sprintf.c

Newlib 嵌入式 C库 标准实现代码

			With <<c>>, specifies that the argument has
			type <<wint_t>>.

			With <<s>>, specifies that the argument is a
			pointer to <<wchar_t>>.

			With <<n>>, specifies that the argument is a
			pointer to a <<long>>.

			With <<a>>, <<A>>, <<e>>, <<E>>, <<f>>, <<F>>,
			<<g>>, or <<G>>, has no effect (because of
			vararg promotion rules, there is no need to
			distinguish between <<float>> and <<double>>).

		o ll
			With <<d>>, <<i>>, <<o>>, <<u>>, <<x>>, or
			<<X>>, specifies that the argument is a
			<<long long>> or <<unsigned long long>>.

			With <<n>>, specifies that the argument is a
			pointer to a <<long long>>.

		o j
			With <<d>>, <<i>>, <<o>>, <<u>>, <<x>>, or
			<<X>>, specifies that the argument is an
			<<intmax_t>> or <<uintmax_t>>.

			With <<n>>, specifies that the argument is a
			pointer to an <<intmax_t>>.

		o z
			With <<d>>, <<i>>, <<o>>, <<u>>, <<x>>, or
			<<X>>, specifies that the argument is a
			<<ssize_t>> or <<size_t>>.

			With <<n>>, specifies that the argument is a
			pointer to a <<ssize_t>>.

		o t
			With <<d>>, <<i>>, <<o>>, <<u>>, <<x>>, or
			<<X>>, specifies that the argument is a
			<<ptrdiff_t>>.

			With <<n>>, specifies that the argument is a
			pointer to a <<ptrdiff_t>>.

		o L
			With <<a>>, <<A>>, <<e>>, <<E>>, <<f>>, <<F>>,
			<<g>>, or <<G>>, specifies that the argument
			is a <<long double>>.

		o-

	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.  If the
			<<l>> size specifier is in effect, a multibyte
			character is printed.

		o C
			Short for <<%lc>>.

		o s
			Prints the elements of a pointer to <<char>>
			until the precision or a null character is
			reached.  If the <<l>> size specifier is in
			effect, the pointer is to an array of
			<<wchar_t>>, and the string is converted to
			multibyte characters before printing.

		o S
			Short for <<%ls>>.

		o d or i
			Prints a signed decimal integer; takes an
			<<int>>.  Leading zeros are inserted as
			necessary to reach the precision.  A precision
			of 0 produces an empty string.

		o D
			Newlib extension, short for <<%ld>>.

		o o
			Prints an unsigned octal integer; takes an
			<<unsigned>>.  Leading zeros are inserted as
			necessary to reach the precision.  A precision
			of 0 produces an empty string.

		o O
			Newlib extension, short for <<%lo>>.

		o u
			Prints an unsigned decimal integer; takes an
			<<unsigned>>.  Leading zeros are inserted as
			necessary to reach the precision.  A precision
			of 0 produces an empty string.

		o U
			Newlib extension, short for <<%lu>>.

		o x
			Prints an unsigned hexadecimal integer (using
			<<abcdef>> as digits beyond <<9>>); takes an
			<<unsigned>>.  Leading zeros are inserted as
			necessary to reach the precision.  A precision
			of 0 produces an empty string.

		o X
			Like <<x>>, but uses <<ABCDEF>> as digits
			beyond <<9>>.

		o f
			Prints a signed value of the form
			<<[-]9999.9999>>, with the precision
			determining how many digits follow the decimal
			point; takes a <<double>> (remember that
			<<float>> promotes to <<double>> as a vararg).
			The low order digit is rounded to even.  If
			the precision results in at most DECIMAL_DIG
			digits, the result is rounded correctly; if
			more than DECIMAL_DIG digits are printed, the
			result is only guaranteed to round back to the
			original value.

