From: Andy Wingo <wingo@igalia.com>
To: ludo@gnu.org (Ludovic Courtès)
Cc: 30066@debbugs.gnu.org
Subject: bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports
Date: Wed, 10 Jan 2018 17:32:04 +0100 [thread overview]
Message-ID: <87fu7dptdn.fsf@igalia.com> (raw)
In-Reply-To: <87tvvtr9ge.fsf@gnu.org> ("Ludovic Courtès"'s message of "Wed, 10 Jan 2018 16:59:29 +0100")
On Wed 10 Jan 2018 16:59, ludo@gnu.org (Ludovic Courtès) writes:
> ludo@gnu.org (Ludovic Courtès) skribis:
>
>> As discussed on IRC, ‘get-bytevector-some’ returns only 1 byte from
>> unbuffered ports:
>
> Here’s a tentative fix. WDYT?
Thanks! Needs a little work though :) Comments inline.
> --- a/libguile/ports.h
> +++ b/libguile/ports.h
> @@ -69,6 +69,7 @@ SCM_INTERNAL SCM scm_i_port_weak_set;
> #define SCM_OPOUTPORTP(x) (SCM_OPPORTP (x) && SCM_OUTPUT_PORT_P (x))
> #define SCM_OPENP(x) (SCM_OPPORTP (x))
> #define SCM_CLOSEDP(x) (!SCM_OPENP (x))
> +#define SCM_UNBUFFEREDP(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_BUF0))
> #define SCM_CLR_PORT_OPEN_FLAG(p) \
> SCM_SET_CELL_WORD_0 ((p), SCM_CELL_WORD_0 (p) & ~SCM_OPN)
> #ifdef BUILDING_LIBGUILE
Please guard this under #ifdef BUILDING_LIBGUILE.
> @@ -487,16 +487,33 @@ SCM_DEFINE (scm_get_bytevector_some, "get-bytevector-some", 1, 0, 0,
>
> SCM_VALIDATE_BINARY_INPUT_PORT (1, port);
>
> - buf = scm_fill_input (port, 0, &cur, &avail);
> - if (avail == 0)
> + if (SCM_UNBUFFEREDP (port))
> {
> - scm_port_buffer_set_has_eof_p (buf, SCM_BOOL_F);
> - return SCM_EOF_VAL;
> + size_t read;
> +
> + bv = scm_c_make_bytevector (4096);
> + read = scm_i_read_bytes (port, bv, 0, SCM_BYTEVECTOR_LENGTH (bv));
> +
> + if (read == 0)
> + return SCM_EOF_VAL;
> + else if (read < SCM_BYTEVECTOR_LENGTH (bv))
> + return scm_c_shrink_bytevector (bv, read);
> + else
> + return bv;
> }
> + else
> + {
> + buf = scm_fill_input (port, 0, &cur, &avail);
> + if (avail == 0)
> + {
> + scm_port_buffer_set_has_eof_p (buf, SCM_BOOL_F);
> + return SCM_EOF_VAL;
> + }
>
> - bv = scm_c_make_bytevector (avail);
> - scm_port_buffer_take (buf, (scm_t_uint8 *) SCM_BYTEVECTOR_CONTENTS (bv),
> - avail, cur, avail);
> + bv = scm_c_make_bytevector (avail);
> + scm_port_buffer_take (buf, (scm_t_uint8 *) SCM_BYTEVECTOR_CONTENTS (bv),
> + avail, cur, avail);
> + }
>
> return bv;
> }
There are tabs in your code; would you mind doing only spaces?
A port being unbuffered doesn't mean that it has no bytes in its
buffer. In particular, scm_unget_bytes may put bytes back into the
buffer. Or, peek-u8 might fill this buffer with one byte.
Also, they port may have buffered write bytes (could be the port has
write buffering but no read buffering). In that case (pt->rw_random)
you need to scm_flush().
I suggest taking the buffered bytes from the read buffer, if any. Then
if the port is unbuffered, make a bytevector and call scm_i_read_bytes;
otherwise do the scm_fill_input path that's there already.
One more thing, if the port goes EOF, you need to
scm_port_buffer_set_has_eof_p.
Regards,
Andy
next prev parent reply other threads:[~2018-01-10 16:32 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 15:02 bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports Ludovic Courtès
2018-01-10 15:59 ` Ludovic Courtès
2018-01-10 16:32 ` Andy Wingo [this message]
2018-01-10 16:58 ` Nala Ginrut
2018-01-10 17:26 ` Andy Wingo
2018-01-10 17:43 ` Nala Ginrut
2018-01-11 14:34 ` Ludovic Courtès
2018-01-11 19:55 ` Mark H Weaver
2018-01-11 21:02 ` Ludovic Courtès
2018-01-11 21:55 ` Mark H Weaver
2018-01-12 9:01 ` Andy Wingo
2018-01-12 10:15 ` Ludovic Courtès
2018-01-12 10:33 ` Andy Wingo
2018-01-13 20:53 ` Ludovic Courtès
2018-02-16 13:19 ` Ludovic Courtès
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