[bpt/guile.git] / libguile / strports.c

/*	Copyright (C) 1995,1996,1998,1999, 2000 Free Software Foundation, Inc.
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * 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
 * 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
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  */

/* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
   gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */

\f

#include "libguile/_scm.h"

#include <stdio.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include "libguile/unif.h"
#include "libguile/eval.h"
#include "libguile/ports.h"
#include "libguile/read.h"
#include "libguile/root.h"
#include "libguile/strings.h"
#include "libguile/modules.h"

#include "libguile/strports.h"

#ifdef HAVE_STRING_H
#include <string.h>
#endif

\f

/* {Ports - string ports}
 *
 */

/* NOTES:
   write_buf/write_end point to the ends of the allocated string.
   read_buf/read_end in principle point to the part of the string which
   has been written to, but this is only updated after a flush.
   read_pos and write_pos in principle should be equal, but this is only true
   when rw_active is SCM_PORT_NEITHER.
*/

static int
stfill_buffer (SCM port)
{
  scm_port *pt = SCM_PTAB_ENTRY (port);
  
  if (pt->read_pos >= pt->read_end)
    return EOF;
  else
    return scm_return_first_int (*pt->read_pos, port);
}

/* change the size of a port's string to new_size.  this doesn't
   change read_buf_size.  */
static void 
st_resize_port (scm_port *pt, off_t new_size)
{
  SCM old_stream = SCM_PACK (pt->stream);
  SCM new_stream = scm_makstr (new_size, 0);
  unsigned long int old_size = SCM_STRING_LENGTH (old_stream);
  unsigned long int min_size = min (old_size, new_size);
  unsigned long int i;

  off_t index = pt->write_pos - pt->write_buf;

  pt->write_buf_size = new_size;

  for (i = 0; i != min_size; ++i)
    SCM_STRING_CHARS (new_stream) [i] = SCM_STRING_CHARS (old_stream) [i];

  /* reset buffer. */
  {
    pt->stream = new_stream;
    pt->read_buf = pt->write_buf = SCM_STRING_UCHARS (new_stream);
    pt->read_pos = pt->write_pos = pt->write_buf + index;
    pt->write_end = pt->write_buf + pt->write_buf_size;
    pt->read_end = pt->read_buf + pt->read_buf_size;
  }
}

/* amount by which write_buf is expanded.  */
#define SCM_WRITE_BLOCK 80

/* ensure that write_pos < write_end by enlarging the buffer when
   necessary.  update read_buf to account for written chars.  */
static void
st_flush (SCM port)
{
  scm_port *pt = SCM_PTAB_ENTRY (port);

  if (pt->write_pos == pt->write_end)
    {
      st_resize_port (pt, pt->write_buf_size + SCM_WRITE_BLOCK);
    }
  pt->read_pos = pt->write_pos;
  if (pt->read_pos > pt->read_end)
    {
      pt->read_end = (unsigned char *) pt->read_pos;
      pt->read_buf_size = pt->read_end - pt->read_buf;
    }
  pt->rw_active = SCM_PORT_NEITHER;
}

static void
st_write (SCM port, const void *data, size_t size)
{
  scm_port *pt = SCM_PTAB_ENTRY (port);
  const char *input = (char *) data;

  while (size > 0)
    {
      int space = pt->write_end - pt->write_pos;
      int write_len = (size > space) ? space : size;
      
      strncpy ((char *) pt->write_pos, input, write_len);
      pt->write_pos += write_len;
      size -= write_len;
      input += write_len;
      if (write_len == space)
	st_flush (port);
    }
}

static void
st_end_input (SCM port, int offset)
{
  scm_port *pt = SCM_PTAB_ENTRY (port);
  
  if (pt->read_pos - pt->read_buf < offset)
    scm_misc_error ("st_end_input", "negative position", SCM_EOL);

  pt->write_pos = (unsigned char *) (pt->read_pos = pt->read_pos - offset);
  pt->rw_active = SCM_PORT_NEITHER;
}

static off_t
st_seek (SCM port, off_t offset, int whence)
{
  scm_port *pt = SCM_PTAB_ENTRY (port);
  off_t target;

