From 5ae34e4c96265f1face970f3458836b3edf2e76d Mon Sep 17 00:00:00 2001
From: Yann Collet <cyan@fb.com>
Date: Tue, 22 Oct 2024 15:19:06 -0700
Subject: [PATCH] ensure `lastBlock` is correctly determined

reported by @terrelln
---
 lib/compress/zstd_compress.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index e7a07a484..edb71ae50 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -4540,8 +4540,8 @@ static size_t ZSTD_compress_frameChunk(ZSTD_CCtx* cctx,
 
     while (remaining) {
         ZSTD_matchState_t* const ms = &cctx->blockState.matchState;
-        U32 const lastBlock = lastFrameChunk & (blockSizeMax >= remaining);
         size_t const blockSize = ZSTD_optimalBlockSize(cctx, ip, remaining, blockSizeMax, cctx->appliedParams.cParams.strategy, savings);
+        U32 const lastBlock = lastFrameChunk & (blockSize == remaining);
         assert(blockSize <= remaining);
 
         /* TODO: See 3090. We reduced MIN_CBLOCK_SIZE from 3 to 2 so to compensate we are adding
-- 
2.47.2