1 /* Copyright (C) 2001, 2006 Free Software Foundation, Inc.
2 *
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public
5 * License as published by the Free Software Foundation; either
6 * version 2.1 of the License, or (at your option) any later version.
7 *
8 * This library is distributed in the hope that it will be useful,
9 * but 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.
12 *
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 02110-1301 USA
16 */
17
18
19
20 /* This is the C part of the (ice-9 rw) module. */
21
22 #ifdef HAVE_CONFIG_H
23 # include <config.h>
24 #endif
25
26 #include <errno.h>
27 #include <string.h>
28
29 #include "libguile/_scm.h"
30 #include "libguile/fports.h"
31 #include "libguile/ports.h"
32 #include "libguile/root.h"
33 #include "libguile/rw.h"
34 #include "libguile/strings.h"
35 #include "libguile/validate.h"
36 #include "libguile/modules.h"
37 #include "libguile/strports.h"
38
39 #ifdef HAVE_UNISTD_H
40 #include <unistd.h>
41 #endif
42 #ifdef HAVE_IO_H
43 #include <io.h>
44 #endif
45
46
47
48 #if defined (EAGAIN)
49 #define SCM_MAYBE_EAGAIN || errno == EAGAIN
50 #else
51 #define SCM_MAYBE_EAGAIN
52 #endif
53
54 #if defined (EWOULDBLOCK)
55 #define SCM_MAYBE_EWOULDBLOCK || errno == EWOULDBLOCK
56 #else
57 #define SCM_MAYBE_EWOULDBLOCK
58 #endif
59
60 /* MAYBE there is EAGAIN way of defining this macro but now I EWOULDBLOCK. */
61 #define SCM_EBLOCK(errno) \
62 (0 SCM_MAYBE_EAGAIN SCM_MAYBE_EWOULDBLOCK)
63
64 SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0,
65 (SCM str, SCM port_or_fdes, SCM start, SCM end),
66 "Read characters from a port or file descriptor into a\n"
67 "string @var{str}. A port must have an underlying file\n"
68 "descriptor --- a so-called fport. This procedure is\n"
69 "scsh-compatible and can efficiently read large strings.\n"
70 "It will:\n\n"
71 "@itemize\n"
72 "@item\n"
73 "attempt to fill the entire string, unless the @var{start}\n"
74 "and/or @var{end} arguments are supplied. i.e., @var{start}\n"
75 "defaults to 0 and @var{end} defaults to\n"
76 "@code{(string-length str)}\n"
77 "@item\n"
78 "use the current input port if @var{port_or_fdes} is not\n"
79 "supplied.\n"
80 "@item\n"
81 "return fewer than the requested number of characters in some\n"
82 "cases, e.g., on end of file, if interrupted by a signal, or if\n"
83 "not all the characters are immediately available.\n"
84 "@item\n"
85 "wait indefinitely for some input if no characters are\n"
86 "currently available,\n"
87 "unless the port is in non-blocking mode.\n"
88 "@item\n"
89 "read characters from the port's input buffers if available,\n"
90 "instead from the underlying file descriptor.\n"
91 "@item\n"
92 "return @code{#f} if end-of-file is encountered before reading\n"
93 "any characters, otherwise return the number of characters\n"
94 "read.\n"
95 "@item\n"
96 "return 0 if the port is in non-blocking mode and no characters\n"
97 "are immediately available.\n"
98 "@item\n"
99 "return 0 if the request is for 0 bytes, with no\n"
100 "end-of-file check.\n"
101 "@end itemize")
102 #define FUNC_NAME s_scm_read_string_x_partial
103 {
104 char *dest;
105 size_t offset;
106 long read_len;
107 long chars_read = 0;
108 int fdes;
109
110 {
111 size_t last;
112
113 SCM_VALIDATE_STRING (1, str);
114 scm_i_get_substring_spec (scm_i_string_length (str),
115 start, &offset, end, &last);
116 read_len = last - offset;
117 }
118
119 if (scm_is_integer (port_or_fdes))
120 fdes = scm_to_int (port_or_fdes);
