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date Mon, 13 Aug 2007 08:45:50 +0200
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1 /* Generic stream implementation -- header file.
2 Copyright (C) 1995 Free Software Foundation, Inc.
3 Copyright (C) 1996 Ben Wing.
4
5 This file is part of XEmacs.
6
7 XEmacs is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
10 later version.
11
12 XEmacs is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with XEmacs; see the file COPYING. If not, write to
19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
21
22 /* Synched up with: Not in FSF. */
23
24 /* Written by Ben Wing. */
25
26 #ifndef _XEMACS_LSTREAM_H_
27 #define _XEMACS_LSTREAM_H_
28
29 /************************************************************************/
30 /* definition of Lstream object */
31 /************************************************************************/
32
33 DECLARE_LRECORD (lstream, struct lstream);
34 #define XLSTREAM(x) XRECORD (x, lstream, struct lstream)
35 #define XSETLSTREAM(x, p) XSETRECORD (x, p, lstream)
36 #define LSTREAMP(x) RECORDP (x, lstream)
37 /* #define CHECK_LSTREAM(x) CHECK_RECORD (x, lstream)
38 Lstream pointers should never escape to the Lisp level, so
39 functions should not be doing this. */
40
41 #ifndef EOF
42 #define EOF (-1)
43 #endif
44
45 typedef enum lstream_buffering
46 {
47 /* No buffering. */
48 LSTREAM_UNBUFFERED,
49 /* Buffer until a '\n' character is reached. */
50 LSTREAM_LINE_BUFFERED,
51 /* Buffer in standard-size (i.e. 512-byte) blocks. */
52 LSTREAM_BLOCK_BUFFERED,
53 /* Buffer in blocks of a specified size. */
54 LSTREAM_BLOCKN_BUFFERED,
55 /* Buffer until the stream is closed (only applies to write-only
56 streams). Only one call to the stream writer will be made,
57 and that is when the stream is closed. */
58 LSTREAM_UNLIMITED
59 } Lstream_buffering;
60
61 /* Methods defining how this stream works. Some may be undefined. */
62
63 /* We do not implement the seek/tell paradigm. I tried to do that,
64 but getting the semantics right in the presence of buffering is
65 extremely tricky and very error-prone and basically not worth it.
66 This is especially the case with complicated streams like
67 decoding streams -- the seek pointer in this case can't be a single
68 integer but has to be a whole complicated structure that records
69 all of the stream's state at the time.
70
71 Rewind semantics are generally easy to implement, so we do provide
72 a rewind method. Even rewind() may not be available on a stream,
73 however -- e.g. on process output. */
74
75 typedef struct lstream_implementation
76 {
77 CONST char *name;
78 int size; /* Number of additional bytes to be allocated with this
79 stream. Access this data using Lstream_data(). */
80 /* Read some data from the stream's end and store it into DATA, which
81 can hold SIZE bytes. Return the number of bytes read. A return
82 value of 0 means no bytes can be read at this time. This may
83 be because of an EOF, or because there is a granularity greater
84 than one byte that the stream imposes on the returned data, and
85 SIZE is less than this granularity. (This will happen frequently
86 for streams that need to return whole characters, because
87 Lstream_read() calls the reader function repeatedly until it
88 has the number of bytes it wants or until 0 is returned.)
89 The lstream functions do not treat a 0 return as EOF or do
90 anything special; however, the calling function will interpret
91 any 0 it gets back as EOF. This will normally not happen unless
92 the caller calls Lstream_read() with a very small size.
93
94 This function can be NULL if the stream is output-only. */
95 /* The omniscient mly, blinded by the irresistable thrall of Common
96 Lisp, thinks that it is bogus that the types and implementations
97 of input and output streams are the same. */
98 int (*reader) (Lstream *stream, unsigned char *data, int size);
99 /* Send some data to the stream's end. Data to be sent is in DATA
100 and is SIZE bytes. Return the number of bytes sent. This
101 function can send and return fewer bytes than is passed in; in
102 that case, the function will just be called again until there is
103 no data left or 0 is returned. A return value of 0 means that no
104 more data can be currently stored, but there is no error; the
105 data will be squirrelled away until the writer can accept
106 data. (This is useful, e.g., of you're dealing with a
107 non-blocking file descriptor and are getting EWOULDBLOCK errors.)
108 This function can be NULL if the stream is input-only. */
109 int (*writer) (Lstream *stream, CONST unsigned char *data, int size);
110 /* Rewind the stream. If this is NULL, the stream is not seekable. */
111 int (*rewinder) (Lstream *stream);
112 /* Indicate whether this stream is seekable -- i.e. it can be rewound.
