Circular Bytevector Copy and Consumable Buffer

I coded a circular-bytevector-copy! function which handles the logic to copy from one vector to another, wrapping around the source and destination vectors as much as necessary.

I coded also a <consumable-buffer> class which implements a FIFO buffer of fix memory size, but implemented with circular reads and writes for efficiency.

(buffer tests)

GitList Installed

I really wanted a nice Git repository viewer, but didn’t want any of the free online services, for various reasons. I looked into Gogs, but it proved too difficult to install on my server. But the simpler GitList software does the job:

There are a number of settings I want to tweak, but it works and looks nice! If anyone has trouble accessing it, let me know.

8sync Examples Part 1

I want to play around with the 8sync framework, but the project is unfortunately lacking an API reference. So, I am writing example code to help me learn each of the modules, and thought I might as well share. Here is some example code for the (8sync agenda) module.

(define-module (8sync agenda examples))

(use-modules (8sync agenda)
             (srfi srfi-26)
             (srfi srfi-31))

(export make-stuff)

(define (make-something thing amt)
  ((rec (l n)
        (when (positive? n)
          (display "Making ") (display thing) (display "\n")
          (l (- n 1)))) amt))

(define (make-stuff)
  (define my-agenda
     #:queue (make-q* (cut make-something "widget" 10)
                      (cut make-something "thingamabob" 5)
                      (cut make-something "sprocket" 5))))
  (run-agenda my-agenda))

This illustrates how an Agenda can be used to interweave the execution of computations, by yielding to other computations during your loop:

scheme@(guile-user)> ,use (8sync agenda examples)
scheme@(guile-user)> (make-stuff)
Making widget
Making thingamabob
Making sprocket
Making widget
Making thingamabob
Making sprocket
Making widget
Making thingamabob
Making sprocket
Making widget
Making thingamabob
Making sprocket
Making widget
Making thingamabob
Making sprocket
Making widget
Making widget
Making widget
Making widget
Making widget
$2 = done

HackRF Shell: (Learning) Delays

I wanted to move on quickly from completing the FFT interface, on to FM demodulation. However, I realized that if the rest of the project was going to practical and modular, I would need some kind of block style I/O buffer management system, like GnuRadio has. And as I started to pursue that, I realized that I would need to properly modularize my code.

Up until now, all the functions were either being dumped into the default module by the C code, or loaded from one Scheme file in the source directory. I took all the external C code and organized it in sensible module divisions, and then took all the C-based Scheme primitives and put them in two modules ((sdr primitives) and (sdr hackrf primitives)). Those two modules are created and loaded when HackRF Shell is launched, while the other modules can be compiled independently.

That all required taking the time to actually learn how the module system works, as well as understanding how to create and fill-out modules through the C interfaces. So, not much amazing progress to the outside observer, but I learned a lot. The FFT demo function is still working:

One neat thing about programming in Guile is that you can jump into various modules at any time, to play around in them or see what variables are defined in them (private and public):

christopher@nightshade:~/Repos/hackrf-shell$ ./hackrf-shell 
HackRF Shell, copyright 2019 Christopher Howard

Initializing primitive functions.
Entering the Scheme shell.

GNU Guile 2.2.3
Copyright (C) 1995-2017 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> (set! %load-path (cons "/home/" %load-path))
scheme@(guile-user)> ,m (sdr hackrf util)
scheme@(sdr hackrf util)> ,b
hackrf-sensible-defaults #<variable 56314e6aaac0 value: #<procedure hackrf-sensible-defaults (d)>>
filename                #<variable 56314e6aa940 value: #<undefined>>
timed-read              #<variable 56314e6aa8a0 value: #<procedure timed-read (d file-path start-h start-m end-h end-m)>>
hackrf-cb-rx-to-file    #<variable 56314e6aa990 value: #<procedure hackrf-cb-rx-to-file (filename)>>
out                     #<variable 56314e6aa9e0 value: #<undefined>>
when-hour-min           #<variable 56314e6bd660 value: #<procedure when-hour-min (h m l)>>
hackrf-cb-rx-to-stream  #<variable 56314e6aaa30 value: #<procedure hackrf-cb-rx-to-stream (out)>>
cb-fft-to-gnuplot       #<variable 56314e6aa8f0 value: #<procedure cb-fft-to-gnuplot (center-freq samp-rate averaging-alpha)>>
scheme@(sdr hackrf util)> hackrf-
hackrf-cb-rx-to-file                  hackrf-open                           hackrf-set-sample-rate
hackrf-cb-rx-to-stream                hackrf-sensible-defaults              hackrf-set-vga-gain
hackrf-close                          hackrf-set-baseband-filter-bandwidth  hackrf-start-rx
hackrf-disable-amp                    hackrf-set-freq                       hackrf-stop-rx
hackrf-enable-amp                     hackrf-set-lna-gain                   
scheme@(sdr hackrf util)> ,m (sdr util)
scheme@(sdr util)> ,b
bv-complex-to-mag       #<variable 56314e6b4700 value: #<procedure bv-complex-to-mag (complex-float-bv n_complex_nums dest-bv)>>
freq-shifter            #<variable 56314e6b4670 value: #<procedure freq-shifter (freq samprate)>>

The next step in my project will be to work out my block-style I/O buffer management system, which will require me to re-learn GOOPS, Guile’s object oriented programming extension, so that will likely still take a while.

git clone git://