			If the value is infinite, the result is
			<<inf>>, and no zero padding is performed.  If
			the value is not a number, the result is
			<<nan>>, and no zero padding is performed.

		o F
			Like <<f>>, but uses <<INF>> and <<NAN>> for
			non-finite numbers.

		o e
			Prints a signed value of the form
			<<[-]9.9999e[+|-]999>>; takes a <<double>>.
			The digit before the decimal point is non-zero
			if the value is non-zero.  The precision
			determines how many digits appear between
			<<.>> and <<e>>, and the exponent always
			contains at least two digits.  The value zero
			has an exponent of zero.  If the value is not
			finite, it is printed like <<f>>.

		o E
			Like <<e>>, but using <<E>> to introduce the
			exponent, and like <<F>> for non-finite
			values.

		o g
			Prints a signed value in either <<f>> or <<e>>
			form, based on the given value and
			precision---an exponent less than -4 or
			greater than the precision selects the <<e>>
			form.  Trailing zeros and the decimal point
			are printed only if necessary; takes a
			<<double>>.

		o G
			Like <<g>>, except use <<F>> or <<E>> form.

		o a
			Prints a signed value of the form
			<<[-]0x1.ffffp[+|-]9>>; takes a <<double>>.
			The letters <<abcdef>> are used for digits
			beyond <<9>>.  The precision determines how
			many digits appear after the decimal point.
			The exponent contains at least one digit, and
			is a decimal value representing the power of
			2; a value of 0 has an exponent of 0.
			Non-finite values are printed like <<f>>.

		o A
			Like <<a>>, except uses <<X>>, <<P>>, and
			<<ABCDEF>> instead of lower case.

		o n
			Takes a pointer to <<int>>, and stores a count
			of the number of bytes written so far.  No
			output is created.

		o p
			Takes a pointer to <<void>>, and prints it in
			an implementation-defined format.  This
			implementation is similar to <<%#tx>>), except
			that <<0x>> appears even for the NULL pointer.

		o-
	O-

        <<_printf_r>>, <<_fprintf_r>>, <<_asprintf_r>>,
        <<_sprintf_r>>, <<_snprintf_r>>, <<_asnprintf_r>> are simply
        reentrant versions of the functions above.

RETURNS
On success, <<sprintf>> and <<asprintf>> return the number of bytes in
the output string, except the concluding <<NUL>> is not counted.
<<snprintf>> returns the number of bytes that would be in the output
string, except the concluding <<NUL>> is not counted.  <<printf>> and
<<fprintf>> return the number of characters transmitted.
<<asnprintf>> returns the original <[str]> if there was enough room,
otherwise it returns an allocated string.

If an error occurs, the result of <<printf>>, <<fprintf>>,
<<snprintf>>, and <<asprintf>> is a negative value, and the result of
<<asnprintf>> is NULL.  No error returns occur for <<sprintf>>.  For
<<printf>> and <<fprintf>>, <<errno>> may be set according to
<<fputc>>.  For <<asprintf>> and <<asnprintf>>, <<errno>> may be set
to ENOMEM if allocation fails, and for <<snprintf>>, <<errno>> may be
set to EOVERFLOW if <[size]> or the output length exceeds INT_MAX.

PORTABILITY
ANSI C requires <<printf>>, <<fprintf>>, <<sprintf>>, and
<<snprintf>>.  <<asprintf>> and <<asnprintf>> are newlib extensions.

The ANSI C standard specifies that implementations must support at
least formatted output of up to 509 characters.  This implementation
has no inherent limit.

Depending on how newlib was configured, not all format specifiers are
supported.

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

#include <_ansi.h>
#include <reent.h>
#include <stdio.h>
#ifdef _HAVE_STDC
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#include <limits.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._file = -1;  /* No file. */
#ifdef _HAVE_STDC
  va_start (ap, fmt);
#else
  va_start (ap);
#endif
  ret = _vfprintf_r (ptr, &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._file = -1;  /* No file. */
#ifdef _HAVE_STDC
  va_start (ap, fmt);
#else
  va_start (ap);
#endif
  ret = _vfprintf_r (_REENT, &f, fmt, ap);
  va_end (ap);
  *f._p = 0;
  return (ret);
}

#endif