  if (pt->rw_active == SCM_PORT_READ && offset == 0 && whence == SEEK_CUR)
    /* special case to avoid disturbing the unread-char buffer.  */
    {
      if (pt->read_buf == pt->putback_buf)
	{
	  target = pt->saved_read_pos - pt->saved_read_buf
	    - (pt->read_end - pt->read_pos);
	}
      else
	{
	  target = pt->read_pos - pt->read_buf;
	}
    }
  else
    /* all other cases.  */
    {
      if (pt->rw_active == SCM_PORT_WRITE)
	st_flush (port);
  
      if (pt->rw_active == SCM_PORT_READ)
	scm_end_input (port);

      switch (whence)
	{
	case SEEK_CUR:
	  target = pt->read_pos - pt->read_buf + offset;
	  break;
	case SEEK_END:
	  target = pt->read_end - pt->read_buf + offset;
	  break;
	default: /* SEEK_SET */
	  target = offset;
	  break;
	}

      if (target < 0)
	scm_misc_error ("st_seek", "negative offset", SCM_EOL);
  
      if (target >= pt->write_buf_size)
	{
	  if (!(SCM_CELL_WORD_0 (port) & SCM_WRTNG))
	    {
	      if (target > pt->write_buf_size)
		{
		  scm_misc_error ("st_seek", 
				  "seek past end of read-only strport",
				  SCM_EOL);
		}
	    }
	  else
	    {
	      st_resize_port (pt, target + (target == pt->write_buf_size
					    ? SCM_WRITE_BLOCK
					    : 0));
	    }
	}
      pt->read_pos = pt->write_pos = pt->read_buf + target;
      if (pt->read_pos > pt->read_end)
	{
	  pt->read_end = (unsigned char *) pt->read_pos;
	  pt->read_buf_size = pt->read_end - pt->read_buf;
	}
    }
  return target;
}

static void
st_truncate (SCM port, off_t length)
{
  scm_port *pt = SCM_PTAB_ENTRY (port);

  if (length > pt->write_buf_size)
    st_resize_port (pt, length);

  pt->read_buf_size = length;
  pt->read_end = pt->read_buf + length;
  if (pt->read_pos > pt->read_end)
    pt->read_pos = pt->read_end;
  
  if (pt->write_pos > pt->read_end)
    pt->write_pos = pt->read_end;
}

SCM 
scm_mkstrport (SCM pos, SCM str, long modes, const char *caller)
{
  SCM z;
  scm_port *pt;
  int str_len;

  SCM_ASSERT (SCM_INUMP(pos) && SCM_INUM(pos) >= 0, pos, SCM_ARG1, caller);
  SCM_ASSERT (SCM_STRINGP (str), str, SCM_ARG1, caller);
  str_len = SCM_STRING_LENGTH (str);
  if (SCM_INUM (pos) > str_len)
    scm_out_of_range (caller, pos);
  if (!((modes & SCM_WRTNG) || (modes & SCM_RDNG)))
    scm_misc_error ("scm_mkstrport", "port must read or write", SCM_EOL);
  SCM_NEWCELL (z);
  SCM_DEFER_INTS;
  pt = scm_add_to_port_table (z);
  SCM_SET_CELL_TYPE (z, scm_tc16_strport | modes);
  SCM_SETPTAB_ENTRY (z, pt);
  SCM_SETSTREAM (z, SCM_UNPACK (str));
  pt->write_buf = pt->read_buf = SCM_STRING_UCHARS (str);
  pt->read_pos = pt->write_pos = pt->read_buf + SCM_INUM (pos);
  pt->write_buf_size = pt->read_buf_size = str_len;
  pt->write_end = pt->read_end = pt->read_buf + pt->read_buf_size;

  pt->rw_random = 1;

  SCM_ALLOW_INTS;

  /* ensure write_pos is writable. */
  if ((modes & SCM_WRTNG) && pt->write_pos == pt->write_end)
    st_flush (z);
  return z;
}

