1671 lines
52 KiB
JavaScript
1671 lines
52 KiB
JavaScript
/*
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* $Id: rawdeflate.js,v 0.3 2009/03/01 19:05:05 dankogai Exp dankogai $
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*
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* Original:
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* http://www.onicos.com/staff/iz/amuse/javascript/expert/deflate.txt
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*/
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(function(){
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/* Copyright (C) 1999 Masanao Izumo <iz@onicos.co.jp>
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* Version: 1.0.1
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* LastModified: Dec 25 1999
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*/
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/* Interface:
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* data = zip_deflate(src);
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*/
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/* constant parameters */
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var zip_WSIZE = 32768; // Sliding Window size
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var zip_STORED_BLOCK = 0;
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var zip_STATIC_TREES = 1;
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var zip_DYN_TREES = 2;
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/* for deflate */
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var zip_DEFAULT_LEVEL = 6;
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var zip_FULL_SEARCH = true;
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var zip_INBUFSIZ = 32768; // Input buffer size
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var zip_INBUF_EXTRA = 64; // Extra buffer
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var zip_OUTBUFSIZ = 1024 * 8;
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var zip_window_size = 2 * zip_WSIZE;
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var zip_MIN_MATCH = 3;
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var zip_MAX_MATCH = 258;
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var zip_BITS = 16;
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// for SMALL_MEM
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var zip_LIT_BUFSIZE = 0x2000;
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var zip_HASH_BITS = 13;
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// for MEDIUM_MEM
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// var zip_LIT_BUFSIZE = 0x4000;
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// var zip_HASH_BITS = 14;
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// for BIG_MEM
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// var zip_LIT_BUFSIZE = 0x8000;
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// var zip_HASH_BITS = 15;
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if(zip_LIT_BUFSIZE > zip_INBUFSIZ)
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alert("error: zip_INBUFSIZ is too small");
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if((zip_WSIZE<<1) > (1<<zip_BITS))
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alert("error: zip_WSIZE is too large");
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if(zip_HASH_BITS > zip_BITS-1)
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alert("error: zip_HASH_BITS is too large");
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if(zip_HASH_BITS < 8 || zip_MAX_MATCH != 258)
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alert("error: Code too clever");
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var zip_DIST_BUFSIZE = zip_LIT_BUFSIZE;
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var zip_HASH_SIZE = 1 << zip_HASH_BITS;
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var zip_HASH_MASK = zip_HASH_SIZE - 1;
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var zip_WMASK = zip_WSIZE - 1;
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var zip_NIL = 0; // Tail of hash chains
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var zip_TOO_FAR = 4096;
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var zip_MIN_LOOKAHEAD = zip_MAX_MATCH + zip_MIN_MATCH + 1;
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var zip_MAX_DIST = zip_WSIZE - zip_MIN_LOOKAHEAD;
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var zip_SMALLEST = 1;
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var zip_MAX_BITS = 15;
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var zip_MAX_BL_BITS = 7;
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var zip_LENGTH_CODES = 29;
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var zip_LITERALS =256;
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var zip_END_BLOCK = 256;
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var zip_L_CODES = zip_LITERALS + 1 + zip_LENGTH_CODES;
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var zip_D_CODES = 30;
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var zip_BL_CODES = 19;
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var zip_REP_3_6 = 16;
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var zip_REPZ_3_10 = 17;
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var zip_REPZ_11_138 = 18;
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var zip_HEAP_SIZE = 2 * zip_L_CODES + 1;
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var zip_H_SHIFT = parseInt((zip_HASH_BITS + zip_MIN_MATCH - 1) /
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zip_MIN_MATCH);
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/* variables */
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var zip_free_queue;
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var zip_qhead, zip_qtail;
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var zip_initflag;
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var zip_outbuf = null;
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var zip_outcnt, zip_outoff;
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var zip_complete;
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var zip_window;
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var zip_d_buf;
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var zip_l_buf;
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var zip_prev;
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var zip_bi_buf;
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var zip_bi_valid;
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var zip_block_start;
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var zip_ins_h;
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var zip_hash_head;
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var zip_prev_match;
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var zip_match_available;
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var zip_match_length;
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var zip_prev_length;
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var zip_strstart;
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var zip_match_start;
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var zip_eofile;
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var zip_lookahead;
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var zip_max_chain_length;
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var zip_max_lazy_match;
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var zip_compr_level;
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var zip_good_match;
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var zip_nice_match;
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var zip_dyn_ltree;
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var zip_dyn_dtree;
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var zip_static_ltree;
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var zip_static_dtree;
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var zip_bl_tree;
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var zip_l_desc;
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var zip_d_desc;
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var zip_bl_desc;
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var zip_bl_count;
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var zip_heap;
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var zip_heap_len;
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var zip_heap_max;
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var zip_depth;
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var zip_length_code;
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var zip_dist_code;
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var zip_base_length;
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var zip_base_dist;
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var zip_flag_buf;
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var zip_last_lit;
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var zip_last_dist;
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var zip_last_flags;
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var zip_flags;
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var zip_flag_bit;
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var zip_opt_len;
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var zip_static_len;
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var zip_deflate_data;
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var zip_deflate_pos;
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/* objects (deflate) */
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var zip_DeflateCT = function() {
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this.fc = 0; // frequency count or bit string
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this.dl = 0; // father node in Huffman tree or length of bit string
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}
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var zip_DeflateTreeDesc = function() {
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this.dyn_tree = null; // the dynamic tree
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this.static_tree = null; // corresponding static tree or NULL
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this.extra_bits = null; // extra bits for each code or NULL
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this.extra_base = 0; // base index for extra_bits
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this.elems = 0; // max number of elements in the tree
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this.max_length = 0; // max bit length for the codes
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this.max_code = 0; // largest code with non zero frequency
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}
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/* Values for max_lazy_match, good_match and max_chain_length, depending on
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* the desired pack level (0..9). The values given below have been tuned to
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* exclude worst case performance for pathological files. Better values may be
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* found for specific files.
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*/
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var zip_DeflateConfiguration = function(a, b, c, d) {
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this.good_length = a; // reduce lazy search above this match length
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this.max_lazy = b; // do not perform lazy search above this match length
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this.nice_length = c; // quit search above this match length
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this.max_chain = d;
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}
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var zip_DeflateBuffer = function() {
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this.next = null;
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this.len = 0;
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this.ptr = new Array(zip_OUTBUFSIZ);
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this.off = 0;
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}
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/* constant tables */
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var zip_extra_lbits = new Array(
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0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0);
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var zip_extra_dbits = new Array(
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0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13);
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var zip_extra_blbits = new Array(
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7);
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var zip_bl_order = new Array(
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16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15);
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var zip_configuration_table = new Array(
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new zip_DeflateConfiguration(0, 0, 0, 0),
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new zip_DeflateConfiguration(4, 4, 8, 4),
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new zip_DeflateConfiguration(4, 5, 16, 8),
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new zip_DeflateConfiguration(4, 6, 32, 32),
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new zip_DeflateConfiguration(4, 4, 16, 16),
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new zip_DeflateConfiguration(8, 16, 32, 32),
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new zip_DeflateConfiguration(8, 16, 128, 128),
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new zip_DeflateConfiguration(8, 32, 128, 256),
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new zip_DeflateConfiguration(32, 128, 258, 1024),
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new zip_DeflateConfiguration(32, 258, 258, 4096));
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/* routines (deflate) */
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var zip_deflate_start = function(level) {
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var i;
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if(!level)
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level = zip_DEFAULT_LEVEL;
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else if(level < 1)
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level = 1;
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else if(level > 9)
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level = 9;
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zip_compr_level = level;
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zip_initflag = false;
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zip_eofile = false;
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if(zip_outbuf != null)
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return;
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zip_free_queue = zip_qhead = zip_qtail = null;
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zip_outbuf = new Array(zip_OUTBUFSIZ);
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zip_window = new Array(zip_window_size);
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zip_d_buf = new Array(zip_DIST_BUFSIZE);
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zip_l_buf = new Array(zip_INBUFSIZ + zip_INBUF_EXTRA);
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zip_prev = new Array(1 << zip_BITS);
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zip_dyn_ltree = new Array(zip_HEAP_SIZE);
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for(i = 0; i < zip_HEAP_SIZE; i++)
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zip_dyn_ltree[i] = new zip_DeflateCT();
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zip_dyn_dtree = new Array(2*zip_D_CODES+1);
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for(i = 0; i < 2*zip_D_CODES+1; i++)
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zip_dyn_dtree[i] = new zip_DeflateCT();
