From c86d38ba63d25498360a8eae759a90399f1ce4b9 Mon Sep 17 00:00:00 2001
From: emmanuel-marty <brothers@puzzlebrothers.com>
Date: Fri, 5 Apr 2019 09:28:16 +0200
Subject: [PATCH] Reduce the number of literals required at the end of a
 compressed block

---
 src/expand.c |  6 +++---
 src/shrink.c | 10 ++++++----
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/expand.c b/src/expand.c
index 8ad316c..6f0121c 100755
--- a/src/expand.c
+++ b/src/expand.c
@@ -115,8 +115,8 @@ static inline FORCE_INLINE int lzsa_expand_match_slow(const unsigned char **ppIn
       int nMaxFast = nMatchLen;
       if (nMaxFast > (pCurOutData - pSrc))
          nMaxFast = (int)(pCurOutData - pSrc);
-      if ((pCurOutData + nMaxFast) > pOutDataFastEnd)
-         nMaxFast = (int)(pOutDataFastEnd - pCurOutData);
+      if ((pCurOutData + nMaxFast) > (pOutDataFastEnd - 15))
+         nMaxFast = (int)(pOutDataFastEnd - 15 - pCurOutData);
 
       if (nMaxFast > 0) {
          const unsigned char *pCopySrc = pSrc;
@@ -202,7 +202,7 @@ int lzsa_expand_block(const unsigned char *pInBlock, int nBlockSize, unsigned ch
             return -1;
 
          int nMatchLen = (int)((unsigned int)(token & 0x0f));
-         if (nMatchLen < (16 - MIN_MATCH_SIZE + 1) && (pSrc + MIN_MATCH_SIZE + nMatchLen) < pCurOutData) {
+         if (nMatchLen < (16 - MIN_MATCH_SIZE + 1) && (pSrc + MIN_MATCH_SIZE + nMatchLen) < pCurOutData && pCurOutData < pOutDataFastEnd) {
             memcpy(pCurOutData, pSrc, 16);
             pCurOutData += (MIN_MATCH_SIZE + nMatchLen);
          }
diff --git a/src/shrink.c b/src/shrink.c
index 1659813..364a41f 100755
--- a/src/shrink.c
+++ b/src/shrink.c
@@ -44,6 +44,9 @@
 
 #define LEAVE_ALONE_MATCH_SIZE 1000
 
+#define LAST_MATCH_OFFSET 4
+#define LAST_LITERALS 1
+
 /** One match */
 typedef struct _lzsa_match {
    unsigned short length;
@@ -357,12 +360,12 @@ static void lzsa_find_all_matches(lsza_compressor *pCompressor, const int nStart
       int m;
 
       for (m = 0; m < NMATCHES_PER_OFFSET; m++) {
-         if (nMatches <= m || i >= (nEndOffset - 11)) {
+         if (nMatches <= m || i > (nEndOffset - LAST_MATCH_OFFSET)) {
             pMatch->length = 0;
             pMatch->offset = 0;
          }
          else {
-            int nMaxLen = (nEndOffset - 5) - i;
+            int nMaxLen = (nEndOffset - LAST_LITERALS) - i;
             if (nMaxLen < 0)
                nMaxLen = 0;
             if (pMatch->length > nMaxLen)
@@ -371,7 +374,6 @@ static void lzsa_find_all_matches(lsza_compressor *pCompressor, const int nStart
 
          pMatch++;
       }
-
    }
 }
 
@@ -619,7 +621,7 @@ static int lzsa_write_block(lsza_compressor *pCompressor, const unsigned char *p
       }
    }
 
-   if (nNumLiterals != 0) {
+   {
       int nNibbleLiteralsLen = (nNumLiterals >= LITERALS_RUN_LEN) ? LITERALS_RUN_LEN : nNumLiterals;
       int nTokenSize = 1 /* nibble */ + lzsa_get_literals_varlen_size(nNumLiterals) + nNumLiterals;