newlib-cygwin/newlib/libc/stdio/swscanf.c

/*
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * and/or other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

/*
FUNCTION
<<swscanf>>, <<fwscanf>>, <<wscanf>>---scan and format wide character input

INDEX
	wscanf
INDEX
	_wscanf_r
INDEX
	fwscanf
INDEX
	_fwscanf_r
INDEX
	swscanf
INDEX
	_swscanf_r

SYNOPSIS
        #include <stdio.h>

        int wscanf(const wchar_t *__restrict <[format]>, ...);
        int fwscanf(FILE *__restrict <[fd]>,
                    const wchar_t *__restrict <[format]>, ...);
        int swscanf(const wchar_t *__restrict <[str]>, 
                    const wchar_t *__restrict <[format]>, ...);

        int _wscanf_r(struct _reent *<[ptr]>, const wchar_t *<[format]>, ...);
        int _fwscanf_r(struct _reent *<[ptr]>, FILE *<[fd]>, 
                      const wchar_t *<[format]>, ...);
        int _swscanf_r(struct _reent *<[ptr]>, const wchar_t *<[str]>,
                      const wchar_t *<[format]>, ...);

DESCRIPTION
        <<wscanf>> scans a series of input fields from standard input,
		one wide character at a time.  Each field is interpreted according to
		a format specifier passed to <<wscanf>> in the format string at
        <<*<[format]>>>.  <<wscanf>> stores the interpreted input from
		each field at the address passed to it as the corresponding argument
		following <[format]>.  You must supply the same number of
		format specifiers and address arguments as there are input fields.

        There must be sufficient address arguments for the given format
        specifiers; if not the results are unpredictable and likely
        disasterous.  Excess address arguments are merely ignored.

        <<wscanf>> often produces unexpected results if the input diverges from
        an expected pattern. Since the combination of <<gets>> or <<fgets>>
        followed by <<swscanf>> is safe and easy, that is the preferred way
        to be certain that a program is synchronized with input at the end
		of a line.

        <<fwscanf>> and <<swscanf>> are identical to <<wscanf>>, other than the
        source of input: <<fwscanf>> reads from a file, and <<swscanf>>
		from a string.

        The routines <<_wscanf_r>>, <<_fwscanf_r>>, and <<_swscanf_r>> are reentrant
        versions of <<wscanf>>, <<fwscanf>>, and <<swscanf>> that take an additional
        first argument pointing to a reentrancy structure.

        The string at <<*<[format]>>> is a wide character sequence composed
        of zero or more directives. Directives are composed of
        one or more whitespace characters, non-whitespace characters,
        and format specifications.

        Whitespace characters are blank (<< >>), tab (<<\t>>), or
		newline (<<\n>>).
        When <<wscanf>> encounters a whitespace character in the format string
        it will read (but not store) all consecutive whitespace characters
        up to the next non-whitespace character in the input.

        Non-whitespace characters are all other ASCII characters except the
        percent sign (<<%>>).  When <<wscanf>> encounters a non-whitespace
        character in the format string it will read, but not store
        a matching non-whitespace character.

        Format specifications tell <<wscanf>> to read and convert characters
        from the input field into specific types of values, and store then
        in the locations specified by the address arguments.

        Trailing whitespace is left unread unless explicitly
        matched in the format string.

        The format specifiers must begin with a percent sign (<<%>>)
        and have the following form:

.       %[*][<[width]>][<[size]>]<[type]>

        Each format specification begins with the percent character (<<%>>).
        The other fields are:
	O+
		o *

		an optional marker; if present, it suppresses interpretation and
        assignment of this input field.

        o <[width]>

		an optional maximum field width: a decimal integer,
		which controls the maximum number of characters that
		will be read before converting the current input field.  If the
		input field has fewer than <[width]> characters, <<wscanf>>
		reads all the characters in the field, and then
		proceeds with the next field and its format specification.

		If a whitespace or a non-convertable wide character occurs
		before <[width]> character are read, the characters up
		to that character are read, converted, and stored.
		Then <<wscanf>> proceeds to the next format specification.

        o <[size]>

		<<h>>, <<j>>, <<l>>, <<L>>, <<t>>, and <<z>> are optional size
		characters which override the default way that <<wscanf>>
		interprets the data type of the corresponding argument.

