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

/* 	Copyright (C) 2001, 2006, 2009, 2011 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 3 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.  */

#ifdef 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.  */
      str = scm_i_string_start_writing (str);
      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.  */
    {
      str = scm_i_string_start_writing (str);
      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;
  scm_t_off 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;
      scm_t_off 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_unlocked (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
4251ae2e	1	/* Copyright (C) 2001, 2006, 2009, 2011 Free Software Foundation, Inc.
b0e5fd8c	2	*
73be1d9e	3	* This library is free software; you can redistribute it and/or
53befeb7 NJ	4	* modify it under the terms of the GNU Lesser General Public License
	5	* as published by the Free Software Foundation; either version 3 of
	6	* the License, or (at your option) any later version.
b0e5fd8c	7	*
53befeb7 NJ	8	* This library is distributed in the hope that it will be useful, but
53befeb7 NJ	9	* WITHOUT ANY WARRANTY; without even the implied warranty of
73be1d9e MV	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
73be1d9e MV	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
53befeb7 NJ	15	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
53befeb7 NJ	16	* 02110-1301 USA
73be1d9e	17	*/
b0e5fd8c GH	18
	19	\f
	20
	21	/* This is the C part of the (ice-9 rw) module. */
	22
dbb605f5	23	#ifdef HAVE_CONFIG_H
7b5a83d3 RB	24	# include <config.h>
	25	#endif
	26
b0e5fd8c	27	#include <errno.h>
fbbdb121	28	#include <string.h>
b0e5fd8c GH	29
	30	#include "libguile/_scm.h"
	31	#include "libguile/fports.h"
	32	#include "libguile/ports.h"
	33	#include "libguile/root.h"
	34	#include "libguile/rw.h"
	35	#include "libguile/strings.h"
	36	#include "libguile/validate.h"
fee12d18 MV	37	#include "libguile/modules.h"
fee12d18 MV	38	#include "libguile/strports.h"
b0e5fd8c GH	39
	40	#ifdef HAVE_UNISTD_H
	41	#include <unistd.h>
	42	#endif
7beabedb MG	43	#ifdef HAVE_IO_H
	44	#include <io.h>
	45	#endif
b0e5fd8c GH	46
	47	\f
	48
	49	#if defined (EAGAIN)
	50	#define SCM_MAYBE_EAGAIN \|\| errno == EAGAIN
	51	#else
	52	#define SCM_MAYBE_EAGAIN
	53	#endif
	54
	55	#if defined (EWOULDBLOCK)
	56	#define SCM_MAYBE_EWOULDBLOCK \|\| errno == EWOULDBLOCK
	57	#else
	58	#define SCM_MAYBE_EWOULDBLOCK
	59	#endif
	60
	61	/* MAYBE there is EAGAIN way of defining this macro but now I EWOULDBLOCK. */
	62	#define SCM_EBLOCK(errno) \
	63	(0 SCM_MAYBE_EAGAIN SCM_MAYBE_EWOULDBLOCK)
	64
	65	SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0,
	66	(SCM str, SCM port_or_fdes, SCM start, SCM end),
99004a28 GH	67	"Read characters from a port or file descriptor into a\n"
	68	"string @var{str}. A port must have an underlying file\n"
	69	"descriptor --- a so-called fport. This procedure is\n"
	70	"scsh-compatible and can efficiently read large strings.\n"
	71	"It will:\n\n"
b0e5fd8c GH	72	"@itemize\n"
	73	"@item\n"
	74	"attempt to fill the entire string, unless the @var{start}\n"
	75	"and/or @var{end} arguments are supplied. i.e., @var{start}\n"
	76	"defaults to 0 and @var{end} defaults to\n"
	77	"@code{(string-length str)}\n"
	78	"@item\n"
	79	"use the current input port if @var{port_or_fdes} is not\n"
	80	"supplied.\n"
	81	"@item\n"
99004a28 GH	82	"return fewer than the requested number of characters in some\n"
	83	"cases, e.g., on end of file, if interrupted by a signal, or if\n"
