shapr

monoidal hashing for data deduplication

problem: find the smallest diff between a file on the server and client, so you can send only the change. rsync does this!

Decades ago, a sliding window was hashed, moving byte by byte. This was very slow. (but can use many cores!)

The naive approach of comparing 8k chunks fails if someone added a single new byte at the beginning. This is called the boundary shift problem.

Content defined chunking (CDC) attempts to describe chunks by their content,

shapr

what I want to communicate to the audience:

You have (my) permission to do anything that you consider beneficial and useful, and you have the ability as well!

All the rules we think are in place are just illusions

if something isn’t being done already, it’s likely there’s no incentive to do that thing (see https://www.noidea.dog/glue ) don’t sacrifice yourself and your future, learn from my mistakes

shapr

	line	value	text
	1	50000.	adjusted gross income you expect in 2025
^		L1
	2a	15000	deductions

	line	value	text
	1a	46000.	taxable 5% income ($4000 rent deduction)

shapr

(defun screenshot-svg ()
  "Save a screenshot of the current frame as an SVG image.
Saves to a temp file and puts the filename in the kill ring."
  (interactive)
  (let* ((filename (make-temp-file "Emacs" nil ".svg"))
	 (data (x-export-frames nil 'svg)))
    (with-temp-file filename
      (insert data))
    (kill-new filename)
    (message filename)))

shapr

;; run-with-timer is meant to be used when delay is specified in seconds
;; this gonna be a list of pairs of
;; (cons (time-convert nil 'integer) (current-idle-time))
;; that is, (now-in-unix-time, emacs-idle-time-in-seconds)
(defvar fl/activity-intervals nil)
;; looks like timers are
;; 1. a timer variable
(defvar fl/write-interval-timer-var nil)

(defun fl/write-interval ()

shapr

(defconst shapr-idle-duration 60)

(defvar shapr-busy-timer nil)

(defun shapr-busy ()
  (when shapr-busy-timer
    (cancel-timer shapr-busy-timer))
  ;; Do some http stuff here
  (setq shapr-busy-timer
          (run-with-idle-timer

shapr

(use-package haskell-mode
  :ensure t
  :delight " hsk"
  :bind (:map haskell-mode-map ([(meta .)] . lsp-find-definition))
  :init
  (progn
    (add-hook 'haskell-mode-hook 'turn-on-haskell-doc-mode)
    (add-hook 'haskell-mode-hook #'lsp-deferred)
    (add-hook 'haskell-literate-mode-hook #'lsp)
    (add-hook 'haskell-mode-hook 'turn-on-haskell-indent)

shapr

/* expand.c */
/* Copyright 1994 by Philip Gage */

#include <stdio.h>

/* Decompress data from input to output */
void expand (FILE *input, FILE *output)
{
  unsigned char left[256], right[256], stack[30];
  short int c, count, i, size;

shapr

/* compress.c */
/* Copyright 1994 by Philip Gage */

#include <stdio.h>

#define BLOCKSIZE 5000   /* Maximum block size */
#define HASHSIZE  4096   /* Size of hash table */
#define MAXCHARS   200   /* Char set per block */
#define THRESHOLD    3   /* Minimum pair count */

shapr

diff --git a/src/Core.hs b/src/Core.hs
index 08b40dd..2741c26 100644
--- a/src/Core.hs
+++ b/src/Core.hs
@@ -80,7 +80,7 @@ main = do
             exitFailure
         print ("main loop starts" :: String)
 
-        SDL.initialize [SDL.InitVideo]
+        SDL.initializeAll