@@ -, +, @@ 
---
 gen_allocdefs.h | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)
--- a/gen_allocdefs.h	
+++ a/gen_allocdefs.h	
@@ -4,24 +4,41 @@ 
 #define GEN_ALLOC_ready(ta,type,field,len,a,i,n,x,base,ta_ready) \
 int ta_ready(x,n) register ta *x; register unsigned int n; \
 { register unsigned int i; \
+  unsigned int nlen; \
   if (x->field) { \
     i = x->a; \
     if (n > i) { \
-      x->a = base + n + (n >> 3); \
-      if (alloc_re(&x->field,i * sizeof(type),x->a * sizeof(type))) return 1; \
+      unsigned int nnum; \
+      if (__builtin_add_overflow(base, n, &nlen)) \
+        return 0; \
+      if (__builtin_add_overflow(nlen, n >> 3, &nlen)) \
+        return 0; \
+      if (__builtin_mul_overflow(nlen, sizeof(type), &nnum)) \
+        return 0; \
+      x->a = nlen; \
+      if (alloc_re(&x->field,i * sizeof(type),nnum)) return 1; \
       x->a = i; return 0; } \
     return 1; } \
   x->len = 0; \
   return !!(x->field = (type *) alloc((x->a = n) * sizeof(type))); }
 
 #define GEN_ALLOC_readyplus(ta,type,field,len,a,i,n,x,base,ta_rplus) \
-int ta_rplus(x,n) register ta *x; register unsigned int n; \
+int ta_rplus(x,n) register ta *x; unsigned int n; \
 { register unsigned int i; \
   if (x->field) { \
     i = x->a; n += x->len; \
+    if (__builtin_add_overflow(n, x->len, &n)) \
+      return 0; \
     if (n > i) { \
-      x->a = base + n + (n >> 3); \
-      if (alloc_re(&x->field,i * sizeof(type),x->a * sizeof(type))) return 1; \
+      unsigned int nlen, nnum; \
+      if (__builtin_add_overflow(base, n, &nlen)) \
+        return 0; \
+      if (__builtin_add_overflow(nlen, n >> 3, &nlen)) \
+        return 0; \
+      if (__builtin_mul_overflow(nlen, sizeof(type), &nnum)) \
+        return 0; \
+      x->a = nlen; \
+      if (alloc_re(&x->field,i * sizeof(type),nnum)) return 1; \
       x->a = i; return 0; } \
     return 1; } \
   x->len = 0; \
--