1 /* Copyright (C) 2001, 2006, 2009, 2011, 2014 Free Software Foundation, Inc.
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public License
5 * as published by the Free Software Foundation; either version 3 of
6 * the License, or (at your option) any later version.
8 * This library is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * Lesser General Public License for more details.
13 * You should have received a copy of the GNU Lesser General Public
14 * License along with this library; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 /* This is the C part of the (ice-9 rw) module. */
30 #include "libguile/_scm.h"
31 #include "libguile/fports.h"
32 #include "libguile/ports.h"
33 #include "libguile/root.h"
34 #include "libguile/rw.h"
35 #include "libguile/strings.h"
36 #include "libguile/validate.h"
37 #include "libguile/modules.h"
38 #include "libguile/strports.h"
48 #define SCM_MAYBE_EAGAIN || errno == EAGAIN
50 #define SCM_MAYBE_EAGAIN
53 #if defined (EWOULDBLOCK)
54 #define SCM_MAYBE_EWOULDBLOCK || errno == EWOULDBLOCK
56 #define SCM_MAYBE_EWOULDBLOCK
59 /* MAYBE there is EAGAIN way of defining this macro but now I EWOULDBLOCK. */
60 #define SCM_EBLOCK(errno) \
61 (0 SCM_MAYBE_EAGAIN SCM_MAYBE_EWOULDBLOCK)
63 SCM_DEFINE (scm_read_string_x_partial
, "read-string!/partial", 1, 3, 0,
64 (SCM str
, SCM port_or_fdes
, SCM start
, SCM end
),
65 "Read characters from a port or file descriptor into a\n"
66 "string @var{str}. A port must have an underlying file\n"
67 "descriptor --- a so-called fport. This procedure is\n"
68 "scsh-compatible and can efficiently read large strings.\n"
72 "attempt to fill the entire string, unless the @var{start}\n"
73 "and/or @var{end} arguments are supplied. i.e., @var{start}\n"
74 "defaults to 0 and @var{end} defaults to\n"
75 "@code{(string-length str)}\n"
77 "use the current input port if @var{port_or_fdes} is not\n"
80 "return fewer than the requested number of characters in some\n"
81 "cases, e.g., on end of file, if interrupted by a signal, or if\n"
82 "not all the characters are immediately available.\n"
84 "wait indefinitely for some input if no characters are\n"
85 "currently available,\n"
86 "unless the port is in non-blocking mode.\n"
88 "read characters from the port's input buffers if available,\n"
89 "instead from the underlying file descriptor.\n"
91 "return @code{#f} if end-of-file is encountered before reading\n"
92 "any characters, otherwise return the number of characters\n"
95 "return 0 if the port is in non-blocking mode and no characters\n"
96 "are immediately available.\n"
98 "return 0 if the request is for 0 bytes, with no\n"
99 "end-of-file check.\n"
101 #define FUNC_NAME s_scm_read_string_x_partial
112 SCM_VALIDATE_STRING (1, str
);
113 scm_i_get_substring_spec (scm_i_string_length (str
),
114 start
, &offset
, end
, &last
);
115 read_len
= last
- offset
;
118 if (scm_is_integer (port_or_fdes
))
119 fdes
= scm_to_int (port_or_fdes
);
122 SCM port
= (SCM_UNBNDP (port_or_fdes
)?
