From 721539026dda02e58addbb618f2102b31a2927f8 Mon Sep 17 00:00:00 2001 From: Ludovic Courtès Date: Mon, 18 Jul 2016 23:14:14 +0200 Subject: Add (guix zlib). * guix/zlib.scm, tests/zlib.scm: New files. * Makefile.am (MODULES): Add guix/zlib.scm. (SCM_TESTS): Add tests/zlib.scm. * m4/guix.m4 (GUIX_LIBGCRYPT_LIBDIR): New macro. * configure.ac (LIBGCRYPT_LIBDIR): Use it. Define and substitute 'LIBZ'. * guix/config.scm.in (%libz): New variable. --- guix/zlib.scm | 234 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 234 insertions(+) create mode 100644 guix/zlib.scm (limited to 'guix/zlib.scm') diff --git a/guix/zlib.scm b/guix/zlib.scm new file mode 100644 index 0000000000..51e5e9e426 --- /dev/null +++ b/guix/zlib.scm @@ -0,0 +1,234 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2016 Ludovic Courtès +;;; +;;; This file is part of GNU Guix. +;;; +;;; GNU Guix is free software; you can redistribute it and/or modify it +;;; under the terms of the GNU General Public License as published by +;;; the Free Software Foundation; either version 3 of the License, or (at +;;; your option) any later version. +;;; +;;; GNU Guix is distributed in the hope that it will be useful, but +;;; WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;;; GNU General Public License for more details. +;;; +;;; You should have received a copy of the GNU General Public License +;;; along with GNU Guix. If not, see . + +(define-module (guix zlib) + #:use-module (rnrs bytevectors) + #:use-module (ice-9 binary-ports) + #:use-module (ice-9 match) + #:use-module (system foreign) + #:use-module (guix config) + #:export (zlib-available? + make-gzip-input-port + make-gzip-output-port + call-with-gzip-input-port + call-with-gzip-output-port + %default-buffer-size + %default-compression-level)) + +;;; Commentary: +;;; +;;; Bindings to the gzip-related part of zlib's API. The main limitation of +;;; this API is that it requires a file descriptor as the source or sink. +;;; +;;; Code: + +(define %zlib + ;; File name of zlib's shared library. When updating via 'guix pull', + ;; '%libz' might be undefined so protect against it. + (delay (dynamic-link (if (defined? '%libz) + %libz + "libz")))) + +(define (zlib-available?) + "Return true if zlib is available, #f otherwise." + (false-if-exception (force %zlib))) + +(define (zlib-procedure ret name parameters) + "Return a procedure corresponding to C function NAME in libz, or #f if +either zlib or the function could not be found." + (match (false-if-exception (dynamic-func name (force %zlib))) + ((? pointer? ptr) + (pointer->procedure ret ptr parameters)) + (#f + #f))) + +(define-wrapped-pointer-type + ;; Scheme counterpart of the 'gzFile' opaque type. + gzip-file? + pointer->gzip-file + gzip-file->pointer + (lambda (obj port) + (format port "#" + (number->string (object-address obj) 16)))) + +(define gzerror + (let ((proc (zlib-procedure '* "gzerror" '(* *)))) + (lambda (gzfile) + (let* ((errnum* (make-bytevector (sizeof int))) + (ptr (proc (gzip-file->pointer gzfile) + (bytevector->pointer errnum*)))) + (values (bytevector-sint-ref errnum* 0 + (native-endianness) (sizeof int)) + (pointer->string ptr)))))) + +(define gzdopen + (let ((proc (zlib-procedure '* "gzdopen" (list int '*)))) + (lambda (fd mode) + "Open file descriptor FD as a gzip stream with the given MODE. MODE must +be a string denoting the how FD is to be opened, such as \"r\" for reading or +\"w9\" for writing data compressed at level 9 to FD. Calling 'gzclose' also +closes FD." + (let ((result (proc fd (string->pointer mode)))) + (if (null-pointer? result) + (throw 'zlib-error 'gzdopen) + (pointer->gzip-file result)))))) + +(define gzread! + (let ((proc (zlib-procedure int "gzread" (list '* '* unsigned-int)))) + (lambda* (gzfile bv #:optional (start 0) (count (bytevector-length bv))) + "Read up to COUNT bytes from GZFILE into BV at offset START. Return the +number of uncompressed bytes actually read." + (let ((ret (proc (gzip-file->pointer gzfile) + (bytevector->pointer bv start) + count))) + (if (< ret 0) + (throw 'zlib-error 'gzread! ret) + ret))))) + +(define