[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/vectors.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 stream = SCM_PACK (pt->stream);

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

  pt->write_buf_size = new_size;

  scm_vector_set_length_x (stream, SCM_MAKINUM (new_size));

  /* reset buffer in case reallocation moved the string. */
  {
    pt->read_buf = pt->write_buf = SCM_STRING_UCHARS (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_ROSTRINGP(str), str, SCM_ARG1, caller);
  str_len = SCM_ROLENGTH (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_ROUCHARS (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 ()
{
#include "libguile/strports.x"
}


/*
  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"
	60	#include "libguile/vectors.h"
07bcf91d	61	#include "libguile/modules.h"
20e6290e	62
a0599745	63	#include "libguile/strports.h"
0f2d19dd	64
95b88819 GH	65	#ifdef HAVE_STRING_H
	66	#include <string.h>
	67	#endif
	68
0f2d19dd JB	69	\f
	70
	71	/* {Ports - string ports}
	72	*
	73	*/
	74
3fe6190f GH	75	/* NOTES:
	76	write_buf/write_end point to the ends of the allocated string.
	77	read_buf/read_end in principle point to the part of the string which
	78	has been written to, but this is only updated after a flush.
	79	read_pos and write_pos in principle should be equal, but this is only true
61e452ba	80	when rw_active is SCM_PORT_NEITHER.
3fe6190f	81	*/
1cc91f1b	82
ee149d03 JB	83	static int
ee149d03 JB	84	stfill_buffer (SCM port)
0f2d19dd	85	{
754c9491	86	scm_port *pt = SCM_PTAB_ENTRY (port);
ee149d03	87
ee149d03 JB	88	if (pt->read_pos >= pt->read_end)
	89	return EOF;
	90	else
41b0806d	91	return scm_return_first_int (*pt->read_pos, port);
0f2d19dd JB	92	}
0f2d19dd JB	93
3fe6190f GH	94	/* change the size of a port's string to new_size. this doesn't
3fe6190f GH	95	change read_buf_size. */
754c9491	96	static void
3fe6190f	97	st_resize_port (scm_port *pt, off_t new_size)
754c9491	98	{
74a16888 DH	99	SCM stream = SCM_PACK (pt->stream);
74a16888 DH	100
3fe6190f GH	101	off_t index = pt->write_pos - pt->write_buf;
	102
	103	pt->write_buf_size = new_size;
	104
74a16888	105	scm_vector_set_length_x (stream, SCM_MAKINUM (new_size));
754c9491	106
754c9491 JB	107	/* reset buffer in case reallocation moved the string. */
754c9491 JB	108	{
322ac0c5	109	pt->read_buf = pt->write_buf = SCM_STRING_UCHARS (stream);
3fe6190f GH	110	pt->read_pos = pt->write_pos = pt->write_buf + index;
	111	pt->write_end = pt->write_buf + pt->write_buf_size;
	112	pt->read_end = pt->read_buf + pt->read_buf_size;
754c9491 JB	113	}
	114	}
	115
3fe6190f GH	116	/* amount by which write_buf is expanded. */
	117	#define SCM_WRITE_BLOCK 80
	118
	119	/* ensure that write_pos < write_end by enlarging the buffer when
	120	necessary. update read_buf to account for written chars. */
ee149d03 JB	121	static void
ee149d03 JB	122	st_flush (SCM port)
0f2d19dd	123	{
754c9491	124	scm_port *pt = SCM_PTAB_ENTRY (port);
ee149d03 JB	125
	126	if (pt->write_pos == pt->write_end)
	127	{
3fe6190f	128	st_resize_port (pt, pt->write_buf_size + SCM_WRITE_BLOCK);
754c9491 JB	129	}
754c9491 JB	130	pt->read_pos = pt->write_pos;
3fe6190f GH	131	if (pt->read_pos > pt->read_end)
	132	{
	133	pt->read_end = (unsigned char *) pt->read_pos;
	134	pt->read_buf_size = pt->read_end - pt->read_buf;
	135	}
61e452ba	136	pt->rw_active = SCM_PORT_NEITHER;
754c9491 JB	137	}
754c9491 JB	138
