[opt] Don't recompute repcodes while emitting sequences
diff --git a/lib/compress/zstd_opt.c b/lib/compress/zstd_opt.c
index 3caa4a1..fe44eba 100644
--- a/lib/compress/zstd_opt.c
+++ b/lib/compress/zstd_opt.c
@@ -1017,6 +1017,17 @@
_shortestPath: /* cur, last_pos, best_mlen, best_off have to be set */
assert(opt[0].mlen == 0);
+ /* Set the next chunk's repcodes based on the repcodes of the beginning
+ * of the last match, and the last sequence. This avoids us having to
+ * update them while traversing the sequences.
+ */
+ if (lastSequence.mlen != 0) {
+ repcodes_t reps = ZSTD_updateRep(opt[cur].rep, lastSequence.off, lastSequence.litlen==0);
+ memcpy(rep, &reps, sizeof(reps));
+ } else {
+ memcpy(rep, opt[cur].rep, sizeof(repcodes_t));
+ }
+
{ U32 const storeEnd = cur + 1;
U32 storeStart = storeEnd;
U32 seqPos = cur;
@@ -1053,20 +1064,6 @@
continue; /* will finish */
}
- /* repcodes update : like ZSTD_updateRep(), but update in place */
- if (offCode >= ZSTD_REP_NUM) { /* full offset */
- rep[2] = rep[1];
- rep[1] = rep[0];
- rep[0] = offCode - ZSTD_REP_MOVE;
- } else { /* repcode */
- U32 const repCode = offCode + (llen==0);
- if (repCode) { /* note : if repCode==0, no change */
- U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
- if (repCode >= 2) rep[2] = rep[1];
- rep[1] = rep[0];
- rep[0] = currentOffset;
- } }
-
assert(anchor + llen <= iend);
ZSTD_updateStats(optStatePtr, llen, anchor, offCode, mlen);
ZSTD_storeSeq(seqStore, llen, anchor, iend, offCode, mlen-MINMATCH);
@@ -1075,7 +1072,6 @@
} }
ZSTD_setBasePrices(optStatePtr, optLevel);
}
-
} /* while (ip < ilimit) */
/* Return the last literals size */
