1 /* Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2005, 2006,
2 * 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public License
6 * as published by the Free Software Foundation; either version 3 of
7 * the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
27 #include "libguile/_scm.h"
34 #include "libguile/bytevectors.h"
35 #include "libguile/eval.h"
36 #include "libguile/ports.h"
37 #include "libguile/read.h"
38 #include "libguile/root.h"
39 #include "libguile/strings.h"
40 #include "libguile/modules.h"
41 #include "libguile/validate.h"
42 #include "libguile/deprecation.h"
43 #include "libguile/srfi-4.h"
45 #include "libguile/strports.h"
53 /* {Ports - string ports}
59 write_buf/write_end point to the ends of the allocated bytevector.
60 read_buf/read_end point to the part of the bytevector which has been
61 written to. read_pos and write_pos are always equal.
63 ENHANCE-ME - output blocks:
65 The current code keeps an output string as a single block. That means
66 when the size is increased the entire old contents must be copied. It'd
67 be more efficient to begin a new block when the old one is full, so
68 there's no re-copying of previous data.
70 To make seeking efficient, keeping the pieces in a vector might be best,
71 though appending is probably the most common operation. The size of each
72 block could be progressively increased, so the bigger the string the
75 When `get-output-string' is called the blocks have to be coalesced into a
76 string, the result could be kept as a single big block. If blocks were
77 strings then `get-output-string' could notice when there's just one and
78 return that with a copy-on-write (though repeated calls to
79 `get-output-string' are probably unlikely).
81 Another possibility would be to extend the port mechanism to let SCM
82 strings come through directly from `display' and friends. That way if a
83 big string is written it can be kept as a copy-on-write, saving time
84 copying and maybe saving some space. */
87 scm_t_bits scm_tc16_strport
;
91 st_fill_input (SCM port
)
93 scm_t_port
*pt
= SCM_PTAB_ENTRY (port
);
95 if (pt
->read_pos
>= pt
->read_end
)
101 /* Change the size of a port's bytevector to NEW_SIZE. This doesn't
102 change `read_buf_size'. */
104 st_resize_port (scm_t_port
*pt
, scm_t_off new_size
)
106 SCM old_stream
= SCM_PACK (pt
->stream
);
107 const signed char *src
= SCM_BYTEVECTOR_CONTENTS (old_stream
);
108 SCM new_stream
= scm_c_make_bytevector (new_size
);
109 signed char *dst
= SCM_BYTEVECTOR_CONTENTS (new_stream
);
110 unsigned long int old_size
= SCM_BYTEVECTOR_LENGTH (old_stream
);
111 unsigned long int min_size
= min (old_size
, new_size
);
113 scm_t_off offset
= pt
->write_pos
- pt
->write_buf
;
115 pt
->write_buf_size
= new_size
;
117 memcpy (dst
, src
, min_size
);
119 scm_remember_upto_here_1 (old_stream
);
123 pt
->stream
= SCM_UNPACK (new_stream
);
124 pt
->read_buf
= pt
->write_buf
= (unsigned char *)dst
;
125 pt
->read_pos
= pt
->write_pos
= pt
->write_buf
+ offset
;
126 pt
->write_end
= pt
->write_buf
+ pt
->write_buf_size
;
127 pt
->read_end
= pt
->read_buf
+ pt
->read_buf_size
;
132 st_write (SCM port
, const void *data
, size_t size
)
134 scm_t_port
*pt
= SCM_PTAB_ENTRY (port
);
136 if (size
> pt
->write_end
- pt
->write_pos
)
137 st_resize_port (pt
, max (pt
->write_buf_size
* 2,
138 pt
->write_end
- pt
->write_pos
+ size
));
140 memcpy ((char *) pt
->write_pos
, data
, size
);
141 pt
->read_pos
= (pt
->write_pos
+= size
);
143 if (pt
->read_pos
> pt
->read_end
)
145 pt
->read_end
= (unsigned char *) pt
->read_pos
;
146 pt
->read_buf_size
= pt
->read_end
- pt
->read_buf
;
151 st_end_input (SCM port
, int offset
)
153 scm_t_port
*pt
= SCM_PTAB_ENTRY (port
);
155 if (pt
->read_pos
- pt
->read_buf
< offset
)
156 scm_misc_error ("st_end_input", "negative position", SCM_EOL
);
158 pt
->write_pos
= (unsigned char *) (pt
->read_pos
= pt
->read_pos
- offset
);
159 pt
->rw_active
= SCM_PORT_NEITHER
;
163 st_seek (SCM port
, scm_t_off offset
