Minor fixes following the discussion on pull request 224:big-marshal

- intern.c: watch out for left shift overflow
- extern.c: refactor caml_output_value_to_block


git-svn-id: http://caml.inria.fr/svn/ocaml/branches/big-marshal@16522 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

2 files changed, 6 insertions, 10 deletions

diff --git a/byterun/extern.c b/byterun/extern.c
index b61a9776c1..abce63123a 100644
--- a/byterun/extern.c
+++ b/byterun/extern.c
@@ -715,19 +715,15 @@ CAMLexport intnat caml_output_value_to_block(value v, value flags,
   extern_ptr = extern_userprovided_output;
   extern_limit = buf + len;
   data_len = extern_value(v, flags, header, &header_len);
-  if (header_len == 20) {
-    /* Good guess! */
-    memcpy(buf, header, 20);
-    return 20 + data_len;
-  } else {
-    /* Need to shift the output to make room for big header. 
+  if (header_len != 20) {
+    /* Bad guess!  Need to shift the output to make room for big header. 
        Make sure there is room. */
     if (header_len + data_len > len)
       caml_failwith("Marshal.to_buffer: buffer overflow");
     memmove(buf + header_len, buf + 20, data_len);
-    memcpy(buf, header, header_len);
-    return header_len + data_len;
   }
+  memcpy(buf, header, header_len);
+  return header_len + data_len;
 }
 
 CAMLprim value caml_output_value_to_buffer(value buf, value ofs, value len,
diff --git a/byterun/intern.c b/byterun/intern.c
index 6f26b65360..828743fb98 100644
--- a/byterun/intern.c
+++ b/byterun/intern.c
@@ -96,7 +96,7 @@ static inline int16_t read16s(void)
 static inline uint32_t read32u(void)
 {
   uint32_t res =
-    (intern_src[0] << 24) + (intern_src[1] << 16)
+    ((uint32_t)(intern_src[0]) << 24) + (intern_src[1] << 16)
     + (intern_src[2] << 8) + intern_src[3];
   intern_src += 4;
   return res;
@@ -105,7 +105,7 @@ static inline uint32_t read32u(void)
 static inline int32_t read32s(void)
 {
   int32_t res =
-    (intern_src[0] << 24) + (intern_src[1] << 16)
+    ((uint32_t)(intern_src[0]) << 24) + (intern_src[1] << 16)
     + (intern_src[2] << 8) + intern_src[3];
   intern_src += 4;
   return res;