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| -rw-r--r-- | printf.cpp | 485 | ||||
| -rw-r--r-- | printf.h | 75 |
2 files changed, 560 insertions, 0 deletions
diff --git a/printf.cpp b/printf.cpp new file mode 100644 index 0000000..ee2c1c5 --- /dev/null +++ b/printf.cpp @@ -0,0 +1,485 @@ +/////////////////////////////////////////////////////////////////////////////// +// \author (c) Marco Paland (info@paland.com) +// 2014, 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. These routines are thread +// safe and reentrant! +// Use this instead of bloated standard/newlib printf cause they use malloc +// for printf (and may not be thread safe). +// +/////////////////////////////////////////////////////////////////////////////// + +#include <stdarg.h> +#include "printf.h" + + +// buffer size used for printf +#define PRINTF_BUFFER_SIZE 128U + +// ntoa conversion buffer size, this must be big enough to hold one converted numeric number +#define NTOA_BUFFER_SIZE 32U + +// ftoa conversion buffer size, this must be big enough to hold one converted float number +#define FTOA_BUFFER_SIZE 32U + +// define this to support floating point (%f) +#define PRINTF_FLOAT_SUPPORT 1 + + +/////////////////////////////////////////////////////////////////////////////// + +// internal flag definitions +#define FLAGS_ZEROPAD (1U << 0U) +#define FLAGS_LEFT (1U << 1U) +#define FLAGS_PLUS (1U << 2U) +#define FLAGS_SPACE (1U << 3U) +#define FLAGS_HASH (1U << 4U) +#define FLAGS_UPPERCASE (1U << 5U) +#define FLAGS_LONG (1U << 6U) +#define FLAGS_LONG_LONG (1U << 7U) + + +// internal strlen, returns the length of the string +static inline size_t _strlen(const char* str) +{ + size_t len = 0U; + while (str[len] != '\0') { + len++; + } + return len; +} + + +// returns 1 if char is a digit, 0 if not +static inline unsigned int _is_digit(char ch) +{ + return (ch >= '0' && ch <= '9') ? 1U : 0U; +} + + +// internal ASCII to unsigned int conversion +static inline unsigned int _atoi(const char** str) +{ + unsigned int i = 0U; + while (_is_digit(**str)) { + i = i * 10U + *((*str)++) - '0'; + } + return i; +} + + +// internal itoa +template<typename T> +static size_t _ntoa(T value, char* buffer, unsigned int base, size_t maxlen, unsigned int width, unsigned int flags) +{ + char buf[NTOA_BUFFER_SIZE]; + size_t len = 0U; + unsigned int negative = 0U; + + if (maxlen == 0) { + return 0U; + } + if (base > 16U) { + return 0U; + } + if (value < 0) { + negative = 1; + value = value * -1; + } + + do { + char digit = (char)(value % base); + buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10; + value /= (T)base; + } while ((len < NTOA_BUFFER_SIZE) && (value > 0)); + // pad zeros + while ((flags & FLAGS_ZEROPAD) && (len < width) && (len < NTOA_BUFFER_SIZE)) { + buf[len++] = '0'; + } + // handle sign + if (len < NTOA_BUFFER_SIZE) { + if (negative) { + buf[len++] = '-'; + } + else if (flags & FLAGS_PLUS) { + buf[len++] = '+'; // ignore the space if the '+' exists + } + else if (flags & FLAGS_SPACE) { + buf[len++] = ' '; + } + } + // pad spaces up to given width + while ((len < width) && (len < NTOA_BUFFER_SIZE)) { + buf[len++] = ' '; + } + + // reverse it + for (size_t i = 0U; (i < len) && (i < maxlen); ++i) { + buffer[i] = buf[len - i - 1]; + } + + return len; +} + + +#if defined(PRINTF_FLOAT_SUPPORT) +static size_t _ftoa(double value, char* buffer, size_t maxlen, unsigned int prec, unsigned int width, unsigned int flags) +{ + // test for NaN + if (!(value == value) && (maxlen > 2U)) { + buffer[0] = 'n'; buffer[1] = 'a'; buffer[2] = 'n'; + return (size_t)3; + } + // if input is larger than thres_max, revert to exponential + const double thres_max = (double)(0x7FFFFFFF); + + char buf[FTOA_BUFFER_SIZE]; + size_t len = 0U; + double diff = 0.0; + + // powers of 10 + static const double pow10[] = {1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000}; + + // limit precision + if (prec > 9U) { + // precision of >= 10 can lead to overflow errors + prec = 9U; + } + + unsigned int negative = 0U; + if (value < 0) { + negative = 1U; + value = value * -1; + } + + int whole = (int)value; + double tmp = (value - whole) * pow10[prec]; + unsigned long