From: Nick Terrell <terrelln@fb.com>
Date: Mon, 12 Oct 2020 21:12:23 +0000 (-0700)
Subject: [lib] Compress directly into output when ZSTD_c_stableOutBuffer is set
X-Git-Tag: v1.4.7~38^2~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6d5dc93d4e34c8420e4fa2779b704ad4ce61df2c;p=thirdparty%2Fzstd.git

[lib] Compress directly into output when ZSTD_c_stableOutBuffer is set

When we have a stable output buffer always compress directly into the
`ZSTD_outBuffer`. We are allowed to return `dstSizeTooSmall`.
---

diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index acd150b9d..1c8fb2fc2 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -4104,7 +4104,7 @@ static size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
                 size_t const iSize = zcs->inBuffPos - zcs->inToCompress;
                 size_t oSize = oend-op;
                 unsigned const lastBlock = (flushMode == ZSTD_e_end) && (ip==iend);
-                if (oSize >= ZSTD_compressBound(iSize))
+                if (oSize >= ZSTD_compressBound(iSize) || zcs->appliedParams.outBufferMode == ZSTD_bm_stable)
                     cDst = op;   /* compress into output buffer, to skip flush stage */
                 else
                     cDst = zcs->outBuff, oSize = zcs->outBuffSize;
@@ -4140,6 +4140,7 @@ static size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
 	    /* fall-through */
         case zcss_flush:
             DEBUGLOG(5, "flush stage");
+            assert(zcs->appliedParams.outBufferMode == ZSTD_bm_buffered);
             {   size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
                 size_t const flushed = ZSTD_limitCopy(op, (size_t)(oend-op),
                             zcs->outBuff + zcs->outBuffFlushedSize, toFlush);