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zip_static_ltree = new Array(zip_L_CODES+2);
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for(i = 0; i < zip_L_CODES+2; i++)
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zip_static_ltree[i] = new zip_DeflateCT();
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zip_static_dtree = new Array(zip_D_CODES);
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for(i = 0; i < zip_D_CODES; i++)
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zip_static_dtree[i] = new zip_DeflateCT();
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zip_bl_tree = new Array(2*zip_BL_CODES+1);
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for(i = 0; i < 2*zip_BL_CODES+1; i++)
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zip_bl_tree[i] = new zip_DeflateCT();
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zip_l_desc = new zip_DeflateTreeDesc();
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zip_d_desc = new zip_DeflateTreeDesc();
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zip_bl_desc = new zip_DeflateTreeDesc();
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zip_bl_count = new Array(zip_MAX_BITS+1);
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zip_heap = new Array(2*zip_L_CODES+1);
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zip_depth = new Array(2*zip_L_CODES+1);
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zip_length_code = new Array(zip_MAX_MATCH-zip_MIN_MATCH+1);
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zip_dist_code = new Array(512);
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zip_base_length = new Array(zip_LENGTH_CODES);
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zip_base_dist = new Array(zip_D_CODES);
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zip_flag_buf = new Array(parseInt(zip_LIT_BUFSIZE / 8));
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}
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var zip_deflate_end = function() {
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zip_free_queue = zip_qhead = zip_qtail = null;
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zip_outbuf = null;
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zip_window = null;
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zip_d_buf = null;
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zip_l_buf = null;
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zip_prev = null;
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zip_dyn_ltree = null;
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zip_dyn_dtree = null;
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zip_static_ltree = null;
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zip_static_dtree = null;
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zip_bl_tree = null;
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zip_l_desc = null;
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zip_d_desc = null;
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zip_bl_desc = null;
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zip_bl_count = null;
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zip_heap = null;
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zip_depth = null;
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zip_length_code = null;
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zip_dist_code = null;
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zip_base_length = null;
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zip_base_dist = null;
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zip_flag_buf = null;
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}
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var zip_reuse_queue = function(p) {
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p.next = zip_free_queue;
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zip_free_queue = p;
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}
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var zip_new_queue = function() {
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var p;
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if(zip_free_queue != null)
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{
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p = zip_free_queue;
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zip_free_queue = zip_free_queue.next;
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}
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else
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p = new zip_DeflateBuffer();
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p.next = null;
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p.len = p.off = 0;
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return p;
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}
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var zip_head1 = function(i) {
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return zip_prev[zip_WSIZE + i];
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}
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var zip_head2 = function(i, val) {
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return zip_prev[zip_WSIZE + i] = val;
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}
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/* put_byte is used for the compressed output, put_ubyte for the
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* uncompressed output. However unlzw() uses window for its
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* suffix table instead of its output buffer, so it does not use put_ubyte
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* (to be cleaned up).
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*/
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var zip_put_byte = function(c) {
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zip_outbuf[zip_outoff + zip_outcnt++] = c;
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if(zip_outoff + zip_outcnt == zip_OUTBUFSIZ)
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zip_qoutbuf();
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}
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/* Output a 16 bit value, lsb first */
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var zip_put_short = function(w) {
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w &= 0xffff;
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if(zip_outoff + zip_outcnt < zip_OUTBUFSIZ - 2) {
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zip_outbuf[zip_outoff + zip_outcnt++] = (w & 0xff);
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zip_outbuf[zip_outoff + zip_outcnt++] = (w >>> 8);
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} else {
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zip_put_byte(w & 0xff);
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zip_put_byte(w >>> 8);
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}
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}
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/* ==========================================================================
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* Insert string s in the dictionary and set match_head to the previous head
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* of the hash chain (the most recent string with same hash key). Return
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* the previous length of the hash chain.
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* IN assertion: all calls to to INSERT_STRING are made with consecutive
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* input characters and the first MIN_MATCH bytes of s are valid
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* (except for the last MIN_MATCH-1 bytes of the input file).
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*/
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var zip_INSERT_STRING = function() {
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zip_ins_h = ((zip_ins_h << zip_H_SHIFT)
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^ (zip_window[zip_strstart + zip_MIN_MATCH - 1] & 0xff))
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& zip_HASH_MASK;
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zip_hash_head = zip_head1(zip_ins_h);
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zip_prev[zip_strstart & zip_WMASK] = zip_hash_head;
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zip_head2(zip_ins_h, zip_strstart);
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}
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/* Send a code of the given tree. c and tree must not have side effects */
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var zip_SEND_CODE = function(c, tree) {
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zip_send_bits(tree[c].fc, tree[c].dl);
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}
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/* Mapping from a distance to a distance code. dist is the distance - 1 and
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* must not have side effects. dist_code[256] and dist_code[257] are never
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* used.
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*/
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var zip_D_CODE = function(dist) {
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return (dist < 256 ? zip_dist_code[dist]
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: zip_dist_code[256 + (dist>>7)]) & 0xff;
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}
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/* ==========================================================================
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* Compares to subtrees, using the tree depth as tie breaker when
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* the subtrees have equal frequency. This minimizes the worst case length.
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*/
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var zip_SMALLER = function(tree, n, m) {
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return tree[n].fc < tree[m].fc ||
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(tree[n].fc == tree[m].fc && zip_depth[n] <= zip_depth[m]);
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}
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/* ==========================================================================
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* read string data
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*/
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var zip_read_buff = function(buff, offset, n) {
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var i;
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for(i = 0; i < n && zip_deflate_pos < zip_deflate_data.length; i++)
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buff[offset + i] =
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zip_deflate_data.charCodeAt(zip_deflate_pos++) & 0xff;
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return i;
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}
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/* ==========================================================================
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* Initialize the "longest match" routines for a new file
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*/
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var zip_lm_init = function() {
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var j;
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/* Initialize the hash table. */
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for(j = 0; j < zip_HASH_SIZE; j++)
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// zip_head2(j, zip_NIL);
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zip_prev[zip_WSIZE + j] = 0;
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/* prev will be initialized on the fly */
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/* Set the default configuration parameters:
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*/
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zip_max_lazy_match = zip_configuration_table[zip_compr_level].max_lazy;
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zip_good_match = zip_configuration_table[zip_compr_level].good_length;
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if(!zip_FULL_SEARCH)
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zip_nice_match = zip_configuration_table[zip_compr_level].nice_length;
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zip_max_chain_length = zip_configuration_table[zip_compr_level].max_chain;
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zip_strstart = 0;
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zip_block_start = 0;
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zip_lookahead = zip_read_buff(zip_window, 0, 2 * zip_WSIZE);
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if(zip_lookahead <= 0) {
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zip_eofile = true;
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zip_lookahead = 0;
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return;
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}
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zip_eofile = false;
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/* Make sure that we always have enough lookahead. This is important
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* if input comes from a device such as a tty.
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*/
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while(zip_lookahead < zip_MIN_LOOKAHEAD && !zip_eofile)
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zip_fill_window();
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/* If lookahead < MIN_MATCH, ins_h is garbage, but this is
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* not important since only literal bytes will be emitted.
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*/
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zip_ins_h = 0;
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for(j = 0; j < zip_MIN_MATCH - 1; j++) {
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// UPDATE_HASH(ins_h, window[j]);
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zip_ins_h = ((zip_ins_h << zip_H_SHIFT) ^ (zip_window[j] & 0xff)) & zip_HASH_MASK;
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}
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}
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/* ==========================================================================
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* Set match_start to the longest match starting at the given string and
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* return its length. Matches shorter or equal to prev_length are discarded,
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* in which case the result is equal to prev_length and match_start is
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* garbage.
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* IN assertions: cur_match is the head of the hash chain for the current
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* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
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*/
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var zip_longest_match = function(cur_match) {
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var chain_length = zip_max_chain_length; // max hash chain length
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var scanp = zip_strstart; // current string
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var matchp; // matched string
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var len; // length of current match
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var best_len = zip_prev_length; // best match length so far
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/* Stop when cur_match becomes <= limit. To simplify the code,
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* we prevent matches with the string of window index 0.
