From d214d8c859051ea5d760006bc3e4e239359d8655 Mon Sep 17 00:00:00 2001
From: "W. Felix Handte" <w@felixhandte.com>
Date: Wed, 2 Sep 2020 13:27:11 -0400
Subject: [PATCH] Shorten Dict Mode Conditionals in Order to Improve
 Readability

---
 lib/compress/zstd_lazy.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c
index 33acf687e..5ce805326 100644
--- a/lib/compress/zstd_lazy.c
+++ b/lib/compress/zstd_lazy.c
@@ -785,16 +785,18 @@ ZSTD_compressBlock_lazy_generic(
     searchMax_f const searchMax = searchFuncs[dictMode][searchMethod == search_binaryTree];
     U32 offset_1 = rep[0], offset_2 = rep[1], savedOffset=0;
 
+    const int isDMS = dictMode == ZSTD_dictMatchState;
+    const int isDDS = dictMode == ZSTD_dedicatedDictSearch;
     const ZSTD_matchState_t* const dms = ms->dictMatchState;
-    const U32 dictLowestIndex      = dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch ?
+    const U32 dictLowestIndex      = isDMS || isDDS ?
                                      dms->window.dictLimit : 0;
-    const BYTE* const dictBase     = dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch ?
+    const BYTE* const dictBase     = isDMS || isDDS ?
                                      dms->window.base : NULL;
-    const BYTE* const dictLowest   = dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch ?
+    const BYTE* const dictLowest   = isDMS || isDDS ?
                                      dictBase + dictLowestIndex : NULL;
-    const BYTE* const dictEnd      = dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch ?
+    const BYTE* const dictEnd      = isDMS || isDDS ?
                                      dms->window.nextSrc : NULL;
-    const U32 dictIndexDelta       = dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch ?
+    const U32 dictIndexDelta       = isDMS || isDDS ?
                                      prefixLowestIndex - (U32)(dictEnd - dictBase) :
                                      0;
     const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest));
@@ -812,7 +814,7 @@ ZSTD_compressBlock_lazy_generic(
         if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
         if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
     }
-    if (dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch) {
+    if (isDMS || isDDS) {
         /* dictMatchState repCode checks don't currently handle repCode == 0
          * disabling. */
         assert(offset_1 <= dictAndPrefixLength);
@@ -832,7 +834,7 @@ ZSTD_compressBlock_lazy_generic(
         const BYTE* start=ip+1;
 
         /* check repCode */
-        if (dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch) {
+        if (isDMS || isDDS) {
             const U32 repIndex = (U32)(ip - base) + 1 - offset_1;
             const BYTE* repMatch = ((dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch)
                                 && repIndex < prefixLowestIndex) ?
@@ -875,7 +877,7 @@ ZSTD_compressBlock_lazy_generic(
                 if ((mlRep >= 4) && (gain2 > gain1))
                     matchLength = mlRep, offset = 0, start = ip;
             }
-            if (dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch) {
+            if (isDMS || isDDS) {
                 const U32 repIndex = (U32)(ip - base) - offset_1;
                 const BYTE* repMatch = repIndex < prefixLowestIndex ?
                                dictBase + (repIndex - dictIndexDelta) :
@@ -910,7 +912,7 @@ ZSTD_compressBlock_lazy_generic(
                     if ((mlRep >= 4) && (gain2 > gain1))
                         matchLength = mlRep, offset = 0, start = ip;
                 }
-                if (dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch) {
+                if (isDMS || isDDS) {
                     const U32 repIndex = (U32)(ip - base) - offset_1;
                     const BYTE* repMatch = repIndex < prefixLowestIndex ?
                                    dictBase + (repIndex - dictIndexDelta) :
@@ -948,7 +950,7 @@ ZSTD_compressBlock_lazy_generic(
                      && (start[-1] == (start-(offset-ZSTD_REP_MOVE))[-1]) )  /* only search for offset within prefix */
                     { start--; matchLength++; }
             }
-            if (dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch) {
+            if (isDMS || isDDS) {
                 U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE));
                 const BYTE* match = (matchIndex < prefixLowestIndex) ? dictBase + matchIndex - dictIndexDelta : base + matchIndex;
                 const BYTE* const mStart = (matchIndex < prefixLowestIndex) ? dictLowest : prefixLowest;
@@ -964,12 +966,11 @@ _storeSequence:
         }
 
         /* check immediate repcode */
-        if (dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch) {
+        if (isDMS || isDDS) {
             while (ip <= ilimit) {
                 U32 const current2 = (U32)(ip-base);
                 U32 const repIndex = current2 - offset_2;
-                const BYTE* repMatch = (dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch)
-                    && repIndex < prefixLowestIndex ?
+                const BYTE* repMatch = repIndex < prefixLowestIndex ?
                         dictBase - dictIndexDelta + repIndex :
                         base + repIndex;
                 if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex) >= 3 /* intentional overflow */)