fix: print(0ULL) output nothing

Fixes stm32duino#2545 Signed-off-by: warmonkey <luoshumymail@gmail.com>
fpistm · Nov 4, 2024 · 3250030 · 3250030
1 parent c35b8ef
commit 3250030
Showing 1 changed file with 41 additions and 35 deletions.
diff --git a/cores/arduino/Print.cpp b/cores/arduino/Print.cpp
@@ -374,46 +374,52 @@ size_t Print::printULLNumber(unsigned long long n64, uint8_t base)
   char buf[64];
   uint8_t i = 0;
   uint8_t innerLoops = 0;
+  size_t bytes = 0;
 
-  // prevent crash if called with base == 1
-  if (base < 2) {
-    base = 10;
-  }
-
-  // process chunks that fit in "16 bit math".
-  uint16_t top = 0xFFFF / base;
-  uint16_t th16 = 1;
-  while (th16 < top) {
-    th16 *= base;
-    innerLoops++;
-  }
+  // Special case workaround https://github.com/arduino/ArduinoCore-API/issues/178
+  if (n64 == 0) {
+    write('0');
+    bytes = 1;
+  } else {
+    // prevent crash if called with base == 1
+    if (base < 2) {
+      base = 10;
+    }
 
-  while (n64 > th16) {
-    // 64 bit math part
-    uint64_t q = n64 / th16;
-    uint16_t r = n64 - q * th16;
-    n64 = q;
-
-    // 16 bit math loop to do remainder. (note buffer is filled reverse)
-    for (uint8_t j = 0; j < innerLoops; j++) {
-      uint16_t qq = r / base;
-      buf[i++] = r - qq * base;
-      r = qq;
+    // process chunks that fit in "16 bit math".
+    uint16_t top = 0xFFFF / base;
+    uint16_t th16 = 1;
+    while (th16 < top) {
+      th16 *= base;
+      innerLoops++;
     }
-  }
 
-  uint16_t n16 = n64;
-  while (n16 > 0) {
-    uint16_t qq = n16 / base;
-    buf[i++] = n16 - qq * base;
-    n16 = qq;
-  }
+    while (n64 > th16) {
+      // 64 bit math part
+      uint64_t q = n64 / th16;
+      uint16_t r = n64 - q * th16;
+      n64 = q;
+
+      // 16 bit math loop to do remainder. (note buffer is filled reverse)
+      for (uint8_t j = 0; j < innerLoops; j++) {
+        uint16_t qq = r / base;
+        buf[i++] = r - qq * base;
+        r = qq;
+      }
+    }
 
-  size_t bytes = i;
-  for (; i > 0; i--) {
-    write((char)(buf[i - 1] < 10 ?
-                 '0' + buf[i - 1] :
-                 'A' + buf[i - 1] - 10));
+    uint16_t n16 = n64;
+    while (n16 > 0) {
+      uint16_t qq = n16 / base;
+      buf[i++] = n16 - qq * base;
+      n16 = qq;
+    }
+    bytes = i;
+    for (; i > 0; i--) {
+      write((char)(buf[i - 1] < 10 ?
+                   '0' + buf[i - 1] :
+                   'A' + buf[i - 1] - 10));
+    }
   }
   return bytes;
 }