		@multitable @columnfractions 0.18 0.30 0.52
		@headitem
		Modifier
		@tab
		Type(s)
		@tab
		@item
		hh
		@tab
		d, i, o, u, x, n
		@tab
		convert input to char, store in char object
		@item
		h
		@tab
		d, i, o, u, x, n
		@tab
		convert input to short, store in short object
		@item
		h
		@tab
		e, f, c, s, p
		@tab
		no effect
		@item
		j
		@tab
		d, i, o, u, x, n
		@tab
		convert input to intmax_t, store in intmax_t object
		@item
		j
		@tab
		all others
		@tab
		no effect
		@item
		l
		@tab
		d, i, o, u, x, n
		@tab
		convert input to long, store in long object
		@item
		l
		@tab
		e, f, g
		@tab
		convert input to double, store in a double object
		@item
		l
		@tab
		c, s, [
		@tab
		the input is stored in a wchar_t object
		@item
		l
		@tab
		p
		@tab
		no effect
		@item
		ll
		@tab
		d, i, o, u, x, n
		@tab
		convert to long long, store in long long object
		@item
		L
		@tab
		d, i, o, u, x, n
		@tab
		convert to long long, store in long long object
		@item
		L
		@tab
		e, f, g, E, G
		@tab
		convert to long double, store in long double object
		@item
		L
		@tab
		all others
		@tab
		no effect
		@item
		t
		@tab
		d, i, o, u, x, n
		@tab
		convert input to ptrdiff_t, store in ptrdiff_t object
		@item
		t
		@tab
		all others
		@tab
		no effect
		@item
		z
		@tab
		d, i, o, u, x, n
		@tab
		convert input to size_t, store in size_t object
		@item
		z
		@tab
		all others
		@tab
		no effect
		@end multitable

        o <[type]>

		A character to specify what kind of conversion
                <<wscanf>> performs.  Here is a table of the conversion
                characters:

		o+
		o %
		No conversion is done; the percent character (<<%>>) is stored.

		o c
		Scans one wide character.  Corresponding <[arg]>: <<(char *arg)>>.
		Otherwise, if an <<l>> specifier is present, the corresponding
		<[arg]> is a <<(wchar_t *arg)>>.

		o s
		Reads a character string into the array supplied.
		Corresponding <[arg]>: <<(char arg[])>>.
		If an <<l>> specifier is present, the corresponding <[arg]> is a <<(wchar_t *arg)>>.

		o [<[pattern]>]
		Reads a non-empty character string into memory
		starting at <[arg]>.  This area must be large
		enough to accept the sequence and a
		terminating null character which will be added
		automatically.  (<[pattern]> is discussed in the paragraph following
		this table).  Corresponding <[arg]>: <<(char *arg)>>.
		If an <<l>> specifier is present, the corresponding <[arg]> is
		a <<(wchar_t *arg)>>.

		o d
		Reads a decimal integer into the corresponding <[arg]>: <<(int *arg)>>.

		o o
		Reads an octal integer into the corresponding <[arg]>: <<(int *arg)>>.

		o u
		Reads an unsigned decimal integer into the corresponding
		<[arg]>: <<(unsigned int *arg)>>.

		o x,X
		Read a hexadecimal integer into the corresponding <[arg]>:
		<<(int *arg)>>.

		o e, f, g
		Read a floating-point number into the corresponding <[arg]>:
		<<(float *arg)>>.

		o E, F, G
		Read a floating-point number into the corresponding <[arg]>:
		<<(double *arg)>>.

		o i
		Reads a decimal, octal or hexadecimal integer into the
		corresponding <[arg]>: <<(int *arg)>>.

		o n
		Stores the number of characters read in the corresponding
		<[arg]>: <<(int *arg)>>.

		o p
                Stores a scanned pointer.  ANSI C leaves the details
		to each implementation; this implementation treats
		<<%p>> exactly the same as <<%U>>.  Corresponding
		<[arg]>: <<(void **arg)>>.
                o-

	A <[pattern]> of characters surrounded by square brackets can be used
	instead of the <<s>> type character.  <[pattern]> is a set of
	characters which define a search set of possible characters making up
	the <<wscanf>> input field.  If the first character in the brackets is a
	caret (<<^>>), the search set is inverted to include all ASCII characters
	except those between the brackets.  There is no range facility as is
	defined in the corresponding non-wide character scanf functions.
	Ranges are not part of the POSIX standard.

