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author | Andreas Rottmann <a.rottmann@gmx.at> | 2011-03-13 22:39:14 +0100 |
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committer | Ludovic Courtès <ludo@gnu.org> | 2011-03-13 22:39:14 +0100 |
commit | a6c377f7d8a311b0ce4f9c5900b1c81c27b2d60c (patch) | |
tree | 7a4bc6be9ea639d40c53385b1e2858ed717a8099 /module/rnrs/io | |
parent | ca33b501a93f8de389c1e3e1bc987f63b6912029 (diff) | |
download | guile-a6c377f7d8a311b0ce4f9c5900b1c81c27b2d60c.tar.gz |
Add `get-string-n' and `get-string-n!' for R6RS ports
* libguile/r6rs-ports.c (scm_get_string_n_x): Implement `get-string-n!'
in C for efficiency.
* libguile/r6rs-ports.h: Add prototype for this function.
* module/ice-9/binary-ports.scm: Export `get-string-n!'.
* module/rnrs/io/ports.scm (get-string-n): Implement based on
`get-string-n!'.
Export both `get-string-n!' and `get-string-n'.
* module/rnrs.scm: Also export these.
* test-suite/tests/r6rs-ports.test (8.2.9 Textual input): Add a few
tests for `get-string-n' and `get-string-n!'.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
Diffstat (limited to 'module/rnrs/io')
-rw-r--r-- | module/rnrs/io/ports.scm | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/module/rnrs/io/ports.scm b/module/rnrs/io/ports.scm index d3a81b7c7..d3b16ac63 100644 --- a/module/rnrs/io/ports.scm +++ b/module/rnrs/io/ports.scm @@ -68,8 +68,9 @@ put-u8 put-bytevector ;; textual input - get-char get-datum get-line get-string-all lookahead-char - + get-char get-datum get-line get-string-all get-string-n get-string-n! + lookahead-char + ;; textual output put-char put-datum put-string @@ -386,6 +387,17 @@ return the characters accumulated in that port." (define (get-string-all port) (with-i/o-decoding-error (read-delimited "" port 'concat))) +(define (get-string-n port count) + "Read up to @var{count} characters from @var{port}. +If no characters could be read before encountering the end of file, +return the end-of-file object, otherwise return a string containing +the characters read." + (let* ((s (make-string count)) + (rv (get-string-n! port s 0 count))) + (cond ((eof-object? rv) rv) + ((= rv count) s) + (else (substring/shared s 0 rv))))) + (define (lookahead-char port) (with-i/o-decoding-error (peek-char port))) |