113 This method is ignored if the stream does not have a rewind
114 method. If this method is not present, the result is determined
115 by whether a rewind method is present. */
116 int (*seekable_p) (Lstream *stream);
117 /* Perform any additional operations necessary to flush the
118 data in this stream. */
119 int (*flusher) (Lstream *stream);
120 /* Perform any additional operations necessary to close this
121 stream down. May be NULL. This function is called when
122 Lstream_close() is called or when the stream is garbage-
123 collected. When this function is called, all pending data
124 in the stream will already have been written out. */
125 int (*closer) (Lstream *stream);
126 /* Mark this object for garbage collection. Same semantics as
127 a standard Lisp_Object marker. This function can be NULL. */
128 Lisp_Object (*marker) (Lisp_Object lstream, void (*markfun) (Lisp_Object));
129 } Lstream_implementation;
130
131 #define DEFINE_LSTREAM_IMPLEMENTATION(name,c_name,size) \
132 Lstream_implementation c_name[1] = \
133 { { (name), (size) } }
134
135 #define LSTREAM_FL_IS_OPEN 1
136 #define LSTREAM_FL_READ 2
137 #define LSTREAM_FL_WRITE 4
138 #define LSTREAM_FL_NO_PARTIAL_CHARS 8
139
140 struct lstream
141 {
142 struct lcrecord_header header;
143 CONST Lstream_implementation *imp; /* methods for this stream */
144 Lstream_buffering buffering; /* type of buffering in use */
145 int buffering_size; /* number of bytes buffered */
146
147 unsigned char *in_buffer; /* holds characters read from stream end */
148 int in_buffer_size; /* allocated size of buffer */
149 int in_buffer_current; /* number of characters in buffer */
150 int in_buffer_ind; /* pointer to next character to take from buffer */
151
152 unsigned char *out_buffer; /* holds characters to write to stream end */
153 int out_buffer_size; /* allocated size of buffer */
154 int out_buffer_ind; /* pointer to next buffer spot to write a character */
155
156 /* The unget buffer is more or less a stack -- things get pushed
157 onto the end and read back from the end. Lstream_read()
158 basically reads backwards from the end to get stuff; Lstream_unread()
159 similarly has to push the data on backwards. */
160 unsigned char *unget_buffer; /* holds characters pushed back onto input */
161 int unget_buffer_size; /* allocated size of buffer */
162 int unget_buffer_ind; /* pointer to next buffer spot to write a character */
163
164 int byte_count;
165 long flags; /* Align pointer for 64 bit machines (kny) */
166 char data[1];
167 };
168
169 #define LSTREAM_TYPE_P(lstr, type) \
170 ((lstr)->imp == lstream_##type)
171
172 #ifdef ERROR_CHECK_TYPECHECK
173 MAC_DECLARE_EXTERN (struct lstream *, MTlstream_data)
174 # define LSTREAM_TYPE_DATA(lstr, type) \
175 MAC_BEGIN \
176 MAC_DECLARE (struct lstream *, MTlstream_data, lstr) \
177 assert (LSTREAM_TYPE_P (MTlstream_data, type)) \
178 MAC_SEP \
179 (struct type##_stream *) Lstream_data (MTlstream_data) \
180 MAC_END
181 #else
182 # define LSTREAM_TYPE_DATA(lstr, type) \
183 ((struct type##_stream *) Lstream_data (lstr))
184 #endif
185
186 /* Declare that lstream-type TYPE has method M; used in
187 initialization routines */
188 #define LSTREAM_HAS_METHOD(type, m) \
189 (lstream_##type->m = type##_##m)
190
191
192 Lstream *Lstream_new (CONST Lstream_implementation *imp,
193 CONST char *mode);
194 void Lstream_reopen (Lstream *lstr);
195 void Lstream_set_buffering (Lstream *lstr, Lstream_buffering buffering,
196 int buffering_size);
197 int Lstream_flush (Lstream *lstr);
198 int Lstream_flush_out (Lstream *lstr);
199 int Lstream_fputc (Lstream *lstr, int c);
200 int Lstream_fgetc (Lstream *lstr);
201 void Lstream_fungetc (Lstream *lstr, int c);
202 int Lstream_read (Lstream *lstr, void *data, int size);
203 int Lstream_write (Lstream *lstr, CONST void *data, int size);
204 void Lstream_unread (Lstream *lstr, CONST void *data, int size);
205 int Lstream_rewind (Lstream *lstr);
206 int Lstream_seekable_p (Lstream *lstr);
207 int Lstream_close (Lstream *lstr);
208 void Lstream_delete (Lstream *lstr);
209 void Lstream_set_character_mode (Lstream *str);
210
211 /* Call the function equivalent if the out buffer is full. Otherwise,
212 add to the end of the out buffer and, if line buffering is called for