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*/
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var limit = (zip_strstart > zip_MAX_DIST ? zip_strstart - zip_MAX_DIST : zip_NIL);
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var strendp = zip_strstart + zip_MAX_MATCH;
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var scan_end1 = zip_window[scanp + best_len - 1];
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var scan_end = zip_window[scanp + best_len];
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/* Do not waste too much time if we already have a good match: */
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if(zip_prev_length >= zip_good_match)
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chain_length >>= 2;
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// Assert(encoder->strstart <= window_size-MIN_LOOKAHEAD, "insufficient lookahead");
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do {
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// Assert(cur_match < encoder->strstart, "no future");
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matchp = cur_match;
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/* Skip to next match if the match length cannot increase
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* or if the match length is less than 2:
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*/
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if(zip_window[matchp + best_len] != scan_end ||
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zip_window[matchp + best_len - 1] != scan_end1 ||
|
|
zip_window[matchp] != zip_window[scanp] ||
|
|
zip_window[++matchp] != zip_window[scanp + 1]) {
|
|
continue;
|
|
}
|
|
|
|
/* The check at best_len-1 can be removed because it will be made
|
|
* again later. (This heuristic is not always a win.)
|
|
* It is not necessary to compare scan[2] and match[2] since they
|
|
* are always equal when the other bytes match, given that
|
|
* the hash keys are equal and that HASH_BITS >= 8.
|
|
*/
|
|
scanp += 2;
|
|
matchp++;
|
|
|
|
/* We check for insufficient lookahead only every 8th comparison;
|
|
* the 256th check will be made at strstart+258.
|
|
*/
|
|
do {
|
|
} while(zip_window[++scanp] == zip_window[++matchp] &&
|
|
zip_window[++scanp] == zip_window[++matchp] &&
|
|
zip_window[++scanp] == zip_window[++matchp] &&
|
|
zip_window[++scanp] == zip_window[++matchp] &&
|
|
zip_window[++scanp] == zip_window[++matchp] &&
|
|
zip_window[++scanp] == zip_window[++matchp] &&
|
|
zip_window[++scanp] == zip_window[++matchp] &&
|
|
zip_window[++scanp] == zip_window[++matchp] &&
|
|
scanp < strendp);
|
|
|
|
len = zip_MAX_MATCH - (strendp - scanp);
|
|
scanp = strendp - zip_MAX_MATCH;
|
|
|
|
if(len > best_len) {
|
|
zip_match_start = cur_match;
|
|
best_len = len;
|
|
if(zip_FULL_SEARCH) {
|
|
if(len >= zip_MAX_MATCH) break;
|
|
} else {
|
|
if(len >= zip_nice_match) break;
|
|
}
|
|
|
|
scan_end1 = zip_window[scanp + best_len-1];
|
|
scan_end = zip_window[scanp + best_len];
|
|
}
|
|
} while((cur_match = zip_prev[cur_match & zip_WMASK]) > limit
|
|
&& --chain_length != 0);
|
|
|
|
return best_len;
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Fill the window when the lookahead becomes insufficient.
|
|
* Updates strstart and lookahead, and sets eofile if end of input file.
|
|
* IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
|
|
* OUT assertions: at least one byte has been read, or eofile is set;
|
|
* file reads are performed for at least two bytes (required for the
|
|
* translate_eol option).
|
|
*/
|
|
var zip_fill_window = function() {
|
|
var n, m;
|
|
|
|
// Amount of free space at the end of the window.
|
|
var more = zip_window_size - zip_lookahead - zip_strstart;
|
|
|
|
/* If the window is almost full and there is insufficient lookahead,
|
|
* move the upper half to the lower one to make room in the upper half.
|
|
*/
|
|
if(more == -1) {
|
|
/* Very unlikely, but possible on 16 bit machine if strstart == 0
|
|
* and lookahead == 1 (input done one byte at time)
|
|
*/
|
|
more--;
|
|
} else if(zip_strstart >= zip_WSIZE + zip_MAX_DIST) {
|
|
/* By the IN assertion, the window is not empty so we can't confuse
|
|
* more == 0 with more == 64K on a 16 bit machine.
|
|
*/
|
|
// Assert(window_size == (ulg)2*WSIZE, "no sliding with BIG_MEM");
|
|
|
|
// System.arraycopy(window, WSIZE, window, 0, WSIZE);
|
|
for(n = 0; n < zip_WSIZE; n++)
|
|
zip_window[n] = zip_window[n + zip_WSIZE];
|
|
|
|
zip_match_start -= zip_WSIZE;
|
|
zip_strstart -= zip_WSIZE; /* we now have strstart >= MAX_DIST: */
|
|
zip_block_start -= zip_WSIZE;
|
|
|
|
for(n = 0; n < zip_HASH_SIZE; n++) {
|
|
m = zip_head1(n);
|
|
zip_head2(n, m >= zip_WSIZE ? m - zip_WSIZE : zip_NIL);
|
|
}
|
|
for(n = 0; n < zip_WSIZE; n++) {
|
|
/* If n is not on any hash chain, prev[n] is garbage but
|
|
* its value will never be used.
|
|
*/
|
|
m = zip_prev[n];
|
|
zip_prev[n] = (m >= zip_WSIZE ? m - zip_WSIZE : zip_NIL);
|
|
}
|
|
more += zip_WSIZE;
|
|
}
|
|
// At this point, more >= 2
|
|
if(!zip_eofile) {
|
|
n = zip_read_buff(zip_window, zip_strstart + zip_lookahead, more);
|
|
if(n <= 0)
|
|
zip_eofile = true;
|
|
else
|
|
zip_lookahead += n;
|
|
}
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Processes a new input file and return its compressed length. This
|
|
* function does not perform lazy evaluationof matches and inserts
|
|
* new strings in the dictionary only for unmatched strings or for short
|
|
* matches. It is used only for the fast compression options.
|
|
*/
|
|
var zip_deflate_fast = function() {
|
|
while(zip_lookahead != 0 && zip_qhead == null) {
|
|
var flush; // set if current block must be flushed
|
|
|
|
/* Insert the string window[strstart .. strstart+2] in the
|
|
* dictionary, and set hash_head to the head of the hash chain:
|
|
*/
|
|
zip_INSERT_STRING();
|
|
|
|
/* Find the longest match, discarding those <= prev_length.
|
|
* At this point we have always match_length < MIN_MATCH
|
|
*/
|
|
if(zip_hash_head != zip_NIL &&
|
|
zip_strstart - zip_hash_head <= zip_MAX_DIST) {
|
|
/* To simplify the code, we prevent matches with the string
|
|
* of window index 0 (in particular we have to avoid a match
|
|
* of the string with itself at the start of the input file).
|
|
*/
|
|
zip_match_length = zip_longest_match(zip_hash_head);
|
|
/* longest_match() sets match_start */
|
|
if(zip_match_length > zip_lookahead)
|
|
zip_match_length = zip_lookahead;
|
|
}
|
|
if(zip_match_length >= zip_MIN_MATCH) {
|
|
// check_match(strstart, match_start, match_length);
|
|
|
|
flush = zip_ct_tally(zip_strstart - zip_match_start,
|
|
zip_match_length - zip_MIN_MATCH);
|
|
zip_lookahead -= zip_match_length;
|
|
|
|
/* Insert new strings in the hash table only if the match length
|
|
* is not too large. This saves time but degrades compression.
|
|
*/
|
|
if(zip_match_length <= zip_max_lazy_match) {
|
|
zip_match_length--; // string at strstart already in hash table
|
|
do {
|
|
zip_strstart++;
|
|
zip_INSERT_STRING();
|
|
/* strstart never exceeds WSIZE-MAX_MATCH, so there are
|
|
* always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
|
|
* these bytes are garbage, but it does not matter since
|
|
* the next lookahead bytes will be emitted as literals.
|
|
*/
|
|
} while(--zip_match_length != 0);
|
|
zip_strstart++;
|
|
} else {
|
|
zip_strstart += zip_match_length;
|
|
zip_match_length = 0;
|
|
zip_ins_h = zip_window[zip_strstart] & 0xff;
|
|
// UPDATE_HASH(ins_h, window[strstart + 1]);
|
|
zip_ins_h = ((zip_ins_h<<zip_H_SHIFT) ^ (zip_window[zip_strstart + 1] & 0xff)) & zip_HASH_MASK;
|
|
|
|
//#if MIN_MATCH != 3
|
|
// Call UPDATE_HASH() MIN_MATCH-3 more times
|
|
//#endif
|
|
|
|
}
|
|
} else {
|
|
/* No match, output a literal byte */
|
|
flush = zip_ct_tally(0, zip_window[zip_strstart] & 0xff);
|
|
zip_lookahead--;
|
|
zip_strstart++;
|
|
}
|
|
if(flush) {
|
|
zip_flush_block(0);
|
|
zip_block_start = zip_strstart;
|
|
}
|
|
|
|
/* Make sure that we always have enough lookahead, except
|
|
* at the end of the input file. We need MAX_MATCH bytes
|
|
* for the next match, plus MIN_MATCH bytes to insert the
|
|
* string following the next match.
