From: W. Felix Handte <w@felixhandte.com>
Date: Fri, 28 Aug 2020 16:38:50 +0000 (-0400)
Subject: Adjust Working Context Table Sizes Back Down
X-Git-Tag: v1.4.7~81^2~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7b5d2f72ea1762660ddab2d8215aa25414e5facc;p=thirdparty%2Fzstd.git

Adjust Working Context Table Sizes Back Down
---

diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index 3c1e54b30..bec9afd79 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -872,6 +872,8 @@ static int ZSTD_dedicatedDictSearch_isSupported(
         int const compressionLevel,
         unsigned long long srcSizeHint,
         size_t const dictSize);
+static void ZSTD_dedicatedDictSearch_revertCParams(
+        ZSTD_compressionParameters* cParams);
 
 /**
  * Initializes the local dict using the requested parameters.
@@ -1661,17 +1663,23 @@ ZSTD_resetCCtx_byAttachingCDict(ZSTD_CCtx* cctx,
                         U64 pledgedSrcSize,
                         ZSTD_buffered_policy_e zbuff)
 {
-    {   const ZSTD_compressionParameters* const cdict_cParams = &cdict->matchState.cParams;
+    {
+        ZSTD_compressionParameters adjusted_cdict_cParams = cdict->matchState.cParams;
         unsigned const windowLog = params.cParams.windowLog;
         assert(windowLog != 0);
         /* Resize working context table params for input only, since the dict
          * has its own tables. */
         /* pledgedSrcSize == 0 means 0! */
-        params.cParams = ZSTD_adjustCParams_internal(*cdict_cParams, pledgedSrcSize, 0);
+
+        if (cdict->matchState.dedicatedDictSearch) {
+            ZSTD_dedicatedDictSearch_revertCParams(&adjusted_cdict_cParams);
+        }
+
+        params.cParams = ZSTD_adjustCParams_internal(adjusted_cdict_cParams, pledgedSrcSize, 0);
         params.cParams.windowLog = windowLog;
         FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
                                                  ZSTDcrp_makeClean, zbuff), "");
-        assert(cctx->appliedParams.cParams.strategy == cdict_cParams->strategy);
+        assert(cctx->appliedParams.cParams.strategy == adjusted_cdict_cParams.strategy);
     }
 
     {   const U32 cdictEnd = (U32)( cdict->matchState.window.nextSrc
@@ -4353,6 +4361,30 @@ static int ZSTD_dedicatedDictSearch_isSupported(int const compressionLevel, unsi
     return (cParams.strategy >= ZSTD_greedy) && (cParams.strategy <= ZSTD_lazy2);
 }
 
+/**
+ * Reverses the adjustment applied to cparams when enabling dedicated dict
+ * search. This is used to recover the params set to be used in the working
+ * context. (Otherwise, those tables would also grow.)
+ */
+static void ZSTD_dedicatedDictSearch_revertCParams(
+        ZSTD_compressionParameters* cParams) {
+    switch (cParams->strategy) {
+        case ZSTD_fast:
+        case ZSTD_dfast:
+            break;
+        case ZSTD_greedy:
+        case ZSTD_lazy:
+        case ZSTD_lazy2:
+            cParams->hashLog -= ZSTD_LAZY_DDSS_BUCKET_LOG;
+            break;
+        case ZSTD_btlazy2:
+        case ZSTD_btopt:
+        case ZSTD_btultra:
+        case ZSTD_btultra2:
+            break;
+    }
+}
+
 /*! ZSTD_getCParams_internal() :
  * @return ZSTD_compressionParameters structure for a selected compression level, srcSize and dictSize.
  *  Note: srcSizeHint 0 means 0, use ZSTD_CONTENTSIZE_UNKNOWN for unknown.