From 024d11ee5fae1b75637bf33f2785d646ad3235c3 Mon Sep 17 00:00:00 2001
From: Alex Kocharin <alex@kocharin.ru>
Date: Wed, 8 Jun 2022 18:51:39 +0300
Subject: [PATCH] Add option to not compute or check check values.

https://github.com/madler/zlib/commit/9852c209ac49c0d8d1192e46115d7c37d4344bbd

+ added macro renaming in
https://github.com/madler/zlib/commit/53ce2713117ef2a8ed682d77b944df991c499252
---
 lib/zlib/inflate.js | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/lib/zlib/inflate.js b/lib/zlib/inflate.js
index b30262e..1989231 100644
--- a/lib/zlib/inflate.js
+++ b/lib/zlib/inflate.js
@@ -100,7 +100,8 @@ const zswap32 = (q) => {
 function InflateState() {
   this.mode = 0;             /* current inflate mode */
   this.last = false;          /* true if processing last block */
-  this.wrap = 0;              /* bit 0 true for zlib, bit 1 true for gzip */
+  this.wrap = 0;              /* bit 0 true for zlib, bit 1 true for gzip,
+                                 bit 2 true to validate check value */
   this.havedict = false;      /* true if dictionary provided */
   this.flags = 0;             /* gzip header method and flags (0 if zlib) */
   this.dmax = 0;              /* zlib header max distance (INFLATE_STRICT) */
@@ -208,7 +209,7 @@ const inflateReset2 = (strm, windowBits) => {
     windowBits = -windowBits;
   }
   else {
-    wrap = (windowBits >> 4) + 1;
+    wrap = (windowBits >> 4) + 5;
     if (windowBits < 48) {
       windowBits &= 15;
     }
@@ -511,7 +512,7 @@ const inflate = (strm, flush) => {
         if (state.head) {
           state.head.text = ((hold >> 8) & 1);
         }
-        if (state.flags & 0x0200) {
+        if ((state.flags & 0x0200) && (state.wrap & 4)) {
           //=== CRC2(state.check, hold);
           hbuf[0] = hold & 0xff;
           hbuf[1] = (hold >>> 8) & 0xff;
@@ -536,7 +537,7 @@ const inflate = (strm, flush) => {
         if (state.head) {
           state.head.time = hold;
         }
-        if (state.flags & 0x0200) {
+        if ((state.flags & 0x0200) && (state.wrap & 4)) {
           //=== CRC4(state.check, hold)
           hbuf[0] = hold & 0xff;
           hbuf[1] = (hold >>> 8) & 0xff;
@@ -564,7 +565,7 @@ const inflate = (strm, flush) => {
           state.head.xflags = (hold & 0xff);
           state.head.os = (hold >> 8);
         }
-        if (state.flags & 0x0200) {
+        if ((state.flags & 0x0200) && (state.wrap & 4)) {
           //=== CRC2(state.check, hold);
           hbuf[0] = hold & 0xff;
           hbuf[1] = (hold >>> 8) & 0xff;
@@ -591,7 +592,7 @@ const inflate = (strm, flush) => {
           if (state.head) {
             state.head.extra_len = hold;
           }
-          if (state.flags & 0x0200) {
+          if ((state.flags & 0x0200) && (state.wrap & 4)) {
             //=== CRC2(state.check, hold);
             hbuf[0] = hold & 0xff;
             hbuf[1] = (hold >>> 8) & 0xff;
@@ -633,7 +634,7 @@ const inflate = (strm, flush) => {
               //        len + copy > state.head.extra_max ?
               //        state.head.extra_max - len : copy);
             }
-            if (state.flags & 0x0200) {
+            if ((state.flags & 0x0200) && (state.wrap & 4)) {
               state.check = crc32(state.check, input, copy, next);
             }
             have -= copy;
@@ -659,7 +660,7 @@ const inflate = (strm, flush) => {
             }
           } while (len && copy < have);
 
-          if (state.flags & 0x0200) {
+          if ((state.flags & 0x0200) && (state.wrap & 4)) {
             state.check = crc32(state.check, input, copy, next);
           }
           have -= copy;
@@ -684,7 +685,7 @@ const inflate = (strm, flush) => {
               state.head.comment += String.fromCharCode(len);
             }
           } while (len && copy < have);
-          if (state.flags & 0x0200) {
+          if ((state.flags & 0x0200) && (state.wrap & 4)) {
             state.check = crc32(state.check, input, copy, next);
           }
           have -= copy;
@@ -706,7 +707,7 @@ const inflate = (strm, flush) => {
             bits += 8;
           }
           //===//
-          if (hold !== (state.check & 0xffff)) {
+          if ((state.wrap & 4) && hold !== (state.check & 0xffff)) {
             strm.msg = 'header crc mismatch';
             state.mode = BAD;
             break;
@@ -1359,15 +1360,15 @@ const inflate = (strm, flush) => {
           _out -= left;
           strm.total_out += _out;
           state.total += _out;
-          if (_out) {
+          if ((state.wrap & 4) && _out) {
             strm.adler = state.check =
-                /*UPDATE(state.check, put - _out, _out);*/
+                /*UPDATE_CHECK(state.check, put - _out, _out);*/
                 (state.flags ? crc32(state.check, output, _out, put - _out) : adler32(state.check, output, _out, put - _out));
 
           }
           _out = left;
           // NB: crc32 stored as signed 32-bit int, zswap32 returns signed too
-          if ((state.flags ? hold : zswap32(hold)) !== state.check) {
+          if ((state.wrap & 4) && (state.flags ? hold : zswap32(hold)) !== state.check) {
             strm.msg = 'incorrect data check';
             state.mode = BAD;
             break;
@@ -1448,8 +1449,8 @@ const inflate = (strm, flush) => {
   strm.total_in += _in;
   strm.total_out += _out;
   state.total += _out;
-  if (state.wrap && _out) {
-    strm.adler = state.check = /*UPDATE(state.check, strm.next_out - _out, _out);*/
+  if ((state.wrap & 4) && _out) {
+    strm.adler = state.check = /*UPDATE_CHECK(state.check, strm.next_out - _out, _out);*/
       (state.flags ? crc32(state.check, output, _out, strm.next_out - _out) : adler32(state.check, output, _out, strm.next_out - _out));
   }
   strm.data_type = state.bits + (state.last ? 64 : 0) +
@@ -1548,4 +1549,5 @@ module.exports.inflatePrime = inflatePrime;
 module.exports.inflateSync = inflateSync;
 module.exports.inflateSyncPoint = inflateSyncPoint;
 module.exports.inflateUndermine = inflateUndermine;
+module.exports.inflateValidate = inflateValidate;
 */