|
|
*/
|
|
while(zip_lookahead < zip_MIN_LOOKAHEAD && !zip_eofile)
|
|
zip_fill_window();
|
|
}
|
|
}
|
|
|
|
var zip_deflate_better = function() {
|
|
/* Process the input block. */
|
|
while(zip_lookahead != 0 && zip_qhead == null) {
|
|
/* Insert the string window[strstart .. strstart+2] in the
|
|
* dictionary, and set hash_head to the head of the hash chain:
|
|
*/
|
|
zip_INSERT_STRING();
|
|
|
|
/* Find the longest match, discarding those <= prev_length.
|
|
*/
|
|
zip_prev_length = zip_match_length;
|
|
zip_prev_match = zip_match_start;
|
|
zip_match_length = zip_MIN_MATCH - 1;
|
|
|
|
if(zip_hash_head != zip_NIL &&
|
|
zip_prev_length < zip_max_lazy_match &&
|
|
zip_strstart - zip_hash_head <= zip_MAX_DIST) {
|
|
/* To simplify the code, we prevent matches with the string
|
|
* of window index 0 (in particular we have to avoid a match
|
|
* of the string with itself at the start of the input file).
|
|
*/
|
|
zip_match_length = zip_longest_match(zip_hash_head);
|
|
/* longest_match() sets match_start */
|
|
if(zip_match_length > zip_lookahead)
|
|
zip_match_length = zip_lookahead;
|
|
|
|
/* Ignore a length 3 match if it is too distant: */
|
|
if(zip_match_length == zip_MIN_MATCH &&
|
|
zip_strstart - zip_match_start > zip_TOO_FAR) {
|
|
/* If prev_match is also MIN_MATCH, match_start is garbage
|
|
* but we will ignore the current match anyway.
|
|
*/
|
|
zip_match_length--;
|
|
}
|
|
}
|
|
/* If there was a match at the previous step and the current
|
|
* match is not better, output the previous match:
|
|
*/
|
|
if(zip_prev_length >= zip_MIN_MATCH &&
|
|
zip_match_length <= zip_prev_length) {
|
|
var flush; // set if current block must be flushed
|
|
|
|
// check_match(strstart - 1, prev_match, prev_length);
|
|
flush = zip_ct_tally(zip_strstart - 1 - zip_prev_match,
|
|
zip_prev_length - zip_MIN_MATCH);
|
|
|
|
/* Insert in hash table all strings up to the end of the match.
|
|
* strstart-1 and strstart are already inserted.
|
|
*/
|
|
zip_lookahead -= zip_prev_length - 1;
|
|
zip_prev_length -= 2;
|
|
do {
|
|
zip_strstart++;
|
|
zip_INSERT_STRING();
|
|
/* strstart never exceeds WSIZE-MAX_MATCH, so there are
|
|
* always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
|
|
* these bytes are garbage, but it does not matter since the
|
|
* next lookahead bytes will always be emitted as literals.
|
|
*/
|
|
} while(--zip_prev_length != 0);
|
|
zip_match_available = 0;
|
|
zip_match_length = zip_MIN_MATCH - 1;
|
|
zip_strstart++;
|
|
if(flush) {
|
|
zip_flush_block(0);
|
|
zip_block_start = zip_strstart;
|
|
}
|
|
} else if(zip_match_available != 0) {
|
|
/* If there was no match at the previous position, output a
|
|
* single literal. If there was a match but the current match
|
|
* is longer, truncate the previous match to a single literal.
|
|
*/
|
|
if(zip_ct_tally(0, zip_window[zip_strstart - 1] & 0xff)) {
|
|
zip_flush_block(0);
|
|
zip_block_start = zip_strstart;
|
|
}
|
|
zip_strstart++;
|
|
zip_lookahead--;
|
|
} else {
|
|
/* There is no previous match to compare with, wait for
|
|
* the next step to decide.
|
|
*/
|
|
zip_match_available = 1;
|
|
zip_strstart++;
|
|
zip_lookahead--;
|
|
}
|
|
|
|
/* Make sure that we always have enough lookahead, except
|
|
* at the end of the input file. We need MAX_MATCH bytes
|
|
* for the next match, plus MIN_MATCH bytes to insert the
|
|
* string following the next match.
|
|
*/
|
|
while(zip_lookahead < zip_MIN_LOOKAHEAD && !zip_eofile)
|
|
zip_fill_window();
|
|
}
|
|
}
|
|
|
|
var zip_init_deflate = function() {
|
|
if(zip_eofile)
|
|
return;
|
|
zip_bi_buf = 0;
|
|
zip_bi_valid = 0;
|
|
zip_ct_init();
|
|
zip_lm_init();
|
|
|
|
zip_qhead = null;
|
|
zip_outcnt = 0;
|
|
zip_outoff = 0;
|
|
|
|
if(zip_compr_level <= 3)
|
|
{
|
|
zip_prev_length = zip_MIN_MATCH - 1;
|
|
zip_match_length = 0;
|
|
}
|
|
else
|
|
{
|
|
zip_match_length = zip_MIN_MATCH - 1;
|
|
zip_match_available = 0;
|
|
}
|
|
|
|
zip_complete = false;
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Same as above, but achieves better compression. We use a lazy
|
|
* evaluation for matches: a match is finally adopted only if there is
|
|
* no better match at the next window position.
|
|
*/
|
|
var zip_deflate_internal = function(buff, off, buff_size) {
|
|
var n;
|
|
|
|
if(!zip_initflag)
|
|
{
|
|
zip_init_deflate();
|
|
zip_initflag = true;
|
|
if(zip_lookahead == 0) { // empty
|
|
zip_complete = true;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
if((n = zip_qcopy(buff, off, buff_size)) == buff_size)
|
|
return buff_size;
|
|
|
|
if(zip_complete)
|
|
return n;
|
|
|
|
if(zip_compr_level <= 3) // optimized for speed
|
|
zip_deflate_fast();
|
|
else
|
|
zip_deflate_better();
|
|
if(zip_lookahead == 0) {
|
|
if(zip_match_available != 0)
|
|
zip_ct_tally(0, zip_window[zip_strstart - 1] & 0xff);
|
|
zip_flush_block(1);
|
|
zip_complete = true;
|
|
}
|
|
return n + zip_qcopy(buff, n + off, buff_size - n);
|
|
}
|
|
|
|
var zip_qcopy = function(buff, off, buff_size) {
|
|
var n, i, j;
|
|
|
|
n = 0;
|
|
while(zip_qhead != null && n < buff_size)
|
|
{
|
|
i = buff_size - n;
|
|
if(i > zip_qhead.len)
|
|
i = zip_qhead.len;
|
|
// System.arraycopy(qhead.ptr, qhead.off, buff, off + n, i);
|
|
for(j = 0; j < i; j++)
|
|
buff[off + n + j] = zip_qhead.ptr[zip_qhead.off + j];
|
|
|
|
zip_qhead.off += i;
|
|
zip_qhead.len -= i;
|
|
n += i;
|
|
if(zip_qhead.len == 0) {
|
|
var p;
|
|
p = zip_qhead;
|
|
zip_qhead = zip_qhead.next;
|
|
zip_reuse_queue(p);
|
|
}
|
|
}
|
|
|
|
if(n == buff_size)
|
|
return n;
|
|
|
|
if(zip_outoff < zip_outcnt) {
|
|
i = buff_size - n;
|
|
if(i > zip_outcnt - zip_outoff)
|
|
i = zip_outcnt - zip_outoff;
|
|
// System.arraycopy(outbuf, outoff, buff, off + n, i);
|
|
for(j = 0; j < i; j++)
|
|
buff[off + n + j] = zip_outbuf[zip_outoff + j];
|
|
zip_outoff += i;
|
|
n += i;
|
|
if(zip_outcnt == zip_outoff)
|
|
zip_outcnt = zip_outoff = 0;
|
|
}
|
|
return n;
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Allocate the match buffer, initialize the various tables and save the
|
|
* location of the internal file attribute (ascii/binary) and method
|
|
* (DEFLATE/STORE).
