_printf

This project is a custom implementation of the printf function. It is divided into several source files that handle different aspects of formatted output, such as buffering, flag processing, number conversion, and string handling.

File Descriptions

• main.h
  Contains the header definitions for the project. It defines key structures such as params (to store flag information, buffer pointers, and other formatting data) and id_f (to associate format specifiers with their corresponding functions). Function prototypes for the main _printf function and its helper routines are declared here.

• _printf.c
  Implements the primary _printf function. It parses the format string, handles flags and conversion specifiers, and writes formatted output to a buffer, which is later printed to standard output.

• buffer_tools.c
  Provides functions to manage the output buffer. Functions include:

  • fill_buffer_c: Adds a single character to the buffer.
  • fill_buffer_str: Adds a string to the buffer.
  • print_buffer: Flushes the buffer content to standard output.

• print_base.c
  Contains functions that convert numbers to various bases:

  • _print_binary: Prints an unsigned integer in binary format.
  • _print_oct: Prints a number in octal.
  • _print_hex: Prints a number in hexadecimal (lowercase).
  • _print_hexa: Prints a number in hexadecimal (uppercase).
  • _print_ptr: Prints the memory address of a pointer in hexadecimal format with a "0x" prefix.

• print_strings.c
  Provides functions for printing characters and strings in various ways:

  • _print_char: Prints a single character.
  • _print_str: Prints a string (handles NULL by printing (null)).
  • _print_rev: Prints a string in reverse order.
  • _print_rot13: Encodes a string using ROT13 before printing it.
  • _print_S: Prints a string while converting non-printable characters (ASCII values below 32 or above 126) into their hexadecimal representation.

• flags_handling.c
  Implements functions to detect and set formatting flags and options from the format string. This includes functions to handle flags (flags_set), width (width_set), precision (precs_set), length modifiers (length_set), and setting the conversion specifier (id_set).

• general_tools2.c
  Contains utility functions such as:

  • get_op_func: Returns the appropriate function pointer based on the conversion specifier.
  • extract_value: Extracts numerical values from the format string (for width or precision), supporting both direct numbers and '*' to fetch the value from the argument list.

• general_tools.c
  Provides additional utility functions including:

  • _strlen: Calculates the length of a string.
  • _strdup: Duplicates a given string into a new memory area.
  • in_charset: Checks if a character exists within a given character set.
  • _atoi: Converts a string to an integer.
  • flags_init: Initializes and validates formatting flags from the format string.

• output_modifiers.c
  Implements modifications to the printed output based on specific flags. For example, adding a plus sign for positive numbers or a space if no plus sign is specified. It also handles special cases for octal and hexadecimal prefixes when the '#' flag is used.

• print_numbers.c
  Contains functions for printing numeric values:

  • _print_int: Handles printing of signed integers, including negative numbers.
  • _print_uint: Handles printing of unsigned integers.

Format Specifiers Table

Specifier	Functionality
%c	Prints a single character.
%s	Prints a string. If the string is NULL, prints (null).
%d	Prints a signed integer.
%i	Prints a signed integer (identical to %d).
%b	Prints an unsigned integer in binary format.
%u	Prints an unsigned integer in decimal format.
%r	Prints a string in reverse order.
%R	Prints a string encoded in ROT13.
%o	Prints a number in octal format.
%x	Prints a number in hexadecimal format (lowercase).
%X	Prints a number in hexadecimal format (uppercase).
%p	Prints the memory address of a pointer in hexadecimal format with a 0x prefix.
%S	Prints a string and converts non-printable characters into hexadecimal codes.

Examples

#include "main.h"

int main(void)
{
    int num = 42;
    char *str = "Hello, World!";

    _printf("String: %s\n", str);
    _printf("Character: %c\n", 'A');
    _printf("Integer: %d\n", num);
    _printf("Binary: %b\n", num);
    _printf("Pointer: %p\n", str);
    _printf("Reverse: %r\n", str);
    _printf("ROT13: %R\n", str);
    _printf("Hex lowercase: %x\n", num);
    _printf("Hex uppercase: %X\n", num);
    _printf("Special string: %S\n", "Test\nNewLine");
    return (0);
}

Flags & Modifiers

Flag	Description
+	Adds + before positive numbers.
(space)	Adds a space before positive numbers if + is absent.
#	Adds 0, 0x, or 0X for octal and hexadecimal values.
0	Pads numbers with zeros when width is specified.
-	Left-aligns output within a given width.

The entire modifier flag was handled, but only some functionalities was developed.

Examples

Basic Usage

_printf("String: %s\n", "Hello");
_printf("Character: %c\n", 'A');
_printf("Integer: %d\n", 42);
_printf("Binary: %b\n", 42);
_printf("Pointer: %p\n", (void *)42);

Flags & Modifiers

_printf("With plus: %+d\n", 42);  // Output: +42
_printf("With space: % d\n", 42); // Output:  42

Compilation

gcc -Wall -Werror -Wextra -pedantic -std=gnu89 -Wno-format *.c

Usage

Once compiled with your main.c archive, you can run the executable and use the custom _printf function in your code as shown in the examples.

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