[sky9x] Stack probe

[sky9x] No sprintf (needed heap)
[sky9x] Bug when retrieving available SD audio files

src/sky9x/massstorage.cpp

@@ -78,17 +78,90 @@ Media medias[MAX_LUNS];
 /** Device LUNs. */
 MSDLun luns[MAX_LUNS];
 
-char *bytes2Str(char *str, uint32_t bytes)
+int itoa(int val, char* buf)
 {
-  if (bytes < 1024*100)
-    sprintf(str, "%lu.%luK", bytes / 1024, (bytes % 1024) / 103);
-  else if (bytes < 1024*1024)
-    sprintf(str, "%luK", bytes / 1024);
-  else if (bytes < 1024*1024*100)
-    sprintf(str, "%lu.%luM", bytes / (1024*1024), (bytes % (1024*1024)) / 104858);
-  else
-    sprintf(str, "%luM", bytes / (1024*1024));
-  return str;
+    const unsigned int radix = 10;
+
+    char* p;
+    unsigned int a;        //every digit
+    int len;
+    char* b;            //start of the digit char
+    char temp;
+    unsigned int u;
+
+    p = buf;
+
+#if 0
+    if (val < 0)
+    {
+        *p++ = '-';
+        val = 0 - val;
+    }
+#endif
+
+    u = (unsigned int)val;
+
+    b = p;
+
+    do
+    {
+        a = u % radix;
+        u /= radix;
+
+        *p++ = a + '0';
+
+    } while (u > 0);
+
+    len = (int)(p - buf);
+
+    *p-- = 0;
+
+    //swap
+    do
+    {
+        temp = *p;
+        *p = *b;
+        *b = temp;
+        --p;
+        ++b;
+
+    } while (b < p);
+
+    return len;
+}
+
+uint8_t write_bytes(char *str, uint32_t bytes)
+{
+  uint8_t len;
+  if (bytes < 1024*100) {
+    len = itoa(bytes / 1024, str);
+    str[len] = '.';
+    str[len+1] = '0' + ((bytes % 1024) / 103);
+    str[len+2] = 'K';
+    str[len+3] = '\0';
+    len += 3;
+  }
+  else if (bytes < 1024*1024) {
+    len = itoa(bytes / 1024, str);
+    str[len] = 'K';
+    str[len+1] = '\0';
+    len += 1;
+  }
+  else if (bytes < 1024*1024*100) {
+    len = itoa(bytes / (1024*1024), str);
+    str[len] = '.';
+    str[len+1] = '0' + ((bytes % (1024*1024)) / 104858);
+    str[len+2] = 'M';
+    str[len+3] = '\0';
+    len += 3;
+  }
+  else {
+    len = itoa(bytes / (1024*1024), str);
+    str[len] = 'M';
+    str[len+1] = '\0';
+    len += 1;
+  }
+  return len;
 }
 
 static void MSDCallbacks_Data( unsigned char flowDirection, unsigned int dataLength,
@@ -99,10 +172,10 @@ static void MSDCallbacks_Data( unsigned char flowDirection, unsigned int dataLen
   else
     msdWriteTotal += dataLength;
 
-  char rdStr[10];
-  char wrStr[10];
-
-  sprintf(statusLineMsg, "USB Rd:%s Wr:%s", bytes2Str(rdStr, msdReadTotal), bytes2Str(wrStr, msdWriteTotal));
+  strcpy(statusLineMsg, "USB Rd:");
+  uint8_t len = write_bytes(statusLineMsg+7, msdReadTotal);
+  strcpy(statusLineMsg+7+len, " Wr:");
+  write_bytes(statusLineMsg+7+len+4, msdWriteTotal);
   showStatusLine();
 }