|
|
*/
|
|
var zip_ct_init = function() {
|
|
var n; // iterates over tree elements
|
|
var bits; // bit counter
|
|
var length; // length value
|
|
var code; // code value
|
|
var dist; // distance index
|
|
|
|
if(zip_static_dtree[0].dl != 0) return; // ct_init already called
|
|
|
|
zip_l_desc.dyn_tree = zip_dyn_ltree;
|
|
zip_l_desc.static_tree = zip_static_ltree;
|
|
zip_l_desc.extra_bits = zip_extra_lbits;
|
|
zip_l_desc.extra_base = zip_LITERALS + 1;
|
|
zip_l_desc.elems = zip_L_CODES;
|
|
zip_l_desc.max_length = zip_MAX_BITS;
|
|
zip_l_desc.max_code = 0;
|
|
|
|
zip_d_desc.dyn_tree = zip_dyn_dtree;
|
|
zip_d_desc.static_tree = zip_static_dtree;
|
|
zip_d_desc.extra_bits = zip_extra_dbits;
|
|
zip_d_desc.extra_base = 0;
|
|
zip_d_desc.elems = zip_D_CODES;
|
|
zip_d_desc.max_length = zip_MAX_BITS;
|
|
zip_d_desc.max_code = 0;
|
|
|
|
zip_bl_desc.dyn_tree = zip_bl_tree;
|
|
zip_bl_desc.static_tree = null;
|
|
zip_bl_desc.extra_bits = zip_extra_blbits;
|
|
zip_bl_desc.extra_base = 0;
|
|
zip_bl_desc.elems = zip_BL_CODES;
|
|
zip_bl_desc.max_length = zip_MAX_BL_BITS;
|
|
zip_bl_desc.max_code = 0;
|
|
|
|
// Initialize the mapping length (0..255) -> length code (0..28)
|
|
length = 0;
|
|
for(code = 0; code < zip_LENGTH_CODES-1; code++) {
|
|
zip_base_length[code] = length;
|
|
for(n = 0; n < (1<<zip_extra_lbits[code]); n++)
|
|
zip_length_code[length++] = code;
|
|
}
|
|
// Assert (length == 256, "ct_init: length != 256");
|
|
|
|
/* Note that the length 255 (match length 258) can be represented
|
|
* in two different ways: code 284 + 5 bits or code 285, so we
|
|
* overwrite length_code[255] to use the best encoding:
|
|
*/
|
|
zip_length_code[length-1] = code;
|
|
|
|
/* Initialize the mapping dist (0..32K) -> dist code (0..29) */
|
|
dist = 0;
|
|
for(code = 0 ; code < 16; code++) {
|
|
zip_base_dist[code] = dist;
|
|
for(n = 0; n < (1<<zip_extra_dbits[code]); n++) {
|
|
zip_dist_code[dist++] = code;
|
|
}
|
|
}
|
|
// Assert (dist == 256, "ct_init: dist != 256");
|
|
dist >>= 7; // from now on, all distances are divided by 128
|
|
for( ; code < zip_D_CODES; code++) {
|
|
zip_base_dist[code] = dist << 7;
|
|
for(n = 0; n < (1<<(zip_extra_dbits[code]-7)); n++)
|
|
zip_dist_code[256 + dist++] = code;
|
|
}
|
|
// Assert (dist == 256, "ct_init: 256+dist != 512");
|
|
|
|
// Construct the codes of the static literal tree
|
|
for(bits = 0; bits <= zip_MAX_BITS; bits++)
|
|
zip_bl_count[bits] = 0;
|
|
n = 0;
|
|
while(n <= 143) { zip_static_ltree[n++].dl = 8; zip_bl_count[8]++; }
|
|
while(n <= 255) { zip_static_ltree[n++].dl = 9; zip_bl_count[9]++; }
|
|
while(n <= 279) { zip_static_ltree[n++].dl = 7; zip_bl_count[7]++; }
|
|
while(n <= 287) { zip_static_ltree[n++].dl = 8; zip_bl_count[8]++; }
|
|
/* Codes 286 and 287 do not exist, but we must include them in the
|
|
* tree construction to get a canonical Huffman tree (longest code
|
|
* all ones)
|
|
*/
|
|
zip_gen_codes(zip_static_ltree, zip_L_CODES + 1);
|
|
|
|
/* The static distance tree is trivial: */
|
|
for(n = 0; n < zip_D_CODES; n++) {
|
|
zip_static_dtree[n].dl = 5;
|
|
zip_static_dtree[n].fc = zip_bi_reverse(n, 5);
|
|
}
|
|
|
|
// Initialize the first block of the first file:
|
|
zip_init_block();
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Initialize a new block.
|
|
*/
|
|
var zip_init_block = function() {
|
|
var n; // iterates over tree elements
|
|
|
|
// Initialize the trees.
|
|
for(n = 0; n < zip_L_CODES; n++) zip_dyn_ltree[n].fc = 0;
|
|
for(n = 0; n < zip_D_CODES; n++) zip_dyn_dtree[n].fc = 0;
|
|
for(n = 0; n < zip_BL_CODES; n++) zip_bl_tree[n].fc = 0;
|
|
|
|
zip_dyn_ltree[zip_END_BLOCK].fc = 1;
|
|
zip_opt_len = zip_static_len = 0;
|
|
zip_last_lit = zip_last_dist = zip_last_flags = 0;
|
|
zip_flags = 0;
|
|
zip_flag_bit = 1;
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Restore the heap property by moving down the tree starting at node k,
|
|
* exchanging a node with the smallest of its two sons if necessary, stopping
|
|
* when the heap property is re-established (each father smaller than its
|
|
* two sons).
|
|
*/
|
|
var zip_pqdownheap = function(
|
|
tree, // the tree to restore
|
|
k) { // node to move down
|
|
var v = zip_heap[k];
|
|
var j = k << 1; // left son of k
|
|
|
|
while(j <= zip_heap_len) {
|
|
// Set j to the smallest of the two sons:
|
|
if(j < zip_heap_len &&
|
|
zip_SMALLER(tree, zip_heap[j + 1], zip_heap[j]))
|
|
j++;
|
|
|
|
// Exit if v is smaller than both sons
|
|
if(zip_SMALLER(tree, v, zip_heap[j]))
|
|
break;
|
|
|
|
// Exchange v with the smallest son
|
|
zip_heap[k] = zip_heap[j];
|
|
k = j;
|
|
|
|
// And continue down the tree, setting j to the left son of k
|
|
j <<= 1;
|
|
}
|
|
zip_heap[k] = v;
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Compute the optimal bit lengths for a tree and update the total bit length
|
|
* for the current block.
|
|
* IN assertion: the fields freq and dad are set, heap[heap_max] and
|
|
* above are the tree nodes sorted by increasing frequency.
|
|
* OUT assertions: the field len is set to the optimal bit length, the
|
|
* array bl_count contains the frequencies for each bit length.
|
|
* The length opt_len is updated; static_len is also updated if stree is
|
|
* not null.
|
|
*/
|
|
var zip_gen_bitlen = function(desc) { // the tree descriptor
|
|
var tree = desc.dyn_tree;
|
|
var extra = desc.extra_bits;
|
|
var base = desc.extra_base;
|
|
var max_code = desc.max_code;
|
|
var max_length = desc.max_length;
|
|
var stree = desc.static_tree;
|
|
var h; // heap index
|
|
var n, m; // iterate over the tree elements
|
|
var bits; // bit length
|
|
var xbits; // extra bits
|
|
var f; // frequency
|
|
var overflow = 0; // number of elements with bit length too large
|
|
|
|
for(bits = 0; bits <= zip_MAX_BITS; bits++)
|
|
zip_bl_count[bits] = 0;
|
|
|
|
/* In a first pass, compute the optimal bit lengths (which may
|
|
* overflow in the case of the bit length tree).
|
|
*/
|
|
tree[zip_heap[zip_heap_max]].dl = 0; // root of the heap
|
|
|
|
for(h = zip_heap_max + 1; h < zip_HEAP_SIZE; h++) {
|
|
n = zip_heap[h];
|
|
bits = tree[tree[n].dl].dl + 1;
|
|
if(bits > max_length) {
|
|
bits = max_length;
|
|
overflow++;
|
|
}
|
|
tree[n].dl = bits;
|
|
// We overwrite tree[n].dl which is no longer needed
|
|
|
|
if(n > max_code)
|
|
continue; // not a leaf node
|
|
|
|
zip_bl_count[bits]++;
|
|
xbits = 0;
|
|
if(n >= base)
|
|
xbits = extra[n - base];
|
|
f = tree[n].fc;
|
|
zip_opt_len += f * (bits + xbits);
|
|
if(stree != null)
|
|
zip_static_len += f * (stree[n].dl + xbits);
|
|
}
|
|
if(overflow == 0)
|
|
return;
|
|
|
|
// This happens for example on obj2 and pic of the Calgary corpus
|
|
|
|
// Find the first bit length which could increase:
|
|
do {
|
|
bits = max_length - 1;
|
|
while(zip_bl_count[bits] == 0)
|
|
bits--;
|
|
zip_bl_count[bits]--; // move one leaf down the tree
|
|
zip_bl_count[bits + 1] += 2; // move one overflow item as its brother
|
|
zip_bl_count[max_length]--;
|
|
/* The brother of the overflow item also moves one step up,
|
|
* but this does not affect bl_count[max_length]
|
|
*/
|
|
overflow -= 2;
|
|
} while(overflow > 0);
|
|
|
|
/* Now recompute all bit lengths, scanning in increasing frequency.
