diff --git a/include/private/parser.h b/include/private/parser.h
index f9bf1692..a72465ed 100644
--- a/include/private/parser.h
+++ b/include/private/parser.h
@@ -1,6 +1,8 @@
 #ifndef XML_PARSER_H_PRIVATE__
 #define XML_PARSER_H_PRIVATE__
 
+#include <limits.h>
+
 #include <libxml/parser.h>
 #include <libxml/xmlversion.h>
 
@@ -153,4 +155,20 @@ xmlExpandEntitiesInAttValue(xmlParserCtxt *ctxt, const xmlChar *str,
 XML_HIDDEN void
 xmlParserCheckEOF(xmlParserCtxt *ctxt, xmlParserErrors code);
 
+static XML_INLINE void
+xmlSaturatedAdd(unsigned long *dst, unsigned long val) {
+    if (val > ULONG_MAX - *dst)
+        *dst = ULONG_MAX;
+    else
+        *dst += val;
+}
+
+static XML_INLINE void
+xmlSaturatedAddSizeT(unsigned long *dst, size_t val) {
+    if (val > ULONG_MAX - *dst)
+        *dst = ULONG_MAX;
+    else
+        *dst += val;
+}
+
 #endif /* XML_PARSER_H_PRIVATE__ */
diff --git a/parser.c b/parser.c
index 291a9c94..4968fc04 100644
--- a/parser.c
+++ b/parser.c
@@ -408,22 +408,6 @@ xmlNsWarn(xmlParserCtxtPtr ctxt, xmlParserErrors error,
                info1, info2, info3, 0, msg, info1, info2, info3);
 }
 
-static void
-xmlSaturatedAdd(unsigned long *dst, unsigned long val) {
-    if (val > ULONG_MAX - *dst)
-        *dst = ULONG_MAX;
-    else
-        *dst += val;
-}
-
-static void
-xmlSaturatedAddSizeT(unsigned long *dst, size_t val) {
-    if (val > ULONG_MAX - *dst)
-        *dst = ULONG_MAX;
-    else
-        *dst += val;
-}
-
 /**
  * Check for non-linear entity expansion behaviour.
  *
diff --git a/parserInternals.c b/parserInternals.c
index bd5a562d..51abd033 100644
--- a/parserInternals.c
+++ b/parserInternals.c
@@ -697,11 +697,7 @@ xmlParserShrink(xmlParserCtxt *ctxt) {
 
         if (res > 0) {
             used -= res;
-            if ((res > ULONG_MAX) ||
-                (in->consumed > ULONG_MAX - (unsigned long)res))
-                in->consumed = ULONG_MAX;
-            else
-                in->consumed += res;
+            xmlSaturatedAddSizeT(&in->consumed, res);
         }
 
         xmlBufUpdateInput(buf->buffer, in, used);
@@ -732,11 +728,7 @@ xmlParserInputShrink(xmlParserInput *in) {
 	ret = xmlBufShrink(in->buf->buffer, used - LINE_LEN);
 	if (ret > 0) {
             used -= ret;
-            if ((ret > ULONG_MAX) ||
-                (in->consumed > ULONG_MAX - (unsigned long)ret))
-                in->consumed = ULONG_MAX;
-            else
-                in->consumed += ret;
+            xmlSaturatedAddSizeT(&in->consumed, ret);
 	}
 
         xmlBufUpdateInput(in->buf->buffer, in, used);