lz_sarray_get_matches(): Remove unnecessary check

[wimlib] / include / wimlib / lz_sarray.h

diff --git a/include/wimlib/lz_sarray.h b/include/wimlib/lz_sarray.h
index 6f878dd2bafd9d89b9d16ba80b88d70fa46e5217..5b63ae7c74e9dcafbb075d7ba2ab4559ac36284d 100644 (file)
--- a/include/wimlib/lz_sarray.h
+++ b/include/wimlib/lz_sarray.h
@@ -137,7 +137,7 @@ struct salink {
                         * prefix (LCP) between the suffix having this rank and
                         * the suffix with the the smallest larger rank that
                         * starts earlier in the window than the suffix having
                         * prefix (LCP) between the suffix having this rank and
                         * the suffix with the the smallest larger rank that
                         * starts earlier in the window than the suffix having

-                        * this rank.
+                        * this rank.  If no such suffix exists, this will be 0.

                         *
                         * Later, during match-finding, after the corresponding
                         * suffix has entered the LZ77 dictionary, this value
                         *
                         * Later, during match-finding, after the corresponding
                         * suffix has entered the LZ77 dictionary, this value


@@ -151,7 +151,8 @@ struct salink {
                         * common prefix (LCP) between the suffix having this
                         * rank and the suffix with the the largest smaller rank
                         * that starts earlier in the window than the suffix
                         * common prefix (LCP) between the suffix having this
                         * rank and the suffix with the the largest smaller rank
                         * that starts earlier in the window than the suffix

-                        * having this rank.
+                        * having this rank.  If no such suffix exists, this
+                        * will be 0.

                         *
                         * Later, during match-finding, after the corresponding
                         * suffix has entered the LZ77 dictionary, this value
                         *
                         * Later, during match-finding, after the corresponding
                         * suffix has entered the LZ77 dictionary, this value


@@ -163,22 +164,24 @@ struct salink {
 
                        /* Distance to the suffix referred to in the description
                         * of "lcpnext" above, but capped to a maximum value to
 
                        /* Distance to the suffix referred to in the description
                         * of "lcpnext" above, but capped to a maximum value to

-                        * save memory.  If the true distance was truncated,
-                        * this will give the distance to the rank of a suffix
-                        * that is lexicographically closer to the current
-                        * suffix than the desired suffix, but appears *later*
-                        * in the window and hence cannot be used as the basis
-                        * for a LZ77 match.  */
+                        * save memory; or, 0 if no such suffix exists.  If the
+                        * true distance was truncated, this will give the
+                        * distance to the rank of a suffix that is
+                        * lexicographically closer to the current suffix than
+                        * the desired suffix, but appears *later* in the window
+                        * and hence cannot be used as the basis for a LZ77
+                        * match.  */

                        lz_sarray_delta_t dist_to_next;
 
                        /* Distance to the suffix referred to in the description
                         * of "lcpprev" above, but capped to a maximum value to
                        lz_sarray_delta_t dist_to_next;
 
                        /* Distance to the suffix referred to in the description
                         * of "lcpprev" above, but capped to a maximum value to

-                        * save memory.  If the true distance was truncated,
-                        * this will give the distance to the rank of a suffix
-                        * that is lexicographically closer to the current
-                        * suffix than the desired suffix, but appears *later*
-                        * in the window and hence cannot be used as the basis
-                        * for a LZ77 match.  */
+                        * save memory; or, 0 if no such suffix exists.  If the
+                        * true distance was truncated, this will give the
+                        * distance to the rank of a suffix that is
+                        * lexicographically closer to the current suffix than
+                        * the desired suffix, but appears *later* in the window
+                        * and hence cannot be used as the basis for a LZ77
+                        * match.  */

                        lz_sarray_delta_t dist_to_prev;
                };
        };
                        lz_sarray_delta_t dist_to_prev;
                };
        };


@@ -315,7 +318,7 @@ lz_sarray_get_matches(struct lz_sarray *mf,
        u32 count_remaining = max_matches_to_consider;
 
        /* pending_offset = offset of lowest-cost match found for the current
        u32 count_remaining = max_matches_to_consider;
 
        /* pending_offset = offset of lowest-cost match found for the current

-        * length, or 0 if no match has been found yet.  */
+        * length, or 0 if none found yet.  */

        lz_sarray_pos_t pending_offset = 0;
 
        /* Note: some 'goto' statements are used in the remainder of this
        lz_sarray_pos_t pending_offset = 0;
 
        /* Note: some 'goto' statements are used in the remainder of this


@@ -367,7 +370,7 @@ extend_left:
                        }
                }
 
                        }
                }
 

-               /* Advance left to next suffix.  */
+               /* Advance left to previous suffix.  */

 
                old_L = L;
                old_lenL = lenL;
 
                old_L = L;
                old_lenL = lenL;


@@ -406,10 +409,10 @@ extend_left:
                                }
                        }
 
                                }
                        }
 

-                       /* Here we have lenL < lenR.  Extend right, unless the
-                        * minimum match length would be underrun.  */
-                       if (lenR == 0)
-                               return nmatches;
+                       /* Here we have lenL < lenR.  Extend right.
+                        * (No check for whether the minimum match length has
+                        * been underrun is needed, provided that such lengths
+                        * are marked as 0.)  */

                        goto extend_right;
                }
        }
                        goto extend_right;
                }
        }


@@ -479,13 +482,7 @@ extend_right:
                                pending_offset = 0;
                        }
 
                                pending_offset = 0;
                        }
 

-                       if (lenR > lenL) {
-                               /* lenR > lenL:  Keep extending right, unless
-                                * the minimum match length would be underrun.
-                                */
-                               if (lenR == 0)
-                                       return nmatches;
-                       } else {
+                       if (lenL >= lenR) {

                                /* lenL >= lenR:  Extend left, unless the
                                 * minimum match length would be underrun, in
                                 * which case we are done.  */
                                /* lenL >= lenR:  Extend left, unless the
                                 * minimum match length would be underrun, in
                                 * which case we are done.  */


@@ -494,6 +491,10 @@ extend_right:
 
                                goto extend_left;
                        }
 
                                goto extend_left;
                        }

+                       /* lenR > lenL:  Keep extending right.
+                        * (No check for whether the minimum match length has
+                        * been underrun is needed, provided that such lengths
+                        * are marked as 0.)  */

                }
        }
 }
                }
        }
 }