|
|
* h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
|
|
* lengths instead of fixing only the wrong ones. This idea is taken
|
|
* from 'ar' written by Haruhiko Okumura.)
|
|
*/
|
|
for(bits = max_length; bits != 0; bits--) {
|
|
n = zip_bl_count[bits];
|
|
while(n != 0) {
|
|
m = zip_heap[--h];
|
|
if(m > max_code)
|
|
continue;
|
|
if(tree[m].dl != bits) {
|
|
zip_opt_len += (bits - tree[m].dl) * tree[m].fc;
|
|
tree[m].fc = bits;
|
|
}
|
|
n--;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Generate the codes for a given tree and bit counts (which need not be
|
|
* optimal).
|
|
* IN assertion: the array bl_count contains the bit length statistics for
|
|
* the given tree and the field len is set for all tree elements.
|
|
* OUT assertion: the field code is set for all tree elements of non
|
|
* zero code length.
|
|
*/
|
|
var zip_gen_codes = function(tree, // the tree to decorate
|
|
max_code) { // largest code with non zero frequency
|
|
var next_code = new Array(zip_MAX_BITS+1); // next code value for each bit length
|
|
var code = 0; // running code value
|
|
var bits; // bit index
|
|
var n; // code index
|
|
|
|
/* The distribution counts are first used to generate the code values
|
|
* without bit reversal.
|
|
*/
|
|
for(bits = 1; bits <= zip_MAX_BITS; bits++) {
|
|
code = ((code + zip_bl_count[bits-1]) << 1);
|
|
next_code[bits] = code;
|
|
}
|
|
|
|
/* Check that the bit counts in bl_count are consistent. The last code
|
|
* must be all ones.
|
|
*/
|
|
// Assert (code + encoder->bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
|
|
// "inconsistent bit counts");
|
|
// Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
|
|
|
|
for(n = 0; n <= max_code; n++) {
|
|
var len = tree[n].dl;
|
|
if(len == 0)
|
|
continue;
|
|
// Now reverse the bits
|
|
tree[n].fc = zip_bi_reverse(next_code[len]++, len);
|
|
|
|
// Tracec(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
|
|
// n, (isgraph(n) ? n : ' '), len, tree[n].fc, next_code[len]-1));
|
|
}
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Construct one Huffman tree and assigns the code bit strings and lengths.
|
|
* Update the total bit length for the current block.
|
|
* IN assertion: the field freq is set for all tree elements.
|
|
* OUT assertions: the fields len and code are set to the optimal bit length
|
|
* and corresponding code. The length opt_len is updated; static_len is
|
|
* also updated if stree is not null. The field max_code is set.
|
|
*/
|
|
var zip_build_tree = function(desc) { // the tree descriptor
|
|
var tree = desc.dyn_tree;
|
|
var stree = desc.static_tree;
|
|
var elems = desc.elems;
|
|
var n, m; // iterate over heap elements
|
|
var max_code = -1; // largest code with non zero frequency
|
|
var node = elems; // next internal node of the tree
|
|
|
|
/* Construct the initial heap, with least frequent element in
|
|
* heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
|
|
* heap[0] is not used.
|
|
*/
|
|
zip_heap_len = 0;
|
|
zip_heap_max = zip_HEAP_SIZE;
|
|
|
|
for(n = 0; n < elems; n++) {
|
|
if(tree[n].fc != 0) {
|
|
zip_heap[++zip_heap_len] = max_code = n;
|
|
zip_depth[n] = 0;
|
|
} else
|
|
tree[n].dl = 0;
|
|
}
|
|
|
|
/* The pkzip format requires that at least one distance code exists,
|
|
* and that at least one bit should be sent even if there is only one
|
|
* possible code. So to avoid special checks later on we force at least
|
|
* two codes of non zero frequency.
|
|
*/
|
|
while(zip_heap_len < 2) {
|
|
var xnew = zip_heap[++zip_heap_len] = (max_code < 2 ? ++max_code : 0);
|
|
tree[xnew].fc = 1;
|
|
zip_depth[xnew] = 0;
|
|
zip_opt_len--;
|
|
if(stree != null)
|
|
zip_static_len -= stree[xnew].dl;
|
|
// new is 0 or 1 so it does not have extra bits
|
|
}
|
|
desc.max_code = max_code;
|
|
|
|
/* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
|
|
* establish sub-heaps of increasing lengths:
|
|
*/
|
|
for(n = zip_heap_len >> 1; n >= 1; n--)
|
|
zip_pqdownheap(tree, n);
|
|
|
|
/* Construct the Huffman tree by repeatedly combining the least two
|
|
* frequent nodes.
|
|
*/
|
|
do {
|
|
n = zip_heap[zip_SMALLEST];
|
|
zip_heap[zip_SMALLEST] = zip_heap[zip_heap_len--];
|
|
zip_pqdownheap(tree, zip_SMALLEST);
|
|
|
|
m = zip_heap[zip_SMALLEST]; // m = node of next least frequency
|
|
|
|
// keep the nodes sorted by frequency
|
|
zip_heap[--zip_heap_max] = n;
|
|
zip_heap[--zip_heap_max] = m;
|
|
|
|
// Create a new node father of n and m
|
|
tree[node].fc = tree[n].fc + tree[m].fc;
|
|
// depth[node] = (char)(MAX(depth[n], depth[m]) + 1);
|
|
if(zip_depth[n] > zip_depth[m] + 1)
|
|
zip_depth[node] = zip_depth[n];
|
|
else
|
|
zip_depth[node] = zip_depth[m] + 1;
|
|
tree[n].dl = tree[m].dl = node;
|
|
|
|
// and insert the new node in the heap
|
|
zip_heap[zip_SMALLEST] = node++;
|
|
zip_pqdownheap(tree, zip_SMALLEST);
|
|
|
|
} while(zip_heap_len >= 2);
|
|
|
|
zip_heap[--zip_heap_max] = zip_heap[zip_SMALLEST];
|
|
|
|
/* At this point, the fields freq and dad are set. We can now
|
|
* generate the bit lengths.
|
|
*/
|
|
zip_gen_bitlen(desc);
|
|
|
|
// The field len is now set, we can generate the bit codes
|
|
zip_gen_codes(tree, max_code);
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Scan a literal or distance tree to determine the frequencies of the codes
|
|
* in the bit length tree. Updates opt_len to take into account the repeat
|
|
* counts. (The contribution of the bit length codes will be added later
|
|
* during the construction of bl_tree.)
|
|
*/
|
|
var zip_scan_tree = function(tree,// the tree to be scanned
|
|
max_code) { // and its largest code of non zero frequency
|
|
var n; // iterates over all tree elements
|
|
var prevlen = -1; // last emitted length
|
|
var curlen; // length of current code
|
|
var nextlen = tree[0].dl; // length of next code
|
|
var count = 0; // repeat count of the current code
|
|
var max_count = 7; // max repeat count
|
|
var min_count = 4; // min repeat count
|
|
|
|
if(nextlen == 0) {
|
|
max_count = 138;
|
|
min_count = 3;
|
|
}
|
|
tree[max_code + 1].dl = 0xffff; // guard
|
|
|
|
for(n = 0; n <= max_code; n++) {
|
|
curlen = nextlen;
|
|
nextlen = tree[n + 1].dl;
|
|
if(++count < max_count && curlen == nextlen)
|
|
continue;
|
|
else if(count < min_count)
|
|
zip_bl_tree[curlen].fc += count;
|
|
else if(curlen != 0) {
|
|
if(curlen != prevlen)
|
|
zip_bl_tree[curlen].fc++;
|
|
zip_bl_tree[zip_REP_3_6].fc++;
|
|
} else if(count <= 10)
|
|
zip_bl_tree[zip_REPZ_3_10].fc++;
|
|
else
|
|
zip_bl_tree[zip_REPZ_11_138].fc++;
|
|
count = 0; prevlen = curlen;
|
|
if(nextlen == 0) {
|
|
max_count = 138;
|
|
min_count = 3;
|
|
} else if(curlen == nextlen) {
|
|
max_count = 6;
|
|
min_count = 3;
|
|
} else {
|
|
max_count = 7;
|
|
min_count = 4;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Send a literal or distance tree in compressed form, using the codes in
|
|
* bl_tree.