/* create a new string from a string port's buffer.  */
SCM scm_strport_to_string (SCM port)
{
  scm_port *pt = SCM_PTAB_ENTRY (port);

  if (pt->rw_active == SCM_PORT_WRITE)
    st_flush (port);
  return scm_makfromstr ((char *) pt->read_buf, pt->read_buf_size, 0);
}

SCM_DEFINE (scm_call_with_output_string, "call-with-output-string", 1, 0, 0, 
           (SCM proc),
	    "Calls the one-argument procedure @var{proc} with a newly created output\n"
	    "port.  When the function returns, the string composed of the characters\n"
	    "written into the port is returned.")
#define FUNC_NAME s_scm_call_with_output_string
{
  SCM p;

  p = scm_mkstrport (SCM_INUM0, 
		     scm_make_string (SCM_INUM0, SCM_UNDEFINED),
		     SCM_OPN | SCM_WRTNG,
                     FUNC_NAME);
  scm_apply (proc, p, scm_listofnull);

  return scm_strport_to_string (p);
}
#undef FUNC_NAME


/* Return a Scheme string obtained by printing a given object.
 */


SCM
scm_strprint_obj (SCM obj)
{
  SCM str;
  SCM port;

  str = scm_makstr (0, 0);
  port = scm_mkstrport (SCM_INUM0, str, SCM_OPN | SCM_WRTNG, "scm_strprint_obj");
  scm_prin1 (obj, port, 1);
  {
    return scm_strport_to_string (port);
  }
}


SCM_DEFINE (scm_call_with_input_string, "call-with-input-string", 2, 0, 0,
           (SCM str, SCM proc),
	    "Calls the one-argument procedure @var{proc} with a newly created input\n"
	    "port from which @var{string}'s contents may be read.  The value yielded\n"
	    "by the @var{proc} is returned.")
#define FUNC_NAME s_scm_call_with_input_string
{
  SCM p = scm_mkstrport(SCM_INUM0, str, SCM_OPN | SCM_RDNG, FUNC_NAME);
  return scm_apply (proc, p, scm_listofnull);
}
#undef FUNC_NAME


/* Given a null-terminated string EXPR containing a Scheme expression
   read it, and return it as an SCM value. */
SCM
scm_read_0str (char *expr)
{
  SCM port = scm_mkstrport (SCM_INUM0,
			    scm_makfrom0str (expr),
			    SCM_OPN | SCM_RDNG,
			    "scm_eval_0str");
  SCM form;

  /* Read expressions from that port; ignore the values.  */
  form = scm_read (port);

  scm_close_port (port);
  return form;
}

/* Given a null-terminated string EXPR containing Scheme program text,
   evaluate it, and return the result of the last expression evaluated.  */
SCM
scm_eval_0str (const char *expr)
{
  return scm_eval_string (scm_makfrom0str (expr));
}


SCM_DEFINE (scm_eval_string, "eval-string", 1, 0, 0, 
            (SCM string),
	    "Evaluate @var{string} as the text representation of a Scheme form\n"
	    "or forms, and return whatever value they produce.\n"
	    "Evaluation takes place in (interaction-environment).")
#define FUNC_NAME s_scm_eval_string
{
  SCM port = scm_mkstrport (SCM_INUM0, string, SCM_OPN | SCM_RDNG,
			    "scm_eval_0str");
  SCM form;
  SCM ans = SCM_UNSPECIFIED;
  SCM module = scm_interaction_environment ();

  /* Read expressions from that port; ignore the values.  */
  while (!SCM_EOF_OBJECT_P (form = scm_read (port)))
    ans = scm_eval_x (form, module);

  /* Don't close the port here; if we re-enter this function via a
     continuation, then the next time we enter it, we'll get an error.
     It's a string port anyway, so there's no advantage to closing it
     early.  */

  return ans;
}
#undef FUNC_NAME

void scm_make_stptob (void); /* Called from ports.c */

void
scm_make_stptob ()
{
  long tc = scm_make_port_type ("string", stfill_buffer, st_write);
  scm_set_port_mark        (tc, scm_markstream);
  scm_set_port_end_input   (tc, st_end_input);
  scm_set_port_flush       (tc, st_flush);
  scm_set_port_seek        (tc, st_seek);
  scm_set_port_truncate    (tc, st_truncate);
}

void
scm_init_strports ()
{
#ifndef SCM_MAGIC_SNARFER
#include "libguile/strports.x"
#endif
}


