From 2d80d3f6b52f9fa454c26c89d2d6a1790e1cecb0 Mon Sep 17 00:00:00 2001
From: Mark Adler <madler@alumni.caltech.edu>
Date: Sat, 21 Jan 2017 01:50:26 -0800
Subject: [PATCH] Limit hash table inserts after switch from stored deflate.

This limits hash table inserts to the available data in the window
and to the sliding window size in deflate_stored(). The hash table
inserts are deferred until deflateParams() switches to a non-zero
compression level.
---
 deflate.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/deflate.c b/deflate.c
index 20bda4f..d368b25 100644
--- a/deflate.c
+++ b/deflate.c
@@ -1513,6 +1513,8 @@ local void fill_window(s)
             s->match_start -= wsize;
             s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
             s->block_start -= (long) wsize;
+            if (s->insert > s->strstart)
+                s->insert = s->strstart;
             slide_hash(s);
             more += wsize;
         }
@@ -1742,6 +1744,7 @@ local block_state deflate_stored(s, flush)
             s->matches = 2;         /* clear hash */
             zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
             s->strstart = s->w_size;
+            s->insert = s->strstart;
         }
         else {
             if (s->window_size - s->strstart <= used) {
@@ -1750,12 +1753,14 @@ local block_state deflate_stored(s, flush)
                 zmemcpy(s->window, s->window + s->w_size, s->strstart);
                 if (s->matches < 2)
                     s->matches++;   /* add a pending slide_hash() */
+                if (s->insert > s->strstart)
+                    s->insert = s->strstart;
             }
             zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
             s->strstart += used;
+            s->insert += MIN(used, s->w_size - s->insert);
         }
         s->block_start = s->strstart;
-        s->insert += MIN(used, s->w_size - s->insert);
     }
     if (s->high_water < s->strstart)
         s->high_water = s->strstart;
@@ -1779,12 +1784,15 @@ local block_state deflate_stored(s, flush)
         if (s->matches < 2)
             s->matches++;           /* add a pending slide_hash() */
         have += s->w_size;          /* more space now */
+        if (s->insert > s->strstart)
+            s->insert = s->strstart;
     }
     if (have > s->strm->avail_in)
         have = s->strm->avail_in;
     if (have) {
         read_buf(s->strm, s->window + s->strstart, have);
         s->strstart += have;
+        s->insert += MIN(have, s->w_size - s->insert);
     }
     if (s->high_water < s->strstart)
         s->high_water = s->strstart;