diff --git a/contrib/minizip/ioapi.c b/contrib/minizip/ioapi.c
index d4bc020c502fbede68103d3235c10085ce704ac3..49ec64af8ad96dea3bce5cea6a665a780c1e3e20 100644
--- a/contrib/minizip/ioapi.c
+++ b/contrib/minizip/ioapi.c
@@ -59,7 +59,7 @@ ZPOS64_T call_ztell64 (const zlib_filefunc64_32_def* pfilefunc,voidpf filestream
     else
     {
         uLong tell_uLong = (*(pfilefunc->ztell32_file))(pfilefunc->zfile_func64.opaque,filestream);
-        if ((tell_uLong) == ((uLong)-1))
+        if ((tell_uLong) == MAXU32)
             return (ZPOS64_T)-1;
         else
             return tell_uLong;
diff --git a/contrib/minizip/ioapi.h b/contrib/minizip/ioapi.h
index f6dce266ac3320cb73c17933677a53a8823a205f..b5c9f93af70aacb9bcbf717ec0024017ef74a967 100644
--- a/contrib/minizip/ioapi.h
+++ b/contrib/minizip/ioapi.h
@@ -86,6 +86,8 @@ typedef  64BIT_INT_CUSTOM_TYPE ZPOS64_T;
 typedef uint64_t ZPOS64_T;
 #else
 
+/* Maximum unsigned 32-bit value used as placeholder for zip64 */
+#define MAXU32 0xffffffff
 
 #if defined(_MSC_VER) || defined(__BORLANDC__)
 typedef unsigned __int64 ZPOS64_T;
diff --git a/contrib/minizip/unzip.c b/contrib/minizip/unzip.c
index 587a2a112b57d3ef46c92f682255f17adcbed943..050014ce405d9095be5a66d2aacd6e1fbce88c13 100644
--- a/contrib/minizip/unzip.c
+++ b/contrib/minizip/unzip.c
@@ -1040,26 +1040,26 @@ local int unz64local_GetCurrentFileInfoInternal (unzFile file,
             {
                                                         uLong uL;
 
-                                                                if(file_info.uncompressed_size == (ZPOS64_T)(unsigned long)-1)
+                                                                if(file_info.uncompressed_size == MAXU32)
                                                                 {
                                                                         if (unz64local_getLong64(&s->z_filefunc, s->filestream,&file_info.uncompressed_size) != UNZ_OK)
                                                                                         err=UNZ_ERRNO;
                                                                 }
 
-                                                                if(file_info.compressed_size == (ZPOS64_T)(unsigned long)-1)
+                                                                if(file_info.compressed_size == MAXU32)
                                                                 {
                                                                         if (unz64local_getLong64(&s->z_filefunc, s->filestream,&file_info.compressed_size) != UNZ_OK)
                                                                                   err=UNZ_ERRNO;
                                                                 }
 
-                                                                if(file_info_internal.offset_curfile == (ZPOS64_T)(unsigned long)-1)
+                                                                if(file_info_internal.offset_curfile == MAXU32)
                                                                 {
                                                                         /* Relative Header offset */
                                                                         if (unz64local_getLong64(&s->z_filefunc, s->filestream,&file_info_internal.offset_curfile) != UNZ_OK)
                                                                                 err=UNZ_ERRNO;
                                                                 }
 
-                                                                if(file_info.disk_num_start == (unsigned long)-1)
+                                                                if(file_info.disk_num_start == MAXU32)
                                                                 {
                                                                         /* Disk Start Number */
                                                                         if (unz64local_getLong(&s->z_filefunc, s->filestream,&uL) != UNZ_OK)