Jira-599. Routine, dtostrf, did not work with the latest toolchain. The call to sprintf in the routine crashed the system. Issue corrected by replacing the call. The routine, printfloat, in Print.cpp, is now usint dtostrf to print out double and float values.

Author: SidLeung

cores/arduino/Print.cpp

@@ -288,62 +288,8 @@ size_t Print::printLongLong(unsigned long long n, uint8_t base) {
 
 size_t Print::printFloat(double number, uint8_t digits)
 {
-  size_t n = 0;
-  int exponent = 0;
-  double tmp;
-
-  if (isnan(number)) return print("nan");
-  if (isinf(number)) return print("inf");
-
-  // Handle negative numbers
-  if (number < 0.0) {
-    n += print('-');
-    number = -number;
-  }
-
-  // Chk if integer part has more than 8 digits.
-  tmp = number;
-  while (true) {
-    tmp /= 10.0;
-    exponent++;
-    if (tmp < 10.0)  break;
-  }
-  if (exponent > 8)
-    number = tmp;
-  else
-    exponent = 0;
-
-  // Round correctly so that print(1.999, 2) prints as "2.00"
-  double rounding = 0.5;
-  for (uint8_t 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;
-  n += print(int_part);
-
-  // Print the decimal point, but only if there are digits beyond
-  if (digits > 0) {
-    n += print(".");
-  }
-
-  // Extract digits from the remainder one at a time
-  while (digits-- > 0)
-  {
-    remainder *= 10.0;
-    int toPrint = int(remainder);
-    n += print(toPrint);
-    remainder -= toPrint;
-  }
+  char str[50];
 
-  // Print the exponent portion
-  if (exponent) {
-    n += print("e+");
-    n += print(exponent);
-  }
-
-  return n;
+  dtostrf(number, 0, digits, str);
+  return(print(str));
 }

cores/arduino/stdlib_noniso.cpp

@@ -147,7 +147,22 @@ char* ultoa( unsigned long val, char *string, int radix )
     return string;
 }
 
-char * dtostrf(double number, unsigned char width, unsigned char prec, char *s) {
+void shiftOutDigit(double *number, int count, char *s)
+{
+    double tmp = *number;
+    int digit;
+
+    while( count ) {
+      tmp *= 10.0;
+      digit = (int)tmp;
+      *s++ = '0' + digit;
+      tmp -= (double)digit;
+      count--;
+    }
+    *number = tmp;
+}
+
+char * dtostrf(double number, signed char width, unsigned char prec, char *s) {
 
     if (isnan(number)) {
         strcpy(s, "nan");
@@ -158,62 +173,62 @@ char * dtostrf(double number, unsigned char width, unsigned char prec, char *s)
         return s;
     }
 
-    char* out = s;
-    int exponent = 0;
-    unsigned char len, expLen;
-    double tmp;
+    char *out = s;
+    int expCnt = 0, digit, totalWidth;
+    double tmp, rounding;
+
+    // Check for left adjustment (spaces)
+    while(width < 0) {
+      *out++ = ' ';
+      width++;
+    }
+    totalWidth = (int)width;
 
     // Handle negative numbers
     if (number < 0.0) {
       *out++ = '-';
       number = -number;
+      if(totalWidth > 0) totalWidth--;
     }
 
-    // The integer portion has to be <= 8 digits.  Otherwise, the
-    // string is in exponent format.
+    // Rounding up to the precision
     tmp = number;
-    for (;;) {
+    rounding = 0.5;
+    for(int i=0; i < prec; i++)
+      rounding /= 10.0;
+    tmp += rounding;
+
+    // Shifting the number to the right
+    while( tmp >= 10.0 ) {
       tmp /= 10.0;
-      exponent++;
-      if (tmp < 10.0)  break;
+      expCnt++;
     }
-    if (exponent > 8)
-      number = tmp;
-    else
-      exponent = 0;
-
-    // Round correctly so that print(1.999, 2) prints as "2.00"
-    double rounding = 0.5;
-    for (uint8_t i = 0; i < prec; ++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;
-    out += sprintf(out, "%ld", int_part);
-
-    // Don't go beyond the given width of the string
-    len = (unsigned char)(out - s);
-    expLen = (exponent == 0) ? 0 : 5;  // 5 places for exponent expression
-    if ((prec + len + expLen) > width)
-      prec = width - len - expLen;
-
-    // Print the decimal point, but only if there are digits beyond
-    if (prec > 0) {
-        *out++ = '.';
-	// Copy character by character to 'out' string
-        for (unsigned char decShift = prec; decShift > 0; decShift--) {
-            remainder *= 10.0;
-            out += sprintf(out, "%d", (int)remainder);
-            remainder -= (double)(int)remainder;
-        }
+    // 1st, print the single digit left after shifting
+    digit = (int)tmp;
+    *out++ = '0' + digit;
+    tmp -= (double)digit;
+    if(totalWidth > 0) totalWidth--;
+
+    // Then the integer portion
+    shiftOutDigit(&tmp, expCnt, out);
+    out += expCnt;
+    if(totalWidth > 0) totalWidth -= expCnt;
+
+    // Then the decimal portion
+    if( prec ) {
+      *out++ = '.';
+      shiftOutDigit(&tmp, prec, out);
+      if(totalWidth > 0) totalWidth -= (prec + 1);
+      out += prec;
     }
 
-    // Print the exponent if exists
-    if (exponent)
-      sprintf(out, "e+%.3d", exponent);
+    // Right adjustment
+    while(totalWidth > 0) {
+      *out++ = ' ';
+      totalWidth--;
+    }
 
+    *out = 0;  // End of string
     return s;
 }

cores/arduino/stdlib_noniso.h

@@ -37,7 +37,7 @@ char* utoa (unsigned int val, char *s, int radix);
 
 char* ultoa (unsigned long val, char *s, int radix);
 
-char* dtostrf (double val, unsigned char width, unsigned char prec, char *s);
+char* dtostrf (double val, signed char width, unsigned char prec, char *s);
 
 #ifdef __cplusplus
 } // extern "C"