/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/
Commit	Line	Data
f2c9fcb0	1	/* Copyright (C) 1995,1996,1998,1999, 2000 Free Software Foundation, Inc.
0f2d19dd JB	2	*
	3	* This program is free software; you can redistribute it and/or modify
	4	* it under the terms of the GNU General Public License as published by
	5	* the Free Software Foundation; either version 2, or (at your option)
	6	* any later version.
	7	*
	8	* This program 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
	11	* GNU General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public License
	14	* along with this software; see the file COPYING. If not, write to
82892bed JB	15	* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
82892bed JB	16	* Boston, MA 02111-1307 USA
0f2d19dd JB	17	*
	18	* As a special exception, the Free Software Foundation gives permission
	19	* for additional uses of the text contained in its release of GUILE.
	20	*
	21	* The exception is that, if you link the GUILE library with other files
	22	* to produce an executable, this does not by itself cause the
	23	* resulting executable to be covered by the GNU General Public License.
	24	* Your use of that executable is in no way restricted on account of
	25	* linking the GUILE library code into it.
	26	*
	27	* This exception does not however invalidate any other reasons why
	28	* the executable file might be covered by the GNU General Public License.
	29	*
	30	* This exception applies only to the code released by the
	31	* Free Software Foundation under the name GUILE. If you copy
	32	* code from other Free Software Foundation releases into a copy of
	33	* GUILE, as the General Public License permits, the exception does
	34	* not apply to the code that you add in this way. To avoid misleading
	35	* anyone as to the status of such modified files, you must delete
	36	* this exception notice from them.
	37	*
	38	* If you write modifications of your own for GUILE, it is your choice
	39	* whether to permit this exception to apply to your modifications.
82892bed	40	* If you do not wish that, delete this exception notice. */
1bbd0b84 GB	41
	42	/* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
	43	gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
	44
0f2d19dd JB	45	\f
0f2d19dd JB	46
a0599745	47	#include "libguile/_scm.h"
681b9005 MD	48
	49	#include <stdio.h>
	50	#ifdef HAVE_UNISTD_H
	51	#include <unistd.h>
	52	#endif
	53
a0599745 MD	54	#include "libguile/unif.h"
	55	#include "libguile/eval.h"
	56	#include "libguile/ports.h"
	57	#include "libguile/read.h"
	58	#include "libguile/root.h"
	59	#include "libguile/strings.h"
07bcf91d	60	#include "libguile/modules.h"
20e6290e	61
a0599745	62	#include "libguile/strports.h"
0f2d19dd	63
95b88819 GH	64	#ifdef HAVE_STRING_H
	65	#include <string.h>
	66	#endif
	67
0f2d19dd JB	68	\f
	69
	70	/* {Ports - string ports}
	71	*
	72	*/
	73
3fe6190f GH	74	/* NOTES:
	75	write_buf/write_end point to the ends of the allocated string.
	76	read_buf/read_end in principle point to the part of the string which
	77	has been written to, but this is only updated after a flush.