	84	"not all the characters are immediately available.\n"
b0e5fd8c	85	"@item\n"
99004a28 GH	86	"wait indefinitely for some input if no characters are\n"
	87	"currently available,\n"
	88	"unless the port is in non-blocking mode.\n"
	89	"@item\n"
	90	"read characters from the port's input buffers if available,\n"
	91	"instead from the underlying file descriptor.\n"
b0e5fd8c GH	92	"@item\n"
	93	"return @code{#f} if end-of-file is encountered before reading\n"
	94	"any characters, otherwise return the number of characters\n"
	95	"read.\n"
	96	"@item\n"
	97	"return 0 if the port is in non-blocking mode and no characters\n"
	98	"are immediately available.\n"
	99	"@item\n"
	100	"return 0 if the request is for 0 bytes, with no\n"
99004a28	101	"end-of-file check.\n"
b0e5fd8c GH	102	"@end itemize")
	103	#define FUNC_NAME s_scm_read_string_x_partial
	104	{
	105	char *dest;
a9d13d44	106	size_t offset;
c014a02e ML	107	long read_len;
c014a02e ML	108	long chars_read = 0;
b0e5fd8c GH	109	int fdes;
	110
	111	{
8824ac88	112	size_t last;
b0e5fd8c	113
8824ac88	114	SCM_VALIDATE_STRING (1, str);
cc95e00a	115	scm_i_get_substring_spec (scm_i_string_length (str),
8824ac88	116	start, &offset, end, &last);
b0e5fd8c GH	117	read_len = last - offset;
	118	}
	119
e11e83f3 MV	120	if (scm_is_integer (port_or_fdes))
e11e83f3 MV	121	fdes = scm_to_int (port_or_fdes);
b0e5fd8c GH	122	else
b0e5fd8c GH	123	{
9de87eea MV	124	SCM port = (SCM_UNBNDP (port_or_fdes)?
9de87eea MV	125	scm_current_input_port () : port_or_fdes);
b0e5fd8c GH	126
	127	SCM_VALIDATE_OPFPORT (2, port);
	128	SCM_VALIDATE_INPUT_PORT (2, port);
	129
	130	/* if there's anything in the port buffers, use it, but then
	131	don't touch the file descriptor. otherwise the
	132	"return immediately if something is available" rule may
	133	be violated. */
9c44cd45	134	str = scm_i_string_start_writing (str);
a9d13d44	135	dest = scm_i_string_writable_chars (str) + offset;
b0e5fd8c	136	chars_read = scm_take_from_input_buffers (port, dest, read_len);
cc95e00a	137	scm_i_string_stop_writing ();
b0e5fd8c GH	138	fdes = SCM_FPORT_FDES (port);
	139	}
	140
	141	if (chars_read == 0 && read_len > 0) /* don't confuse read_len == 0 with
	142	EOF. */
	143	{
9c44cd45	144	str = scm_i_string_start_writing (str);
a9d13d44	145	dest = scm_i_string_writable_chars (str) + offset;
b0e5fd8c	146	SCM_SYSCALL (chars_read = read (fdes, dest, read_len));
cc95e00a	147	scm_i_string_stop_writing ();
b0e5fd8c GH	148	if (chars_read == -1)
	149	{
	150	if (SCM_EBLOCK (errno))
	151	chars_read = 0;
	152	else
	153	SCM_SYSERROR;
	154	}
	155	else if (chars_read == 0)
8824ac88 MV	156	{
	157	scm_remember_upto_here_1 (str);
	158	return SCM_BOOL_F;
	159	}
b0e5fd8c	160	}
8824ac88 MV	161
8824ac88 MV	162	scm_remember_upto_here_1 (str);
b9bd8526	163	return scm_from_long (chars_read);
b0e5fd8c GH	164	}
	165	#undef FUNC_NAME
	166
99004a28 GH	167	SCM_DEFINE (scm_write_string_partial, "write-string/partial", 1, 3, 0,
	168	(SCM str, SCM port_or_fdes, SCM start, SCM end),
	169	"Write characters from a string @var{str} to a port or file\n"
	170	"descriptor. A port must have an underlying file descriptor\n"
	171	"--- a so-called fport. This procedure is\n"
	172	"scsh-compatible and can efficiently write large strings.\n"
	173	"It will:\n\n"
	174	"@itemize\n"
	175	"@item\n"
	176	"attempt to write the entire string, unless the @var{start}\n"
	177	"and/or @var{end} arguments are supplied. i.e., @var{start}\n"
	178	"defaults to 0 and @var{end} defaults to\n"
	179	"@code{(string-length str)}\n"
