ilp-sys / ft_printf

simplified, structured printf

FT_PRINTF

Custom printf of 42 C School

---

/* unlike original printf, this project doesn't support buffer manegement */

0. Based Concepts

• Variadic arguments in <stdarg.h>
• Handling a number of arguments
• Standard output's buffer I/O
• Condition checks using flags (or bitwise calculation)

1. Implementation

How the printf's buffer works?

Buffer is a block of memory which belongs to a kernal stream and is used to hold stream data temporarily. Stdout is line buffered by default(ISO). Characters written to a line buffered stream are transmitted to the file in blocks when a newline character is encountered.

Parameters

printf    : %[Flag][Width][.Precision][Length]Specifier
ft_printf : %[Flag][Width][.Precision]Specifier

notes!

• Precision . means .0.
• A precision of 0 means that no character is written for the value 0.
• For integer, numbers 0 flag is ignored if the precision is explicitly specified, also ignored when - flag is present.

Flag dependancies

spec/flag	%c	%s	%p	%d	%i	%u	%x	%X	%%
width	o	o	o	o	o	o	o	o	x
precision	x	o	o	o	o	x	o	o	x
-	o	o	o	o	o	o	o	o	x
0	x	x	o	o	o	x	o	o	x
#	x	x	x	x	x	x	o	o	x
SPACE	x	x	o	o	x	x	x	x	x
+	x	x	o	o	x	x	x	x	x

Tags

                         / check_flag
                         - check_width
ft_printf - ft_vsprintf  - check_precision
                         \ check_conversion - conversion %, c, s
                                            \ conversion p, int, x - print_numbers

2. Makefile

$(NAME) : $(OBJS)
	$(MAKE) -C $(LIBFT_DIR) all	  //go into the libft dir and run make all
	@cp $(LIBFT_DIR) $(LIBFT_LIB) $@ //cp the archived file as the name of the target
	$(AR) $@ $^	                //append printf's objs

3. Reference

• tovalds github
  
• apple opensource
  
• cpp reference
  
• libc printf

4. Tester

• paulo-santana - examine over a thousand cases.
  
• francinette - Integrated testing framework for 42