os/ossrv/genericopenlibs/cstdlib/LSTDIO/SSCANF.C
author sl
Tue, 10 Jun 2014 14:32:02 +0200
changeset 1 260cb5ec6c19
permissions -rw-r--r--
Update contrib.
     1 /* SSCANF.C
     2  * 
     3  * Portions Copyright (c) 1990-2006 Nokia Corporation and/or its subsidiary(-ies).
     4  * All rights reserved.
     5  */
     6 
     7 /*
     8  * Copyright (c) 1990 The Regents of the University of California.
     9  * All rights reserved.
    10  *
    11  * Redistribution and use in source and binary forms are permitted
    12  * provided that the above copyright notice and this paragraph are
    13  * duplicated in all such forms and that any documentation,
    14  * advertising materials, and other materials related to such
    15  * distribution and use acknowledge that the software was developed
    16  * by the University of California, Berkeley.  The name of the
    17  * University may not be used to endorse or promote products derived
    18  * from this software without specific prior written permission.
    19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
    20  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
    21  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
    22  */
    23 
    24 /*
    25 
    26 FUNCTION
    27 	<<scanf>>, <<fscanf>>, <<sscanf>>---scan and format input
    28 
    29 INDEX
    30 	scanf
    31 INDEX
    32 	fscanf
    33 INDEX
    34 	sscanf
    35 
    36 ANSI_SYNOPSIS
    37         #include <stdio.h>
    38 
    39         int scanf(const char *<[format]> [, <[arg]>, ...]);
    40         int fscanf(FILE *<[fd]>, const char *<[format]> [, <[arg]>, ...]);
    41         int sscanf(const char *<[str]>, const char *<[format]> 
    42                    [, <[arg]>, ...]);
    43 
    44 
    45 TRAD_SYNOPSIS
    46 	#include <stdio.h>
    47 
    48 	int scanf(<[format]> [, <[arg]>, ...])
    49 	char *<[format]>;
    50 
    51 	int fscanf(<[fd]>, <[format]> [, <[arg]>, ...]);
    52 	FILE *<[fd]>;
    53 	char *<[format]>;
    54 
    55 	int sscanf(<[str]>, <[format]> [, <[arg]>, ...]);
    56 	char *<[str]>;
    57 	char *<[format]>;
    58 
    59 
    60 DESCRIPTION
    61         <<scanf>> scans a series of input fields from standard input,
    62 		one character at a time.  Each field is interpreted according to
    63 		a format specifier passed to <<scanf>> in the format string at
    64         <<*<[format]>>>.  <<scanf>> stores the interpreted input from
    65 		each field at the address passed to it as the corresponding argument
    66 		following <[format]>.  You must supply the same number of
    67 		format specifiers and address arguments as there are input fields.
    68 
    69         There must be sufficient address arguments for the given format
    70         specifiers; if not the results are unpredictable and likely
    71         disasterous.  Excess address arguments are merely ignored.
    72 
    73         <<scanf>> often produces unexpected results if the input diverges from
    74         an expected pattern. Since the combination of <<gets>> or <<fgets>>
    75         followed by <<sscanf>> is safe and easy, that is the preferred way
    76         to be certain that a program is synchronized with input at the end
    77 		of a line.
    78 
    79         <<fscanf>> and <<sscanf>> are identical to <<scanf>>, other than the
    80         source of input: <<fscanf>> reads from a file, and <<sscanf>>
    81 		from a string.
    82 
    83         The string at <<*<[format]>>> is a character sequence composed
    84         of zero or more directives. Directives are composed of
    85         one or more whitespace characters, non-whitespace characters,
    86         and format specifications.
    87 
    88         Whitespace characters are blank (<< >>), tab (<<\t>>), or
    89 		newline (<<\n>>).
    90         When <<scanf>> encounters a whitespace character in the format string
    91         it will read (but not store) all consecutive whitespace characters
    92         up to the next non-whitespace character in the input.