31703ab8	139	static void
8aa011a1	140	st_write (SCM port, const void *data, size_t size)
31703ab8 GH	141	{
	142	scm_port *pt = SCM_PTAB_ENTRY (port);
	143	const char input = (char ) data;
	144
	145	while (size > 0)
	146	{
	147	int space = pt->write_end - pt->write_pos;
	148	int write_len = (size > space) ? space : size;
	149
a4c7145b	150	strncpy ((char *) pt->write_pos, input, write_len);
31703ab8 GH	151	pt->write_pos += write_len;
	152	size -= write_len;
	153	input += write_len;
	154	if (write_len == space)
	155	st_flush (port);
	156	}
	157	}
	158
754c9491	159	static void
affc96b5	160	st_end_input (SCM port, int offset)
754c9491 JB	161	{
754c9491 JB	162	scm_port *pt = SCM_PTAB_ENTRY (port);
7dcb364d	163
cd19d608 GH	164	if (pt->read_pos - pt->read_buf < offset)
	165	scm_misc_error ("st_end_input", "negative position", SCM_EOL);
	166
a3c8b9fc	167	pt->write_pos = (unsigned char *) (pt->read_pos = pt->read_pos - offset);
61e452ba	168	pt->rw_active = SCM_PORT_NEITHER;
754c9491 JB	169	}
	170
	171	static off_t
	172	st_seek (SCM port, off_t offset, int whence)
	173	{
	174	scm_port *pt = SCM_PTAB_ENTRY (port);
	175	off_t target;
	176
7dcb364d GH	177	if (pt->rw_active == SCM_PORT_READ && offset == 0 && whence == SEEK_CUR)
7dcb364d GH	178	/* special case to avoid disturbing the unread-char buffer. */
754c9491	179	{
7dcb364d GH	180	if (pt->read_buf == pt->putback_buf)
	181	{
	182	target = pt->saved_read_pos - pt->saved_read_buf
	183	- (pt->read_end - pt->read_pos);
	184	}
	185	else
	186	{
	187	target = pt->read_pos - pt->read_buf;
	188	}
754c9491	189	}
7dcb364d GH	190	else
7dcb364d GH	191	/* all other cases. */
754c9491	192	{
7dcb364d GH	193	if (pt->rw_active == SCM_PORT_WRITE)
	194	st_flush (port);
	195
	196	if (pt->rw_active == SCM_PORT_READ)
	197	scm_end_input (port);
	198
	199	switch (whence)
	200	{
	201	case SEEK_CUR:
	202	target = pt->read_pos - pt->read_buf + offset;
	203	break;
	204	case SEEK_END:
	205	target = pt->read_end - pt->read_buf + offset;
	206	break;
	207	default: /* SEEK_SET */
	208	target = offset;
	209	break;
	210	}
	211
	212	if (target < 0)
	213	scm_misc_error ("st_seek", "negative offset", SCM_EOL);
	214
	215	if (target >= pt->write_buf_size)
3fe6190f	216	{
206d3de3	217	if (!(SCM_CELL_WORD_0 (port) & SCM_WRTNG))
3fe6190f	218	{
7dcb364d GH	219	if (target > pt->write_buf_size)
	220	{
	221	scm_misc_error ("st_seek",
	222	"seek past end of read-only strport",
	223	SCM_EOL);
	224	}
	225	}
	226	else
	227	{
	228	st_resize_port (pt, target + (target == pt->write_buf_size
	229	? SCM_WRITE_BLOCK
	230	: 0));
3fe6190f GH	231	}
3fe6190f GH	232	}
7dcb364d GH	233	pt->read_pos = pt->write_pos = pt->read_buf + target;
7dcb364d GH	234	if (pt->read_pos > pt->read_end)
3fe6190f	235	{
7dcb364d GH	236	pt->read_end = (unsigned char *) pt->read_pos;
7dcb364d GH	237	pt->read_buf_size = pt->read_end - pt->read_buf;
3fe6190f	238	}
ee149d03	239	}
754c9491 JB	240	return target;
	241	}
	242
	243	static void
affc96b5	244	st_truncate (SCM port, off_t length)
754c9491 JB	245	{
754c9491 JB	246	scm_port *pt = SCM_PTAB_ENTRY (port);
3fe6190f GH	247
	248	if (length > pt->write_buf_size)
	249	st_resize_port (pt, length);
	250
	251	pt->read_buf_size = length;
	252	pt->read_end = pt->read_buf + length;
	253	if (pt->read_pos > pt->read_end)
	254	pt->read_pos = pt->read_end;
754c9491	255
3fe6190f GH	256	if (pt->write_pos > pt->read_end)
