Limit hash table inserts after switch from stored deflate.

rlidwka · rlidwka · commit b57943467960 · 2022-06-10T20:10:56.000+03:00
madler/zlib@2d80d3f
diff --git a/lib/zlib/deflate.js b/lib/zlib/deflate.js
@@ -380,6 +380,9 @@ const fill_window = (s) => {
       s.strstart -= _w_size;
       /* we now have strstart >= MAX_DIST */
       s.block_start -= _w_size;
+      if (s.insert > s.strstart) {
+        s.insert = s.strstart;
+      }
       slide_hash(s);
       more += _w_size;
     }
@@ -591,6 +594,7 @@ const deflate_stored = (s, flush) => {
       //zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
       s.window.set(s.strm.input.subarray(s.strm.next_in - s.w_size, s.strm.next_in), 0);
       s.strstart = s.w_size;
+      s.insert = s.strstart;
     }
     else {
       if (s.window_size - s.strstart <= used) {
@@ -601,13 +605,16 @@ const deflate_stored = (s, flush) => {
         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.window.set(s.strm.input.subarray(s.strm.next_in - used, s.strm.next_in), s.strstart);
       s.strstart += used;
+      s.insert += used > s.w_size - s.insert ? s.w_size - s.insert : used;
     }
     s.block_start = s.strstart;
-    s.insert += used > s.w_size - s.insert ? s.w_size - s.insert : used;
   }
   if (s.high_water < s.strstart) {
     s.high_water = s.strstart;
@@ -636,13 +643,17 @@ const deflate_stored = (s, flush) => {
       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 += have > s.w_size - s.insert ? s.w_size - s.insert : have;
   }
   if (s.high_water < s.strstart) {
     s.high_water = s.strstart;

Original file line number	Diff line number	Diff line change
`@@ -380,6 +380,9 @@ const fill_window = (s) => {`
`380`	`380`	`s.strstart -= _w_size;`
`381`	`381`	`/* we now have strstart >= MAX_DIST */`
`382`	`382`	`s.block_start -= _w_size;`
	`383`	`+ if (s.insert > s.strstart) {`
	`384`	`+ s.insert = s.strstart;`
	`385`	`+ }`
`383`	`386`	`slide_hash(s);`
`384`	`387`	`more += _w_size;`
`385`	`388`	`}`
`@@ -591,6 +594,7 @@ const deflate_stored = (s, flush) => {`
`591`	`594`	`//zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);`
`592`	`595`	`s.window.set(s.strm.input.subarray(s.strm.next_in - s.w_size, s.strm.next_in), 0);`
`593`	`596`	`s.strstart = s.w_size;`
	`597`	`+ s.insert = s.strstart;`
`594`	`598`	`}`
`595`	`599`	`else {`
`596`	`600`	`if (s.window_size - s.strstart <= used) {`
`@@ -601,13 +605,16 @@ const deflate_stored = (s, flush) => {`
`601`	`605`	`if (s.matches < 2) {`
`602`	`606`	`s.matches++; /* add a pending slide_hash() */`
`603`	`607`	`}`
	`608`	`+ if (s.insert > s.strstart) {`
	`609`	`+ s.insert = s.strstart;`
	`610`	`+ }`
`604`	`611`	`}`
`605`	`612`	`//zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);`
`606`	`613`	`s.window.set(s.strm.input.subarray(s.strm.next_in - used, s.strm.next_in), s.strstart);`
`607`	`614`	`s.strstart += used;`
	`615`	`+ s.insert += used > s.w_size - s.insert ? s.w_size - s.insert : used;`
`608`	`616`	`}`
`609`	`617`	`s.block_start = s.strstart;`
`610`		`- s.insert += used > s.w_size - s.insert ? s.w_size - s.insert : used;`
`611`	`618`	`}`
`612`	`619`	`if (s.high_water < s.strstart) {`
`613`	`620`	`s.high_water = s.strstart;`
`@@ -636,13 +643,17 @@ const deflate_stored = (s, flush) => {`
`636`	`643`	`s.matches++; /* add a pending slide_hash() */`
`637`	`644`	`}`
`638`	`645`	`have += s.w_size; /* more space now */`
	`646`	`+ if (s.insert > s.strstart) {`
	`647`	`+ s.insert = s.strstart;`
	`648`	`+ }`
`639`	`649`	`}`
`640`	`650`	`if (have > s.strm.avail_in) {`
`641`	`651`	`have = s.strm.avail_in;`
`642`	`652`	`}`
`643`	`653`	`if (have) {`
`644`	`654`	`read_buf(s.strm, s.window, s.strstart, have);`
`645`	`655`	`s.strstart += have;`
	`656`	`+ s.insert += have > s.w_size - s.insert ? s.w_size - s.insert : have;`
`646`	`657`	`}`
`647`	`658`	`if (s.high_water < s.strstart) {`
`648`	`659`	`s.high_water = s.strstart;`