    93 
    94         Non-whitespace characters are all other ASCII characters except the
    95         percent sign (<<%>>).  When <<scanf>> encounters a non-whitespace
    96         character in the format string it will read, but not store
    97         a matching non-whitespace character.
    98 
    99         Format specifications tell <<scanf>> to read and convert characters
   100         from the input field into specific types of values, and store then
   101         in the locations specified by the address arguments.
   102 
   103         Trailing whitespace is left unread unless explicitly
   104         matched in the format string.
   105 
   106         The format specifiers must begin with a percent sign (<<%>>)
   107         and have the following form:
   108 
   109 .       %[*][<[width]>][<[size]>]<[type]>
   110 
   111         Each format specification begins with the percent character (<<%>>).
   112         The other fields are:
   113 	o+
   114 		o *
   115 		an optional marker; if present, it suppresses interpretation and
   116         assignment of this input field.
   117 
   118         o <[width]>
   119 		an optional maximum field width: a decimal integer,
   120 		which controls the maximum number of characters that
   121 		will be read before converting the current input field.  If the
   122 		input field has fewer than <[width]> characters, <<scanf>>
   123 		reads all the characters in the field, and then
   124 		proceeds with the next field and its format specification.
   125 
   126 		If a whitespace or a non-convertable character occurs
   127 		before <[width]> character are read, the characters up
   128 		to that character are read, converted, and stored.
   129 		Then <<scanf>> proceeds to the next format specification.
   130 
   131         o size
   132 		<<h>>, <<l>>, and <<L>> are optional size characters which
   133 		override the default way that <<scanf>> interprets the
   134 		data type of the corresponding argument.
   135 
   136 
   137 .Modifier   Type(s)
   138 .   h       d, i, o, u, x     convert input to short,
   139 .                             store in short object
   140 .
   141 .   h       D, I, O, U, X     no effect
   142 .           e, f, c, s, n, p
   143 .
   144 .   l       d, i, o, u, x     convert input to long,
   145 .                             store in long object
   146 .
   147 .   l       e, f, g           convert input to double
   148 .                             store in a double object
   149 .
   150 .   l       D, I, O, U, X     no effect
   151 .           c, s, n, p
   152 .
   153 .   L       d, i, o, u, x     convert to long double,
   154 .                             store in long double
   155 .
   156 .   L      all others         no effect
   157 
   158 
   159         o <[type]>
   160 
   161 		A character to specify what kind of conversion
   162                 <<scanf>> performs.  Here is a table of the conversion
   163                 characters:
   164 
   165 		o+
   166 		o  %
   167 		No conversion is done; the percent character (<<%>>) is stored.
   168 
   169 		o c
   170 		Scans one character.  Corresponding <[arg]>: <<(char *arg)>>.
   171 
   172 		o s
   173 		Reads a character string into the array supplied.
   174 		Corresponding <[arg]>: <<(char arg[])>>.
   175 
   176 		o  [<[pattern]>]
   177 		Reads a non-empty character string into memory
   178 		starting at <[arg]>.  This area must be large
   179 		enough to accept the sequence and a
   180 		terminating null character which will be added
   181 		automatically.  (<[pattern]> is discussed in the paragraph following
   182 		this table). Corresponding <[arg]>: <<(char *arg)>>.
   183 
   184 		o d
   185 		Reads a decimal integer into the corresponding <[arg]>: <<(int *arg)>>.
   186 
   187 		o D
   188 		Reads a decimal integer into the corresponding
   189 		<[arg]>: <<(long *arg)>>.
   190 
   191 		o o
   192 		Reads an octal integer into the corresponding <[arg]>: <<(int *arg)>>.
   193 
   194 		o O
   195 		Reads an octal integer into the corresponding <[arg]>: <<(long *arg)>>.
   196 
   197 		o u
   198 		Reads an unsigned decimal integer into the corresponding
   199 		<[arg]>: <<(unsigned int *arg)>>.