, int whence
)
165 scm_t_port
*pt
= SCM_PTAB_ENTRY (port
);
168 if (pt
->rw_active
== SCM_PORT_READ
&& offset
== 0 && whence
== SEEK_CUR
)
169 /* special case to avoid disturbing the unread-char buffer. */
171 if (pt
->read_buf
== pt
->putback_buf
)
173 target
= pt
->saved_read_pos
- pt
->saved_read_buf
174 - (pt
->read_end
- pt
->read_pos
);
178 target
= pt
->read_pos
- pt
->read_buf
;
182 /* all other cases. */
184 if (pt
->rw_active
== SCM_PORT_READ
)
185 scm_end_input_unlocked (port
);
187 pt
->rw_active
= SCM_PORT_NEITHER
;
192 target
= pt
->read_pos
- pt
->read_buf
+ offset
;
195 target
= pt
->read_end
- pt
->read_buf
+ offset
;
197 default: /* SEEK_SET */
203 scm_misc_error ("st_seek", "negative offset", SCM_EOL
);
205 if (target
>= pt
->write_buf_size
)
207 if (!(SCM_CELL_WORD_0 (port
) & SCM_WRTNG
))
209 if (target
> pt
->write_buf_size
)
211 scm_misc_error ("st_seek",
212 "seek past end of read-only strport",
216 else if (target
== pt
->write_buf_size
)
217 st_resize_port (pt
, target
* 2);
219 pt
->read_pos
= pt
->write_pos
= pt
->read_buf
+ target
;
220 if (pt
->read_pos
> pt
->read_end
)
222 pt
->read_end
= (unsigned char *) pt
->read_pos
;
223 pt
->read_buf_size
= pt
->read_end
- pt
->read_buf
;
230 st_truncate (SCM port
, scm_t_off length
)
232 scm_t_port
*pt
= SCM_PTAB_ENTRY (port
);
234 if (length
> pt
->write_buf_size
)
235 st_resize_port (pt
, length
);
237 pt
->read_buf_size
= length
;
238 pt
->read_end
= pt
->read_buf
+ length
;
239 if (pt
->read_pos
> pt
->read_end
)
240 pt
->read_pos
= pt
->write_pos
= pt
->read_end
;
243 /* The initial size in bytes of a string port's buffer. */
244 #define INITIAL_BUFFER_SIZE 128
246 /* Return a new string port with MODES. If STR is #f, a new backing
247 buffer is allocated; otherwise STR must be a string and a copy of it
248 serves as the buffer for the new port. */
250 scm_mkstrport (SCM pos
, SCM str
, long modes
, const char *caller
)
254 const char *encoding
;
255 size_t read_buf_size
, str_len
, c_pos
;
258 if (!((modes
& SCM_WRTNG
) || (modes
& SCM_RDNG
)))
259 scm_misc_error ("scm_mkstrport", "port must read or write", SCM_EOL
);
261 encoding
= scm_i_default_port_encoding ();
263 if (scm_is_false (str
))
265 /* Allocate a new buffer to write to. */
266 str_len
= INITIAL_BUFFER_SIZE
;
267 buf
= scm_c_make_bytevector (str_len
);
268 c_buf
= (char *) SCM_BYTEVECTOR_CONTENTS (buf
);
270 /* Reset `read_buf_size'. It will contain the actual number of
271 bytes written to the port. */
277 /* STR is a string. */
280 SCM_ASSERT (scm_is_string (str
), str
, SCM_ARG1
, caller
);
282 /* Create a copy of STR in ENCODING. */
283 copy
= scm_to_stringn (str
, &str_len
, encoding
,
284 SCM_FAILED_CONVERSION_ERROR
);
285 buf
= scm_c_make_bytevector (str_len
);
286 c_buf
= (char *) SCM_BYTEVECTOR_CONTENTS (buf
);
287 memcpy (c_buf
, copy
, str_len
);
290 c_pos
= scm_to_unsigned_integer (pos
, 0, str_len
);
291 read_buf_size
= str_len
;
294 z
= scm_c_make_port_with_encoding (scm_tc16_strport
, modes
,
296 scm_i_default_port_conversion_handler (),
299 pt
= SCM_PTAB_ENTRY (z
);
301 pt
->write_buf
= pt
->read_buf
= (unsigned char *) c_buf
;
302 pt
->read_pos
= pt
->write_pos
= pt
->read_buf
+ c_pos
;
303 pt
->read_buf_size
= read_buf_size
;
304 pt
->write_buf_size
= str_len
;
305 pt
->write_end
= pt
->read_end
= pt
->read_buf
+ pt
->read_buf_size
;
311 /* Create a new string from the buffer of PORT, a string port, converting from
312 PORT's encoding to the standard string representation. */
314 scm_strport_to_string (SCM port
)
316 scm_t_port
*pt
= SCM_PTAB_ENTRY (port
);
318 if (pt
->read_buf_size
== 0)
321 return scm_from_stringn ((char *)pt
->read_buf
, pt
->read_buf_size
,
322 pt
->encoding
, pt
->ilseq_handler
);
325 SCM_DEFINE (scm_object_to_string
, "object->string", 1, 1, 0,
326 (SCM obj
, SCM printer
),
327 "Return a Scheme string obtained by printing @var{obj}.\n"
328 "Printing function can be specified by the optional second\n"
329 "argument @var{printer} (default: @code{write}).")
