From 320c306db37de99efabe426eab964efbca28a964 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers3@gmail.com>
Date: Sat, 1 Jan 2022 19:49:14 -0600
Subject: [PATCH] hc_matchfinder: make skip_positions() return void

---
 lib/deflate_compress.c | 48 ++++++++++++++++++++++--------------------
 lib/hc_matchfinder.h   |  8 ++-----
 2 files changed, 27 insertions(+), 29 deletions(-)

diff --git a/lib/deflate_compress.c b/lib/deflate_compress.c
index 808b77e..7dc7fac 100644
--- a/lib/deflate_compress.c
+++ b/lib/deflate_compress.c
@@ -2182,13 +2182,13 @@ deflate_compress_greedy(struct libdeflate_compressor * restrict c,
 				/* Match found. */
 				deflate_choose_match(c, length, offset, &seq);
 				observe_match(&c->split_stats, length);
-				in_next = hc_matchfinder_skip_positions(
-						&c->p.g.hc_mf,
-						&in_cur_base,
-						in_next + 1,
-						in_end,
-						length - 1,
-						next_hashes);
+				hc_matchfinder_skip_positions(&c->p.g.hc_mf,
+							      &in_cur_base,
+							      in_next + 1,
+							      in_end,
+							      length - 1,
+							      next_hashes);
+				in_next += length;
 			} else {
 				/* No match found. */
 				deflate_choose_literal(c, *in_next, seq);
@@ -2295,13 +2295,13 @@ deflate_compress_lazy_generic(struct libdeflate_compressor * restrict c,
 			if (cur_len >= nice_len) {
 				deflate_choose_match(c, cur_len, cur_offset,
 						     &seq);
-				in_next = hc_matchfinder_skip_positions(
-						&c->p.g.hc_mf,
-						&in_cur_base,
-						in_next,
-						in_end,
-						cur_len - 1,
-						next_hashes);
+				hc_matchfinder_skip_positions(&c->p.g.hc_mf,
+							      &in_cur_base,
+							      in_next,
+							      in_end,
+							      cur_len - 1,
+							      next_hashes);
+				in_next += cur_len - 1;
 				continue;
 			}
 
@@ -2384,14 +2384,16 @@ deflate_compress_lazy_generic(struct libdeflate_compressor * restrict c,
 				 */
 				deflate_choose_match(c, cur_len, cur_offset,
 						     &seq);
-				if (cur_len > 3)
-					in_next = hc_matchfinder_skip_positions(
+				if (cur_len > 3) {
+					hc_matchfinder_skip_positions(
 							&c->p.g.hc_mf,
 							&in_cur_base,
 							in_next,
 							in_end,
 							cur_len - 3,
 							next_hashes);
+					in_next += cur_len - 3;
+				}
 			} else { /* !lazy2 */
 				/*
 				 * No better match at the next position.  Output
@@ -2399,13 +2401,13 @@ deflate_compress_lazy_generic(struct libdeflate_compressor * restrict c,
 				 */
 				deflate_choose_match(c, cur_len, cur_offset,
 						     &seq);
-				in_next = hc_matchfinder_skip_positions(
-							&c->p.g.hc_mf,
-							&in_cur_base,
-							in_next,
-							in_end,
-							cur_len - 2,
-							next_hashes);
+				hc_matchfinder_skip_positions(&c->p.g.hc_mf,
+							      &in_cur_base,
+							      in_next,
+							      in_end,
+							      cur_len - 2,
+							      next_hashes);
+				in_next += cur_len - 2;
 			}
 			/* Check if it's time to output another block. */
 		} while (in_next < in_max_block_end &&
diff --git a/lib/hc_matchfinder.h b/lib/hc_matchfinder.h
index 23daead..9f1f799 100644
--- a/lib/hc_matchfinder.h
+++ b/lib/hc_matchfinder.h
@@ -357,10 +357,8 @@ out:
  *	The precomputed hash codes for the sequence beginning at @in_next.
  *	These will be used and then updated with the precomputed hashcodes for
  *	the sequence beginning at @in_next + @count.
- *
- * Returns @in_next + @count.
  */
-static forceinline const u8 *
+static forceinline void
 hc_matchfinder_skip_positions(struct hc_matchfinder * const restrict mf,
 			      const u8 ** const restrict in_base_p,
 			      const u8 *in_next,
@@ -374,7 +372,7 @@ hc_matchfinder_skip_positions(struct hc_matchfinder * const restrict mf,
 	u32 remaining = count;
 
 	if (unlikely(count + 5 > in_end - in_next))
-		return &in_next[count];
+		return;
 
 	cur_pos = in_next - *in_base_p;
 	hash3 = next_hashes[0];
@@ -399,8 +397,6 @@ hc_matchfinder_skip_positions(struct hc_matchfinder * const restrict mf,
 	prefetchw(&mf->hash4_tab[hash4]);
 	next_hashes[0] = hash3;
 	next_hashes[1] = hash4;
-
-	return in_next;
 }
 
 #endif /* LIB_HC_MATCHFINDER_H */