hexedit:

https://github.com/petergeoghegan/pg_hexedit

I've invested quite a lot of effort in it, and it would be nice to have support for multiple hex editors. That was anticipated to some degree:

https://github.com/petergeoghegan/pg_hexedit#supporting-othe...

I understand why you favor a declarative template format for describing files with tags -- that probably scales really nicely. What I'm doing is pretty grotty, but works surprisingly well in practice. I procedurally generate a description of each file in a shell script, and then open the file in wxHexEditor. I'm generating huge XML files, which is slow, but there are simple workarounds to get acceptable performance.

wxHexEditor doesn't support declarative tags. But even if it did I might not want to use them; the on-disk format of PostgreSQL is much more complicated than most file formats, and isn't supposed to be consumed by third party tools. Writing a C program that uses the struct definitions from the server itself makes the complexity quite manageable -- the tool is basically feature complete, even though I haven't spent a huge amount of time on it.

That said, it would be great if I could adapt pg_hexedit to a hex editor that had some kind of "best of both worlds" support for tags - tags that can be generated lazily and on-demand, when a portion of the file needs to be drawn or redrawn. This would be easy to adapt to -- Postgres relation files always consist of a series of 8KiB blocks/pages. My tool can easily generate tags for any single block without knowing any special context or having any expensive-to-generate state -- I just need a block number (i.e. an 8KiB-aligned byte offset).