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libc/newlib/libc/stdio/sprintf.c

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/*
* 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,
* advertising materials, and 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
<<printf>>, <<fprintf>>, <<asprintf>>, <<sprintf>>, <<snprintf>>---format output
INDEX
fprintf
INDEX
printf
INDEX
asprintf
INDEX
sprintf
INDEX
snprintf
ANSI_SYNOPSIS
#include <stdio.h>
int printf(const char *<[format]> [, <[arg]>, ...]);
int fprintf(FILE *<[fd]>, const char *<[format]> [, <[arg]>, ...]);
int sprintf(char *<[str]>, const char *<[format]> [, <[arg]>, ...]);
int asprintf(char **<[strp]>, const char *<[format]> [, <[arg]>, ...]);
int snprintf(char *<[str]>, size_t <[size]>, const char *<[format]> [, <[arg]>, ...]);
TRAD_SYNOPSIS
#include <stdio.h>
int printf(<[format]> [, <[arg]>, ...])
char *<[format]>;
int fprintf(<[fd]>, <[format]> [, <[arg]>, ...]);
FILE *<[fd]>;
char *<[format]>;
int asprintf(<[strp]>, <[format]> [, <[arg]>, ...]);
char **<[strp]>;
char *<[format]>;
int sprintf(<[str]>, <[format]> [, <[arg]>, ...]);
char *<[str]>;
char *<[format]>;
int snprintf(<[str]>, size_t <[size]>, <[format]> [, <[arg]>, ...]);
char *<[str]>;
size_t <[size]>;
char *<[format]>;
DESCRIPTION
<<printf>> accepts a series of arguments, applies to each a
format specifier from <<*<[format]>>>, and writes the
formatted data to <<stdout>>, terminated with a null character.
The behavior of <<printf>> is undefined if there are not enough
arguments for the format.
<<printf>> returns when it reaches the end of the format string.
If there are more arguments than the format requires, excess
arguments are ignored.
<<fprintf>>, <<asprintf>>, <<sprintf>> and <<snprintf>> are identical
to <<printf>>, other than the destination of the formatted output:
<<fprintf>> sends the output to a specified file <[fd]>, while
<<asprintf>> stores the output in a dynamically allocated buffer,
while <<sprintf>> stores the output in the specified char array
<[str]> and <<snprintf>> limits number of characters written to
<[str]> to at most <[size]> (including terminating <<0>>). For
<<sprintf>> and <<snprintf>>, the behavior is undefined if the
output <<*<[str]>>> overlaps with one of the arguments. For
<<asprintf>>, <[strp]> points to a pointer to char which is filled
in with the dynamically allocated buffer. <[format]> is a pointer
to a charater string containing two types of objects: ordinary
characters (other than <<%>>), which are copied unchanged to the
output, and conversion specifications, each of which is introduced
by <<%>>. (To include <<%>> in the output, use <<%%>> in the format
string.) A conversion specification has the following form:
. %[<[flags]>][<[width]>][.<[prec]>][<[size]>][<[type]>]
The fields of the conversion specification have the following meanings:
O+
o <[flags]>
an optional sequence of characters which control
output justification, numeric signs, decimal points,
trailing zeroes, and octal and hex prefixes.
The flag characters are minus (<<->>), plus (<<+>>),
space ( ), zero (<<0>>), and sharp (<<#>>). They can
appear in any combination.
o+
o -
The result of the conversion is left justified, and the right is
padded with blanks. If you do not use this flag, the result is right
justified, and padded on the left.
o +
The result of a signed conversion (as determined by <[type]>)
will always begin with a plus or minus sign. (If you do not use
this flag, positive values do not begin with a plus sign.)
o " " (space)
If the first character of a signed conversion specification
is not a sign, or if a signed conversion results in no
characters, the result will begin with a space. If the
space ( ) flag and the plus (<<+>>) flag both appear,
the space flag is ignored.
o 0
If the <[type]> character is <<d>>, <<i>>, <<o>>, <<u>>,
<<x>>, <<X>>, <<e>>, <<E>>, <<f>>, <<g>>, or <<G>>: leading zeroes,
are used to pad the field width (following any indication of sign or
base); no spaces are used for padding. If the zero (<<0>>) and
minus (<<->>) flags both appear, the zero (<<0>>) flag will
be ignored. For <<d>>, <<i>>, <<o>>, <<u>>, <<x>>, and <<X>>
conversions, if a precision <[prec]> is specified, the zero (<<0>>)
flag is ignored.
Note that <<0>> is interpreted as a flag, not as the beginning
of a field width.
o #
The result is to be converted to an alternative form, according
to the next character:
o+
o 0
increases precision to force the first digit
of the result to be a zero.
o x
a non-zero result will have a <<0x>> prefix.
o X
a non-zero result will have a <<0X>> prefix.
o e, E or f
The result will always contain a decimal point
even if no digits follow the point.
(Normally, a decimal point appears only if a
digit follows it.) Trailing zeroes are removed.
o g or G
same as <<e>> or <<E>>, but trailing zeroes
are not removed.
o all others
undefined.
o-
o-
o <[width]>
<[width]> is an optional minimum field width. You can either
specify it directly as a decimal integer, or indirectly by
using instead an asterisk (<<*>>), in which case an <<int>>
argument is used as the field width. Negative field widths
are not supported; if you attempt to specify a negative field
width, it is interpreted as a minus (<<->>) flag followed by a
positive field width.
o <[prec]>
an optional field; if present, it is introduced with `<<.>>'
(a period). This field gives the maximum number of
characters to print in a conversion; the minimum number of
digits of an integer to print, for conversions with <[type]>
<<d>>, <<i>>, <<o>>, <<u>>, <<x>>, and <<X>>; the maximum number of
significant digits, for the <<g>> and <<G>> conversions;
or the number of digits to print after the decimal
point, for <<e>>, <<E>>, and <<f>> conversions. You can specify
the precision either directly as a decimal integer or
indirectly by using an asterisk (<<*>>), in which case
an <<int>> argument is used as the precision. Supplying a negative
precision is equivalent to omitting the precision.