121 else
122 {
123 SCM port = (SCM_UNBNDP (port_or_fdes)?
124 scm_current_input_port () : port_or_fdes);
125
126 SCM_VALIDATE_OPFPORT (2, port);
127 SCM_VALIDATE_INPUT_PORT (2, port);
128
129 /* if there's anything in the port buffers, use it, but then
130 don't touch the file descriptor. otherwise the
131 "return immediately if something is available" rule may
132 be violated. */
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);
137 }
138
139 if (chars_read == 0 && read_len > 0) /* don't confuse read_len == 0 with
140 EOF. */
141 {
142 dest = scm_i_string_writable_chars (str) + offset;
143 SCM_SYSCALL (chars_read = read (fdes, dest, read_len));
144 scm_i_string_stop_writing ();
145 if (chars_read == -1)
146 {
147 if (SCM_EBLOCK (errno))
148 chars_read = 0;
149 else
150 SCM_SYSERROR;
151 }
152 else if (chars_read == 0)
153 {
154 scm_remember_upto_here_1 (str);
155 return SCM_BOOL_F;
156 }
157 }
158
159 scm_remember_upto_here_1 (str);
160 return scm_from_long (chars_read);
161 }
162 #undef FUNC_NAME
163
164 SCM_DEFINE (scm_write_string_partial, "write-string/partial", 1, 3, 0,
165 (SCM str, SCM port_or_fdes, SCM start, SCM end),
166 "Write characters from a string @var{str} to a port or file\n"
167 "descriptor. A port must have an underlying file descriptor\n"
168 "--- a so-called fport. This procedure is\n"
169 "scsh-compatible and can efficiently write large strings.\n"
170 "It will:\n\n"
171 "@itemize\n"
172 "@item\n"
173 "attempt to write the entire string, unless the @var{start}\n"
174 "and/or @var{end} arguments are supplied. i.e., @var{start}\n"
175 "defaults to 0 and @var{end} defaults to\n"
176 "@code{(string-length str)}\n"
177 "@item\n"
178 "use the current output port if @var{port_of_fdes} is not\n"
179 "supplied.\n"
180 "@item\n"
181 "in the case of a buffered port, store the characters in the\n"
182 "port's output buffer, if all will fit. If they will not fit\n"
183 "then any existing buffered characters will be flushed\n"
184 "before attempting\n"
185 "to write the new characters directly to the underlying file\n"
186 "descriptor. If the port is in non-blocking mode and\n"
187 "buffered characters can not be flushed immediately, then an\n"
188 "@code{EAGAIN} system-error exception will be raised (Note:\n"
189 "scsh does not support the use of non-blocking buffered ports.)\n"
190 "@item\n"
191 "write fewer than the requested number of\n"
192 "characters in some cases, e.g., if interrupted by a signal or\n"
193 "if not all of the output can be accepted immediately.\n"
194 "@item\n"
195 "wait indefinitely for at least one character\n"
196 "from @var{str} to be accepted by the port, unless the port is\n"
197 "in non-blocking mode.\n"
198 "@item\n"
199 "return the number of characters accepted by the port.\n"
200 "@item\n"
201 "return 0 if the port is in non-blocking mode and can not accept\n"
202 "at least one character from @var{str} immediately\n"
203 "@item\n"
204 "return 0 immediately if the request size is 0 bytes.\n"
205 "@end itemize")
206 #define FUNC_NAME s_scm_write_string_partial
207 {
208 const char *src;
209 long write_len;
210 int fdes;
211
212 {
213 size_t offset;
214 size_t last;
215
216 SCM_VALIDATE_STRING (1, str);
217 src = scm_i_string_chars (str);
218 scm_i_get_substring_spec (scm_i_string_length (str),
219 start, &offset, end, &last);
220 src += offset;
221 write_len = last - offset;
222 }
223
224 if (write_len == 0)
225 return SCM_INUM0;
226
227 if (scm_is_integer (port_or_fdes))
228 fdes = scm_to_int (port_or_fdes);
229 else
230 {
231 SCM port = (SCM_UNBNDP (port_or_fdes)?
232 scm_current_output_port () : port_or_fdes);
233 scm_t_port *pt;
234 off_t space;
235
236 SCM_VALIDATE_OPFPORT (2, port);
237 SCM_VALIDATE_OUTPUT_PORT (2, port);
238 pt = SCM_PTAB_ENTRY (port);
239 /* filling the last character in the buffer would require a flush. */
240 space = pt->write_end - pt->write_pos - 1;
241 if (space >= write_len)
242 {
243 memcpy (pt->write_pos, src, write_len);
244 pt->write_pos += write_len;
245 return scm_from_long (write_len);
246 }
247 if (pt->write_pos > pt->write_buf)
248 scm_flush (port);
249 fdes = SCM_FPORT_FDES (port);
250 }
251 {
252 long rv;
253
254 SCM_SYSCALL (rv = write (fdes, src, write_len));
255 if (rv == -1)
256 {
257 if (SCM_EBLOCK (errno))
258 rv = 0;
259 else
260 SCM_SYSERROR;
261 }
262
263 scm_remember_upto_here_1 (str);
264 return scm_from_long (rv);
265 }
266 }
267 #undef FUNC_NAME
268
269 SCM
scm_init_rw_builtins()270 scm_init_rw_builtins ()
271 {
272 #include "libguile/rw.x"
273
274 return SCM_UNSPECIFIED;
275 }
276
277 void
scm_init_rw()278 scm_init_rw ()
279 {
280 scm_c_define_gsubr ("%init-rw-builtins", 0, 0, 0, scm_init_rw_builtins);
281 }
282
283 /*
284 Local Variables:
285 c-file-style: "gnu"
286 End:
287 */
288