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inftree now uses packed tables directly

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This commit is contained in:
Vitaly Puzrin 2014-03-13 02:12:37 +04:00
parent 35e1b51738
commit 8ce9f4fb3c
2 changed files with 32 additions and 41 deletions
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52
lib/zlib/inflate.js
View file

@ -106,14 +106,6 @@ function Code() {
this.val = 0; /* offset in table or code value */
}
Code.prototype.clone = function() {
var new_code = new Code();
new_code.op = this.op;
new_code.bits = this.bits;
new_code.val = this.val;
return new_code;
};
function CodeTable(length) {
// Packed data: [ bits, op, value], 1byte + 1byte +2 bytes
this.data = utils.array32Create(length);
@ -126,12 +118,8 @@ CodeTable.prototype.fill = function(idx, code) {
code.val = packed & 0xffff;
};
CodeTable.prototype.set = function(idx, code) {
this.data[idx] = (code.bits << 24) | (code.op << 16) | code.val;
};
CodeTable.prototype.copy = function(table) {
utils.arraySet(this.data,table.data,0,table.data.length,0);
utils.arraySet(this.data, table.data, 0, table.data.length, 0);
};
function InflateState() {
@ -188,8 +176,6 @@ function InflateState() {
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 */
this.here = new Code();
}
function InfTableOptions(type, lens, lens_index, codes, table, table_index, bits, work) {
@ -201,7 +187,6 @@ function InfTableOptions(type, lens, lens_index, codes, table, table_index, bits
this.table_index = table_index;
this.bits = bits;
this.work = work;
this.here = new Code();
}
function inflateResetKeep(strm) {
@ -442,7 +427,8 @@ function inflate(strm, flush) {
var from; /* where to copy match bytes from */
var from_source;
var here = new Code(); /* current decoding table entry */
var last; /* parent table entry */
//var last; /* parent table entry */
var last_bits, last_op, last_val; // paked "last" denormalized
var len; /* length to copy for repeats, bits to drop */
var ret; /* return code */
var hbuf = utils.arrayCreate(4); /* buffer for gzip header crc calculation */
@ -1165,11 +1151,13 @@ function inflate(strm, flush) {
//---//
}
if (here.op && (here.op & 0xf0) === 0) {
last = here.clone();
last_bits = here.bits;
last_op = here.op;
last_val = here.val;
for (;;) {
state.lencode.fill(last.val +
((hold & ((1 << (last.bits + last.op)) -1))/*BITS(last.bits + last.op)*/ >> last.bits), here);
if ((last.bits + here.bits) <= bits) { break; }
state.lencode.fill(last_val +
((hold & ((1 << (last_bits + last_op)) -1))/*BITS(last.bits + last.op)*/ >> last_bits), here);
if ((last_bits + here.bits) <= bits) { break; }
//--- PULLBYTE() ---//
if (have === 0) { break inf_leave; }
have--;
@ -1178,10 +1166,10 @@ function inflate(strm, flush) {
//---//
}
//--- DROPBITS(last.bits) ---//
hold >>>= last.bits;
bits -= last.bits;
hold >>>= last_bits;
bits -= last_bits;
//---//
state.back += last.bits;
state.back += last_bits;
}
//--- DROPBITS(here.bits) ---//
hold >>>= here.bits;
@ -1244,11 +1232,13 @@ function inflate(strm, flush) {
//---//
}
if ((here.op & 0xf0) === 0) {
last = here.clone();
last_bits = here.bits;
last_op = here.op;
last_val = here.val;
for (;;) {
state.distcode.fill(last.val +
((hold & ((1 << (last.bits + last.op)) -1))/*BITS(last.bits + last.op)*/ >> last.bits), here);
if ((last.bits + here.bits) <= bits) { break; }
state.distcode.fill(last_val +
((hold & ((1 << (last_bits + last_op)) -1))/*BITS(last.bits + last.op)*/ >> last_bits), here);
if ((last_bits + here.bits) <= bits) { break; }
//--- PULLBYTE() ---//
if (have === 0) { break inf_leave; }
have--;
@ -1257,10 +1247,10 @@ function inflate(strm, flush) {
//---//
}
//--- DROPBITS(last.bits) ---//
hold >>>= last.bits;
bits -= last.bits;
hold >>>= last_bits;
bits -= last_bits;
//---//
state.back += last.bits;
state.back += last_bits;
}
//--- DROPBITS(here.bits) ---//
hold >>>= here.bits;

21
lib/zlib/inftrees.js
View file

@ -41,8 +41,8 @@ module.exports = function inflate_table(opts)
codes = opts.codes,
table = opts.table,
bits = opts.bits,
work = opts.work,
here = opts.here; /* table entry for duplication */
work = opts.work;
//here = opts.here; /* table entry for duplication */
var len = 0; /* a code's length in bits */
var sym = 0; /* index of code symbols */
@ -67,6 +67,7 @@ module.exports = function inflate_table(opts)
var extra = null;
var extra_index = 0;
var here_bits, here_op, here_val;
/*
Process a set of code lengths to create a canonical Huffman code. The
@ -235,18 +236,18 @@ module.exports = function inflate_table(opts)
for (;;) {
i++;
/* create table entry */
here.bits = len - drop;
here_bits = len - drop;
if (work[sym] < end) {
here.op = 0;
here.val = work[sym];
here_op = 0;
here_val = work[sym];
}
else if (work[sym] > end) {
here.op = extra[extra_index + work[sym]];
here.val = base[base_index + work[sym]];
here_op = extra[extra_index + work[sym]];
here_val = base[base_index + work[sym]];
}
else {
here.op = 32 + 64; /* end of block */
here.val = 0;
here_op = 32 + 64; /* end of block */
here_val = 0;
}
/* replicate for those indices with low len bits equal to huff */
@ -255,7 +256,7 @@ module.exports = function inflate_table(opts)
min = fill; /* save offset to next table */
do {
fill -= incr;
table.set(next + (huff >> drop) + fill, here);
table.data[next + (huff >> drop) + fill] = (here_bits << 24) | (here_op << 16) | here_val |0;
} while (fill !== 0);
/* backwards increment the len-bit code huff */