	78	read_pos and write_pos in principle should be equal, but this is only true
61e452ba	79	when rw_active is SCM_PORT_NEITHER.
3fe6190f	80	*/
1cc91f1b	81
ee149d03 JB	82	static int
ee149d03 JB	83	stfill_buffer (SCM port)
0f2d19dd	84	{
754c9491	85	scm_port *pt = SCM_PTAB_ENTRY (port);
ee149d03	86
ee149d03 JB	87	if (pt->read_pos >= pt->read_end)
	88	return EOF;
	89	else
41b0806d	90	return scm_return_first_int (*pt->read_pos, port);
0f2d19dd JB	91	}
0f2d19dd JB	92
3fe6190f GH	93	/* change the size of a port's string to new_size. this doesn't
3fe6190f GH	94	change read_buf_size. */
754c9491	95	static void
3fe6190f	96	st_resize_port (scm_port *pt, off_t new_size)
754c9491	97	{
94115ae3 DH	98	SCM old_stream = SCM_PACK (pt->stream);
	99	SCM new_stream = scm_makstr (new_size, 0);
	100	unsigned long int old_size = SCM_STRING_LENGTH (old_stream);
	101	unsigned long int min_size = min (old_size, new_size);
	102	unsigned long int i;
74a16888	103
3fe6190f GH	104	off_t index = pt->write_pos - pt->write_buf;
	105
	106	pt->write_buf_size = new_size;
	107
94115ae3 DH	108	for (i = 0; i != min_size; ++i)
94115ae3 DH	109	SCM_STRING_CHARS (new_stream) [i] = SCM_STRING_CHARS (old_stream) [i];
754c9491	110
94115ae3	111	/* reset buffer. */
754c9491	112	{
94115ae3 DH	113	pt->stream = new_stream;
94115ae3 DH	114	pt->read_buf = pt->write_buf = SCM_STRING_UCHARS (new_stream);
3fe6190f GH	115	pt->read_pos = pt->write_pos = pt->write_buf + index;
	116	pt->write_end = pt->write_buf + pt->write_buf_size;
	117	pt->read_end = pt->read_buf + pt->read_buf_size;
754c9491 JB	118	}
	119	}
	120
3fe6190f GH	121	/* amount by which write_buf is expanded. */
	122	#define SCM_WRITE_BLOCK 80
	123
	124	/* ensure that write_pos < write_end by enlarging the buffer when
	125	necessary. update read_buf to account for written chars. */
ee149d03 JB	126	static void
ee149d03 JB	127	st_flush (SCM port)
0f2d19dd	128	{
754c9491	129	scm_port *pt = SCM_PTAB_ENTRY (port);
ee149d03 JB	130
	131	if (pt->write_pos == pt->write_end)
	132	{
3fe6190f	133	st_resize_port (pt, pt->write_buf_size + SCM_WRITE_BLOCK);
754c9491 JB	134	}
754c9491 JB	135	pt->read_pos = pt->write_pos;
3fe6190f GH	136	if (pt->read_pos > pt->read_end)
	137	{
	138	pt->read_end = (unsigned char *) pt->read_pos;
	139	pt->read_buf_size = pt->read_end - pt->read_buf;
	140	}
61e452ba	141	pt->rw_active = SCM_PORT_NEITHER;
754c9491 JB	142	}
754c9491 JB	143
31703ab8	144	static void
8aa011a1	145	st_write (SCM port, const void *data, size_t size)
31703ab8 GH	146	{
	147	scm_port *pt = SCM_PTAB_ENTRY (port);
	148	const char input = (char ) data;
	149
	150	while (size > 0)
	151	{
	152	int space = pt->write_end - pt->write_pos;
	153	int write_len = (size > space) ? space : size;
	154
a4c7145b	155	strncpy ((char *) pt->write_pos, input, write_len);
31703ab8 GH	156	pt->write_pos += write_len;
	157	size -= write_len;
	158	input += write_len;
	159	if (write_len == space)
	160	st_flush (port);
	161	}
	162	}
	163
754c9491	164	static void
affc96b5	165	st_end_input (SCM port, int offset)
754c9491 JB	166	{
754c9491 JB	167	scm_port *pt = SCM_PTAB_ENTRY (port);