	Here are some <[pattern]> examples:
		o+
		o %[abcd]
		matches wide character strings containing only
		<<a>>, <<b>>, <<c>>, and <<d>>.

		o %[^abcd]
		matches wide character strings containing any characters except
		<<a>>, <<b>>, <<c>>, or <<d>>.

		o %[A-DW-Z]
		Note: No wide character ranges, so this expression matches wide
		character strings containing <<A>>, <<->>, <<D>>, <<W>>, <<Z>>.
		o-

	Floating point numbers (for field types <<e>>, <<f>>, <<g>>, <<E>>,
	<<F>>, <<G>>) must correspond to the following general form:

.		[+/-] ddddd[.]ddd [E|e[+|-]ddd]

	where objects inclosed in square brackets are optional, and <<ddd>>
	represents decimal, octal, or hexadecimal digits.
	O-

RETURNS
        <<wscanf>> returns the number of input fields successfully
        scanned, converted and stored; the return value does
        not include scanned fields which were not stored.

        If <<wscanf>> attempts to read at end-of-file, the return
        value is <<EOF>>.

        If no fields were stored, the return value is <<0>>.

        <<wscanf>> might stop scanning a particular field before
        reaching the normal field end character, or may
        terminate entirely.

        <<wscanf>> stops scanning and storing the current field
        and moves to the next input field (if any)
        in any of the following situations:

	O+
	o       The assignment suppressing character (<<*>>) appears
	after the <<%>> in the format specification; the current
	input field is scanned but not stored.

	o       <[width]> characters have been read (<[width]> is a
	width specification, a positive decimal integer).

	o       The next wide character read cannot be converted
	under the the current format (for example,
	if a <<Z>> is read when the format is decimal).

	o       The next wide character in the input field does not appear
	in the search set (or does appear in the inverted search set).
	O-

	When <<wscanf>> stops scanning the current input field for one of
	these reasons, the next character is considered unread and
	used as the first character of the following input field, or the
	first character in a subsequent read operation on the input.

	<<wscanf>> will terminate under the following circumstances:

	O+
	o       The next wide character in the input field conflicts
	with a corresponding non-whitespace character in the
	format string.

	o       The next wide character in the input field is <<WEOF>>.

	o       The format string has been exhausted.
	O-

	When the format string contains a wide character sequence that is
	not part of a format specification, the same wide character
	sequence must appear in the input; <<wscanf>> will
	scan but not store the matched characters.  If a
	conflict occurs, the first conflicting wide character remains in the
	input as if it had never been read.

PORTABILITY
<<wscanf>> is C99, POSIX-1.2008.

Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
*/

#include <_ansi.h>
#include <reent.h>
#include <stdio.h>
#include <wchar.h>
#include <stdarg.h>
#include "local.h"

#ifndef _REENT_ONLY 

int 
swscanf (const wchar_t *__restrict str, const wchar_t *__restrict fmt, ...)
{
  int ret;
  va_list ap;
  FILE f;

  f._flags = __SRD | __SSTR;
  f._bf._base = f._p = (unsigned char *) str;
  f._bf._size = f._r = wcslen (str) * sizeof (wchar_t);
  f._read = __seofread;
  f._ub._base = NULL;
  f._lb._base = NULL;
  f._flags2 = 0;
  f._ur = 0;
  f._file = -1;  /* No file. */
  va_start (ap, fmt);
  ret = __ssvfwscanf_r (_REENT, &f, fmt, ap);
  va_end (ap);
  return ret;
}

#endif /* !_REENT_ONLY */

int 
_swscanf_r (struct _reent *ptr, const wchar_t *str, const wchar_t *fmt, ...)
{
  int ret;
  va_list ap;
  FILE f;

  f._flags = __SRD | __SSTR;
  f._bf._base = f._p = (unsigned char *) str;
  f._bf._size = f._r = wcslen (str) * sizeof (wchar_t);
  f._read = __seofread;
  f._ub._base = NULL;
  f._lb._base = NULL;
  f._file = -1;  /* No file. */
  va_start (ap, fmt);
  ret = __ssvfwscanf_r (ptr, &f, fmt, ap);
  va_end (ap);
  return ret;
}