add function fc_ftoa

HISTORY

@@ -1,4 +1,8 @@
 
+Version 1.80  2025-09-10
+  * getIpaddrByNameEx: IPv4 has priority over IPv6
+  * shared_func.[hc]: add function fc_ftoa
+
 Version 1.79  2025-08-29
   * logger.h export function log_it_ex3
   * shared_func.[hc]: add function bytes_to_human_str

src/logger.c

@@ -136,8 +136,8 @@ static int log_print_header(LogContext *pContext)
     if (pContext->current_size < 0)
     {
         result = errno != 0 ? errno : EACCES;
-        fprintf(stderr, "lseek file \"%s\" fail, " \
-                "errno: %d, error info: %s\n", \
+        fprintf(stderr, "lseek file \"%s\" fail, "
+                "errno: %d, error info: %s\n",
                 pContext->log_filename, result, STRERROR(result));
     }
     else {

src/shared_func.c

@@ -4406,6 +4406,119 @@ int fc_itoa(int64_t n, char *buff)
     return (start - buff) + len;
 }
 
+int fc_ftoa(double d, const int scale, char *buff)
+{
+    int len;
+    int i;
+    bool positive;
+    int64_t n;
+    double fraction;
+    char *p;
+
+    positive = (d >= 0.00);
+    switch (scale)
+    {
+        case 0:
+            d += (positive ? 5e-1 : -5e-1);
+            break;
+        case 1:
+            d += (positive ? 5e-2 : -5e-2);
+            break;
+        case 2:
+            d += (positive ? 5e-3 : -5e-3);
+            break;
+        case 3:
+            d += (positive ? 5e-4 : -5e-4);
+            break;
+        case 4:
+            d += (positive ? 5e-5 : -5e-5);
+            break;
+        case 5:
+            d += (positive ? 5e-6 : -5e-6);
+            break;
+        case 6:
+            d += (positive ? 5e-7 : -5e-7);
+            break;
+        case 7:
+            d += (positive ? 5e-8 : -5e-8);
+            break;
+        case 8:
+            d += (positive ? 5e-9 : -5e-9);
+            break;
+        case 9:
+            d += (positive ? 5e-10 : -5e-10);
+            break;
+        case 10:
+            d += (positive ? 5e-11 : -5e-11);
+            break;
+        case 11:
+            d += (positive ? 5e-12 : -5e-12);
+            break;
+        case 12:
+            d += (positive ? 5e-13 : -5e-13);
+            break;
+        case 13:
+            d += (positive ? 5e-14 : -5e-14);
+            break;
+        case 14:
+            d += (positive ? 5e-15 : -5e-15);
+            break;
+        case 15:
+            d += (positive ? 5e-16 : -5e-16);
+            break;
+        case 16:
+            d += (positive ? 5e-17 : -5e-17);
+            break;
+        default:
+            d += (positive ? 5e-18 : -5e-18);
+            break;
+    }
+
+    n = (int64_t)d;
+    if (n > -10 && n < 10)
+    {
+        if (positive)
+        {
+            *buff = '0' + n;
+            len = 1;
+        }
+        else
+        {
+            *buff = '-';
+            *(buff+1) = '0' + (-1) * n;
+            len = 2;
+        }
+    }
+    else
+    {
+        len = fc_itoa(n, buff);
+    }
+    if (scale <= 0)
+    {
+        return len;
+    }
+
+    p = buff + len;
+    *p++ = '.';
+    if (positive)
+    {
+        fraction = d - (double)n;
+    }
+    else
+    {
+        fraction = (double)n - d;
+    }
+    for (i=0; i<scale; i++)
+    {
+        fraction *= 10;
+        n = (int)fraction;
+        fraction -= n;
+        *p++ = '0' + n;
+    }
+
+    return p - buff;
+}
+
 int fc_compare_int64_ptr(const int64_t *n1, const int64_t *n2)
 {
     return fc_compare_int64(*n1, *n2);

src/shared_func.h

@@ -1603,12 +1603,28 @@ bool fc_path_contains(const string_t *path, const string_t *needle,
 
 /** itoa output as decimal number
  *  parameters:
- *      n: the number to convert
- *      buff: store the converted string
- *  return: string length
+ *      n: the integer number to convert
+ *      buff: store the converted string, NOT null-terminated
+ *  return: converted string length
 */
 int fc_itoa(int64_t n, char *buff);
 
+/** ftoa output as decimal number
+ *  parameters:
+ *      d: the double number to convert
+ *      scale: number of decimal places (round off)
+ *      buff: store the converted string, NOT null-terminated
+ *  return: converted string length
+*/
+int fc_ftoa(double d, const int scale, char *buff);
+
+/** output as decimal number
+ *  parameters:
+ *      n: the integer number to convert
+ *      buff: store the converted string, null-terminated
+ *      padding_len: padding length (padding with charactor '0')
+ *  return: converted string length
+*/
 static inline int fc_ltostr_ex(int64_t n, char *buff, const int padding_len)
 {
     int len;