7dcb364d	168
cd19d608 GH	169	if (pt->read_pos - pt->read_buf < offset)
	170	scm_misc_error ("st_end_input", "negative position", SCM_EOL);
	171
a3c8b9fc	172	pt->write_pos = (unsigned char *) (pt->read_pos = pt->read_pos - offset);
61e452ba	173	pt->rw_active = SCM_PORT_NEITHER;
754c9491 JB	174	}
	175
	176	static off_t
	177	st_seek (SCM port, off_t offset, int whence)
	178	{
	179	scm_port *pt = SCM_PTAB_ENTRY (port);
	180	off_t target;
	181
7dcb364d GH	182	if (pt->rw_active == SCM_PORT_READ && offset == 0 && whence == SEEK_CUR)
7dcb364d GH	183	/* special case to avoid disturbing the unread-char buffer. */
754c9491	184	{
7dcb364d GH	185	if (pt->read_buf == pt->putback_buf)
	186	{
	187	target = pt->saved_read_pos - pt->saved_read_buf
	188	- (pt->read_end - pt->read_pos);
	189	}
	190	else
	191	{
	192	target = pt->read_pos - pt->read_buf;
	193	}
754c9491	194	}
7dcb364d GH	195	else
7dcb364d GH	196	/* all other cases. */
754c9491	197	{
7dcb364d GH	198	if (pt->rw_active == SCM_PORT_WRITE)
	199	st_flush (port);
	200
	201	if (pt->rw_active == SCM_PORT_READ)
	202	scm_end_input (port);
	203
	204	switch (whence)
	205	{
	206	case SEEK_CUR:
	207	target = pt->read_pos - pt->read_buf + offset;
	208	break;
	209	case SEEK_END:
	210	target = pt->read_end - pt->read_buf + offset;
	211	break;
	212	default: /* SEEK_SET */
	213	target = offset;
	214	break;
	215	}
	216
	217	if (target < 0)
	218	scm_misc_error ("st_seek", "negative offset", SCM_EOL);
	219
	220	if (target >= pt->write_buf_size)
3fe6190f	221	{
206d3de3	222	if (!(SCM_CELL_WORD_0 (port) & SCM_WRTNG))
3fe6190f	223	{
7dcb364d GH	224	if (target > pt->write_buf_size)
	225	{
	226	scm_misc_error ("st_seek",
	227	"seek past end of read-only strport",
	228	SCM_EOL);
	229	}
	230	}
	231	else
	232	{
	233	st_resize_port (pt, target + (target == pt->write_buf_size
	234	? SCM_WRITE_BLOCK
	235	: 0));
3fe6190f GH	236	}
3fe6190f GH	237	}
7dcb364d GH	238	pt->read_pos = pt->write_pos = pt->read_buf + target;
7dcb364d GH	239	if (pt->read_pos > pt->read_end)
3fe6190f	240	{
7dcb364d GH	241	pt->read_end = (unsigned char *) pt->read_pos;
7dcb364d GH	242	pt->read_buf_size = pt->read_end - pt->read_buf;
3fe6190f	243	}
ee149d03	244	}
754c9491 JB	245	return target;
	246	}
	247
	248	static void
affc96b5	249	st_truncate (SCM port, off_t length)
754c9491 JB	250	{
754c9491 JB	251	scm_port *pt = SCM_PTAB_ENTRY (port);
3fe6190f GH	252
	253	if (length > pt->write_buf_size)
	254	st_resize_port (pt, length);
	255
	256	pt->read_buf_size = length;
	257	pt->read_end = pt->read_buf + length;
	258	if (pt->read_pos > pt->read_end)
	259	pt->read_pos = pt->read_end;
754c9491	260
3fe6190f GH	261	if (pt->write_pos > pt->read_end)
3fe6190f GH	262	pt->write_pos = pt->read_end;
0f2d19dd JB	263	}
0f2d19dd JB	264
0f2d19dd	265	SCM
1bbd0b84	266	scm_mkstrport (SCM pos, SCM str, long modes, const char *caller)
0f2d19dd JB	267	{
0f2d19dd JB	268	SCM z;
754c9491 JB	269	scm_port *pt;
	270	int str_len;
	271
	272	SCM_ASSERT (SCM_INUMP(pos) && SCM_INUM(pos) >= 0, pos, SCM_ARG1, caller);
a6d9e5ab DH	273	SCM_ASSERT (SCM_STRINGP (str), str, SCM_ARG1, caller);
