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

/* 	Copyright (C) 2001 Free Software Foundation, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

\f

/* This is the C part of the (ice-9 rw) module.  */

#if HAVE_CONFIG_H
#  include <config.h>
#endif

#include <errno.h>
#include <string.h>

#include "libguile/_scm.h"
#include "libguile/fports.h"
#include "libguile/ports.h"
#include "libguile/root.h"
#include "libguile/rw.h"
#include "libguile/strings.h"
#include "libguile/validate.h"
#include "libguile/modules.h"
#include "libguile/strports.h"

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_IO_H
#include <io.h>
#endif

\f

#if defined (EAGAIN)
#define SCM_MAYBE_EAGAIN || errno == EAGAIN
#else
#define SCM_MAYBE_EAGAIN
#endif

#if defined (EWOULDBLOCK)
#define SCM_MAYBE_EWOULDBLOCK || errno == EWOULDBLOCK
#else
#define SCM_MAYBE_EWOULDBLOCK
#endif

/* MAYBE there is EAGAIN way of defining this macro but now I EWOULDBLOCK.  */
#define SCM_EBLOCK(errno) \
   (0 SCM_MAYBE_EAGAIN SCM_MAYBE_EWOULDBLOCK)

SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0,
	    (SCM str, SCM port_or_fdes, SCM start, SCM end),
	    "Read characters from a port or file descriptor into a\n"
	    "string @var{str}.  A port must have an underlying file\n"
	    "descriptor --- a so-called fport.  This procedure is\n"
	    "scsh-compatible and can efficiently read large strings.\n"
	    "It will:\n\n"
	    "@itemize\n"
	    "@item\n"
	    "attempt to fill the entire string, unless the @var{start}\n"
	    "and/or @var{end} arguments are supplied.  i.e., @var{start}\n"
	    "defaults to 0 and @var{end} defaults to\n"
	    "@code{(string-length str)}\n"
	    "@item\n"
	    "use the current input port if @var{port_or_fdes} is not\n"
	    "supplied.\n" 
	    "@item\n"
	    "return fewer than the requested number of characters in some\n"
	    "cases, e.g., on end of file, if interrupted by a signal, or if\n"
	    "not all the characters are immediately available.\n"
	    "@item\n"
	    "wait indefinitely for some input if no characters are\n"
	    "currently available,\n"
	    "unless the port is in non-blocking mode.\n"
	    "@item\n"
	    "read characters from the port's input buffers if available,\n"
	    "instead from the underlying file descriptor.\n"
	    "@item\n"
	    "return @code{#f} if end-of-file is encountered before reading\n"
            "any characters, otherwise return the number of characters\n"
	    "read.\n"
	    "@item\n"
	    "return 0 if the port is in non-blocking mode and no characters\n"
	    "are immediately available.\n"
	    "@item\n"
	    "return 0 if the request is for 0 bytes, with no\n"
	    "end-of-file check.\n"
	    "@end itemize")
#define FUNC_NAME s_scm_read_string_x_partial
{
  char *dest;
  size_t offset;
  long read_len;
  long chars_read = 0;
  int fdes;

  {
    size_t last;

    SCM_VALIDATE_STRING (1, str);
    scm_i_get_substring_spec (scm_i_string_length (str),
			      start, &offset, end, &last);
    read_len = last - offset;
  }

  if (scm_is_integer (port_or_fdes))
    fdes = scm_to_int (port_or_fdes);
  else
    {
      SCM port = (SCM_UNBNDP (port_or_fdes)?
		  scm_current_input_port () : port_or_fdes);

      SCM_VALIDATE_OPFPORT (2, port);
      SCM_VALIDATE_INPUT_PORT (2, port);

      /* if there's anything in the port buffers, use it, but then
	 don't touch the file descriptor.  otherwise the
	 "return immediately if something is available" rule may
	 be violated.  */
      dest = scm_i_string_writable_chars (str) + offset;
      chars_read = scm_take_from_input_buffers (port, dest, read_len);
      scm_i_string_stop_writing ();
      fdes = SCM_FPORT_FDES (port);
    }

  if (chars_read == 0 && read_len > 0) /* don't confuse read_len == 0 with
					  EOF.  */
    {
      dest = scm_i_string_writable_chars (str) + offset;
      SCM_SYSCALL (chars_read = read (fdes, dest, read_len));
      scm_i_string_stop_writing ();
      if (chars_read == -1)
	{
	  if (SCM_EBLOCK (errno))
	    chars_read = 0;
	  else
	    SCM_SYSERROR;
        }
      else if (chars_read == 0)
	{
	  scm_remember_upto_here_1 (str);
	  return SCM_BOOL_F;
	}
    }

  scm_remember_upto_here_1 (str);
  return scm_from_long (chars_read);
}
#undef FUNC_NAME

