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 }