diff --git a/minilzo/minilzo.c b/minilzo/minilzo.c
index 34ce0f0..ecfdf66 100644
--- a/minilzo/minilzo.c
+++ b/minilzo/minilzo.c
@@ -3547,6 +3547,8 @@ DO_COMPRESS      ( const lzo_bytep in , lzo_uint  in_len,
 #undef TEST_LBO
 #undef NEED_IP
 #undef NEED_OP
+#undef TEST_IV
+#undef TEST_OV
 #undef HAVE_TEST_IP
 #undef HAVE_TEST_OP
 #undef HAVE_NEED_IP
@@ -3561,6 +3563,7 @@ DO_COMPRESS      ( const lzo_bytep in , lzo_uint  in_len,
 #  if (LZO_TEST_OVERRUN_INPUT >= 2)
 #    define NEED_IP(x) \
             if ((lzo_uint)(ip_end - ip) < (lzo_uint)(x))  goto input_overrun
+#    define TEST_IV(x)          if ((x) > (lzo_uint)0 - (511)) goto input_overrun
 #  endif
 #endif
 
@@ -3572,6 +3575,7 @@ DO_COMPRESS      ( const lzo_bytep in , lzo_uint  in_len,
 #    undef TEST_OP
 #    define NEED_OP(x) \
             if ((lzo_uint)(op_end - op) < (lzo_uint)(x))  goto output_overrun
+#    define TEST_OV(x)          if ((x) > (lzo_uint)0 - (511)) goto output_overrun
 #  endif
 #endif
 
@@ -3602,11 +3606,13 @@ DO_COMPRESS      ( const lzo_bytep in , lzo_uint  in_len,
 #  define HAVE_NEED_IP 1
 #else
 #  define NEED_IP(x)            ((void) 0)
+#  define TEST_IV(x)            ((void) 0)
 #endif
 #if defined(NEED_OP)
 #  define HAVE_NEED_OP 1
 #else
 #  define NEED_OP(x)            ((void) 0)
+#  define TEST_OV(x)            ((void) 0)
 #endif
 
 #if defined(HAVE_TEST_IP) || defined(HAVE_NEED_IP)
@@ -3687,6 +3693,7 @@ DO_DECOMPRESS  ( const lzo_bytep in , lzo_uint  in_len,
             {
                 t += 255;
                 ip++;
+                TEST_IV(t);
                 NEED_IP(1);
             }
             t += 15 + *ip++;
@@ -3835,6 +3842,7 @@ match:
                     {
                         t += 255;
                         ip++;
+                        TEST_OV(t);
                         NEED_IP(1);
                     }
                     t += 31 + *ip++;
@@ -3879,6 +3887,7 @@ match:
                     {
                         t += 255;
                         ip++;
+                        TEST_OV(t);
                         NEED_IP(1);
                     }
                     t += 7 + *ip++;
@@ -4073,6 +4082,8 @@ lookbehind_overrun:
 #undef TEST_LBO
 #undef NEED_IP
 #undef NEED_OP
+#undef TEST_IV
+#undef TEST_OV
 #undef HAVE_TEST_IP
 #undef HAVE_TEST_OP
 #undef HAVE_NEED_IP
@@ -4087,6 +4098,7 @@ lookbehind_overrun:
 #  if (LZO_TEST_OVERRUN_INPUT >= 2)
 #    define NEED_IP(x) \
             if ((lzo_uint)(ip_end - ip) < (lzo_uint)(x))  goto input_overrun
+#    define TEST_IV(x)          if ((x) > (lzo_uint)0 - (511)) goto input_overrun
 #  endif
 #endif
 
@@ -4098,6 +4110,7 @@ lookbehind_overrun:
 #    undef TEST_OP
 #    define NEED_OP(x) \
             if ((lzo_uint)(op_end - op) < (lzo_uint)(x))  goto output_overrun
+#    define TEST_OV(x)          if ((x) > (lzo_uint)0 - (511)) goto output_overrun
 #  endif
 #endif
 
@@ -4128,11 +4141,13 @@ lookbehind_overrun:
 #  define HAVE_NEED_IP 1
 #else
 #  define NEED_IP(x)            ((void) 0)
+#  define TEST_IV(x)            ((void) 0)
 #endif
 #if defined(NEED_OP)
 #  define HAVE_NEED_OP 1
 #else
 #  define NEED_OP(x)            ((void) 0)
+#  define TEST_OV(x)            ((void) 0)
 #endif
 
