ft_printf

( a 42 School Project )

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Table o'Contents

• About 📌
• Usage 🏁
• Implementation 📜
• Constrains
• Mandatory Requirements:exclamation:
• Bonus Requirements 🤑
• Structure 🚧
  • Mandatory Files & Folder Structure
  • Mandatory Processing Flow
  • Bonus Structure:exclamation:
    • Bonus Files & Folder Structure
  • Bonus Processing Flow
  • License ©️

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About 📌

Because ft_putnbr() and ft_putstr() aren't enough!

This project is an exploration into how printf() works. The objective is to write a library that mimics the behaviour of printf(). A re-code challenge with the aim of revealing how variadic functions work in C. This project is an exercise on how to build a well-planned, well-structured extensible code base.

ft_printf (Subject English)

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Usage 🏁

1. Clone the repo:

git clone git@github.com:PedroZappa/42_ft_printf.git 

2. Initialize local submodules configuration:

git submodule init

3. Update submodules:

git submodule update --recursive --remote

4. Build the project:

make bonus

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Implementation 📜

In this project printf() is implemented with the following prototype:

void	ft_printf(const char *format, ...);

Constrains

• To accomplish this, the implementation is limited to the use of libft (which makes its performance slower than the standard printf()) and a restricted set of standard functions.

  For memory allocation and deallocation: malloc() and free();

  To write into the allocated memory: write();

  To support variadic functionality: va_start(), va_arg(), va_copy(), va_end();

• ft_printf() doesn't handle overflows and unexpected inputs the same way the real printf() would.

Mandatory Requirements:exclamation:

• Do NOT implement the buffer management of the original printf();

• The function has to handle the following conversions (format specifiers):

  Format	Meaning
  %c	Prints a single char;
  %s	Prints a string of characters (char *);
  %p	Prints a Pointer Address in hexadecimal (void *);
  %d	Prints a decimal (base 10) number;
  %i	Prints an integer in base 10;
  %u	Prints an unsigned decimal (base 10) number;
  %x	Prints a number in hexadecimal (base 16) lowercase format;
  %X	Prints a number in hexadecimal (base 16) uppercase format;
  %%	Prints a % character;

• Format specifiers obey the following prototype:

  %[flags][width][.precision]specifier

• The function must behave like printf();

• The library has to be built using the command ar;

Bonus Requirements 🤑

• Handle any combination of the following flags and minimum field width under all conversions;

  Flag	Description
  -	Left justify within given field width
  0	Left-pads the number with zeroes (0) where padding is specified
  .	Precision

  .precision	Description
  .number	For integer specifiers (%d, %i, %u, %x, %X) - specifies the minimum number of digits to be written. If the value to be written is shorter than this number the result is padded with leading zeroes. The value is not truncated even if the result is longer. A precision of 0 mean that no value is written for the value '0'; For s, this is the maximum numbers of characters to be printed. By default all characters are printed until the null terminator is found;
  .	The precision is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted;

  Width	Description
  (number)	Minimum number of characters to be printed. If the value to be printed is shorter than this value, it is padded with blanks. The value is not truncated even if the result is larger

• Plus the following flags (yes,one of them is a blank):

  Flag	Description
  #	When used with x or X specifiers the value is prefixed with 0, 0x or 0X respectively for values different than zero
  	If no sign is going to be written, print a space before the value
  +	Forces a plus or minus sign before printing the result

Structure 🚧

Mandatory Files & Folder Structure

ft_printf()s mandatory code base has the following file structure:

---
title ft_printf Structure
---
classDiagram
    class Makefile
    Makefile <-- File0
    class File0["ft_printf.h"]
    class libft["libft.h"]
    File0 <-- File1
    File0 <-- File2
    File0 <-- File3
    File0 <-- File4
    File0 <-- File5
    libft --> File0
    class File1["ft_printf.c"]
    File1 : ft_printf()
    File1 : ft_newformat()
    File1 : ft_print_specifier()
    class File2["ft_parse.c"]
    File2 : ft_parse()
    File2 : ft_parse_width()
    File2 : ft_parse_prec()
    File2 : ft_parse_bonus()
    class File3["ft_print_chars.c"]
    File3 : ft_print_char()
    File3 : ft_print_str()
    class File4["ft_print_nbrs.c"]
    File4 : ft_print_diu()
    File4 : ft_print_nbr()
    File4 : ft_sign()
    class File5["ft_print_hex.c"]
    File5 : ft_print_x()
    File5 : ft_print_p()
    File5 : ft_recurhex()
    File5 : ft_sharp()

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Mandatory Processing Flow

The subprocesses of ft_printf mandatory implementation are called in the following order:

---
title ft_printf Processing Flow
---
graph LR;
    ft_printf-->ft_parse;
    ft_parse-->ft_newformat;
    ft_parse-->ft_parse_width;
    ft_parse-->ft_parse_prec;
    ft_parse-->ft_parse_bonus;
    ft_parse-->ft_print_specifier;
    ft_print_specifier-->ft_print_char;
    ft_print_specifier-->ft_print_str;
    ft_print_specifier-->ft_print_diu;
    ft_print_specifier-->ft_print_x;
    ft_print_specifier-->ft_print_ptr;
    ft_print_diu-->ft_print_nbr;
    ft_print_nbr-->ft_sign;
    ft_print_hex-->ft_print_recur_hex;
    ft_print_hex-->ft_sharp;
    ft_print_ptr-->ft_print_recur_hex;

