bt_matchfinder: add BT_MATCHFINDER_REQUIRED_NBYTES

[wimlib] / include / wimlib / bt_matchfinder.h

diff --git a/include/wimlib/bt_matchfinder.h b/include/wimlib/bt_matchfinder.h
index c7f2ba8eaebd9c039d9d7441724d598de2dd6541..3d295cd91fe8e50afb1c5479ce9d62a9c9c5dd6a 100644 (file)
--- a/include/wimlib/bt_matchfinder.h
+++ b/include/wimlib/bt_matchfinder.h
@@ -123,6 +123,11 @@ TEMPLATED(bt_right_child)(struct TEMPLATED(bt_matchfinder) *mf, u32 node)
        return &mf->child_tab[(node << 1) + 1];
 }
 
+/* The minimum permissible value of 'max_len' for bt_matchfinder_get_matches()
+ * and bt_matchfinder_skip_position().  There must be sufficiently many bytes
+ * remaining to load a 32-bit integer from the *next* position.  */
+#define BT_MATCHFINDER_REQUIRED_NBYTES 5
+
 /* Advance the binary tree matchfinder by one byte, optionally recording
  * matches.  @record_matches should be a compile-time constant.  */
 static inline struct lz_match *
@@ -266,7 +271,8 @@ TEMPLATED(bt_matchfinder_advance_one_byte)(struct TEMPLATED(bt_matchfinder) * co
  *     The current position in the input buffer (the position of the sequence
  *     being matched against).
  * @max_len
- *     The maximum permissible match length at this position.  Must be >= 5.
+ *     The maximum permissible match length at this position.  Must be >=
+ *     BT_MATCHFINDER_REQUIRED_NBYTES.
  * @nice_len
  *     Stop searching if a match of at least this length is found.
  *     Must be <= @max_len.