Re: xxd -i vs DIY Was: C23 thoughts and opinions

On 29/05/2024 18:41, bart wrote:

Below is a version with no declarations at all. It is in a dynamic scripting language.
 It runs in 7.3 seconds (or 6.4 seconds if newlines are dispensed with).

That is slower that native code solutions, but it is still faster than xxd!
My scripting language doesn't normally run under Linux (to make the comparison with xxd fairer), but I managed to make it work for this test:
   C:\qx52>mc -c -linux qc
   M6 Compiling qc.m to qc.c
   C:\qx52>wsl
   root@DESKTOP-11:/mnt/c/qx52# gcc -O3 qc.c -o qc -lm -ldl -fno-builtin
   root@DESKTOP-11:/mnt/c/qx52# time ./qc -nosys fred
   real    0m10.562s
   user    0m9.198s
   sys     0m0.681s
   root@DESKTOP-11:/mnt/c/qx52#
I start off under Windows, run a transpiler on a special version of it that is transpilable, then compile that C file it under WSL. (The -nosys option leaves out standard libs using WinAPI.)
It takes 10.5 seconds; not as fast as on Windows, but there I'm using an accelerator which needs inline assembly, which I can't turn into C.
Here is how xxd fared on a slightly faster second run:
   root@DESKTOP-11:/mnt/c/qx52# time xxd -i <data100 >xxd.txt
   real    0m33.066s
Conclusion: beating xxd is apparently not hard if even a scripting language can do so. I wonder what slows it down? The output format is more bloated, but that can only be part of it.