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Bonus Structure:exclamation:

Bonus Files & Folder Structure

ft_printf()s bonus code base has the following file structure:

---
title ft_printf w/ Bonus Structure
---
classDiagram
    class Makefile
    class libft["libft.h"]
    
    class ft_printf_h["ft_printf_bonus.h"]
    class ft_printf["ft_printf_bonus.c"]
    class ft_flag_utils["ft_flag_utils_bonus.c"]
    class ft_flags["ft_flags_bonus.c"]
    class ft_parse["ft_parse_bonus.c"]
    class ft_print_c["ft_print_c_bonus.c"]
    class ft_print_di["ft_print_di_bonus.c"]
    class ft_print_hex["ft_print_hex_bonus.c"]
    class ft_print_p["ft_print_p_bonus.c"]
    class ft_print_s["ft_print_s_bonus.c"]
    class ft_print_u["ft_print_u_bonus.c"]
   
    Makefile <-- ft_printf_h
    libft --> ft_printf_h
    ft_printf_h --> ft_printf
    ft_printf_h --> ft_flag_utils
    ft_printf_h --> ft_flags
    ft_printf_h --> ft_parse
    ft_printf_h --> ft_print_c
    ft_printf_h --> ft_print_di
    ft_printf_h --> ft_print_hex
    ft_printf_h --> ft_print_p
    ft_printf_h --> ft_print_s
    ft_printf_h --> ft_print_u
    
    ft_printf : ft_printf()
    ft_flag_utils : ft_isflag()
    ft_flag_utils : ft_isspecif()
    ft_flag_utils : ft_isflagtype()
    ft_flag_utils : ft_isflagtype()
    ft_flag_utils : ft_pad_width()
    ft_flags : ft_newformat()
    ft_flags : ft_resetformat()
    ft_flags : ft_flag_minus()
    ft_flags : ft_flag_digit()
    ft_flags : ft_flag_width()
    ft_flags : ft_flag_prec()
    ft_parse : ft_parse_bonus()
    ft_parse : ft_parse_flags()
    ft_parse : ft_parse_arg()
    ft_parse : ft_parse_width()
    ft_parse : ft_parse_prec()
    ft_print_c : ft_print_c()
    ft_print_di : ft_print_di()
    ft_print_di : ft_print_integer()
    ft_print_di : ft_print_precision()
    ft_print_di : ft_print_i()
    ft_print_hex : ft_print_x()
    ft_print_hex : ft_print_hexa()
    ft_print_hex : ft_print_puthex()
    ft_print_hex : ft_print_putx_prefix()
    ft_print_p : ft_print_p()
    ft_print_p : ft_print_ptr()
    ft_print_p : ft_print_address()
    ft_print_p : ft_ptrlen()
    ft_print_s : ft_print_s()
    ft_print_s : ft_putstr()
    ft_print_s : ft_print_s_precision()
    ft_print_s : ft_print_str()
    ft_print_u : ft_print_u()
    ft_print_u : ft_print_uint()
    ft_print_u : ft_print_uint()
    ft_print_u : ft_print_unsigned()

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Bonus Processing Flow

The subprocesses of ft_printf bonus implementation are called in the following order:

---
title ft_printf Bonus Processing Flow
---
graph LR;
    ft_printf-->ft_newformat;
    ft_printf-->ft_parse_bonus;
    ft_parse_bonus-->ft_parse_flags;
    ft_parse_bonus-->ft_parse_arg;
    ft_parse_flags-->ft_flag_minus;
    ft_parse_flags-->ft_parse_width;
    ft_parse_flags-->ft_parse_prec;
    ft_parse_flags-->ft_isspecif;
    ft_parse_arg-->ft_putchar_fd;
    ft_parse_arg-->ft_print_c;
    ft_parse_arg-->ft_print_s;
    ft_parse_arg-->ft_print_di;
    ft_parse_arg-->ft_print_u;
    ft_parse_arg-->ft_print_x;
    ft_parse_arg-->ft_print_p;

    ft_print_c-->ft_putchar_fd;
    ft_print_c-->ft_pad_width;
    ft_print_s-->ft_pad_width;
    ft_print_s-->ft_putstr;
    ft_putstr-->ft_pad_width;
    ft_putstr-->ft_print_s_precision;
    ft_print_di-->ft_pad_width;
    ft_print_di-->ft_print_integer;
    ft_print_integer-->ft_print_sign_precision;
    ft_print_integer-->ft_print_i;
    ft_print_integer-->ft_pad_width;
    ft_print_i-->ft_pad_width;
    ft_print_i-->ft_print_str;
    ft_print_x -->ft_print_hexa;
    ft_print_x-->ft_pad_width;
    ft_print_hexa-->ft_putx_prefix
    ft_print_hexa-->ft_puthex
    ft_print_hexa-->ft_pad_width;
    ft_puthex-->ft_putx_prefix;
    ft_puthex-->ft_pad_width;
    ft_puthex-->ft_print_str;
    ft_print_p-->ft_print_ptr;
    ft_print_p-->ft_pad_width;
    ft_print_ptr-->ft_print_str;
    ft_print_ptr-->ft_print_address;
    ft_print_ptr-->ft_ptrlen;
    ft_print_address-->ft_print_address;

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License ©️

This work is published under the terms of 42 Unlicense.

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