 #if defined(HAVE_TEST_IP) || defined(HAVE_NEED_IP)
@@ -4213,6 +4228,7 @@ DO_DECOMPRESS  ( const lzo_bytep in , lzo_uint  in_len,
             {
                 t += 255;
                 ip++;
+                TEST_IV(t);
                 NEED_IP(1);
             }
             t += 15 + *ip++;
@@ -4361,6 +4377,7 @@ match:
                     {
                         t += 255;
                         ip++;
+                        TEST_OV(t);
                         NEED_IP(1);
                     }
                     t += 31 + *ip++;
@@ -4405,6 +4422,7 @@ match:
                     {
                         t += 255;
                         ip++;
+                        TEST_OV(t);
                         NEED_IP(1);
                     }
                     t += 7 + *ip++;
diff --git a/src/lzo1_d.ch b/src/lzo1_d.ch
index 40a5bfd..c442d9c 100644
--- a/src/lzo1_d.ch
+++ b/src/lzo1_d.ch
@@ -76,6 +76,8 @@
 #undef TEST_LBO
 #undef NEED_IP
 #undef NEED_OP
+#undef TEST_IV
+#undef TEST_OV
 #undef HAVE_TEST_IP
 #undef HAVE_TEST_OP
 #undef HAVE_NEED_IP
@@ -91,6 +93,7 @@
 #  if (LZO_TEST_OVERRUN_INPUT >= 2)
 #    define NEED_IP(x) \
             if ((lzo_uint)(ip_end - ip) < (lzo_uint)(x))  goto input_overrun
+#    define TEST_IV(x)          if ((x) > (lzo_uint)0 - (511)) goto input_overrun
 #  endif
 #endif
 
@@ -102,6 +105,7 @@
 #    undef TEST_OP              /* don't need both of the tests here */
 #    define NEED_OP(x) \
             if ((lzo_uint)(op_end - op) < (lzo_uint)(x))  goto output_overrun
+#    define TEST_OV(x)          if ((x) > (lzo_uint)0 - (511)) goto output_overrun
 #  endif
 #endif
 
@@ -135,11 +139,13 @@
 #  define HAVE_NEED_IP 1
 #else
 #  define NEED_IP(x)            ((void) 0)
+#  define TEST_IV(x)            ((void) 0)
 #endif
 #if defined(NEED_OP)
 #  define HAVE_NEED_OP 1
 #else
 #  define NEED_OP(x)            ((void) 0)
+#  define TEST_OV(x)            ((void) 0)
 #endif
 
 
diff --git a/src/lzo1b_d.ch b/src/lzo1b_d.ch
index fe5f361..36b4b6b 100644
--- a/src/lzo1b_d.ch
+++ b/src/lzo1b_d.ch
@@ -187,6 +187,7 @@ match:
                 {
                     t += 255;
                     ip++;
+                    TEST_OV(t);
                     NEED_IP(1);
                 }
                 t += (M4_MIN_LEN - M3_MIN_LEN) + *ip++;
diff --git a/src/lzo1f_d.ch b/src/lzo1f_d.ch
index 9e942f5..0c2199e 100644
--- a/src/lzo1f_d.ch
+++ b/src/lzo1f_d.ch
@@ -84,6 +84,7 @@ DO_DECOMPRESS  ( const lzo_bytep in , lzo_uint  in_len,
             {
                 t += 255;
                 ip++;
+                TEST_IV(t);
                 NEED_IP(1);
             }
             t += 31 + *ip++;
@@ -138,6 +139,7 @@ match:
                         {
                             t += 255;
                             ip++;
+                            TEST_OV(t);
                             NEED_IP(1);
                         }
                         t += 31 + *ip++;
diff --git a/src/lzo1x_d.ch b/src/lzo1x_d.ch
index 49cf326..c804cc7 100644
--- a/src/lzo1x_d.ch
+++ b/src/lzo1x_d.ch
@@ -120,6 +120,7 @@ DO_DECOMPRESS  ( const lzo_bytep in , lzo_uint  in_len,
             {
                 t += 255;
                 ip++;
+                TEST_IV(t);
                 NEED_IP(1);
             }
             t += 15 + *ip++;
@@ -273,6 +274,7 @@ match:
                     {
                         t += 255;
                         ip++;
+                        TEST_OV(t);
                         NEED_IP(1);
                     }
                     t += 31 + *ip++;
@@ -317,6 +319,7 @@ match:
                     {
                         t += 255;
                         ip++;
+                        TEST_OV(t);
                         NEED_IP(1);
                     }
                     t += 7 + *ip++;
diff --git a/src/lzo2a_d.ch b/src/lzo2a_d.ch
index 48e51ca..954f07e 100644
--- a/src/lzo2a_d.ch
+++ b/src/lzo2a_d.ch
@@ -131,6 +131,7 @@ DO_DECOMPRESS    ( const lzo_bytep in , lzo_uint  in_len,
             {
                 t += 255;
                 ip++;
+                TEST_OV(t);
                 NEED_IP(1);
             }
             t += *ip++;