213 and the character marks the end of a line, write out the buffer. */
214
215 #define Lstream_putc(stream, c) \
216 ((stream)->out_buffer_ind >= (stream)->out_buffer_size ? \
217 Lstream_fputc (stream, c) : \
218 ((stream)->out_buffer[(stream)->out_buffer_ind++] = \
219 (unsigned char) (c), \
220 (stream)->byte_count++, \
221 (stream)->buffering == LSTREAM_LINE_BUFFERED && \
222 (stream)->out_buffer[(stream)->out_buffer_ind - 1] == '\n' ? \
223 Lstream_flush_out (stream) : 0))
224
225 /* Retrieve from unget buffer if there are any characters there;
226 else retrieve from in buffer if there's anything there;
227 else call the function equivalent */
228 #define Lstream_getc(stream) \
229 ((stream)->unget_buffer_ind > 0 ? \
230 ((stream)->byte_count++, \
231 (stream)->unget_buffer[--(stream)->unget_buffer_ind]) : \
232 (stream)->in_buffer_ind < (stream)->in_buffer_current ? \
233 ((stream)->byte_count++, \
234 (stream)->in_buffer[(stream)->in_buffer_ind++]) : \
235 Lstream_fgetc (stream))
236
237 /* Add to the end if it won't overflow buffer; otherwise call the
238 function equivalent */
239 #define Lstream_ungetc(stream, c) \
240 ((stream)->unget_buffer_ind >= (stream)->unget_buffer_size ? \
241 Lstream_fungetc (stream, c) : \
242 (void) ((stream)->byte_count--, \
243 ((stream)->unget_buffer[(stream)->unget_buffer_ind++] = \
244 (unsigned char) (c))))
245
246 #define Lstream_data(stream) ((void *) ((stream)->data))
247 #define Lstream_byte_count(stream) ((stream)->byte_count)
248
249
250
251 /************************************************************************/
252 /* working with an Lstream as a stream of Emchars */
253 /************************************************************************/
254
255 # define Lstream_get_emchar(stream) Lstream_getc (stream)
256 # define Lstream_put_emchar(stream, ch) Lstream_putc (stream, ch)
257 # define Lstream_unget_emchar(stream, ch) Lstream_ungetc (stream, ch)
258
259
260
261 /************************************************************************/
262 /* Lstream implementations */
263 /************************************************************************/
264
265 /* Flags we can pass to the filedesc and stdio streams. */
266
267 /* If set, close the descriptor or FILE * when the stream is closed. */
268 #define LSTR_CLOSING 1
269
270 /* If set, allow quitting out of the actual I/O. */
271 #define LSTR_ALLOW_QUIT 2
272
273 /* If set and filedesc_stream_set_pty_flushing() has been called
274 on the stream, do not send more than pty_max_bytes on a single
275 line without flushing the data out using the eof_char. */
276 #define LSTR_PTY_FLUSHING 4
277
278 /* If set, an EWOULDBLOCK error is not treated as an error but
279 simply causes the write function to return 0 as the number
280 of bytes written out. */
281 #define LSTR_BLOCKED_OK 8
282
283 Lisp_Object make_stdio_input_stream (FILE *stream, int flags);
284 Lisp_Object make_stdio_output_stream (FILE *stream, int flags);
285 Lisp_Object make_filedesc_input_stream (int filedesc, int offset, int count,
286 int flags);
287 Lisp_Object make_filedesc_output_stream (int filedesc, int offset, int count,
288 int flags);
289 void filedesc_stream_set_pty_flushing (Lstream *stream,
290 int pty_max_bytes,
291 Bufbyte eof_char);
292 int filedesc_stream_was_blocked (Lstream *stream);
293 Lisp_Object make_lisp_string_input_stream (Lisp_Object string,
294 Bytecount offset,
295 Bytecount len);
296 Lisp_Object make_fixed_buffer_input_stream (CONST unsigned char *buf,
297 int size);
298 Lisp_Object make_fixed_buffer_output_stream (unsigned char *buf,
299 int size);
300 CONST unsigned char *fixed_buffer_input_stream_ptr (Lstream *stream);
301 unsigned char *fixed_buffer_output_stream_ptr (Lstream *stream);
302 Lisp_Object make_resizing_buffer_output_stream (void);
303 unsigned char *resizing_buffer_stream_ptr (Lstream *stream);
304 Lisp_Object make_dynarr_output_stream (unsigned_char_dynarr *dyn);
305 #define LSTR_SELECTIVE 1
306 #define LSTR_IGNORE_ACCESSIBLE 2
307 Lisp_Object make_lisp_buffer_input_stream (struct buffer *buf, Bufpos start,
308 Bufpos end, int flags);
309 Lisp_Object make_lisp_buffer_output_stream (struct buffer *buf, Bufpos pos,
310 int flags);
311 Bufpos lisp_buffer_stream_startpos (Lstream *stream);
312
313 #endif /* _XEMACS_LSTREAM_H_ */