diff options
Diffstat (limited to 'guix/lzlib.scm')
| -rw-r--r-- | guix/lzlib.scm | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/guix/lzlib.scm b/guix/lzlib.scm index deb900f352..a484315c0e 100644 --- a/guix/lzlib.scm +++ b/guix/lzlib.scm @@ -1,5 +1,6 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2019 Pierre Neidhardt <mail@ambrevar.xyz> +;;; Copyright © 2019 Ludovic Courtès <ludo@gnu.org> ;;; ;;; This file is part of GNU Guix. ;;; @@ -23,9 +24,11 @@ #:use-module (ice-9 match) #:use-module (system foreign) #:use-module (guix config) + #:use-module (srfi srfi-11) #:export (lzlib-available? make-lzip-input-port make-lzip-output-port + make-lzip-input-port/compressed call-with-lzip-input-port call-with-lzip-output-port %default-member-length-limit @@ -515,6 +518,24 @@ the end-of-stream has been reached." (loop rd))) read)) +(define (lzwrite! encoder source source-offset source-count + target target-offset target-count) + "Write up to SOURCE-COUNT bytes from SOURCE to ENCODER, and read up to +TARGET-COUNT bytes into TARGET at TARGET-OFFSET. Return two values: the +number of bytes read from SOURCE, and the number of bytes written to TARGET, +possibly zero." + (define read + (if (> (lz-compress-write-size encoder) 0) + (match (lz-compress-write encoder source source-offset source-count) + (0 (lz-compress-finish encoder) 0) + (n n)) + 0)) + + (define written + (lz-compress-read encoder target target-offset target-count)) + + (values read written)) + (define* (lzwrite encoder bv lz-port #:optional (start 0) (count (bytevector-length bv))) "Write up to COUNT bytes from BV at offset START into LZ-PORT. Return @@ -597,6 +618,56 @@ port is closed." (lz-compress-close encoder) (close-port port)))) +(define* (make-lzip-input-port/compressed port + #:key + (level %default-compression-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." + (define encoder (apply lz-compress-open + (car (assoc-ref %compression-levels level)))) + + (define input-buffer (make-bytevector 8192)) + (define input-len 0) + (define input-offset 0) + + (define input-eof? #f) + + (define (read! bv start count) + (cond + (input-eof? + (match (lz-compress-read encoder bv start count) + (0 (if (lz-compress-finished? encoder) + 0 + (read! bv start count))) + (n n))) + ((= input-offset input-len) + (match (get-bytevector-n! port input-buffer 0 + (bytevector-length input-buffer)) + ((? eof-object?) + (set! input-eof? #t) + (lz-compress-finish encoder)) + (count + (set! input-offset 0) + (set! input-len count))) + (read! bv start count)) + (else + (let-values (((read written) + (lzwrite! encoder + input-buffer input-offset + (- input-len input-offset) + bv start count))) + (set! input-offset (+ input-offset read)) + + ;; Make sure we don't return zero except on EOF. + (if (= 0 written) + (read! bv start count) + written))))) + + (make-custom-binary-input-port "lzip-input/compressed" + read! #f #f + (lambda () + (close-port port)))) + (define* (call-with-lzip-input-port port proc) "Call PROC with a port that wraps PORT and decompresses data read from it. PORT is closed upon completion." |