3fe6190f GH	257	pt->write_pos = pt->read_end;
0f2d19dd JB	258	}
0f2d19dd JB	259
0f2d19dd	260	SCM
1bbd0b84	261	scm_mkstrport (SCM pos, SCM str, long modes, const char *caller)
0f2d19dd JB	262	{
0f2d19dd JB	263	SCM z;
754c9491 JB	264	scm_port *pt;
	265	int str_len;
	266
	267	SCM_ASSERT (SCM_INUMP(pos) && SCM_INUM(pos) >= 0, pos, SCM_ARG1, caller);
0c95b57d	268	SCM_ASSERT (SCM_ROSTRINGP(str), str, SCM_ARG1, caller);
754c9491 JB	269	str_len = SCM_ROLENGTH (str);
	270	if (SCM_INUM (pos) > str_len)
	271	scm_out_of_range (caller, pos);
	272	if (!((modes & SCM_WRTNG) \|\| (modes & SCM_RDNG)))
	273	scm_misc_error ("scm_mkstrport", "port must read or write", SCM_EOL);
0f2d19dd JB	274	SCM_NEWCELL (z);
	275	SCM_DEFER_INTS;
	276	pt = scm_add_to_port_table (z);
54778cd3	277	SCM_SET_CELL_TYPE (z, scm_tc16_strport \| modes);
0f2d19dd	278	SCM_SETPTAB_ENTRY (z, pt);
74a16888	279	SCM_SETSTREAM (z, SCM_UNPACK (str));
a4c7145b	280	pt->write_buf = pt->read_buf = SCM_ROUCHARS (str);
754c9491 JB	281	pt->read_pos = pt->write_pos = pt->read_buf + SCM_INUM (pos);
	282	pt->write_buf_size = pt->read_buf_size = str_len;
	283	pt->write_end = pt->read_end = pt->read_buf + pt->read_buf_size;
3fe6190f	284
0de97b83	285	pt->rw_random = 1;
3fe6190f	286
0f2d19dd	287	SCM_ALLOW_INTS;
3fe6190f GH	288
3fe6190f GH	289	/* ensure write_pos is writable. */
754c9491 JB	290	if ((modes & SCM_WRTNG) && pt->write_pos == pt->write_end)
754c9491 JB	291	st_flush (z);
0f2d19dd JB	292	return z;
	293	}
	294
3fe6190f GH	295	/* create a new string from a string port's buffer. */
	296	SCM scm_strport_to_string (SCM port)
	297	{
	298	scm_port *pt = SCM_PTAB_ENTRY (port);
	299
	300	if (pt->rw_active == SCM_PORT_WRITE)
	301	st_flush (port);
a4c7145b	302	return scm_makfromstr ((char *) pt->read_buf, pt->read_buf_size, 0);
3fe6190f GH	303	}
3fe6190f GH	304
3b3b36dd	305	SCM_DEFINE (scm_call_with_output_string, "call-with-output-string", 1, 0, 0,
1bbd0b84	306	(SCM proc),
b380b885 MD	307	"Calls the one-argument procedure @var{proc} with a newly created output\n"
	308	"port. When the function returns, the string composed of the characters\n"
	309	"written into the port is returned.")
1bbd0b84	310	#define FUNC_NAME s_scm_call_with_output_string
0f2d19dd JB	311	{
0f2d19dd JB	312	SCM p;
754c9491 JB	313
	314	p = scm_mkstrport (SCM_INUM0,
	315	scm_make_string (SCM_INUM0, SCM_UNDEFINED),
	316	SCM_OPN \| SCM_WRTNG,
1bbd0b84	317	FUNC_NAME);
0f2d19dd	318	scm_apply (proc, p, scm_listofnull);
3fe6190f GH	319
3fe6190f GH	320	return scm_strport_to_string (p);
0f2d19dd	321	}
1bbd0b84	322	#undef FUNC_NAME
0f2d19dd JB	323
	324
	325
	326	/* Return a Scheme string obtained by printing a given object.
	327	*/
	328
1cc91f1b	329
0f2d19dd	330	SCM
1bbd0b84	331	scm_strprint_obj (SCM obj)
0f2d19dd JB	332	{
	333	SCM str;
	334	SCM port;
	335
3fe6190f GH	336	str = scm_makstr (0, 0);
3fe6190f GH	337	port = scm_mkstrport (SCM_INUM0, str, SCM_OPN \| SCM_WRTNG, "scm_strprint_obj");
87818069	338	scm_prin1 (obj, port, 1);
0f2d19dd	339	{
3fe6190f	340	return scm_strport_to_string (port);
0f2d19dd JB	341	}
	342	}
	343
	344
	345
	346
3b3b36dd	347	SCM_DEFINE (scm_call_with_input_string, "call-with-input-string", 2, 0, 0,
1bbd0b84	348	(SCM str, SCM proc),
b380b885 MD	349	"Calls the one-argument procedure @var{proc} with a newly created input\n"
	350	"port from which @var{string}'s contents may be read. The value yielded\n"
	351	"by the @var{proc} is returned.")
