diff --git a/Sources/Plasma/CoreLib/plString.cpp b/Sources/Plasma/CoreLib/plString.cpp
index 9b179949..08bab171 100644
--- a/Sources/Plasma/CoreLib/plString.cpp
+++ b/Sources/Plasma/CoreLib/plString.cpp
@@ -924,14 +924,28 @@ plStringStream &plStringStream::operator<<(const char *text)
 plStringStream &plStringStream::operator<<(int num)
 {
     char buffer[12];
-    snprintf(buffer, 12, "%d", num);
+    snprintf(buffer, arrsize(buffer), "%d", num);
     return operator<<(buffer);
 }
 
 plStringStream &plStringStream::operator<<(unsigned int num)
 {
     char buffer[12];
-    snprintf(buffer, 12, "%u", num);
+    snprintf(buffer, arrsize(buffer), "%u", num);
+    return operator<<(buffer);
+}
+
+plStringStream &plStringStream::operator<<(int64_t num)
+{
+    char buffer[24];
+    snprintf(buffer, arrsize(buffer), "%lld", num);
+    return operator<<(buffer);
+}
+
+plStringStream &plStringStream::operator<<(uint64_t num)
+{
+    char buffer[24];
+    snprintf(buffer, arrsize(buffer), "%llu", num);
     return operator<<(buffer);
 }
 
diff --git a/Sources/Plasma/CoreLib/plString.h b/Sources/Plasma/CoreLib/plString.h
index 536031ea..3304ffac 100644
--- a/Sources/Plasma/CoreLib/plString.h
+++ b/Sources/Plasma/CoreLib/plString.h
@@ -753,6 +753,12 @@ public:
     /** Append a base-10 formatted unsigned integer to the stream. */
     plStringStream &operator<<(unsigned int num);
 
+    /** Append a base-10 formatted signed 64-bit integer to the stream. */
+    plStringStream &operator<<(int64_t num);
+
+    /** Append a base-10 formatted unsigned 64-bit integer to the stream. */
+    plStringStream &operator<<(uint64_t num);
+
     /** Append a base-10 formatted float to the stream. */
     plStringStream &operator<<(float num) { return operator<<(static_cast<double>(num)); }