rekahsoft
/
guix
1
1
Fork 0
Code Issues Pull Requests Releases Wiki Activity

lzlib: Define 'dictionary-size+match-length-limit'. 

* guix/lzlib.scm (%compression-levels): Splice the rest of each element.
(dictionary-size+match-length-limit): New procedure.
(make-lzip-output-port, make-lzip-input-port/compressed): Use it.
* tests/lzlib.scm ("Bytevector of size relative to Lzip internal buffers (2 * dictionary)"):
Use 'dictionary-size+match-length-limit' instead of 'assoc-ref'.
This commit is contained in:
Ludovic Courtès 2020-01-16 21:42:27 +01:00
parent 584e46b1e0
commit 3597c0396b
No known key found for this signature in database
GPG Key ID: 090B11993D9AEBB5
2 changed files with 27 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
guix/lzlib.scm
View File

@ -1,6 +1,6 @@
;;; GNU Guix --- Functional package management for GNU ;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2019 Pierre Neidhardt <mail@ambrevar.xyz> ;;; Copyright © 2019 Pierre Neidhardt <mail@ambrevar.xyz>
;;; Copyright © 2019 Ludovic Courtès <ludo@gnu.org> ;;; Copyright © 2019, 2020 Ludovic Courtès <ludo@gnu.org>
;;; ;;;
;;; This file is part of GNU Guix. ;;; This file is part of GNU Guix.
;;; ;;;
@ -32,7 +32,8 @@
call-with-lzip-input-port call-with-lzip-input-port
call-with-lzip-output-port call-with-lzip-output-port
%default-member-length-limit %default-member-length-limit
%default-compression-level)) %default-compression-level
dictionary-size+match-length-limit))
;;; Commentary: ;;; Commentary:
;;; ;;;
@ -569,20 +570,27 @@ the number of uncompressed bytes written, a non-negative integer."
;; Alist of (levels (dictionary-size match-length-limit)). 0 is the fastest. ;; Alist of (levels (dictionary-size match-length-limit)). 0 is the fastest.
;; See bbexample.c in lzlib's source. ;; See bbexample.c in lzlib's source.
(define %compression-levels (define %compression-levels
`((0 (65535 16)) `((0 65535 16)
(1 (,(bitwise-arithmetic-shift-left 1 20) 5)) (1 ,(bitwise-arithmetic-shift-left 1 20) 5)
(2 (,(bitwise-arithmetic-shift-left 3 19) 6)) (2 ,(bitwise-arithmetic-shift-left 3 19) 6)
(3 (,(bitwise-arithmetic-shift-left 1 21) 8)) (3 ,(bitwise-arithmetic-shift-left 1 21) 8)
(4 (,(bitwise-arithmetic-shift-left 3 20) 12)) (4 ,(bitwise-arithmetic-shift-left 3 20) 12)
(5 (,(bitwise-arithmetic-shift-left 1 22) 20)) (5 ,(bitwise-arithmetic-shift-left 1 22) 20)
(6 (,(bitwise-arithmetic-shift-left 1 23) 36)) (6 ,(bitwise-arithmetic-shift-left 1 23) 36)
(7 (,(bitwise-arithmetic-shift-left 1 24) 68)) (7 ,(bitwise-arithmetic-shift-left 1 24) 68)
(8 (,(bitwise-arithmetic-shift-left 3 23) 132)) (8 ,(bitwise-arithmetic-shift-left 3 23) 132)
(9 (,(bitwise-arithmetic-shift-left 1 25) 273)))) (9 ,(bitwise-arithmetic-shift-left 1 25) 273)))
(define %default-compression-level (define %default-compression-level
6) 6)
(define (dictionary-size+match-length-limit level)
"Return two values: the dictionary size for LEVEL, and its match-length
limit. LEVEL must be a compression level, an integer between 0 and 9."
(match (assv-ref %compression-levels level)
((dictionary-size match-length-limit)
(values dictionary-size match-length-limit))))
(define* (make-lzip-input-port port) (define* (make-lzip-input-port port)
"Return an input port that decompresses data read from PORT, a file port. "Return an input port that decompresses data read from PORT, a file port.
PORT is automatically closed when the resulting port is closed." PORT is automatically closed when the resulting port is closed."
@ -602,8 +610,9 @@ PORT is automatically closed when the resulting port is closed."
"Return an output port that compresses data at the given LEVEL, using PORT, "Return an output port that compresses data at the given LEVEL, using PORT,
a file port, as its sink. PORT is automatically closed when the resulting a file port, as its sink. PORT is automatically closed when the resulting
port is closed." port is closed."
(define encoder (apply lz-compress-open (define encoder
(car (assoc-ref %compression-levels level)))) (call-with-values (lambda () (dictionary-size+match-length-limit level))
lz-compress-open))
(define (write! bv start count) (define (write! bv start count)
(lzwrite encoder bv port start count)) (lzwrite encoder bv port start count))
@ -626,8 +635,9 @@ port is closed."
(level %default-compression-level)) (level %default-compression-level))
"Return an input port that compresses data read from PORT, with the given LEVEL. "Return an input port that compresses data read from PORT, with the given LEVEL.
PORT is automatically closed when the resulting port is closed." PORT is automatically closed when the resulting port is closed."
(define encoder (apply lz-compress-open (define encoder
(car (assoc-ref %compression-levels level)))) (call-with-values (lambda () (dictionary-size+match-length-limit level))
lz-compress-open))
(define input-buffer (make-bytevector 8192)) (define input-buffer (make-bytevector 8192))
(define input-len 0) (define input-len 0)

3
tests/lzlib.scm
View File

@ -87,8 +87,7 @@
(test-assert* "Bytevector of size relative to Lzip internal buffers (2 * dictionary)" (test-assert* "Bytevector of size relative to Lzip internal buffers (2 * dictionary)"
(compress-and-decompress (compress-and-decompress
(random-bytevector (random-bytevector
(* 2 (car (car (assoc-ref (@@ (guix lzlib) %compression-levels) (* 2 (dictionary-size+match-length-limit %default-compression-level)))))
(@@ (guix lzlib) %default-compression-level))))))))
(test-assert* "Bytevector of size relative to Lzip internal buffers (64KiB)" (test-assert* "Bytevector of size relative to Lzip internal buffers (64KiB)"
(compress-and-decompress (random-bytevector (* 64 1024)))) (compress-and-decompress (random-bytevector (* 64 1024))))