SCM_DEFINE (scm_write_string_partial, "write-string/partial", 1, 3, 0,
	    (SCM str, SCM port_or_fdes, SCM start, SCM end),
	    "Write characters from a string @var{str} to a port or file\n"
	    "descriptor.  A port must have an underlying file descriptor\n"
	    "--- a so-called fport.  This procedure is\n"
	    "scsh-compatible and can efficiently write large strings.\n"
	    "It will:\n\n"
	    "@itemize\n"
	    "@item\n"
	    "attempt to write the entire string, unless the @var{start}\n"
	    "and/or @var{end} arguments are supplied.  i.e., @var{start}\n"
	    "defaults to 0 and @var{end} defaults to\n"
	    "@code{(string-length str)}\n"
	    "@item\n"
	    "use the current output port if @var{port_of_fdes} is not\n"
	    "supplied.\n"
	    "@item\n"
	    "in the case of a buffered port, store the characters in the\n"
	    "port's output buffer, if all will fit.  If they will not fit\n"
	    "then any existing buffered characters will be flushed\n"
	    "before attempting\n"
	    "to write the new characters directly to the underlying file\n"
	    "descriptor.  If the port is in non-blocking mode and\n"
	    "buffered characters can not be flushed immediately, then an\n"
	    "@code{EAGAIN} system-error exception will be raised (Note:\n"
	    "scsh does not support the use of non-blocking buffered ports.)\n"
	    "@item\n"
	    "write fewer than the requested number of\n"
	    "characters in some cases, e.g., if interrupted by a signal or\n"
	    "if not all of the output can be accepted immediately.\n"
	    "@item\n"
	    "wait indefinitely for at least one character\n"
	    "from @var{str} to be accepted by the port, unless the port is\n"
	    "in non-blocking mode.\n"
	    "@item\n"
	    "return the number of characters accepted by the port.\n"
	    "@item\n"
	    "return 0 if the port is in non-blocking mode and can not accept\n"
	    "at least one character from @var{str} immediately\n"
	    "@item\n"
	    "return 0 immediately if the request size is 0 bytes.\n"
	    "@end itemize")
#define FUNC_NAME s_scm_write_string_partial
{
  const char *src;
  long write_len;
  int fdes;

  {
    size_t offset;
    size_t last;

    SCM_VALIDATE_STRING (1, str);
    src = scm_i_string_chars (str);
    scm_i_get_substring_spec (scm_i_string_length (str),
			      start, &offset, end, &last);
    src += offset;
    write_len = last - offset;
  }

  if (write_len == 0)
    return SCM_INUM0;

  if (scm_is_integer (port_or_fdes))
    fdes = scm_to_int (port_or_fdes);
  else
    {
      SCM port = (SCM_UNBNDP (port_or_fdes)?
		  scm_current_output_port () : port_or_fdes);
      scm_t_port *pt;
      off_t space;

      SCM_VALIDATE_OPFPORT (2, port);
      SCM_VALIDATE_OUTPUT_PORT (2, port);
      pt = SCM_PTAB_ENTRY (port);
      /* filling the last character in the buffer would require a flush.  */
      space = pt->write_end - pt->write_pos - 1;
      if (space >= write_len)
	{
	  memcpy (pt->write_pos, src, write_len);
	  pt->write_pos += write_len;
	  return scm_from_long (write_len);
	}
      if (pt->write_pos > pt->write_buf)
	scm_flush (port);
      fdes = SCM_FPORT_FDES (port);
    }
  {
    long rv;

    SCM_SYSCALL (rv = write (fdes, src, write_len));
    if (rv == -1)
      {
	if (SCM_EBLOCK (errno))
	  rv = 0;
	else
	  SCM_SYSERROR;
      }

    scm_remember_upto_here_1 (str);
    return scm_from_long (rv);
  }
}
#undef FUNC_NAME

SCM 
scm_init_rw_builtins ()
{
#include "libguile/rw.x"

  return SCM_UNSPECIFIED;
}

void
scm_init_rw ()
{
  scm_c_define_gsubr ("%init-rw-builtins", 0, 0, 0, scm_init_rw_builtins);
}

