diff --git a/mozilla/string/obsolete/nsStr.cpp b/mozilla/string/obsolete/nsStr.cpp
index 16bcdc9b99a..5f1f3288007 100644
--- a/mozilla/string/obsolete/nsStr.cpp
+++ b/mozilla/string/obsolete/nsStr.cpp
@@ -77,11 +77,11 @@ public:
     }
   }
 
-  virtual PRBool Alloc(nsStr& aDest,PRInt32 aCount) {
+  virtual PRBool Alloc(nsStr& aDest,PRUint32 aCount) {
     
     //we're given the acount value in charunits; we have to scale up by the charsize.
-    int     theShift=4;
-    PRInt32 theNewCapacity=eDefaultSize;
+    int       theShift=4;
+    PRUint32  theNewCapacity=eDefaultSize;
     while(theNewCapacity<aCount){ 
       theNewCapacity<<=1;
       theShift++;
diff --git a/mozilla/xpcom/ds/nsStr.cpp b/mozilla/xpcom/ds/nsStr.cpp
index 16bcdc9b99a..5f1f3288007 100644
--- a/mozilla/xpcom/ds/nsStr.cpp
+++ b/mozilla/xpcom/ds/nsStr.cpp
@@ -77,11 +77,11 @@ public:
     }
   }
 
-  virtual PRBool Alloc(nsStr& aDest,PRInt32 aCount) {
+  virtual PRBool Alloc(nsStr& aDest,PRUint32 aCount) {
     
     //we're given the acount value in charunits; we have to scale up by the charsize.
-    int     theShift=4;
-    PRInt32 theNewCapacity=eDefaultSize;
+    int       theShift=4;
+    PRUint32  theNewCapacity=eDefaultSize;
     while(theNewCapacity<aCount){ 
       theNewCapacity<<=1;
       theShift++;
diff --git a/mozilla/xpcom/string/obsolete/nsStr.cpp b/mozilla/xpcom/string/obsolete/nsStr.cpp
index 16bcdc9b99a..5f1f3288007 100644
--- a/mozilla/xpcom/string/obsolete/nsStr.cpp
+++ b/mozilla/xpcom/string/obsolete/nsStr.cpp
@@ -77,11 +77,11 @@ public:
     }
   }
 
-  virtual PRBool Alloc(nsStr& aDest,PRInt32 aCount) {
+  virtual PRBool Alloc(nsStr& aDest,PRUint32 aCount) {
     
     //we're given the acount value in charunits; we have to scale up by the charsize.
-    int     theShift=4;
-    PRInt32 theNewCapacity=eDefaultSize;
+    int       theShift=4;
+    PRUint32  theNewCapacity=eDefaultSize;
     while(theNewCapacity<aCount){ 
       theNewCapacity<<=1;
       theShift++;