123 scm_current_input_port () : port_or_fdes
);
125 SCM_VALIDATE_OPFPORT (2, port
);
126 SCM_VALIDATE_INPUT_PORT (2, port
);
128 /* if there's anything in the port buffers, use it, but then
129 don't touch the file descriptor. otherwise the
130 "return immediately if something is available" rule may
132 str
= scm_i_string_start_writing (str
);
133 dest
= scm_i_string_writable_chars (str
) + offset
;
134 chars_read
= scm_take_from_input_buffers (port
, dest
, read_len
);
135 scm_i_string_stop_writing ();
136 fdes
= SCM_FPORT_FDES (port
);
139 if (chars_read
== 0 && read_len
> 0) /* don't confuse read_len == 0 with
142 str
= scm_i_string_start_writing (str
);
143 dest
= scm_i_string_writable_chars (str
) + offset
;
144 SCM_SYSCALL (chars_read
= read (fdes
, dest
, read_len
));
145 scm_i_string_stop_writing ();
146 if (chars_read
== -1)
148 if (SCM_EBLOCK (errno
))
153 else if (chars_read
== 0)
155 scm_remember_upto_here_1 (str
);
160 scm_remember_upto_here_1 (str
);
161 return scm_from_long (chars_read
);
165 SCM_DEFINE (scm_write_string_partial
, "write-string/partial", 1, 3, 0,
166 (SCM str
, SCM port_or_fdes
, SCM start
, SCM end
),
167 "Write characters from a string @var{str} to a port or file\n"
168 "descriptor. A port must have an underlying file descriptor\n"
169 "--- a so-called fport. This procedure is\n"
170 "scsh-compatible and can efficiently write large strings.\n"
174 "attempt to write the entire string, unless the @var{start}\n"
175 "and/or @var{end} arguments are supplied. i.e., @var{start}\n"
176 "defaults to 0 and @var{end} defaults to\n"
177 "@code{(string-length str)}\n"
179 "use the current output port if @var{port_of_fdes} is not\n"
182 "in the case of a buffered port, store the characters in the\n"
183 "port's output buffer, if all will fit. If they will not fit\n"
184 "then any existing buffered characters will be flushed\n"
185 "before attempting\n"
186 "to write the new characters directly to the underlying file\n"
187 "descriptor. If the port is in non-blocking mode and\n"
188 "buffered characters can not be flushed immediately, then an\n"
189 "@code{EAGAIN} system-error exception will be raised (Note:\n"
190 "scsh does not support the use of non-blocking buffered ports.)\n"
192 "write fewer than the requested number of\n"
193 "characters in some cases, e.g., if interrupted by a signal or\n"
194 "if not all of the output can be accepted immediately.\n"
196 "wait indefinitely for at least one character\n"
197 "from @var{str} to be accepted by the port, unless the port is\n"
198 "in non-blocking mode.\n"
200 "return the number of characters accepted by the port.\n"
202 "return 0 if the port is in non-blocking mode and can not accept\n"
203 "at least one character from @var{str} immediately\n"
205 "return 0 immediately if the request size is 0 bytes.\n"
207 #define FUNC_NAME s_scm_write_string_partial
217 SCM_VALIDATE_STRING (1, str
);
218 src
= scm_i_string_chars (str
);
219 scm_i_get_substring_spec (scm_i_string_length (str
),
220 start
, &offset
, end
, &last
);
222 write_len
= last
- offset
;
228 if (scm_is_integer (port_or_fdes
))
229 fdes
= scm_to_int (port_or_fdes
);
232 SCM port
= (SCM_UNBNDP (port_or_fdes
)?
233 scm_current_output_port () : port_or_fdes
);
237 SCM_VALIDATE_OPFPORT (2, port
);
238 SCM_VALIDATE_OUTPUT_PORT (2, port
);
239 pt
= SCM_PTAB_ENTRY (port
);
240 /* filling the last character in the buffer would require a flush. */
241 space
= pt
->write_end
- pt
->write_pos
- 1;
242 if (space
>= write_len
)
244 memcpy (pt
->write_pos
, src
, write_len
);
245 pt
->write_pos
+= write_len
;
246 return scm_from_long (write_len
);
248 if (pt
->write_pos
> pt
->write_buf
)
249 scm_flush_unlocked (port
);
250 fdes
= SCM_FPORT_FDES (port
);
255 SCM_SYSCALL (rv
= write (fdes
, src
, write_len
));
258 if (SCM_EBLOCK (errno
))
264 scm_remember_upto_here_1 (str
);
265 return scm_from_long (rv
);
271 scm_init_rw_builtins ()
273 #include "libguile/rw.x"
275 return SCM_UNSPECIFIED
;
281 scm_c_define_gsubr ("%init-rw-builtins", 0, 0, 0, scm_init_rw_builtins
);