stdio.h

/*
 * stdio.h - Kernel printing and input interface
 *
 * Tiny printf, sprintf and snprintf implementation, optimized for speed on
 * embedded systems with a very limited resources.
 * These routines are thread safe and reentrant.
 *
 * Author: (c) Marco Paland (info@paland.com)
 *             2014-2019, PALANDesign Hannover, Germany
 */

#pragma once

#include <stdarg.h>
#include <stddef.h>


/**
 * Output a character to a custom device like UART, used by the printf() function
 * This function is declared here only. You have to write your custom implementation somewhere
 * \param character Character to output
 */
void _putchar(char character);


/**
 * Tiny printf implementation
 * You have to implement _putchar if you use printf()
 * To avoid conflicts with the regular printf() API it is overridden by macro defines
 * and internal underscore-appended functions like printf_() are used
 * \param format A string that specifies the format of the output
 * \return The number of characters that are written into the array, not counting the terminating null character
 */
#define kprintf printf_
int printf_(const char* format, ...);


/**
 * Tiny sprintf implementation
 * Due to security reasons (buffer overflow) YOU SHOULD CONSIDER USING (V)SNPRINTF INSTEAD!
 * \param buffer A pointer to the buffer where to store the formatted string. MUST be big enough to store the output!
 * \param format A string that specifies the format of the output
 * \return The number of characters that are WRITTEN into the buffer, not counting the terminating null character
 */
#define ksprintf sprintf_
int sprintf_(char* buffer, const char* format, ...);


/**
 * Tiny snprintf/vsnprintf implementation
 * \param buffer A pointer to the buffer where to store the formatted string
 * \param count The maximum number of characters to store in the buffer, including a terminating null character
 * \param format A string that specifies the format of the output
 * \param va A value identifying a variable arguments list
 * \return The number of characters that COULD have been written into the buffer, not counting the terminating
 *         null character. A value equal or larger than count indicates truncation. Only when the returned value
 *         is non-negative and less than count, the string has been completely written.
 */
#define ksnprintf  snprintf_
#define kvsnprintf vsnprintf_
int  snprintf_(char* buffer, size_t count, const char* format, ...);
int vsnprintf_(char* buffer, size_t count, const char* format, va_list va);


/**
 * Tiny vprintf implementation
 * \param format A string that specifies the format of the output
 * \param va A value identifying a variable arguments list
 * \return The number of characters that are WRITTEN into the buffer, not counting the terminating null character
 */
#define kvprintf vprintf_
int vprintf_(const char* format, va_list va);


/**
 * printf with output function
 * You may use this as dynamic alternative to printf() with its fixed _putchar() output
 * \param out An output function which takes one character and an argument pointer
 * \param arg An argument pointer for user data passed to output function
 * \param format A string that specifies the format of the output
 * \return The number of characters that are sent to the output function, not counting the terminating null character
 */
int fctprintf(void (*out)(char character, void* arg), void* arg, const char* format, ...);


/**
 * Get a character from the active TTY
 * \return The character read
 */
int _getchar(void);


/**
 * Tiny scanf implementation
 * \param format A string that specifies the format of the input
 * \return The number of successfully matched and assigned input items
 */
#define kscanf scanf_
int scanf_(const char* format, ...);


/**
 * Tiny vscanf implementation
 * \param format A string that specifies the format of the input
 * \param va A value identifying a variable arguments list
 * \return The number of successfully matched and assigned input items
 */
#define kvscanf vscanf_
int vscanf_(const char* format, va_list va);