   200 			
   201 
   202 		o U
   203 		Reads an unsigned decimal integer into the corresponding <[arg]>:
   204 		<<(unsigned long *arg)>>.
   205 
   206 		o x,X
   207 		Read a hexadecimal integer into the corresponding <[arg]>:
   208 		<<(int *arg)>>.
   209 
   210 		o e, f, g
   211 		Read a floating point number into the corresponding <[arg]>:
   212 		<<(float *arg)>>.
   213 
   214 		o E, F, G
   215 		Read a floating point number into the corresponding <[arg]>:
   216 		<<(double *arg)>>.
   217 
   218 		o  i
   219 		Reads a decimal, octal or hexadecimal integer into the
   220 		corresponding <[arg]>: <<(int *arg)>>.
   221 
   222 		o  I
   223 		Reads a decimal, octal or hexadecimal integer into the
   224 		corresponding <[arg]>: <<(long *arg)>>.
   225 
   226 		o  n
   227 		Stores the number of characters read in the corresponding
   228 		<[arg]>: <<(int *arg)>>.
   229 
   230 		o  p
   231                 Stores a scanned pointer.  ANSI C leaves the details
   232 		to each implementation; this implementation treats
   233 		<<%p>> exactly the same as <<%U>>.  Corresponding
   234 		<[arg]>: <<(void **arg)>>.  
   235                 o-
   236 
   237 	A <[pattern]> of characters surrounded by square brackets can be used
   238 	instead of the <<s>> type character.  <[pattern]> is a set of
   239 	characters which define a search set of possible characters making up
   240 	the <<scanf>> input field.  If the first character in the brackets is a
   241 	caret (<<^>>), the search set is inverted to include all ASCII characters
   242 	except those between the brackets.  There is also a range facility
   243 	which you can use as a shortcut. <<%[0-9] >> matches all decimal digits.
   244 	The hyphen must not be the first or last character in the set.
   245 	The character prior to the hyphen must be lexically less than the
   246 	character after it.
   247 
   248 	Here are some <[pattern]> examples:
   249 		o+
   250 		o %[abcd]
   251 		matches strings containing only <<a>>, <<b>>, <<c>>, and <<d>>.
   252 
   253 		o %[^abcd]
   254 		matches strings containing any characters except <<a>>, <<b>>,
   255 		<<c>>, or <<d>>
   256 
   257 		o %[A-DW-Z]
   258 		matches strings containing <<A>>, <<B>>, <<C>>, <<D>>, <<W>>,
   259 		<<X>>, <<Y>>, <<Z>>
   260 
   261 		o %[z-a]
   262 		matches the characters  <<z>>, <<->>, and <<a>>
   263 		o-
   264 
   265 	Floating point numbers (for field types <<e>>, <<f>>, <<g>>, <<E>>,
   266 	<<F>>, <<G>>) must correspond to the following general form:
   267 
   268 .		[+/-] ddddd[.]ddd [E|e[+|-]ddd]
   269 
   270 	where objects inclosed in square brackets are optional, and <<ddd>>
   271 	represents decimal, octal, or hexadecimal digits.
   272 	o-
   273 
   274 RETURNS
   275         <<scanf>> returns the number of input fields successfully
   276         scanned, converted and stored; the return value does
   277         not include scanned fields which were not stored.
   278 
   279         If <<scanf>> attempts to read at end-of-file, the return
   280         value is <<EOF>>.
   281 
   282         If no fields were stored, the return value is <<0>>.
   283 
   284         <<scanf>> might stop scanning a particular field before
   285         reaching the normal field end character, or may
   286         terminate entirely.
   287 
   288         <<scanf>> stops scanning and storing the current field
   289         and moves to the next input field (if any)
   290         in any of the following situations:
   291 
   292 	O+
   293 	o       The assignment suppressing character (<<*>>) appears
   294 	after the <<%>> in the format specification; the current
   295 	input field is scanned but not stored.