gzwrite + (let ((proc (zlib-procedure int "gzwrite" (list '* '* unsigned-int)))) + (lambda* (gzfile bv #:optional (start 0) (count (bytevector-length bv))) + "Write up to COUNT bytes from BV at offset START into GZFILE. Return +the number of uncompressed bytes written, a strictly positive integer." + (let ((ret (proc (gzip-file->pointer gzfile) + (bytevector->pointer bv start) + count))) + (if (<= ret 0) + (throw 'zlib-error 'gzwrite ret) + ret))))) + +(define gzbuffer! + (let ((proc (zlib-procedure int "gzbuffer" (list '* unsigned-int)))) + (lambda (gzfile size) + "Change the internal buffer size of GZFILE to SIZE bytes." + (let ((ret (proc (gzip-file->pointer gzfile) size))) + (unless (zero? ret) + (throw 'zlib-error 'gzbuffer! ret)))))) + +(define gzeof? + (let ((proc (zlib-procedure int "gzeof" '(*)))) + (lambda (gzfile) + "Return true if the end-of-file has been reached on GZFILE." + (not (zero? (proc (gzip-file->pointer gzfile))))))) + +(define gzclose + (let ((proc (zlib-procedure int "gzclose" '(*)))) + (lambda (gzfile) + "Close GZFILE." + (let ((ret (proc (gzip-file->pointer gzfile)))) + (unless (zero? ret) + (throw 'zlib-error 'gzclose ret (gzerror gzfile))))))) + + + +;;; +;;; Port interface. +;;; + +(define %default-buffer-size + ;; Default buffer size, as documented in . + 8192) + +(define %default-compression-level + ;; Z_DEFAULT_COMPRESSION. + -1) + +(define (close-procedure gzfile port) + "Return a procedure that closes GZFILE, ensuring its underlying PORT is +closed even if closing GZFILE triggers an exception." + (lambda () + (catch 'zlib-error + (lambda () + ;; 'gzclose' closes the underlying file descriptor. 'close-port' + ;; calls close(2), gets EBADF, which is ignores. + (gzclose gzfile) + (close-port port)) + (lambda args + ;; Make sure PORT is closed despite the zlib error. + (close-port port) + (apply throw args))))) + +(define* (make-gzip-input-port port #:key (buffer-size %default-buffer-size)) + "Return an input port that decompresses data read from PORT, a file port. +PORT is automatically closed when the resulting port is closed. BUFFER-SIZE +is the size in bytes of the internal buffer, 8 KiB by default; using a larger +buffer increases decompression speed." + (define gzfile + (gzdopen (fileno port) "r")) + + (define (read! bv start count) + ;; XXX: Can 'gzread!' return zero even though we haven't reached the EOF? + (gzread! gzfile bv start count)) + + (unless (= buffer-size %default-buffer-size) + (gzbuffer! gzfile buffer-size)) + + (make-custom-binary-input-port "gzip-input" read! #f #f + (close-procedure gzfile port))) + +(define* (make-gzip-output-port port + #:key + (level %default-compression-level) + (buffer-size %default-buffer-size)) + "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 +port is closed." + (define gzfile + (gzdopen (fileno port) + (string-append "w" (number->string level)))) + + (define (write! bv start count) + (gzwrite gzfile bv start count)) + + (unless (= buffer-size %default-buffer-size) + (gzbuffer! gzfile buffer-size)) + + (make-custom-binary-output-port "gzip-output" write! #f #f + (close-procedure gzfile port))) + +(define* (call-with-gzip-input-port port proc + #:key (buffer-size %default-buffer-size)) + "Call PROC with a port that wraps PORT and decompresses data read from it. +PORT is closed upon completion. The gzip internal buffer size is set to +BUFFER-SIZE bytes." + (let ((gzip (make-gzip-input-port port #:buffer-size buffer-size))) + (dynamic-wind + (const #t) + (lambda () + (proc gzip)) + (lambda () + (close-port gzip))))) + +(define* (call-with-gzip-output-port port proc + #:key + (level %default-compression-level) + (buffer-size %default-buffer-size)) + "Call PROC with an output port that wraps PORT and compresses data. PORT is +close upon completion. The gzip internal buffer size is set to BUFFER-SIZE +bytes." + (let ((gzip (make-gzip-output-port port + #:level level + #:buffer-size buffer-size))) + (dynamic-wind + (const #t) + (lambda () + (proc gzip)) + (lambda () + (close-port gzip))))) + +;;; zlib.scm ends here -- cgit v1.2.3