1 files changed, 10 insertions, 3 deletions
diff --git a/lzf_c.c b/lzf_c.c
index 268313a..c1847f3 100644
--- a/lzf_c.c
+++ b/lzf_c.c
@@ -113,12 +113,19 @@ lzf_compress (const void *const in_data, unsigned int in_len,
         u8 *out_end = op + out_len;
   const u8 *ref;
 
-  unsigned int hval;
-#if WIN32
-  unsigned _int64 off; /* workaround for microsoft bug (they claim to support POSIX) */
+  /* off requires a type wide enough to hold a general pointer difference.
+   * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
+   * works for differences within a single object). We also assume that no
+   * no bit pattern traps. Since the only platform that is both non-POSIX
+   * and fails to support both assumptions is windows 64 bit, we make a
+   * special workaround for it.
+   */
+#if defined (WIN32) && defined (_M_X64)
+  unsigned _int64 off; /* workaround for missing POSIX compliance */
 #else
   unsigned long off;
 #endif
+  unsigned int hval;
   int lit;
 
   if (!in_len || !out_len)