mirror/guile
mirror/guile
1
Fork 0
mirror of https://git.savannah.gnu.org/git/guile.git synced 2025-06-30 06:50:31 +02:00
Code Activity

* rw.c (scm_write_string_partial): new procedure implementing

Browse source 
write-string/partial in (ice-9 rw).
	* rw.h: declare scm_write_string_partial.
This commit is contained in:
Gary Houston 2001-06-04 21:48:25 +00:00
parent f480396be5
commit 99004a2863
2 changed files with 120 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

124
libguile/rw.c
View file

@ -79,9 +79,11 @@
SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0,
(SCM str, SCM port_or_fdes, SCM start, SCM end),
"Read characters from an fport or file descriptor into a\n"
"string @var{str}. This procedure is scsh-compatible\n"
"and can efficiently read large strings. It will:\n\n"
"Read characters from a port or file descriptor into a\n"
"string @var{str}. A port must have an underlying file\n"
"descriptor --- a so-called fport. This procedure is\n"
"scsh-compatible and can efficiently read large strings.\n"
"It will:\n\n"
"@itemize\n"
"@item\n"
"attempt to fill the entire string, unless the @var{start}\n"
@ -92,11 +94,16 @@ SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0,
"use the current input port if @var{port_or_fdes} is not\n"
"supplied.\n"
"@item\n"
"read any characters that are currently available,\n"
"without waiting for the rest (short reads are possible).\n\n"
"return fewer than the requested number of characters in some\n"
"cases, e.g., on end of file, if interrupted by a signal, or if\n"
"not all the characters are immediately available.\n"
"@item\n"
"wait for as long as it needs to for the first character to\n"
"become available, unless the port is in non-blocking mode\n"
"wait indefinitely for some input if no characters are\n"
"currently available,\n"
"unless the port is in non-blocking mode.\n"
"@item\n"
"read characters from the port's input buffers if available,\n"
"instead from the underlying file descriptor.\n"
"@item\n"
"return @code{#f} if end-of-file is encountered before reading\n"
"any characters, otherwise return the number of characters\n"
@ -106,7 +113,7 @@ SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0,
"are immediately available.\n"
"@item\n"
"return 0 if the request is for 0 bytes, with no\n"
"end-of-file check\n"
"end-of-file check.\n"
"@end itemize")
#define FUNC_NAME s_scm_read_string_x_partial
{
@ -160,6 +167,107 @@ SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0,
}
#undef FUNC_NAME
SCM_DEFINE (scm_write_string_partial, "write-string/partial", 1, 3, 0,
(SCM str, SCM port_or_fdes, SCM start, SCM end),
"Write characters from a string @var{str} to a port or file\n"
"descriptor. A port must have an underlying file descriptor\n"
"--- a so-called fport. This procedure is\n"
"scsh-compatible and can efficiently write large strings.\n"
"It will:\n\n"
"@itemize\n"
"@item\n"
"attempt to write the entire string, unless the @var{start}\n"
"and/or @var{end} arguments are supplied. i.e., @var{start}\n"
"defaults to 0 and @var{end} defaults to\n"
"@code{(string-length str)}\n"
"@item\n"
"use the current output port if @var{port_of_fdes} is not\n"
"supplied.\n"
"@item\n"
"in the case of a buffered port, store the characters in the\n"
"port's output buffer, if all will fit. If they will not fit\n"
"then any existing buffered characters will be flushed\n"
"before attempting\n"
"to write the new characters directly to the underlying file\n"
"descriptor. If the port is in non-blocking mode and\n"
"buffered characters can not be flushed immediately, then an\n"
"@code{EAGAIN} system-error exception will be raised (Note:\n"
"scsh does not support the use of non-blocking buffered ports.)\n"
"@item\n"
"write fewer than the requested number of\n"
"characters in some cases, e.g., if interrupted by a signal or\n"
"if not all of the output can be accepted immediately.\n"
"@item\n"
"wait indefinitely for at least one character\n"
"from @var{str} to be accepted by the port, unless the port is\n"
"in non-blocking mode.\n"
"@item\n"
"return the number of characters accepted by the port.\n"
"@item\n"
"return 0 if the port is in non-blocking mode and can not accept\n"
"at least one character from @var{str} immediately\n"
"@item\n"
"return 0 immediately if the request size is 0 bytes.\n"
"@end itemize")
#define FUNC_NAME s_scm_write_string_partial
{
char *src;
long write_len;
int fdes;
{
long offset;
long last;
SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, src, 3, start, offset,
4, end, last);
src += offset;
write_len = last - offset;
}
if (write_len == 0)
return SCM_INUM0;
if (SCM_INUMP (port_or_fdes))
fdes = SCM_INUM (port_or_fdes);
else
{
SCM port = SCM_UNBNDP (port_or_fdes) ? scm_cur_outp : port_or_fdes;
scm_port_t *pt;
off_t space;
SCM_VALIDATE_OPFPORT (2, port);
SCM_VALIDATE_OUTPUT_PORT (2, port);
pt = SCM_PTAB_ENTRY (port);
/* filling the last character in the buffer would require a flush. */
space = pt->write_end - pt->write_pos - 1;
if (space >= write_len)
{
memcpy (pt->write_pos, src, write_len);
pt->write_pos += write_len;
return scm_long2num (write_len);
}
if (pt->write_pos > pt->write_buf)
scm_flush (port);
fdes = SCM_FPORT_FDES (port);
}
{
long rv;
SCM_SYSCALL (rv = write (fdes, src, write_len));
if (rv == -1)
{
if (SCM_EBLOCK (errno))
rv = 0;
else
SCM_SYSERROR;
}
return scm_long2num (rv);
}
}
#undef FUNC_NAME
SCM
scm_init_rw_builtins ()
{

6
libguile/rw.h
View file

@ -13,8 +13,7 @@
* 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
* * You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA
@ -48,6 +47,9 @@
extern SCM scm_read_string_x_partial (SCM str, SCM port_or_fdes, SCM start,
SCM end);
extern SCM scm_write_string_partial (SCM str, SCM port_or_fdes, SCM start,
SCM end);
SCM scm_init_rw_builtins (void);
void scm_init_rw (void);