330 #define FUNC_NAME s_scm_object_to_string
334 if (!SCM_UNBNDP (printer
))
335 SCM_VALIDATE_PROC (2, printer
);
337 port
= scm_mkstrport (SCM_INUM0
, SCM_BOOL_F
,
338 SCM_OPN
| SCM_WRTNG
, FUNC_NAME
);
340 if (SCM_UNBNDP (printer
))
341 scm_write (obj
, port
);
343 scm_call_2 (printer
, obj
, port
);
345 result
= scm_strport_to_string (port
);
347 /* Explicitly close PORT so that the iconv CDs associated with it are
348 deallocated right away. This is important because CDs use a lot of
349 memory that's not visible to the GC, so not freeing them can lead
350 to almost large heap usage. See
351 <http://wingolog.org/archives/2011/02/25/ports-weaks-gc-and-dark-matter>
353 scm_close_port (port
);
360 scm_call_with_output_string (SCM proc
)
362 static SCM var
= SCM_BOOL_F
;
364 if (scm_is_false (var
))
365 var
= scm_c_private_lookup ("guile", "call-with-output-string");
367 return scm_call_1 (scm_variable_ref (var
), proc
);
371 scm_call_with_input_string (SCM string
, SCM proc
)
373 static SCM var
= SCM_BOOL_F
;
375 if (scm_is_false (var
))
376 var
= scm_c_private_lookup ("guile", "call-with-input-string");
378 return scm_call_2 (scm_variable_ref (var
), string
, proc
);
381 SCM_DEFINE (scm_open_input_string
, "open-input-string", 1, 0, 0,
383 "Take a string and return an input port that delivers characters\n"
384 "from the string. The port can be closed by\n"
385 "@code{close-input-port}, though its storage will be reclaimed\n"
386 "by the garbage collector if it becomes inaccessible.")
387 #define FUNC_NAME s_scm_open_input_string
389 SCM p
= scm_mkstrport(SCM_INUM0
, str
, SCM_OPN
| SCM_RDNG
, FUNC_NAME
);
394 SCM_DEFINE (scm_open_output_string
, "open-output-string", 0, 0, 0,
396 "Return an output port that will accumulate characters for\n"
397 "retrieval by @code{get-output-string}. The port can be closed\n"
398 "by the procedure @code{close-output-port}, though its storage\n"
399 "will be reclaimed by the garbage collector if it becomes\n"
401 #define FUNC_NAME s_scm_open_output_string
405 p
= scm_mkstrport (SCM_INUM0
, SCM_BOOL_F
,
412 SCM_DEFINE (scm_get_output_string
, "get-output-string", 1, 0, 0,
414 "Given an output port created by @code{open-output-string},\n"
415 "return a string consisting of the characters that have been\n"
416 "output to the port so far.")
417 #define FUNC_NAME s_scm_get_output_string
419 SCM_VALIDATE_OPOUTSTRPORT (1, port
);
420 return scm_strport_to_string (port
);
425 /* Given a null-terminated string EXPR containing a Scheme expression
426 read it, and return it as an SCM value. */
428 scm_c_read_string (const char *expr
)
430 SCM port
= scm_mkstrport (SCM_INUM0
,
431 scm_from_locale_string (expr
),
433 "scm_c_read_string");
436 form
= scm_read (port
);
438 scm_close_port (port
);
442 /* Given a null-terminated string EXPR containing Scheme program text,
443 evaluate it, and return the result of the last expression evaluated. */
445 scm_c_eval_string (const char *expr
)
447 return scm_eval_string (scm_from_locale_string (expr
));
451 scm_c_eval_string_in_module (const char *expr
, SCM module
)
453 return scm_eval_string_in_module (scm_from_locale_string (expr
), module
);
457 SCM_DEFINE (scm_eval_string_in_module
, "eval-string", 1, 1, 0,
458 (SCM string
, SCM module
),
459 "Evaluate @var{string} as the text representation of a Scheme\n"
460 "form or forms, and return whatever value they produce.\n"
461 "Evaluation takes place in the given module, or the current\n"
462 "module when no module is given.\n"
463 "While the code is evaluated, the given module is made the\n"
464 "current one. The current module is restored when this\n"
465 "procedure returns.")
466 #define FUNC_NAME s_scm_eval_string_in_module
468 static SCM eval_string
= SCM_BOOL_F
, k_module
= SCM_BOOL_F
;
470 if (scm_is_false (eval_string
))
472 eval_string
= scm_c_public_lookup ("ice-9 eval-string", "eval-string");
473 k_module
= scm_from_locale_keyword ("module");
476 if (SCM_UNBNDP (module
))
477 module
= scm_current_module ();
479 SCM_VALIDATE_MODULE (2, module
);
481 return scm_call_3 (scm_variable_ref (eval_string
), string
, k_module
, module
);
486 scm_eval_string (SCM string
)
488 return scm_eval_string_in_module (string
, SCM_UNDEFINED
);
494 scm_t_bits tc
= scm_make_port_type ("string", st_fill_input
, st_write
);
496 scm_set_port_end_input (tc
, st_end_input
);
497 scm_set_port_seek (tc
, st_seek
);
498 scm_set_port_truncate (tc
, st_truncate
);
506 scm_tc16_strport
= scm_make_stptob ();
508 #include "libguile/strports.x"