	180	"@item\n"
	181	"use the current output port if @var{port_of_fdes} is not\n"
	182	"supplied.\n"
	183	"@item\n"
	184	"in the case of a buffered port, store the characters in the\n"
	185	"port's output buffer, if all will fit. If they will not fit\n"
	186	"then any existing buffered characters will be flushed\n"
	187	"before attempting\n"
	188	"to write the new characters directly to the underlying file\n"
	189	"descriptor. If the port is in non-blocking mode and\n"
	190	"buffered characters can not be flushed immediately, then an\n"
	191	"@code{EAGAIN} system-error exception will be raised (Note:\n"
	192	"scsh does not support the use of non-blocking buffered ports.)\n"
	193	"@item\n"
	194	"write fewer than the requested number of\n"
	195	"characters in some cases, e.g., if interrupted by a signal or\n"
	196	"if not all of the output can be accepted immediately.\n"
	197	"@item\n"
	198	"wait indefinitely for at least one character\n"
	199	"from @var{str} to be accepted by the port, unless the port is\n"
	200	"in non-blocking mode.\n"
	201	"@item\n"
	202	"return the number of characters accepted by the port.\n"
	203	"@item\n"
	204	"return 0 if the port is in non-blocking mode and can not accept\n"
	205	"at least one character from @var{str} immediately\n"
	206	"@item\n"
	207	"return 0 immediately if the request size is 0 bytes.\n"
	208	"@end itemize")
	209	#define FUNC_NAME s_scm_write_string_partial
	210	{
cc95e00a	211	const char *src;
f1ce9199	212	scm_t_off write_len;
99004a28 GH	213	int fdes;
	214
	215	{
8824ac88 MV	216	size_t offset;
8824ac88 MV	217	size_t last;
99004a28	218
8824ac88	219	SCM_VALIDATE_STRING (1, str);
cc95e00a MV	220	src = scm_i_string_chars (str);
cc95e00a MV	221	scm_i_get_substring_spec (scm_i_string_length (str),
8824ac88	222	start, &offset, end, &last);
99004a28 GH	223	src += offset;
	224	write_len = last - offset;
	225	}
	226
	227	if (write_len == 0)
	228	return SCM_INUM0;
	229
e11e83f3 MV	230	if (scm_is_integer (port_or_fdes))
e11e83f3 MV	231	fdes = scm_to_int (port_or_fdes);
99004a28 GH	232	else
99004a28 GH	233	{
9de87eea MV	234	SCM port = (SCM_UNBNDP (port_or_fdes)?
9de87eea MV	235	scm_current_output_port () : port_or_fdes);
92c2555f	236	scm_t_port *pt;
f1ce9199	237	scm_t_off space;
99004a28 GH	238
	239	SCM_VALIDATE_OPFPORT (2, port);
	240	SCM_VALIDATE_OUTPUT_PORT (2, port);
	241	pt = SCM_PTAB_ENTRY (port);
	242	/* filling the last character in the buffer would require a flush. */
	243	space = pt->write_end - pt->write_pos - 1;
	244	if (space >= write_len)
	245	{
	246	memcpy (pt->write_pos, src, write_len);
	247	pt->write_pos += write_len;
b9bd8526	248	return scm_from_long (write_len);
99004a28 GH	249	}
99004a28 GH	250	if (pt->write_pos > pt->write_buf)
4251ae2e	251	scm_flush_unlocked (port);
99004a28 GH	252	fdes = SCM_FPORT_FDES (port);
	253	}
	254	{
	255	long rv;
	256
	257	SCM_SYSCALL (rv = write (fdes, src, write_len));
	258	if (rv == -1)
	259	{
	260	if (SCM_EBLOCK (errno))
	261	rv = 0;
	262	else
	263	SCM_SYSERROR;
	264	}
8824ac88 MV	265
8824ac88 MV	266	scm_remember_upto_here_1 (str);
b9bd8526	267	return scm_from_long (rv);
99004a28 GH	268	}
	269	}
	270	#undef FUNC_NAME
	271
e615ee8d MV	272	SCM
e615ee8d MV	273	scm_init_rw_builtins ()
b0e5fd8c	274	{
b0e5fd8c	275	#include "libguile/rw.x"
b0e5fd8c	276
e615ee8d MV	277	return SCM_UNSPECIFIED;
	278	}
	279
	280	void
	281	scm_init_rw ()
	282	{
9a441ddb	283	scm_c_define_gsubr ("%init-rw-builtins", 0, 0, 0, scm_init_rw_builtins);
b0e5fd8c GH	284	}
	285
	286	/*
	287	Local Variables:
	288	c-file-style: "gnu"
	289	End:
	290	*/