   296 
   297 	o       <[width]> characters have been read (<[width]> is a
   298 	width specification, a positive decimal integer).
   299 
   300 	o       The next character read cannot be converted
   301 	under the the current format (for example,
   302 	if a <<Z>> is read when the format is decimal).
   303 
   304 	o       The next character in the input field does not appear
   305 	in the search set (or does appear in the inverted search set).
   306 	O-
   307 
   308 	When <<scanf>> stops scanning the current input field for one of
   309 	these reasons, the next character is considered unread and
   310 	used as the first character of the following input field, or the
   311 	first character in a subsequent read operation on the input.
   312 
   313 	<<scanf>> will terminate under the following circumstances:
   314 
   315 	O+
   316 	o       The next character in the input field conflicts
   317 	with a corresponding non-whitespace character in the
   318 	format string.
   319 
   320 	o       The next character in the input field is <<EOF>>.
   321 
   322 	o       The format string has been exhausted.
   323 	O-
   324 
   325 	When the format string contains a character sequence that is
   326 	not part of a format specification, the same character
   327 	sequence must appear in the input; <<scanf>> will
   328 	scan but not store the matched characters.  If a
   329 	conflict occurs, the first conflicting character remains in the input
   330 	as if it had never been read.
   331 
   332 PORTABILITY
   333 <<scanf>> is ANSI C.
   334 
   335 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
   336 <<lseek>>, <<read>>, <<sbrk>>, <<write>>.
   337 */
   338 
   339 #include <_ansi.h>
   340 #include <reent.h>
   341 #include <stdio.h>
   342 #include <string.h>
   343 #include <stdarg.h>
   344 #include "LOCAL.H"
   345 
   346 static
   347 int
   348 eofread (void* cookie,char *buf,int len)
   349 {
   350   	cookie=cookie;
   351 	buf=buf;
   352 	len=len;
   353 	return 0;
   354 }
   355 
   356 /**
   357 Read formatted data from string.
   358 Reads data from the buffer specified and stores it
   359 into the locations given by argument(s).
   360 Locations pointed by each argument are filled with their corresponding type
   361 of value requested in the format string.
   362 
   363 @param str Buffer containing the string to be parsed for data. 
   364 @param fmt String that can contain one or more of these items:
   365 	   Whitespace characters: the function will read and ignore any whitespace
   366  	   characters (this includes blank, newline and tab characters) encountered
   367  	   before the next non-whitespace character. This includes any quantity of
   368  	   whitespace characters (including none). On-whitespace characters (any
   369  	   character not including blank, newline, tab, or any format specifier
   370  	   begining with % character): this cause that the function read and discard
   371  	   any character that match the given non-whitespace character. If this
   372  	   character is not found the function ends returning error.
   373  	   Format specifiers: A sequence of characters begining with '%' indicates
   374  	   that next data has to be readed and stored at the location pointed by its
   375  	   corresponding argument with a given format that is specified following this
   376  	   prototype: %[*][width][modifiers]type
   377  
   378 @return	On Success, The number of items succesfully read. This count doesn't include any
   379  		ignored fields.
   380 		On Failure, returns EOF, if an error has occurred before the first assignation
   381 		could be done and errno may be set.
   382 */
   383 EXPORT_C int sscanf(const char *str, const char *fmt, ...)
   384 {
   385   int ret;
   386   va_list ap;
   387   FILE f;
   388 
   389   f._data = _REENT2;
   390   if (!f._data)
   391 	return EOF; // Memory for library globals is not allocated (errno not set). 
   392   
   393   f._flags = __SRD;
   394   f._bf._base = f._p = (unsigned char *) str;
   395   f._bf._size = f._r = strlen (str);
   396   f._read = eofread;
   397   f._ub._base = NULL;
   398   f._lb._base = NULL;
   399   
   400   va_start (ap, fmt);
   401   ret = __svfscanf (&f, fmt, ap);
   402   va_end (ap);
   403   return ret;
   404 }