remove codes table variable & add switching between fixed and dynamic tables for inflate, issue #22

lib/zlib/inflate.js

@@ -85,7 +85,7 @@ var    SYNC = 32;      /* looking for synchronization bytes to restart inflate()
 
 var ENOUGH_LENS = 852;
 var ENOUGH_DISTS = 592;
-var ENOUGH =  (ENOUGH_LENS+ENOUGH_DISTS);
+//var ENOUGH =  (ENOUGH_LENS+ENOUGH_DISTS);
 
 var MAX_WBITS = 15;
 /* 32K LZ77 window */
@@ -143,12 +143,16 @@ function InflateState() {
   this.have = 0;              /* number of code lengths in lens[] */
   this.next = null;              /* next available space in codes[] */
 
-  //unsigned short array
-  //todo: test later with Uint16Array
   this.lens = new utils.Buf16(320); /* temporary storage for code lengths */
   this.work = new utils.Buf16(288); /* work area for code table building */
 
-  this.codes = new utils.Buf32(ENOUGH);       /* space for code tables */
+  /*
+   because we don't have pointers in js, we use lencode and distcode directly
+   as buffers so we don't need codes
+  */
+  //this.codes = new utils.Buf32(ENOUGH);       /* space for code tables */
+  this.lendyn = null;              /* dynamic table for length/literal codes (JS specific) */
+  this.distdyn = null;             /* dynamic table for distance codes (JS specific) */
   this.sane = 0;                   /* if false, allow invalid distance too far */
   this.back = 0;                   /* bits back of last unprocessed length/lit */
   this.was = 0;                    /* initial length of match */
@@ -172,8 +176,8 @@ function inflateResetKeep(strm) {
   state.hold = 0;
   state.bits = 0;
   //state.lencode = state.distcode = state.next = state.codes;
-  state.lencode = new utils.Buf32(ENOUGH);
-  state.distcode = new utils.Buf32(ENOUGH);
+  state.lencode = state.lendyn = new utils.Buf32(ENOUGH_LENS);
+  state.distcode = state.distdyn = new utils.Buf32(ENOUGH_DISTS);
 
   state.sane = 1;
   state.back = -1;
@@ -907,7 +911,8 @@ function inflate(strm, flush) {
       // We have separate tables & no pointers. 2 commented lines below not needed.
       //state.next = state.codes;
       //state.lencode = state.next;
-      utils.arraySet(state.lencode, state.codes, 0, state.codes.length, 0);
+      // Switch to use dynamic table
+      state.lencode = state.lendyn;
       state.lenbits = 7;
 
       opts = {bits: state.lenbits};
@@ -1039,8 +1044,6 @@ function inflate(strm, flush) {
       /* build code tables -- note: do not change the lenbits or distbits
          values here (9 and 6) without reading the comments in inftrees.h
          concerning the ENOUGH constants, which depend on those values */
-      //state.lencode.copy(state.codes);
-      utils.arraySet(state.lencode, state.codes, 0, state.codes.length, 0);
       state.lenbits = 9;
 
       opts = {bits: state.lenbits};
@@ -1058,7 +1061,8 @@ function inflate(strm, flush) {
 
       state.distbits = 6;
       //state.distcode.copy(state.codes);
-      utils.arraySet(state.distcode, state.codes, 0, state.codes.length, 0);
+      // Switch to use dynamic table
+      state.distcode = state.distdyn;
       opts = {bits: state.distbits};
       ret = inflate_table(DISTS, state.lens, state.nlen, state.ndist, state.distcode, 0, state.work, opts);
       // We have separate tables & no pointers. 2 commented lines below not needed.

test/inflate.js

@@ -24,7 +24,7 @@ describe('Inflate defaults', function () {
     testInflate(samples, { raw: true }, { raw: true }, done);
   });
 
-  it.skip('inflate raw from compressed samples', function(done) {
+  it('inflate raw from compressed samples', function(done) {
     var compressed_samples = helpers.loadSamples('samples_deflated_raw');
     helpers.testSamples(zlib.createInflateRaw, pako.inflateRaw, compressed_samples, {}, done);
   });