If only a period is specified the precision is zero.
If a precision appears with any other conversion <[type]>
than those listed here, the behavior is undefined.
o <[size]>
<<h>>, <<l>>, and <<L>> are optional size characters which
override the default way that <<printf>> interprets the
data type of the corresponding argument. <<h>> forces
the following <<d>>, <<i>>, <<o>>, <<u>>, <<x>> or <<X>> conversion
<[type]> to apply to a <<short>> or <<unsigned short>>. <<h>> also
forces a following <<n>> <[type]> to apply to
a pointer to a <<short>>. Similarily, an
<<l>> forces the following <<d>>, <<i>>, <<o>>, <<u>>,
<<x>> or <<X>> conversion <[type]> to apply to a <<long>> or
<<unsigned long>>. <<l>> also forces a following <<n>> <[type]> to
apply to a pointer to a <<long>>. If an <<h>>
or an <<l>> appears with another conversion
specifier, the behavior is undefined. <<L>> forces a
following <<e>>, <<E>>, <<f>>, <<g>> or <<G>> conversion <[type]> to
apply to a <<long double>> argument. If <<L>> appears with
any other conversion <[type]>, the behavior is undefined.
o <[type]>
<[type]> specifies what kind of conversion <<printf>> performs.
Here is a table of these:
o+
o %
prints the percent character (<<%>>)
o c
prints <[arg]> as single character
o s
prints characters until precision is reached or a null terminator
is encountered; takes a string pointer
o d
prints a signed decimal integer; takes an <<int>> (same as <<i>>)
o i
prints a signed decimal integer; takes an <<int>> (same as <<d>>)
o o
prints a signed octal integer; takes an <<int>>
o u
prints an unsigned decimal integer; takes an <<int>>
o x
prints an unsigned hexadecimal integer (using <<abcdef>> as
digits beyond <<9>>); takes an <<int>>
o X
prints an unsigned hexadecimal integer (using <<ABCDEF>> as
digits beyond <<9>>); takes an <<int>>
o f
prints a signed value of the form <<[-]9999.9999>>; takes
a floating point number
o e
prints a signed value of the form <<[-]9.9999e[+|-]999>>; takes a
floating point number
o E
prints the same way as <<e>>, but using <<E>> to introduce the
exponent; takes a floating point number
o g
prints a signed value in either <<f>> or <<e>> form, based on given
value and precision---trailing zeros and the decimal point are
printed only if necessary; takes a floating point number
o G
prints the same way as <<g>>, but using <<E>> for the exponent if an
exponent is needed; takes a floating point number
o n
stores (in the same object) a count of the characters written;
takes a pointer to <<int>>
o p
prints a pointer in an implementation-defined format.
This implementation treats the pointer as an
<<unsigned long>> (same as <<Lu>>).
o-
O-
RETURNS
<<sprintf>> and <<asprintf>> return the number of bytes in the output string,
save that the concluding <<NULL>> is not counted.
<<printf>> and <<fprintf>> return the number of characters transmitted.
If an error occurs, <<printf>> and <<fprintf>> return <<EOF>> and
<<asprintf>> returns -1. No error returns occur for <<sprintf>>.
PORTABILITY
The ANSI C standard specifies that implementations must
support at least formatted output of up to 509 characters.
Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
*/
#include <stdio.h>
#ifdef _HAVE_STDC
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#include <limits.h>
#include <_ansi.h>
#include "local.h"
int
#ifdef _HAVE_STDC
_DEFUN (_sprintf_r, (ptr, str, fmt), struct _reent *ptr _AND char *str _AND _CONST char *fmt _DOTS)
#else
_sprintf_r (ptr, str, fmt, va_alist)
struct _reent *ptr;
char *str;
_CONST char *fmt;
va_dcl
#endif
{
int ret;
va_list ap;
FILE f;
f._flags = __SWR | __SSTR;
f._bf._base = f._p = (unsigned char *) str;
f._bf._size = f._w = INT_MAX;
f._data = ptr;
#ifdef _HAVE_STDC
va_start (ap, fmt);
#else
va_start (ap);
#endif
ret = vfprintf (&f, fmt, ap);
va_end (ap);
*f._p = 0;
return (ret);
}
#ifndef _REENT_ONLY
int
#ifdef _HAVE_STDC
_DEFUN (sprintf, (str, fmt), char *str _AND _CONST char *fmt _DOTS)
#else
sprintf (str, fmt, va_alist)
char *str;
_CONST char *fmt;
va_dcl
#endif
{
int ret;
va_list ap;
FILE f;
f._flags = __SWR | __SSTR;
f._bf._base = f._p = (unsigned char *) str;
f._bf._size = f._w = INT_MAX;
f._data = _REENT;
#ifdef _HAVE_STDC
va_start (ap, fmt);
#else
va_start (ap);
#endif
ret = vfprintf (&f, fmt, ap);
va_end (ap);
*f._p = 0;
return (ret);
}
#endif
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