util.c File Reference

Utility functionality for high-precision logging voltage/current meter. More...

#include "util.h"
#include <stdint.h>

Go to the source code of this file.

Macros
#define	TO_DEC(i)   (i <= 9 ? '0' + i : '?') /* return "?" if out of range */

Functions
float	bytes_to_float (uint8_t byte0, uint8_t byte1, uint8_t byte2, uint8_t byte3)
	Convert four bytes into a float. More...
void	splitFloat (float fValue, uint16_t *beforeComma, uint16_t *afterComma, uint8_t decimalPlaces)
	Split a float value in two uint values (before and after the comma). More...
void	uint32_to_charDec (char *buf, uint32_t value, uint8_t totalChars)
	Convert a uint32_t value to a decimal char array (string). More...

Detailed Description

Utility functionality for high-precision logging voltage/current meter.

Version

1.0

Author

Brecht Van Eeckhoudt

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Versions

• v1.0: Initial version.

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License

Copyright (C) 2021 - Brecht Van Eeckhoudt

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

A copy of the GNU General Public License can be found in the LICENSE file along with this source code.

Definition in file util.c.

Macro Definition Documentation

TO_DEC

#define TO_DEC

(

i

)

(i <= 9 ? '0' + i : '?') /* return "?" if out of range */

Definition at line 42 of file util.c.

Function Documentation

bytes_to_float()

float bytes_to_float	(	uint8_t	byte0,
		uint8_t	byte1,
		uint8_t	byte2,
		uint8_t	byte3
	)

Convert four bytes into a float.

Parameters

[in]	byte0	First byte.
[in]	byte1	Second byte.
[in]	byte2	Third byte.
[in]	byte3	Fourth byte.

Returns

The converted float-value.

Definition at line 72 of file util.c.

{
    /* Define union */
    union
    {
        float fValue;
        uint8_t byte[4];
    } data;
 
    /* Assign the four bytes to the union array */
    data.byte[0]=byte0;
    data.byte[1]=byte1;
    data.byte[2]=byte2;
    data.byte[3]=byte3;
 
    return (data.fValue);
}

splitFloat()

void splitFloat	(	float	fValue,
		uint16_t *	beforeComma,
		uint16_t *	afterComma,
		uint8_t	decimalPlaces
	)

Split a float value in two uint values (before and after the comma).

Parameters

[in]	fValue	The float value to convert.
[in,out]	beforeComma	Pointer to the uint16_t value before the comma.
[in,out]	afterComma	Pointer to the uint16_t value after the comma.
[in]	decimalPlaces	Amount of decimal places to use after the comma.

Definition at line 107 of file util.c.

{
    /* Separate value before comma */
    *beforeComma = (uint16_t)fValue;
 
    /* Separate value after comma according to given argument */
    float multiplicationFactor = 1.0;
    for (uint8_t counter = 0; counter < decimalPlaces; counter++) multiplicationFactor *= 10.0;
    *afterComma = (uint16_t)((float)(fValue-(*beforeComma))*multiplicationFactor);
 
    /* Round up if necessary */
    uint8_t roundingNumber = (uint8_t)(((float)(fValue-(*beforeComma))*(multiplicationFactor*10.0))-(*afterComma)*10);
    if (roundingNumber > 4)
    {
        (*afterComma)++;
        if ((decimalPlaces == 1) && (*afterComma) == 10)
        {
            (*beforeComma)++;
            (*afterComma) = 0;
        }
    }
}

uint32_to_charDec()

void uint32_to_charDec	(	char *	buf,
		uint32_t	value,
		uint8_t	totalChars
	)

Convert a uint32_t value to a decimal char array (string).

This method can also add a specific amount of leading zero's if necessary.

Parameters

[out]	buf	The buffer to put the resulting string in. This needs to have a length of 10: char buf[10];!
[in]	value	The uint32_t value to convert to a string.
[in]	totalChars	Total amount of characters, to be filled with leading zero's if necessary. If a value <= 1 is given, no zero's will be added

Definition at line 149 of file util.c.

{
    if (value == 0)
    {
        uint8_t counter;
        for (counter = 0; counter < totalChars; counter++)
        {
            buf[counter] = '0';
        }
 
        buf[counter++] = '\0'; /* NULL termination character */
    }
    else
    {
        /* MAX uint32_t value = FFFFFFFFh = 4294967295d (10 decimal chars) */
        char backwardsBuf[10];
 
        uint32_t calcval = value;
        uint8_t length = 0;
        uint8_t lengthCounter = 0;
 
 
        /* Loop until the value is zero (separate characters 0-9) and calculate length */
        while (calcval)
        {
            uint32_t rem = calcval % 10;
            backwardsBuf[length] = TO_DEC(rem); /* Convert to ASCII character */
            length++;
 
            calcval = calcval - rem;
            calcval = calcval / 10;
        }
 
        uint8_t index = 0;
        uint8_t addedZeros = 0;
 
        /* Add leading zero's if necessary */
        if (totalChars > 1)
        {
            /* Calculate power */
            uint16_t power = 1;
            while (totalChars != 1) {
                power *= 10;
                totalChars--;
            }
 
            /* Print leading zero's if necessary */
            if (value < power)
            {
                /* Add the correct amount of zero's */
                uint16_t checkValue = value;
                while (checkValue < power)
                {
                    buf[index] = '0';
                    addedZeros++;
                    checkValue *= 10;
                    index++;
                }
            }
        }
 
        /* Backwards counter */
        lengthCounter = length;
 
        /* Reverse the characters in the buffer for the final string */
        while (index < (length + addedZeros))
        {
            buf[index] = backwardsBuf[lengthCounter-1];
            lengthCounter--;
            index++;
        }
 
        /* Add NULL termination character */
        buf[(length + addedZeros)] = '\0';
    }
}