RawDoFmt

NAME

RawDoFmt - format data into a character stream.

SYNOPSIS

NextData = RawDoFmt(FormatString, DataStream, PutChProc, PutChData);
APTR RawDoFmt(STRPTR,APTR,void (*)(),APTR);

FUNCTION

Perform "C"-language-like formatting of a data stream, outputting
the result a character at a time.  Where % formatting commands are
found in the FormatString, they will be replaced with the
corresponding element in the DataStream.  %% must be used in the
string if a % is desired in the output.

RawDoFmt() returns a pointer to the end of the DataStream
(The next argument that would have been processed).  This allows
multiple formatting passes to be made using the same data.

INPUTS

FormatString - a "C"-language-like NULL terminated format string,
	with the following supported % options:

%[flags][width.precision][length]type

flags  - supported values are:

	0 - The field will be padded with leading 0's
	for type X, x, B, b, O, o, u, i and d.
	Valid only when width is specified.

	- - Left-justify within the given field boundary.
	This overrides 0 flag.

width  - supported values are:

	number - Minimum number of characters to be printed.
	If the value to be printed is shorter than this number,
	the result is padded with blank spaces.

	* - The width is not specified in the format string,
	but as an additional integer value argument preceding
	the argument that has to be formatted.

.precision  - supported values are:

	.number - For type s, maximum number of characters to
	output from a string. For type X, x, B, b, O, o, u, i and d,
	minimum number of digits to output.

	. - If the period is specified without an explicit value
	for precision, 0 is assumed.

	.* - The precision is not specified in the format string,
	but as an additional integer value argument preceding
	the argument that has to be formatted.

	If precision is specified, it overrides 0 flag.

length - supported values are:

	l - size of input data becomes long	(default is int).
	ll - size of input data becomes long long.

type   - supported types are:

	d - decimal
	i - decimal with sign
	u - unsigned decimal

	c - character
	s - string, a pointer to a NULL terminated
	byte string. A NULL pointer is treated
	as an empty string.

	o - octal with preceding "0o".
	O - octal

	x - hexadecimal with preceding "0x".
	X - hexadecimal

	b - binaty with preceding "0b".
	B - binary

	p - pointer (with preceding "0x").

DataStream - a stream of data that is interpreted according to
	the format string.  Often this is a pointer into
	the task's stack.

PutChProc  - the procedure to call with each character to be
	output, called as:

	PutChProc(char,  PutChData);

	the procedure is called with a NULL Char ('\0') at the end of
	the format string.

PutChData - a value that is passed through to the PutChProc
	procedure.  This is untouched by RawDoFmt, and may be
	modified by the PutChProc.

EXAMPLE

	#include "exec_funcs.h"

	APTR SysBase = NULL;

	void addch(char ch, char** str)
	{
		char* p = *str;
		*p = ch;
		(*str)++;
	}

	void (*paddch)(char , char** ) = &addch;

	void mysprintf (char* buf, char* fmt, ...)
	{
		va_list vl;
		va_start(vl,fmt);
		RawDoFmt(fmt, vl, paddch, buf);
		va_end(vl);
	}

	int main(APTR sysBase)
	{
		SysBase = sysBase;
		char buffer [50];
		int m = 10;
		int n = 5;
		int k = -6;

		mysprintf (buffer, "%010d", k);
		mysprintf (buffer, "%*.*s", m, n, "srinivas");

		return 0;
	}