Diff: util.cpp

Revision:

18:c2f3df4ef5fe

Parent:

3:42f3821c4e54

--- a/util.cpp	Thu Nov 29 17:17:52 2018 +0000
+++ b/util.cpp	Thu Nov 29 17:21:37 2018 +0000
@@ -1,4 +1,8 @@
 #include <math.h>
+#include <string.h>
+
+#define MAXBUF 32
+#define MAXDIGITS 10
 
 /** 
  * Clamp a value (angle) between min (non-inclusive) and max (inclusive)
@@ -81,13 +85,112 @@
   return f;
 }
 
+
+char *cvntos(unsigned long n)
+{
+    static char buf[MAXBUF+1]; // +1 null termination
+    char *str = buf+MAXBUF;
+    int i;
+
+    // ensure null termination
+    *str-- = '\0';
+
+    for (i = 0; i < MAXBUF; i++) {
+        unsigned long m = n;
+        n /= 10;
+        char c = m - 10 * n;
+        *--str = c + '0';
+        if (n == 0) break;
+    }
+
+    return str;
+}
+
+
+
+char *cvitos(long n)
+{
+    static char buf[MAXBUF+2]; // +1 for sign, +1 for null termination
+    char *str = buf;
+
+    *str = '\0';
+    if (n < 0) {
+        *str++ = '-';
+        *str = '\0';
+        n = -n;
+    }
+    strcat(str, cvntos(n));
+
+    return buf;
+}
+
+
+
+char *cvftos(double number, int digits)
+{
+    static char buf[MAXBUF+3+MAXDIGITS]; // +1 for termination, +1 for sign, +1 for ., +MAXDIGITS for digits
+    char *str = buf;
+    int i;
+
+    // ensure proper null termination
+    *str = '\0';
+
+    // Limited buffer space for decimals
+    if (digits > MAXDIGITS)
+        digits = MAXDIGITS;
+
+    if (isnan(number)) {
+        strcpy(buf, "nan");
+    } else if (isinf(number)) {
+        strcpy(buf, "inf");
+    } else if (number > 4294967040.0 || number < -4294967040.0) {  // constant determined empirically
+        strcpy(buf, "ovf");
+    } else {
+
+        // Handle negative numbers
+        if (number < 0.0) {
+            // Add the sign
+            strcat(str, "-");
+            number = -number;
+        }
+
+        // Round correctly so that print(1.999, 2) prints as "2.00"
+        double rounding = 0.5;
+        for (i=0; i < digits; i++)
+            rounding /= 10.0;
+        number += rounding;
+
+        // Extract the integer part of the number and print it
+        unsigned long int_part = (unsigned long)number;
+        double remainder = number - (double)int_part;
+
+        // Add the integer part
+        strcat(str, cvntos(int_part));
+        // Add the decimal point
+        char *s = str + strlen(str);
+        *s++ = '.';
+
+        // Extract digits from the remainder one at a time
+        while (digits-- > 0) {
+            remainder *= 10.0;
+            int toPrint = (int) remainder;
+            *s++ = toPrint + '0';
+            remainder -= (double) toPrint;
+        }
+        *s = '\0';
+    }
+
+    return str;
+}
+
+
 // copy t to s until delimiter is reached
 // return location of delimiter+1 in t
 // if s or t null, return null
 char *split(char *s, char *t, int max, char delim)
 {
   int i = 0;
-  
+
   if (s == 0 || t == 0)
     return 0;
 
@@ -96,6 +199,6 @@
     i++;
   }
   *s = 0;
-    
+
   return t+1;
 }