Dryer/lib/tinyavrlib/num2str.c

/**
 * NUM2STR - Functions to handle the conversion of numeric vales to strings.
 *
 * @author	Neven Boyanov
 *
 * This is part of the Tinusaur/TinyAVRLib project.
 *
 * Copyright (c) 2017 Neven Boyanov, The Tinusaur Team. All Rights Reserved.
 * Distributed as open source software under MIT License, see LICENSE.txt file.
 * Retain in your source code the link http://tinusaur.org to the Tinusaur project.
 *
 * Source code available at: https://bitbucket.org/tinusaur/tinyavrlib
 *
 */

// ============================================================================

#include "num2str.h"

// ----------------------------------------------------------------------------
//  NOTE: The resulting ASCII text should not be terminated with '\0' in the 
//        functions below because the buffer might be part of a larger text.
// ----------------------------------------------------------------------------

uint8_t usint2decascii(uint16_t num, char *buffer) {
	const unsigned short powers[] = { 10000u, 1000u, 100u, 10u, 1u }; // The "const unsigned short" combination gives shortest code.
	char digit; // "digit" is stored in a char array, so it should be of type char.
	uint8_t digits = USINT2DECASCII_MAX_DIGITS - 1;
	for (uint8_t pos = 0; pos < 5; pos++) { // "pos" is index in array.
		digit = 0;
		while (num >= powers[pos]) {
			digit++;
			num -= powers[pos];
		}
		// Fixed width, space (or anything else) padded result, digits offset.
		// Note: Determines the offset of the first significant digit.
		// Note: Could be used for variable width, not padded, left aligned result.
		if (digits == USINT2DECASCII_MAX_DIGITS - 1) {
			if (digit == 0) {
				if (pos < USINT2DECASCII_MAX_DIGITS - 1)	// Check position, so single "0" will be handled properly.
					digit = 0;//!!! -16;	// Use: "-16" for space (' '), "-3" for dash/minus ('-'), "0" for zero ('0'), etc. ...
			} else {
				digits = pos;
			}
		}
		buffer[pos] = digit + '0';	// Convert to ASCII

	}
	return digits;
}

// ----------------------------------------------------------------------------

uint8_t usint2hexascii(uint16_t num, char *buffer) {
	for (int8_t pos = USINT2HEXASCII_MAX_DIGITS - 1; pos >= 0 ; pos--) { // "pos" is index in an array.
		char digit = num & 0x000f;
		if (digit <= 9) {
			buffer[pos] = digit + '0';	// Convert to ASCII
		} else {
			buffer[pos] = digit + 'A' - 10;	// Convert to ASCII
		}
		num = num >> 4;
	}
	return 4;
}

// ----------------------------------------------------------------------------
// NOTE: The buffer should be always at least MAX_DIGITS in length - the function works with 16-bit numbers.

uint8_t usint2binascii(uint16_t num, char *buffer) {
	uint16_t power = 0x8000;	// This is the 1000 0000 0000 0000 binary number.
	char digit; // "digit" is stored in a char array, so it should be of type char.
	uint8_t digits = USINT2BINASCII_MAX_DIGITS - 1;
	for (uint8_t pos = 0; pos < USINT2BINASCII_MAX_DIGITS; pos++) { // "pos" is index in an array.
		digit = 0;
		if (num >= power) {
			digit++;
			num -= power;
		}
		// Fixed width, space ('0', or anything else) padded result, digits offset.
		// Note: Determines the offset of the first significant digit.
		// Note: Could be used for variable width, not padded, left aligned result.
		if (digits == USINT2BINASCII_MAX_DIGITS - 1) {
			if (digit == 0) {
				if (pos < USINT2BINASCII_MAX_DIGITS - 1) // Check position, so single "0" will be handled properly.
					digit = 0; // Use: "-16" for space (' '), "-3" for dash/minus ('-'), "0" for zero ('0'), etc.
			} else {
				digits = pos;
			}
		}
		buffer[pos] = digit + '0';	// Convert to ASCII
		power = power >> 1;
	}
	return digits;
}

// ============================================================================