1bbd0b84	352	#define FUNC_NAME s_scm_call_with_input_string
0f2d19dd	353	{
1bbd0b84	354	SCM p = scm_mkstrport(SCM_INUM0, str, SCM_OPN \| SCM_RDNG, FUNC_NAME);
0f2d19dd JB	355	return scm_apply (proc, p, scm_listofnull);
0f2d19dd JB	356	}
1bbd0b84	357	#undef FUNC_NAME
0f2d19dd	358
1cc91f1b	359
cd07a097	360
a8aa30d8 MD	361	/* Given a null-terminated string EXPR containing a Scheme expression
	362	read it, and return it as an SCM value. */
	363	SCM
1bbd0b84	364	scm_read_0str (char *expr)
a8aa30d8	365	{
3fe6190f	366	SCM port = scm_mkstrport (SCM_INUM0,
a8aa30d8 MD	367	scm_makfrom0str (expr),
	368	SCM_OPN \| SCM_RDNG,
	369	"scm_eval_0str");
	370	SCM form;
	371
	372	/* Read expressions from that port; ignore the values. */
deca31e1	373	form = scm_read (port);
a8aa30d8 MD	374
	375	scm_close_port (port);
	376	return form;
	377	}
	378
cd07a097	379	/* Given a null-terminated string EXPR containing Scheme program text,
a8aa30d8 MD	380	evaluate it, and return the result of the last expression evaluated. */
a8aa30d8 MD	381	SCM
6e706938	382	scm_eval_0str (const char *expr)
cd07a097	383	{
b377f53e JB	384	return scm_eval_string (scm_makfrom0str (expr));
	385	}
	386
	387
a1ec6916	388	SCM_DEFINE (scm_eval_string, "eval-string", 1, 0, 0,
1bbd0b84	389	(SCM string),
b380b885	390	"Evaluate @var{string} as the text representation of a Scheme form\n"
2a2a730b	391	"or forms, and return whatever value they produce.\n"
07bcf91d	392	"Evaluation takes place in (interaction-environment).")
1bbd0b84	393	#define FUNC_NAME s_scm_eval_string
b377f53e	394	{
3fe6190f	395	SCM port = scm_mkstrport (SCM_INUM0, string, SCM_OPN \| SCM_RDNG,
cd07a097 JB	396	"scm_eval_0str");
cd07a097 JB	397	SCM form;
b377f53e	398	SCM ans = SCM_UNSPECIFIED;
07bcf91d	399	SCM module = scm_interaction_environment ();
cd07a097 JB	400
cd07a097 JB	401	/* Read expressions from that port; ignore the values. */
0c32d76c	402	while (!SCM_EOF_OBJECT_P (form = scm_read (port)))
07bcf91d	403	ans = scm_eval_x (form, module);
cd07a097	404
0d7368d7 JB	405	/* Don't close the port here; if we re-enter this function via a
	406	continuation, then the next time we enter it, we'll get an error.
	407	It's a string port anyway, so there's no advantage to closing it
	408	early. */
	409
a8aa30d8	410	return ans;
cd07a097	411	}
1bbd0b84	412	#undef FUNC_NAME
cd07a097	413
0b6881fa	414	void scm_make_stptob (void); /* Called from ports.c */
cd07a097	415
0b6881fa MD	416	void
0b6881fa MD	417	scm_make_stptob ()
0f2d19dd	418	{
affc96b5	419	long tc = scm_make_port_type ("string", stfill_buffer, st_write);
6c747373	420	scm_set_port_mark (tc, scm_markstream);
affc96b5 GH	421	scm_set_port_end_input (tc, st_end_input);
affc96b5 GH	422	scm_set_port_flush (tc, st_flush);
6c747373	423	scm_set_port_seek (tc, st_seek);
affc96b5	424	scm_set_port_truncate (tc, st_truncate);
0f2d19dd JB	425	}
0f2d19dd JB	426
0f2d19dd JB	427	void
0f2d19dd JB	428	scm_init_strports ()
0f2d19dd	429	{
a0599745	430	#include "libguile/strports.x"
0f2d19dd JB	431	}
0f2d19dd JB	432
89e00824 ML	433
	434	/*
	435	Local Variables:
	436	c-file-style: "gnu"
	437	End:
	438	*/