frac = (unsigned long)tmp; + diff = tmp - frac; + + if (diff > 0.5) { + ++frac; + // handle rollover, e.g. case 0.99 with prec 1 is 1.0 + if (frac >= pow10[prec]) { + frac = 0; + ++whole; + } + } + else if ((diff == 0.5) && ((frac == 0) || (frac & 1))) { + // if halfway, round up if odd, OR if last digit is 0 + ++frac; + } + + // for very large numbers switch back to native sprintf for exponentials. anyone want to write code to replace this? + // normal printf behavior is to print EVERY whole number digit which can be 100s of characters overflowing your buffers == bad + if (value > thres_max) { + return 0; + } + + if (prec == 0) { + diff = value - whole; + if (diff > 0.5) { + // greater than 0.5, round up, e.g. 1.6 -> 2 + ++whole; + } + else if (diff == 0.5 && (whole & 1)) { + // exactly 0.5 and ODD, then round up */ + // 1.5 -> 2, but 2.5 -> 2 + ++whole; + } + } + else { + unsigned int count = prec; + // now do fractional part, as an unsigned number + do { + --count; + buf[len++] = (char)(48U + (frac % 10U)); + } while ((len < FTOA_BUFFER_SIZE) && (frac /= 10U)); + // add extra 0s + while ((len < FTOA_BUFFER_SIZE) && (count-- > 0)) { + buf[len++] = '0'; + } + if (len < FTOA_BUFFER_SIZE) { + // add decimal + buf[len++] = '.'; + } + } + + // do whole part + // Take care of sign + // Conversion. Number is reversed. + size_t wlen = 0U; + do { + buf[len++] = (char)(48 + (whole % 10)); + wlen++; + } while ((len < FTOA_BUFFER_SIZE) && (whole /= 10)); + // pad zeros + while ((flags & FLAGS_ZEROPAD) && (wlen < width) && (len < FTOA_BUFFER_SIZE)) { + buf[len++] = '0'; + wlen++; + } + // handle sign + if (len < FTOA_BUFFER_SIZE) { + if (negative) { + buf[len++] = '-'; + } + else if (flags & FLAGS_PLUS) { + buf[len++] = '+'; // ignore the space if the '+' exists + } + else if (flags & FLAGS_SPACE) { + buf[len++] = ' '; + } + } + // pad spaces up to given width + while ((wlen < width) && (len < FTOA_BUFFER_SIZE)) { + buf[len++] = ' '; + wlen++; + } + + // reverse it + for (size_t i = 0U; (i < len) && (i < maxlen); ++i) { + buffer[i] = buf[len - i - 1]; + } + + return len; +} +#endif + + +// internal vsnprintf +static size_t vsnprintf(char* buffer, size_t buffer_len, const char* format, va_list va) +{ + unsigned int flags, width, precision, n; + size_t idx = 0U; + + while (idx < buffer_len) { + // end reached? + if (*format == '\0') { + buffer[idx] = '\0'; + break; + } + + // format specifier? + if (*format != '%') { + buffer[idx++] = *format; + format++; + continue; + } + + // evaluate flags + flags = 0U; + do { + format++; + switch (*format) { + case '0': flags |= FLAGS_ZEROPAD; n = 1U; break; + case '-': flags |= FLAGS_LEFT; n = 1U; break; + case '+': flags |= FLAGS_PLUS; n = 1U; break; + case ' ': flags |= FLAGS_SPACE; n = 1U; break; + case '#': flags |= FLAGS_HASH; n = 1U; break; + default : n = 0U; break; + } + } while (n); + + // evaluate width field + width = 1U; + if (_is_digit(*format)) { + width = _atoi(&format); + } + else if (*format == '*') { + width = (unsigned int)va_arg(va, int); + format++; + } + + // evaluate precision field + precision = 0; + if (*format == '.') { + format++; + if (_is_digit(*format)) { + precision = _atoi(&format); + } + else if (*format == '*') { + precision = (unsigned int)va_arg(va, int); + format++; + } + } + + // evaluate the length field + if (*format == 'l' || *format == 'L') { + flags |= FLAGS_LONG; + format++; + } + if ((*format == 'l') && (flags & FLAGS_LONG)) { + flags |= FLAGS_LONG_LONG; + format++; + } + + // evaluate specifier + switch (*format) { + case 'u' : + case 'd' : + case 'i' : + case 'x' : + case 'X' : + case 'o' : + case 'b' : { + // set the base + unsigned int base; + if (*format == 'x' || *format == 'X') { + base = 16U; + } + else if (*format == 'o') { + base = 8U; + } + else if (*format == 'b') { + base = 2U; + } + else { + base = 10U; + } + // uppercase + if (*format == 'X') { + flags |= FLAGS_UPPERCASE; + } + + if (flags & FLAGS_HASH) { + if (buffer_len - idx > 0U) { + buffer[idx++] = '0'; + } + if ((*format == 'x') && (buffer_len - idx > 0U)) { + buffer[idx++] = 'x'; + } + if ((*format == 'X') && (buffer_len - idx > 0U)) { + buffer[idx++] = 