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/
Commit	Line	Data
b0e5fd8c GH	1	/* Copyright (C) 2001 Free Software Foundation, Inc.
b0e5fd8c GH	2	*
73be1d9e MV	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.
b0e5fd8c	7	*
73be1d9e MV	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.
b0e5fd8c	12	*
73be1d9e MV	13	* You should have received a copy of the GNU Lesser General Public
73be1d9e MV	14	* License along with this library; if not, write to the Free Software
92205699	15	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
73be1d9e	16	*/
b0e5fd8c GH	17
	18	\f
	19
	20	/* This is the C part of the (ice-9 rw) module. */
	21
7b5a83d3 RB	22	#if HAVE_CONFIG_H
	23	# include <config.h>
	24	#endif
	25
b0e5fd8c	26	#include <errno.h>
fbbdb121	27	#include <string.h>
b0e5fd8c GH	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"
fee12d18 MV	36	#include "libguile/modules.h"
fee12d18 MV	37	#include "libguile/strports.h"
b0e5fd8c GH	38
	39	#ifdef HAVE_UNISTD_H
	40	#include <unistd.h>
	41	#endif
7beabedb MG	42	#ifdef HAVE_IO_H
	43	#include <io.h>
	44	#endif
b0e5fd8c GH	45
	46	\f
	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),
99004a28 GH	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"
b0e5fd8c GH	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"
99004a28 GH	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"
b0e5fd8c	84	"@item\n"
99004a28 GH	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"
b0e5fd8c GH	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"
99004a28	100	"end-of-file check.\n"
b0e5fd8c GH	101	"@end itemize")
	102	#define FUNC_NAME s_scm_read_string_x_partial
	103	{
	104	char *dest;
a9d13d44	105	size_t offset;
c014a02e ML	106	long read_len;
c014a02e ML	107	long chars_read = 0;
b0e5fd8c GH	108	int fdes;
	109
	110	{
8824ac88	111	size_t last;
b0e5fd8c	112
8824ac88	113	SCM_VALIDATE_STRING (1, str);
cc95e00a	114	scm_i_get_substring_spec (scm_i_string_length (str),
8824ac88	115	start, &offset, end, &last);
b0e5fd8c GH	116	read_len = last - offset;
	117	}
	118
e11e83f3 MV	119	if (scm_is_integer (port_or_fdes))
e11e83f3 MV	120	fdes = scm_to_int (port_or_fdes);
b0e5fd8c GH	121	else
b0e5fd8c GH	122	{
9de87eea MV	123	SCM port = (SCM_UNBNDP (port_or_fdes)?
9de87eea MV	124	scm_current_input_port () : port_or_fdes);
b0e5fd8c GH	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. */
a9d13d44	133	dest = scm_i_string_writable_chars (str) + offset;
b0e5fd8c	134	chars_read = scm_take_from_input_buffers (port, dest, read_len);
cc95e00a	135	scm_i_string_stop_writing ();
b0e5fd8c GH	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	{
a9d13d44	142	dest = scm_i_string_writable_chars (str) + offset;
b0e5fd8c	143	SCM_SYSCALL (chars_read = read (fdes, dest, read_len));
cc95e00a	144	scm_i_string_stop_writing ();
b0e5fd8c GH	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)
8824ac88 MV	153	{
	154	scm_remember_upto_here_1 (str);
	155	return SCM_BOOL_F;
	156	}
b0e5fd8c	157	}
8824ac88 MV	158
8824ac88 MV	159	scm_remember_upto_here_1 (str);
b9bd8526	160	return scm_from_long (chars_read);
b0e5fd8c GH	161	}
	162	#undef FUNC_NAME
	163
99004a28 GH	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	{
cc95e00a	208	const char *src;
99004a28 GH	209	long write_len;
	210	int fdes;
	211
	212	{
8824ac88 MV	213	size_t offset;
8824ac88 MV	214	size_t last;
99004a28	215
8824ac88	216	SCM_VALIDATE_STRING (1, str);
cc95e00a MV	217	src = scm_i_string_chars (str);
cc95e00a MV	218	scm_i_get_substring_spec (scm_i_string_length (str),
8824ac88	219	start, &offset, end, &last);
99004a28 GH	220	src += offset;
	221	write_len = last - offset;
	222	}
	223
	224	if (write_len == 0)
	225	return SCM_INUM0;
	226
e11e83f3 MV	227	if (scm_is_integer (port_or_fdes))
e11e83f3 MV	228	fdes = scm_to_int (port_or_fdes);
99004a28 GH	229	else
99004a28 GH	230	{
9de87eea MV	231	SCM port = (SCM_UNBNDP (port_or_fdes)?
9de87eea MV	232	scm_current_output_port () : port_or_fdes);
92c2555f	233	scm_t_port *pt;
99004a28 GH	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;
b9bd8526	245	return scm_from_long (write_len);
99004a28 GH	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	}
8824ac88 MV	262
8824ac88 MV	263	scm_remember_upto_here_1 (str);
b9bd8526	264	return scm_from_long (rv);
99004a28 GH	265	}
	266	}
	267	#undef FUNC_NAME
	268
e615ee8d MV	269	SCM
e615ee8d MV	270	scm_init_rw_builtins ()
b0e5fd8c	271	{
b0e5fd8c	272	#include "libguile/rw.x"
b0e5fd8c	273
e615ee8d MV	274	return SCM_UNSPECIFIED;
	275	}
	276
	277	void
	278	scm_init_rw ()
	279	{
9a441ddb	280	scm_c_define_gsubr ("%init-rw-builtins", 0, 0, 0, scm_init_rw_builtins);
b0e5fd8c GH	281	}
	282
	283	/*
	284	Local Variables:
	285	c-file-style: "gnu"
	286	End:
	287	*/