From: Yann Collet <cyan@fb.com>
Date: Fri, 12 Jul 2019 18:34:53 +0000 (-0700)
Subject: double-fast: changed the trade-off for a smaller positive change
X-Git-Tag: v1.4.1^2~4^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e8a7f5d3ce0ebb36e4ad850ab12463b1127dba17;p=thirdparty%2Fzstd.git

double-fast: changed the trade-off for a smaller positive change

same number of complementary insertions, just organized differently
(long at `ip-2`, short at `ip-1`).
---

diff --git a/.gitignore b/.gitignore
index 0c840b6b6..4c297053b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,7 +14,7 @@
 *.dylib
 
 # Executables
-zstd.
+/zstd
 zstdmt
 *.exe
 *.out
diff --git a/lib/compress/zstd_double_fast.c b/lib/compress/zstd_double_fast.c
index bdb26ef80..b65fd41e7 100644
--- a/lib/compress/zstd_double_fast.c
+++ b/lib/compress/zstd_double_fast.c
@@ -257,19 +257,10 @@ _match_stored:
             /* Complementary insertion */
             /* done after iLimit test, as candidates could be > iend-8 */
             {   U32 const indexToInsert = current+2;
-                hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] =
-                    hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] =
-                        indexToInsert;
-            }
-            {   const BYTE* const ipToInsert = ip - 2;
-                hashLong[ZSTD_hashPtr(ipToInsert, hBitsL, 8)] =
-                    hashSmall[ZSTD_hashPtr(ipToInsert, hBitsS, mls)] =
-                        (U32)(ipToInsert-base);
-            }
-            {   const BYTE* const ipToInsert = ip - 1;
-                hashLong[ZSTD_hashPtr(ipToInsert, hBitsL, 8)] =
-                    hashSmall[ZSTD_hashPtr(ipToInsert, hBitsS, mls)] =
-                        (U32)(ipToInsert-base);
+                hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
+                hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
+                hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
+                hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
             }
 
             /* check immediate repcode */