From: Yann Collet <cyan@fb.com>
Date: Fri, 11 May 2018 22:54:06 +0000 (-0700)
Subject: replaced FSE_count by FSE_count_simple
X-Git-Tag: v1.3.5~3^2~55^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F1127%2Fhead;p=thirdparty%2Fzstd.git

replaced FSE_count by FSE_count_simple

to reduce usage of stack memory.

Also : tweaked a few comments, as suggested by @terrelln
---

diff --git a/lib/compress/zstd_compress_internal.h b/lib/compress/zstd_compress_internal.h
index 25d3137a2..0f1830a5e 100644
--- a/lib/compress/zstd_compress_internal.h
+++ b/lib/compress/zstd_compress_internal.h
@@ -97,8 +97,8 @@ typedef struct {
     U32  log2matchLengthSum;     /* pow2 to compare log2(mlfreq) to */
     U32  log2offCodeSum;         /* pow2 to compare log2(offreq) to */
     /* end : updated by ZSTD_setLog2Prices */
-    ZSTD_OptPrice_e priceType;   /* prices follow a pre-defined cost structure, statistics are irrelevant */
-    const ZSTD_entropyCTables_t* symbolCosts;  /* pre-calculated symbol costs, from dictionary */
+    ZSTD_OptPrice_e priceType;   /* prices can be determined dynamically, or follow dictionary statistics, or a pre-defined cost structure */
+    const ZSTD_entropyCTables_t* symbolCosts;  /* pre-calculated dictionary statistics */
 } optState_t;
 
 typedef struct {
diff --git a/lib/compress/zstd_opt.c b/lib/compress/zstd_opt.c
index 29c4c9136..76144f730 100644
--- a/lib/compress/zstd_opt.c
+++ b/lib/compress/zstd_opt.c
@@ -97,9 +97,9 @@ static void ZSTD_rescaleFreqs(optState_t* const optPtr,
         } else {  /* not a dictionary */
 
             assert(optPtr->litFreq != NULL);
-            optPtr->litSum = 0;
             {   unsigned lit = MaxLit;
-                FSE_count(optPtr->litFreq, &lit, src, srcSize);   /* use raw first block to init statistics */
+                FSE_count_simple(optPtr->litFreq, &lit, src, srcSize);   /* use raw first block to init statistics */
+                optPtr->litSum = 0;
                 for (lit=0; lit<=MaxLit; lit++) {
                     optPtr->litFreq[lit] = 1 + (optPtr->litFreq[lit] >> (ZSTD_FREQ_DIV+1));
                     optPtr->litSum += optPtr->litFreq[lit];
@@ -244,7 +244,7 @@ static int ZSTD_litLengthContribution(U32 const litLength, const optState_t* con
     /* dynamic statistics */
     {   U32 const llCode = ZSTD_LLcode(litLength);
         int const contribution = (LL_bits[llCode]
-                        + ZSTD_highbit32(optPtr->litLengthFreq[0]+1)
+                        + ZSTD_highbit32(optPtr->litLengthFreq[0]+1) /* note: log2litLengthSum cancels out with following one */
                         - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1))
                         * BITCOST_MULTIPLIER;
 #if 1