|
|
*/
|
|
var zip_send_tree = function(tree, // the tree to be scanned
|
|
max_code) { // and its largest code of non zero frequency
|
|
var n; // iterates over all tree elements
|
|
var prevlen = -1; // last emitted length
|
|
var curlen; // length of current code
|
|
var nextlen = tree[0].dl; // length of next code
|
|
var count = 0; // repeat count of the current code
|
|
var max_count = 7; // max repeat count
|
|
var min_count = 4; // min repeat count
|
|
|
|
/* tree[max_code+1].dl = -1; */ /* guard already set */
|
|
if(nextlen == 0) {
|
|
max_count = 138;
|
|
min_count = 3;
|
|
}
|
|
|
|
for(n = 0; n <= max_code; n++) {
|
|
curlen = nextlen;
|
|
nextlen = tree[n+1].dl;
|
|
if(++count < max_count && curlen == nextlen) {
|
|
continue;
|
|
} else if(count < min_count) {
|
|
do { zip_SEND_CODE(curlen, zip_bl_tree); } while(--count != 0);
|
|
} else if(curlen != 0) {
|
|
if(curlen != prevlen) {
|
|
zip_SEND_CODE(curlen, zip_bl_tree);
|
|
count--;
|
|
}
|
|
// Assert(count >= 3 && count <= 6, " 3_6?");
|
|
zip_SEND_CODE(zip_REP_3_6, zip_bl_tree);
|
|
zip_send_bits(count - 3, 2);
|
|
} else if(count <= 10) {
|
|
zip_SEND_CODE(zip_REPZ_3_10, zip_bl_tree);
|
|
zip_send_bits(count-3, 3);
|
|
} else {
|
|
zip_SEND_CODE(zip_REPZ_11_138, zip_bl_tree);
|
|
zip_send_bits(count-11, 7);
|
|
}
|
|
count = 0;
|
|
prevlen = curlen;
|
|
if(nextlen == 0) {
|
|
max_count = 138;
|
|
min_count = 3;
|
|
} else if(curlen == nextlen) {
|
|
max_count = 6;
|
|
min_count = 3;
|
|
} else {
|
|
max_count = 7;
|
|
min_count = 4;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Construct the Huffman tree for the bit lengths and return the index in
|
|
* bl_order of the last bit length code to send.
|
|
*/
|
|
var zip_build_bl_tree = function() {
|
|
var max_blindex; // index of last bit length code of non zero freq
|
|
|
|
// Determine the bit length frequencies for literal and distance trees
|
|
zip_scan_tree(zip_dyn_ltree, zip_l_desc.max_code);
|
|
zip_scan_tree(zip_dyn_dtree, zip_d_desc.max_code);
|
|
|
|
// Build the bit length tree:
|
|
zip_build_tree(zip_bl_desc);
|
|
/* opt_len now includes the length of the tree representations, except
|
|
* the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
|
|
*/
|
|
|
|
/* Determine the number of bit length codes to send. The pkzip format
|
|
* requires that at least 4 bit length codes be sent. (appnote.txt says
|
|
* 3 but the actual value used is 4.)
|
|
*/
|
|
for(max_blindex = zip_BL_CODES-1; max_blindex >= 3; max_blindex--) {
|
|
if(zip_bl_tree[zip_bl_order[max_blindex]].dl != 0) break;
|
|
}
|
|
/* Update opt_len to include the bit length tree and counts */
|
|
zip_opt_len += 3*(max_blindex+1) + 5+5+4;
|
|
// Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
|
|
// encoder->opt_len, encoder->static_len));
|
|
|
|
return max_blindex;
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Send the header for a block using dynamic Huffman trees: the counts, the
|
|
* lengths of the bit length codes, the literal tree and the distance tree.
|
|
* IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
|
|
*/
|
|
var zip_send_all_trees = function(lcodes, dcodes, blcodes) { // number of codes for each tree
|
|
var rank; // index in bl_order
|
|
|
|
// Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
|
|
// Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
|
|
// "too many codes");
|
|
// Tracev((stderr, "\nbl counts: "));
|
|
zip_send_bits(lcodes-257, 5); // not +255 as stated in appnote.txt
|
|
zip_send_bits(dcodes-1, 5);
|
|
zip_send_bits(blcodes-4, 4); // not -3 as stated in appnote.txt
|
|
for(rank = 0; rank < blcodes; rank++) {
|
|
// Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
|
|
zip_send_bits(zip_bl_tree[zip_bl_order[rank]].dl, 3);
|
|
}
|
|
|
|
// send the literal tree
|
|
zip_send_tree(zip_dyn_ltree,lcodes-1);
|
|
|
|
// send the distance tree
|
|
zip_send_tree(zip_dyn_dtree,dcodes-1);
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Determine the best encoding for the current block: dynamic trees, static
|
|
* trees or store, and output the encoded block to the zip file.
|
|
*/
|
|
var zip_flush_block = function(eof) { // true if this is the last block for a file
|
|
var opt_lenb, static_lenb; // opt_len and static_len in bytes
|
|
var max_blindex; // index of last bit length code of non zero freq
|
|
var stored_len; // length of input block
|
|
|
|
stored_len = zip_strstart - zip_block_start;
|
|
zip_flag_buf[zip_last_flags] = zip_flags; // Save the flags for the last 8 items
|
|
|
|
// Construct the literal and distance trees
|
|
zip_build_tree(zip_l_desc);
|
|
// Tracev((stderr, "\nlit data: dyn %ld, stat %ld",
|
|
// encoder->opt_len, encoder->static_len));
|
|
|
|
zip_build_tree(zip_d_desc);
|
|
// Tracev((stderr, "\ndist data: dyn %ld, stat %ld",
|
|
// encoder->opt_len, encoder->static_len));
|
|
/* At this point, opt_len and static_len are the total bit lengths of
|
|
* the compressed block data, excluding the tree representations.
|
|
*/
|
|
|
|
/* Build the bit length tree for the above two trees, and get the index
|
|
* in bl_order of the last bit length code to send.
|
|
*/
|
|
max_blindex = zip_build_bl_tree();
|
|
|
|
// Determine the best encoding. Compute first the block length in bytes
|
|
opt_lenb = (zip_opt_len +3+7)>>3;
|
|
static_lenb = (zip_static_len+3+7)>>3;
|
|
|
|
// Trace((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
|
|
// opt_lenb, encoder->opt_len,
|
|
// static_lenb, encoder->static_len, stored_len,
|
|
// encoder->last_lit, encoder->last_dist));
|
|
|
|
if(static_lenb <= opt_lenb)
|
|
opt_lenb = static_lenb;
|
|
if(stored_len + 4 <= opt_lenb // 4: two words for the lengths
|
|
&& zip_block_start >= 0) {
|
|
var i;
|
|
|
|
/* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
|
|
* Otherwise we can't have processed more than WSIZE input bytes since
|
|
* the last block flush, because compression would have been
|
|
* successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
|
|
* transform a block into a stored block.
|
|
*/
|
|
zip_send_bits((zip_STORED_BLOCK<<1)+eof, 3); /* send block type */
|
|
zip_bi_windup(); /* align on byte boundary */
|
|
zip_put_short(stored_len);
|
|
zip_put_short(~stored_len);
|
|
|
|
// copy block
|
|
/*
|
|
p = &window[block_start];
|
|
for(i = 0; i < stored_len; i++)
|
|
put_byte(p[i]);
|
|
*/
|
|
for(i = 0; i < stored_len; i++)
|
|
zip_put_byte(zip_window[zip_block_start + i]);
|
|
|
|
} else if(static_lenb == opt_lenb) {
|
|
zip_send_bits((zip_STATIC_TREES<<1)+eof, 3);
|
|
zip_compress_block(zip_static_ltree, zip_static_dtree);
|
|
} else {
|
|
zip_send_bits((zip_DYN_TREES<<1)+eof, 3);
|
|
zip_send_all_trees(zip_l_desc.max_code+1,
|
|
zip_d_desc.max_code+1,
|
|
max_blindex+1);
|
|
zip_compress_block(zip_dyn_ltree, zip_dyn_dtree);
|
|
}
|
|
|
|
zip_init_block();
|
|
|
|
if(eof != 0)
|
|
zip_bi_windup();
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Save the match info and tally the frequency counts. Return true if
|
|
* the current block must be flushed.