a6d9e5ab DH	274	str_len = SCM_STRING_LENGTH (str);
754c9491 JB	275	if (SCM_INUM (pos) > str_len)
	276	scm_out_of_range (caller, pos);
	277	if (!((modes & SCM_WRTNG) \|\| (modes & SCM_RDNG)))
	278	scm_misc_error ("scm_mkstrport", "port must read or write", SCM_EOL);
0f2d19dd JB	279	SCM_NEWCELL (z);
	280	SCM_DEFER_INTS;
	281	pt = scm_add_to_port_table (z);
54778cd3	282	SCM_SET_CELL_TYPE (z, scm_tc16_strport \| modes);
0f2d19dd	283	SCM_SETPTAB_ENTRY (z, pt);
74a16888	284	SCM_SETSTREAM (z, SCM_UNPACK (str));
34f0f2b8	285	pt->write_buf = pt->read_buf = SCM_STRING_UCHARS (str);
754c9491 JB	286	pt->read_pos = pt->write_pos = pt->read_buf + SCM_INUM (pos);
	287	pt->write_buf_size = pt->read_buf_size = str_len;
	288	pt->write_end = pt->read_end = pt->read_buf + pt->read_buf_size;
3fe6190f	289
0de97b83	290	pt->rw_random = 1;
3fe6190f	291
0f2d19dd	292	SCM_ALLOW_INTS;
3fe6190f GH	293
3fe6190f GH	294	/* ensure write_pos is writable. */
754c9491 JB	295	if ((modes & SCM_WRTNG) && pt->write_pos == pt->write_end)
754c9491 JB	296	st_flush (z);
0f2d19dd JB	297	return z;
	298	}
	299
3fe6190f GH	300	/* create a new string from a string port's buffer. */
	301	SCM scm_strport_to_string (SCM port)
	302	{
	303	scm_port *pt = SCM_PTAB_ENTRY (port);
	304
	305	if (pt->rw_active == SCM_PORT_WRITE)
	306	st_flush (port);
a4c7145b	307	return scm_makfromstr ((char *) pt->read_buf, pt->read_buf_size, 0);
3fe6190f GH	308	}
3fe6190f GH	309
3b3b36dd	310	SCM_DEFINE (scm_call_with_output_string, "call-with-output-string", 1, 0, 0,
1bbd0b84	311	(SCM proc),
b380b885 MD	312	"Calls the one-argument procedure @var{proc} with a newly created output\n"
	313	"port. When the function returns, the string composed of the characters\n"
	314	"written into the port is returned.")
1bbd0b84	315	#define FUNC_NAME s_scm_call_with_output_string
0f2d19dd JB	316	{
0f2d19dd JB	317	SCM p;
754c9491 JB	318
	319	p = scm_mkstrport (SCM_INUM0,
	320	scm_make_string (SCM_INUM0, SCM_UNDEFINED),
	321	SCM_OPN \| SCM_WRTNG,
1bbd0b84	322	FUNC_NAME);
0f2d19dd	323	scm_apply (proc, p, scm_listofnull);
3fe6190f GH	324
3fe6190f GH	325	return scm_strport_to_string (p);
0f2d19dd	326	}
1bbd0b84	327	#undef FUNC_NAME
0f2d19dd JB	328
	329
	330
	331	/* Return a Scheme string obtained by printing a given object.
	332	*/
	333
1cc91f1b	334
0f2d19dd	335	SCM
1bbd0b84	336	scm_strprint_obj (SCM obj)
0f2d19dd JB	337	{
	338	SCM str;
	339	SCM port;
	340
3fe6190f GH	341	str = scm_makstr (0, 0);
3fe6190f GH	342	port = scm_mkstrport (SCM_INUM0, str, SCM_OPN \| SCM_WRTNG, "scm_strprint_obj");
87818069	343	scm_prin1 (obj, port, 1);
0f2d19dd	344	{
3fe6190f	345	return scm_strport_to_string (port);
0f2d19dd JB	346	}
	347	}
	348
	349
	350
	351
3b3b36dd	352	SCM_DEFINE (scm_call_with_input_string, "call-with-input-string", 2, 0, 0,
1bbd0b84	353	(SCM str, SCM proc),
b380b885 MD	354	"Calls the one-argument procedure @var{proc} with a newly created input\n"
	355	"port from which @var{string}'s contents may be read. The value yielded\n"
	356	"by the @var{proc} is returned.")
1bbd0b84	357	#define FUNC_NAME s_scm_call_with_input_string
