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83 lines
1.7 KiB
83 lines
1.7 KiB
#include <esp8266.h>
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/* reverse: reverse string s in place */
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static void str_reverse(char *s)
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{
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for (int i = 0, j = (int)(strlen(s) - 1); i < j; i++, j--) {
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char c = s[i];
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s[i] = s[j];
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s[j] = c;
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}
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}
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/* itoa: convert n to characters in s. returns length */
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int my_itoa(int n, char *s)
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{
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int i, sign;
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if ((sign = n) < 0) /* record sign */
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n = -n; /* make n positive */
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i = 0;
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do { /* generate digits in reverse order */
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s[i++] = n % 10 + '0'; /* get next digit */
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} while ((n /= 10) > 0); /* delete it */
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if (sign < 0)
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s[i++] = '-';
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s[i] = '\0';
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str_reverse(s);
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return i;
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}
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int my_ftoa(char *buffer, float f, int precision)
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{
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// add 0.5 * 10^-precision
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float rounder = 0.5;
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for (int i = 0; i < precision; i++) rounder *= 0.1;
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f += rounder;
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int wholePart = (int) f;
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// Deposit the whole part of the number.
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int length = my_itoa(wholePart, buffer);
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// Now work on the faction if we need one.
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if (precision > 0) {
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// We do, so locate the end of the string and insert
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// a decimal point.
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char *endOfString = buffer + length;
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//while (*endOfString != '\0') endOfString++;
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*endOfString++ = '.';
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length++;
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// Now work on the fraction, be sure to turn any negative
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// values positive.
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if (f < 0) {
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f *= -1;
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wholePart *= -1;
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}
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float fraction = f - wholePart;
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while (precision > 0) {
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// Multiply by ten and pull out the digit.
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fraction *= 10;
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int dig = (int) fraction;
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*endOfString++ = (char)('0' + dig);
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// Update the fraction and move on to the
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// next digit.
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fraction -= dig;
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precision--;
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length++;
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}
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// Terminate the string.
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*endOfString = 0;
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}
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return length;
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}
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