/**
*****************************************************************************
**
**  File        : tiny_printf.c
**
**  Abstract    : Atollic TrueSTUDIO Minimal printf/sprintf/fprintf
**
**                The argument contains a format string that may include
**                conversion specifications. Each conversion specification
**                is introduced by the character %, and ends with a
**                conversion specifier.
**
**                The following conversion specifiers are supported
**                cdisuxX%
**
**                Usage:
**                c    character
**                d,i  signed integer (-sign added, + sign not supported)
**                s    character string
**                u    unsigned integer as decimal
**                x,X  unsigned integer as hexadecimal (uppercase letter)
**                %    % is written (conversion specification is '%%')
**
**                Note:
**                Character padding is not supported
**
**  Environment : Atollic TrueSTUDIO
**
**  Distribution: The file is distributed “as is,?without any warranty
**                of any kind.
**
**  (c)Copyright Atollic AB.
**  You may use this file as-is or modify it according to the needs of your
**  project. Distribution of this file (unmodified or modified) is not
**  permitted. Atollic AB permit registered Atollic TrueSTUDIO(R) users the
**  rights to distribute the assembled, compiled & linked contents of this
**  file as part of an application binary file, provided that it is built
**  using the Atollic TrueSTUDIO(R) Pro toolchain.
**
*****************************************************************************
*/

/* Includes */
#include <stdarg.h>
#include <stdio.h>


/* External function prototypes (defined in syscalls.c) */
extern int _write(int fd, char *str, int len);

/* Private function prototypes */
void ts_itoa(char **buf, unsigned int d, int base);
int ts_formatstring(char *buf, const char *fmt, va_list va);
int ts_formatlength(const char *fmt, va_list va);

/* Private functions */

/**
**---------------------------------------------------------------------------
**  Abstract: Convert integer to ascii
**  Returns:  void
**---------------------------------------------------------------------------
*/
void ts_itoa(char **buf, unsigned int d, int base)
{
	int div = 1;
	while (d/div >= base)
		div *= base;

	while (div != 0)
	{
		int num = d/div;
		d = d%div;
		div /= base;
		if (num > 9)
			*((*buf)++) = (num-10) + 'A';
		else
			*((*buf)++) = num + '0';
	}
}

/**
**---------------------------------------------------------------------------
**  Abstract: Writes arguments va to buffer buf according to format fmt
**  Returns:  Length of string
**---------------------------------------------------------------------------
*/
int ts_formatstring(char *buf, const char *fmt, va_list va)
{
	char *start_buf = buf;
	while(*fmt)
	{
		/* Character needs formating? */
		if (*fmt == '%')
		{
			switch (*(++fmt))
			{
			  case 'c':
				*buf++ = va_arg(va, int);
				break;
			  case 'd':
			  case 'i':
				{
					signed int val = va_arg(va, signed int);
					if (val < 0)
					{
						val *= -1;
						*buf++ = '-';
					}
					ts_itoa(&buf, val, 10);
				}
				break;
			  case 's':
				{
					char * arg = va_arg(va, char *);
					while (*arg)
					{
						*buf++ = *arg++;
					}
				}
				break;
			  case 'u':
					ts_itoa(&buf, va_arg(va, unsigned int), 10);
				break;
			  case 'x':
			  case 'X':
					ts_itoa(&buf, va_arg(va, int), 16);
				break;
			  case '%':
				  *buf++ = '%';
				  break;
			}
			fmt++;
		}
		/* Else just copy */
		else
		{
			*buf++ = *fmt++;
		}
	}
	*buf = 0;

	return (int)(buf - start_buf);
}


/**
**---------------------------------------------------------------------------
**  Abstract: Calculate maximum length of the resulting string from the
**            format string and va_list va
**  Returns:  Maximum length
**---------------------------------------------------------------------------
*/
int ts_formatlength(const char *fmt, va_list va)
{
	int length = 0;
	while (*fmt)
	{
		if (*fmt == '%')
		{
			++fmt;
			switch (*fmt)
			{
			  case 'c':
		  		  va_arg(va, int);
				  ++length;
				  break;
			  case 'd':
			  case 'i':
			  case 'u':
				  /* 32 bits integer is max 11 characters with minus sign */
				  length += 11;
				  va_arg(va, int);
				  break;
			  case 's':
			  	  {
			  		  char * str = va_arg(va, char *);
			  		  while (*str++)
			  			  ++length;
			  	  }
				  break;
			  case 'x':
			  case 'X':
				  /* 32 bits integer as hex is max 8 characters */
				  length += 8;
				  va_arg(va, unsigned int);
				  break;
			  default:
				  ++length;
				  break;
			}
		}
		else
		{
			++length;
		}
		++fmt;
	}
	return length;
}

/**
**===========================================================================
**  Abstract: Loads data from the given locations and writes them to the
**            given character string according to the format parameter.
**  Returns:  Number of bytes written
**===========================================================================
*/
int sprintf(char *buf, const char *fmt, ...)
{
	int length;
	va_list va;
	va_start(va, fmt);
	length = ts_formatstring(buf, fmt, va);
	va_end(va);
	return length;
}

/**
**===========================================================================
**  Abstract: Loads data from the given locations and writes them to the
**            given file stream according to the format parameter.
**  Returns:  Number of bytes written
**===========================================================================
*/
int fprintf(FILE * stream, const char *fmt, ...)
{
	int length = 0;
	va_list va;
	va_start(va, fmt);
	length = ts_formatlength(fmt, va);
	va_end(va);
	{
		char buf[length];
		va_start(va, fmt);
		length = ts_formatstring(buf, fmt, va);
		length = _write(stream->_file, buf, length);
		va_end(va);
	}
	return length;
}

/**
**===========================================================================
**  Abstract: Loads data from the given locations and writes them to the
**            standard output according to the format parameter.
**  Returns:  Number of bytes written
**
**===========================================================================
*/
int printf(const char *fmt, ...)
{
	int length = 0;
	va_list va;
	va_start(va, fmt);
	length = ts_formatlength(fmt, va);
	va_end(va);
	{
		char buf[length];
		va_start(va, fmt);
		length = ts_formatstring(buf, fmt, va);
		length = _write(1, buf, length);
		va_end(va);
	}
	return length;
}