0f2d19dd	358	{
1bbd0b84	359	SCM p = scm_mkstrport(SCM_INUM0, str, SCM_OPN \| SCM_RDNG, FUNC_NAME);
0f2d19dd JB	360	return scm_apply (proc, p, scm_listofnull);
0f2d19dd JB	361	}
1bbd0b84	362	#undef FUNC_NAME
0f2d19dd	363
1cc91f1b	364
cd07a097	365
a8aa30d8 MD	366	/* Given a null-terminated string EXPR containing a Scheme expression
	367	read it, and return it as an SCM value. */
	368	SCM
1bbd0b84	369	scm_read_0str (char *expr)
a8aa30d8	370	{
3fe6190f	371	SCM port = scm_mkstrport (SCM_INUM0,
a8aa30d8 MD	372	scm_makfrom0str (expr),
	373	SCM_OPN \| SCM_RDNG,
	374	"scm_eval_0str");
	375	SCM form;
	376
	377	/* Read expressions from that port; ignore the values. */
deca31e1	378	form = scm_read (port);
a8aa30d8 MD	379
	380	scm_close_port (port);
	381	return form;
	382	}
	383
cd07a097	384	/* Given a null-terminated string EXPR containing Scheme program text,
a8aa30d8 MD	385	evaluate it, and return the result of the last expression evaluated. */
a8aa30d8 MD	386	SCM
6e706938	387	scm_eval_0str (const char *expr)
cd07a097	388	{
b377f53e JB	389	return scm_eval_string (scm_makfrom0str (expr));
	390	}
	391
	392
a1ec6916	393	SCM_DEFINE (scm_eval_string, "eval-string", 1, 0, 0,
1bbd0b84	394	(SCM string),
b380b885	395	"Evaluate @var{string} as the text representation of a Scheme form\n"
2a2a730b	396	"or forms, and return whatever value they produce.\n"
07bcf91d	397	"Evaluation takes place in (interaction-environment).")
1bbd0b84	398	#define FUNC_NAME s_scm_eval_string
b377f53e	399	{
3fe6190f	400	SCM port = scm_mkstrport (SCM_INUM0, string, SCM_OPN \| SCM_RDNG,
cd07a097 JB	401	"scm_eval_0str");
cd07a097 JB	402	SCM form;
b377f53e	403	SCM ans = SCM_UNSPECIFIED;
07bcf91d	404	SCM module = scm_interaction_environment ();
cd07a097 JB	405
cd07a097 JB	406	/* Read expressions from that port; ignore the values. */
0c32d76c	407	while (!SCM_EOF_OBJECT_P (form = scm_read (port)))
07bcf91d	408	ans = scm_eval_x (form, module);
cd07a097	409
0d7368d7 JB	410	/* Don't close the port here; if we re-enter this function via a
	411	continuation, then the next time we enter it, we'll get an error.
	412	It's a string port anyway, so there's no advantage to closing it
	413	early. */
	414
a8aa30d8	415	return ans;
cd07a097	416	}
1bbd0b84	417	#undef FUNC_NAME
cd07a097	418
0b6881fa	419	void scm_make_stptob (void); /* Called from ports.c */
cd07a097	420
0b6881fa MD	421	void
0b6881fa MD	422	scm_make_stptob ()
0f2d19dd	423	{
affc96b5	424	long tc = scm_make_port_type ("string", stfill_buffer, st_write);
6c747373	425	scm_set_port_mark (tc, scm_markstream);
affc96b5 GH	426	scm_set_port_end_input (tc, st_end_input);
affc96b5 GH	427	scm_set_port_flush (tc, st_flush);
6c747373	428	scm_set_port_seek (tc, st_seek);
affc96b5	429	scm_set_port_truncate (tc, st_truncate);
0f2d19dd JB	430	}
0f2d19dd JB	431
0f2d19dd JB	432	void
0f2d19dd JB	433	scm_init_strports ()
0f2d19dd	434	{
8dc9439f	435	#ifndef SCM_MAGIC_SNARFER
a0599745	436	#include "libguile/strports.x"
8dc9439f	437	#endif
0f2d19dd JB	438	}
0f2d19dd JB	439
89e00824 ML	440
	441	/*
	442	Local Variables:
	443	c-file-style: "gnu"
	444	End:
	445	*/