From 5b8aaa2c203e456d2ca133b3403224a98aef2816 Mon Sep 17 00:00:00 2001 From: Richard Qin Date: Sat, 2 May 2026 01:30:14 +0800 Subject: feat: add tiny printf implementation for embedded systems --- na/lib/printf.h | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 na/lib/printf.h (limited to 'na/lib/printf.h') diff --git a/na/lib/printf.h b/na/lib/printf.h new file mode 100644 index 0000000..8aa23cf --- /dev/null +++ b/na/lib/printf.h @@ -0,0 +1,129 @@ +/////////////////////////////////////////////////////////////////////////////// +// \author (c) Marco Paland (info@paland.com) +// 2014-2019, PALANDesign Hannover, Germany +// +// \license The MIT License (MIT) +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. +// +// \brief Tiny printf, sprintf and snprintf implementation, optimized for speed on +// embedded systems with a very limited resources. +// Use this instead of bloated standard/newlib printf. +// These routines are thread safe and reentrant. +// +/////////////////////////////////////////////////////////////////////////////// + +#ifndef _PRINTF_H_ +#define _PRINTF_H_ + +#include + +/* LumeOS: avoid stddef.h — define types from compiler builtins directly. + * This works in both C and C++ and matches our types.h definition. */ +#ifndef _SIZE_T_DEFINED +#define _SIZE_T_DEFINED +typedef __SIZE_TYPE__ size_t; +typedef __PTRDIFF_TYPE__ ptrdiff_t; +typedef __INTMAX_TYPE__ intmax_t; +#endif + +/* LumeOS: kernel does not need floating-point formatted output */ +#define PRINTF_DISABLE_SUPPORT_FLOAT +#define PRINTF_DISABLE_SUPPORT_EXPONENTIAL + + +#ifdef __cplusplus +extern "C" { +#endif + + +/** + * 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 printf 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 sprintf 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 snprintf snprintf_ +#define vsnprintf 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 vprintf 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, ...); + + +#ifdef __cplusplus +} +#endif + + +#endif // _PRINTF_H_ -- cgit v1.2.3