'X'; + } + } + + // convert the integer + if (*format == 'i' || *format == 'd') { + // signed + if (flags & FLAGS_LONG_LONG) { + idx += _ntoa<long long>(va_arg(va, long long), &buffer[idx], base, buffer_len - idx, width, flags); + } + else if (flags & FLAGS_LONG) { + idx += _ntoa<long>(va_arg(va, long), &buffer[idx], base, buffer_len - idx, width, flags); + } + else { + idx += _ntoa<int>(va_arg(va, int), &buffer[idx], base, buffer_len - idx, width, flags); + } + } + else { + // unsigned + if (flags & FLAGS_LONG_LONG) { + idx += _ntoa<unsigned long long>(va_arg(va, unsigned long long), &buffer[idx], base, buffer_len - idx, width, flags); + } + else if (flags & FLAGS_LONG) { + idx += _ntoa<unsigned long>(va_arg(va, unsigned long), &buffer[idx], base, buffer_len - idx, width, flags); + } + else { + idx += _ntoa<unsigned int>(va_arg(va, unsigned int), &buffer[idx], base, buffer_len - idx, width, flags); + } + } + format++; + break; + } +#if defined(PRINTF_FLOAT_SUPPORT) + case 'f' : + case 'F' : + idx += _ftoa(va_arg(va, double), &buffer[idx], buffer_len - idx, precision, width, flags); + format++; + break; +#endif + case 'c' : + buffer[idx++] = (char)va_arg(va, int); + format++; + break; + + case 's' : { + char* p = va_arg(va, char*); + while ((idx < buffer_len) && (*p != 0)) { + buffer[idx++] = *(p++); + } + format++; + break; + } + + case 'p' : + width = sizeof(void*) * 2U; + flags |= FLAGS_ZEROPAD; + if (sizeof(void*) > sizeof(long)) { + idx +=_ntoa<unsigned long long>(reinterpret_cast<unsigned long long>(va_arg(va, void*)), &buffer[idx], 16U, buffer_len - idx, width, flags); + } + else { + idx += _ntoa<unsigned long>(reinterpret_cast<unsigned long>(va_arg(va, void*)), &buffer[idx], 16U, buffer_len - idx, width, flags); + } + format++; + break; + + case '%' : + buffer[idx++] = '%'; + format++; + break; + + default : + buffer[idx++] = *format; + break; + } + } + + return idx; +} + +/////////////////////////////////////////////////////////////////////////////// + +int printf(const char* format, ...) +{ + va_list va; + va_start(va, format); + char buffer[PRINTF_BUFFER_SIZE]; + int ret = (int)vsnprintf(buffer, PRINTF_BUFFER_SIZE, format, va); + va_end(va); + for (int i = 0; i < ret; ++i) { + _putchar(buffer[i]); + } + return ret; +} + + +int sprintf(char* buffer, const char* format, ...) +{ + va_list va; + va_start(va, format); + int ret = (int)vsnprintf(buffer, (size_t)-1, format, va); + va_end(va); + return ret; +} + + +int snprintf(char* buffer, size_t count, const char* format, ...) +{ + va_list va; + va_start(va, format); + int ret = (int)vsnprintf(buffer, count, format, va); + va_end(va); + return ret; +} diff --git a/printf.h b/printf.h new file mode 100644 index 0000000..8981c9e --- /dev/null +++ b/printf.h @@ -0,0 +1,75 @@ +/////////////////////////////////////////////////////////////////////////////// +// \author (c) Marco Paland (info@paland.com) +// 2014, PALANDesign Hannover, Germany +// +// \license The MIT License (MIT) +// +// This file is part of the turnkey-board. +// 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 <stddef.h> + +/** + * Output a character to a custom device like UART. + * This function is declared here only. You have to write your custom implementation somewhere. + * \param character to output + * \return On success, the character written is returned + */ +int _putchar(char character); + + +/** + * Tiny printf implementation + * You have to implement _putchar if you use printf() + * \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 + */ +int printf(const char* format, ...); + + +/** + * Tiny sprintf implementation + * Due to security reasons YOU SHOULD CONSIDER USING SNPRINTF INSTEAD! + * \param buffer A pointer to the buffer where to store the formatted string + * \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 + */ +int sprintf(char* buffer, const char* format, ...); + + +/** + * Tiny snprintf 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 + * \return The number of characters that are written into the array, not counting the terminating null character + */ +int snprintf(char* buffer, size_t count, const char* format, ...); + +#endif // _PRINTF_H_ |