From: Yann Collet <yann.collet.73@gmail.com>
Date: Mon, 16 Dec 2024 00:14:38 +0000 (-0800)
Subject: minor optimization for ZSTD_compressSequencesAndLiterals()
X-Git-Tag: v1.5.7^2~48^2~29
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1c8f5b0f11c9fbcd47135a658dca9b927a0b27b7;p=thirdparty%2Fzstd.git

minor optimization for ZSTD_compressSequencesAndLiterals()

does not need to track and update internal `litPtr`.
note: does not measurably impact performance.
---

diff --git a/lib/compress/zstd_compress_internal.h b/lib/compress/zstd_compress_internal.h
index 294835946..10bd8ca70 100644
--- a/lib/compress/zstd_compress_internal.h
+++ b/lib/compress/zstd_compress_internal.h
@@ -742,13 +742,10 @@ ZSTD_storeSeqOnly(SeqStore_t* seqStorePtr,
               size_t matchLength)
 {
     assert((size_t)(seqStorePtr->sequences - seqStorePtr->sequencesStart) < seqStorePtr->maxNbSeq);
-    /* update seqStorePtr->lit, so that we know how many literals were or will be copied */
-    assert(seqStorePtr->maxNbLit <= 128 KB);
-    assert(seqStorePtr->lit + litLength <= seqStorePtr->litStart + seqStorePtr->maxNbLit);
-    seqStorePtr->lit += litLength;
 
     /* literal Length */
-    if (litLength>0xFFFF) {
+    assert(litLength <= ZSTD_BLOCKSIZE_MAX);
+    if (UNLIKELY(litLength>0xFFFF)) {
         assert(seqStorePtr->longLengthType == ZSTD_llt_none); /* there can only be a single long length */
         seqStorePtr->longLengthType = ZSTD_llt_literalLength;
         seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
@@ -759,9 +756,10 @@ ZSTD_storeSeqOnly(SeqStore_t* seqStorePtr,
     seqStorePtr->sequences[0].offBase = offBase;
 
     /* match Length */
+    assert(matchLength <= ZSTD_BLOCKSIZE_MAX);
     assert(matchLength >= MINMATCH);
     {   size_t const mlBase = matchLength - MINMATCH;
-        if (mlBase>0xFFFF) {
+        if (UNLIKELY(mlBase>0xFFFF)) {
             assert(seqStorePtr->longLengthType == ZSTD_llt_none); /* there can only be a single long length */
             seqStorePtr->longLengthType = ZSTD_llt_matchLength;
             seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
@@ -811,6 +809,7 @@ ZSTD_storeSeq(SeqStore_t* seqStorePtr,
     } else {
         ZSTD_safecopyLiterals(seqStorePtr->lit, literals, litEnd, litLimit_w);
     }
+    seqStorePtr->lit += litLength;
 
     ZSTD_storeSeqOnly(seqStorePtr, litLength, offBase, matchLength);
 }