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01/03: syscalls: Extract 'bytes->string'.
From: |
Ludovic Courtès |
Subject: |
01/03: syscalls: Extract 'bytes->string'. |
Date: |
Thu, 19 Jan 2017 22:48:06 +0000 (UTC) |
civodul pushed a commit to branch master
in repository guix.
commit 57f068bec5349e250ce321262609ca8978a81f7f
Author: Ludovic Courtès <address@hidden>
Date: Thu Jan 19 23:20:57 2017 +0100
syscalls: Extract 'bytes->string'.
* guix/build/syscalls.scm (bytes->string): New procedure.
(bytevector->string-list): Use it.
---
guix/build/syscalls.scm | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 2e37846..c06013c 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -900,6 +900,15 @@ bytevector BV at INDEX."
;; The most terrible interface, live from Scheme.
(syscall->procedure int "ioctl" (list int unsigned-long '*)))
+(define (bytes->string bytes)
+ "Read BYTES, a list of bytes, and return the null-terminated string decoded
+from there, or #f if that would be an empty string."
+ (match (take-while (negate zero?) bytes)
+ (()
+ #f)
+ (non-zero
+ (list->string (map integer->char non-zero)))))
+
(define (bytevector->string-list bv stride len)
"Return the null-terminated strings found in BV every STRIDE bytes. Read at
most LEN bytes from BV."
@@ -911,9 +920,7 @@ most LEN bytes from BV."
(reverse result))
(_
(loop (drop bytes stride)
- (cons (list->string (map integer->char
- (take-while (negate zero?) bytes)))
- result))))))
+ (cons (bytes->string bytes) result))))))
(define* (network-interface-names #:optional sock)
"Return the names of existing network interfaces. This is typically limited