|
|
*/
|
|
var zip_ct_tally = function(
|
|
dist, // distance of matched string
|
|
lc) { // match length-MIN_MATCH or unmatched char (if dist==0)
|
|
zip_l_buf[zip_last_lit++] = lc;
|
|
if(dist == 0) {
|
|
// lc is the unmatched char
|
|
zip_dyn_ltree[lc].fc++;
|
|
} else {
|
|
// Here, lc is the match length - MIN_MATCH
|
|
dist--; // dist = match distance - 1
|
|
// Assert((ush)dist < (ush)MAX_DIST &&
|
|
// (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
|
|
// (ush)D_CODE(dist) < (ush)D_CODES, "ct_tally: bad match");
|
|
|
|
zip_dyn_ltree[zip_length_code[lc]+zip_LITERALS+1].fc++;
|
|
zip_dyn_dtree[zip_D_CODE(dist)].fc++;
|
|
|
|
zip_d_buf[zip_last_dist++] = dist;
|
|
zip_flags |= zip_flag_bit;
|
|
}
|
|
zip_flag_bit <<= 1;
|
|
|
|
// Output the flags if they fill a byte
|
|
if((zip_last_lit & 7) == 0) {
|
|
zip_flag_buf[zip_last_flags++] = zip_flags;
|
|
zip_flags = 0;
|
|
zip_flag_bit = 1;
|
|
}
|
|
// Try to guess if it is profitable to stop the current block here
|
|
if(zip_compr_level > 2 && (zip_last_lit & 0xfff) == 0) {
|
|
// Compute an upper bound for the compressed length
|
|
var out_length = zip_last_lit * 8;
|
|
var in_length = zip_strstart - zip_block_start;
|
|
var dcode;
|
|
|
|
for(dcode = 0; dcode < zip_D_CODES; dcode++) {
|
|
out_length += zip_dyn_dtree[dcode].fc * (5 + zip_extra_dbits[dcode]);
|
|
}
|
|
out_length >>= 3;
|
|
// Trace((stderr,"\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
|
|
// encoder->last_lit, encoder->last_dist, in_length, out_length,
|
|
// 100L - out_length*100L/in_length));
|
|
if(zip_last_dist < parseInt(zip_last_lit/2) &&
|
|
out_length < parseInt(in_length/2))
|
|
return true;
|
|
}
|
|
return (zip_last_lit == zip_LIT_BUFSIZE-1 ||
|
|
zip_last_dist == zip_DIST_BUFSIZE);
|
|
/* We avoid equality with LIT_BUFSIZE because of wraparound at 64K
|
|
* on 16 bit machines and because stored blocks are restricted to
|
|
* 64K-1 bytes.
|
|
*/
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Send the block data compressed using the given Huffman trees
|
|
*/
|
|
var zip_compress_block = function(
|
|
ltree, // literal tree
|
|
dtree) { // distance tree
|
|
var dist; // distance of matched string
|
|
var lc; // match length or unmatched char (if dist == 0)
|
|
var lx = 0; // running index in l_buf
|
|
var dx = 0; // running index in d_buf
|
|
var fx = 0; // running index in flag_buf
|
|
var flag = 0; // current flags
|
|
var code; // the code to send
|
|
var extra; // number of extra bits to send
|
|
|
|
if(zip_last_lit != 0) do {
|
|
if((lx & 7) == 0)
|
|
flag = zip_flag_buf[fx++];
|
|
lc = zip_l_buf[lx++] & 0xff;
|
|
if((flag & 1) == 0) {
|
|
zip_SEND_CODE(lc, ltree); /* send a literal byte */
|
|
// Tracecv(isgraph(lc), (stderr," '%c' ", lc));
|
|
} else {
|
|
// Here, lc is the match length - MIN_MATCH
|
|
code = zip_length_code[lc];
|
|
zip_SEND_CODE(code+zip_LITERALS+1, ltree); // send the length code
|
|
extra = zip_extra_lbits[code];
|
|
if(extra != 0) {
|
|
lc -= zip_base_length[code];
|
|
zip_send_bits(lc, extra); // send the extra length bits
|
|
}
|
|
dist = zip_d_buf[dx++];
|
|
// Here, dist is the match distance - 1
|
|
code = zip_D_CODE(dist);
|
|
// Assert (code < D_CODES, "bad d_code");
|
|
|
|
zip_SEND_CODE(code, dtree); // send the distance code
|
|
extra = zip_extra_dbits[code];
|
|
if(extra != 0) {
|
|
dist -= zip_base_dist[code];
|
|
zip_send_bits(dist, extra); // send the extra distance bits
|
|
}
|
|
} // literal or match pair ?
|
|
flag >>= 1;
|
|
} while(lx < zip_last_lit);
|
|
|
|
zip_SEND_CODE(zip_END_BLOCK, ltree);
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Send a value on a given number of bits.
|
|
* IN assertion: length <= 16 and value fits in length bits.
|
|
*/
|
|
var zip_Buf_size = 16; // bit size of bi_buf
|
|
var zip_send_bits = function(
|
|
value, // value to send
|
|
length) { // number of bits
|
|
/* If not enough room in bi_buf, use (valid) bits from bi_buf and
|
|
* (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
|
|
* unused bits in value.
|
|
*/
|
|
if(zip_bi_valid > zip_Buf_size - length) {
|
|
zip_bi_buf |= (value << zip_bi_valid);
|
|
zip_put_short(zip_bi_buf);
|
|
zip_bi_buf = (value >> (zip_Buf_size - zip_bi_valid));
|
|
zip_bi_valid += length - zip_Buf_size;
|
|
} else {
|
|
zip_bi_buf |= value << zip_bi_valid;
|
|
zip_bi_valid += length;
|
|
}
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Reverse the first len bits of a code, using straightforward code (a faster
|
|
* method would use a table)
|
|
* IN assertion: 1 <= len <= 15
|
|
*/
|
|
var zip_bi_reverse = function(
|
|
code, // the value to invert
|
|
len) { // its bit length
|
|
var res = 0;
|
|
do {
|
|
res |= code & 1;
|
|
code >>= 1;
|
|
res <<= 1;
|
|
} while(--len > 0);
|
|
return res >> 1;
|
|
}
|
|
|
|
/* ==========================================================================
|
|
* Write out any remaining bits in an incomplete byte.
|
|
*/
|
|
var zip_bi_windup = function() {
|
|
if(zip_bi_valid > 8) {
|
|
zip_put_short(zip_bi_buf);
|
|
} else if(zip_bi_valid > 0) {
|
|
zip_put_byte(zip_bi_buf);
|
|
}
|
|
zip_bi_buf = 0;
|
|
zip_bi_valid = 0;
|
|
}
|
|
|
|
var zip_qoutbuf = function() {
|
|
if(zip_outcnt != 0) {
|
|
var q, i;
|
|
q = zip_new_queue();
|
|
if(zip_qhead == null)
|
|
zip_qhead = zip_qtail = q;
|
|
else
|
|
zip_qtail = zip_qtail.next = q;
|
|
q.len = zip_outcnt - zip_outoff;
|
|
// System.arraycopy(zip_outbuf, zip_outoff, q.ptr, 0, q.len);
|
|
for(i = 0; i < q.len; i++)
|
|
q.ptr[i] = zip_outbuf[zip_outoff + i];
|
|
zip_outcnt = zip_outoff = 0;
|
|
}
|
|
}
|
|
|
|
var zip_deflate = function(str, level) {
|
|
var i, j;
|
|
|
|
zip_deflate_data = str;
|
|
zip_deflate_pos = 0;
|
|
if(typeof level == "undefined")
|
|
level = zip_DEFAULT_LEVEL;
|
|
zip_deflate_start(level);
|
|
|
|
var buff = new Array(1024);
|
|
var aout = [];
|
|
while((i = zip_deflate_internal(buff, 0, buff.length)) > 0) {
|
|
var cbuf = new Array(i);
|
|
for(j = 0; j < i; j++){
|
|
cbuf[j] = String.fromCharCode(buff[j]);
|
|
}
|
|
aout[aout.length] = cbuf.join("");
|
|
}
|
|
zip_deflate_data = null; // G.C.
|
|
return aout.join("");
|
|
}
|
|
|
|
if (! window.RawDeflate) RawDeflate = {};
|
|
RawDeflate.deflate = zip_deflate;
|
|
|
|
})();
|