From 346f3a9817b1e0812565396b9811a1ce5adc97b8 Mon Sep 17 00:00:00 2001 From: jules Date: Fri, 13 Dec 2013 15:28:31 -0500 Subject: reorganize --- gif-encode/LZWEncoder.js | 328 ----------------------------------------------- 1 file changed, 328 deletions(-) delete mode 100644 gif-encode/LZWEncoder.js (limited to 'gif-encode/LZWEncoder.js') diff --git a/gif-encode/LZWEncoder.js b/gif-encode/LZWEncoder.js deleted file mode 100644 index e3c512a..0000000 --- a/gif-encode/LZWEncoder.js +++ /dev/null @@ -1,328 +0,0 @@ -/** -* This class handles LZW encoding -* Adapted from Jef Poskanzer's Java port by way of J. M. G. Elliott. -* @author Kevin Weiner (original Java version - kweiner@fmsware.com) -* @author Thibault Imbert (AS3 version - bytearray.org) -* @version 0.1 AS3 implementation -*/ - -//import flash.utils.ByteArray; - -LZWEncoder = function() -{ - var exports = {}; - /*private_static*/ var EOF/*int*/ = -1; - /*private*/ var imgW/*int*/; - /*private*/ var imgH/*int*/ - /*private*/ var pixAry/*ByteArray*/; - /*private*/ var initCodeSize/*int*/; - /*private*/ var remaining/*int*/; - /*private*/ var curPixel/*int*/; - - // GIFCOMPR.C - GIF Image compression routines - // Lempel-Ziv compression based on 'compress'. GIF modifications by - // David Rowley (mgardi@watdcsu.waterloo.edu) - // General DEFINEs - - /*private_static*/ var BITS/*int*/ = 12; - /*private_static*/ var HSIZE/*int*/ = 5003; // 80% occupancy - - // GIF Image compression - modified 'compress' - // Based on: compress.c - File compression ala IEEE Computer, June 1984. - // By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas) - // Jim McKie (decvax!mcvax!jim) - // Steve Davies (decvax!vax135!petsd!peora!srd) - // Ken Turkowski (decvax!decwrl!turtlevax!ken) - // James A. Woods (decvax!ihnp4!ames!jaw) - // Joe Orost (decvax!vax135!petsd!joe) - - /*private*/ var n_bits/*int*/ // number of bits/code - /*private*/ var maxbits/*int*/ = BITS; // user settable max # bits/code - /*private*/ var maxcode/*int*/ // maximum code, given n_bits - /*private*/ var maxmaxcode/*int*/ = 1 << BITS; // should NEVER generate this code - /*private*/ var htab/*Array*/ = new Array; - /*private*/ var codetab/*Array*/ = new Array; - /*private*/ var hsize/*int*/ = HSIZE; // for dynamic table sizing - /*private*/ var free_ent/*int*/ = 0; // first unused entry - - // block compression parameters -- after all codes are used up, - // and compression rate changes, start over. - - /*private*/ var clear_flg/*Boolean*/ = false; - - // Algorithm: use open addressing double hashing (no chaining) on the - // prefix code / next character combination. We do a variant of Knuth's - // algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime - // secondary probe. Here, the modular division first probe is gives way - // to a faster exclusive-or manipulation. Also do block compression with - // an adaptive reset, whereby the code table is cleared when the compression - // ratio decreases, but after the table fills. The variable-length output - // codes are re-sized at this point, and a special CLEAR code is generated - // for the decompressor. Late addition: construct the table according to - // file size for noticeable speed improvement on small files. Please direct - // questions about this implementation to ames!jaw. - - /*private*/ var g_init_bits/*int*/; - /*private*/ var ClearCode/*int*/; - /*private*/ var EOFCode/*int*/; - - // output - // Output the given code. - // Inputs: - // code: A n_bits-bit integer. If == -1, then EOF. This assumes - // that n_bits =< wordsize - 1. - // Outputs: - // Outputs code to the file. - // Assumptions: - // Chars are 8 bits long. - // Algorithm: - // Maintain a BITS character long buffer (so that 8 codes will - // fit in it exactly). Use the VAX insv instruction to insert each - // code in turn. When the buffer fills up empty it and start over. - - /*private*/ var cur_accum/*int*/ = 0; - /*private*/ var cur_bits/*int*/ = 0; - /*private*/ var masks/*Array*/ = [ 0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F, 0x003F, 0x007F, 0x00FF, 0x01FF, 0x03FF, 0x07FF, 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF ]; - - // Number of characters so far in this 'packet' - /*private*/ var a_count/*int*/; - - // Define the storage for the packet accumulator - /*private*/ var accum/*ByteArray*/ = []; - - var LZWEncoder = exports.LZWEncoder = function LZWEncoder (width/*int*/, height/*int*/, pixels/*ByteArray*/, color_depth/*int*/) - { - - imgW = width; - imgH = height; - pixAry = pixels; - initCodeSize = Math.max(2, color_depth); - - } - - // Add a character to the end of the current packet, and if it is 254 - // characters, flush the packet to disk. - var char_out = function char_out(c/*Number*/, outs/*ByteArray*/)/*void*/ - { - accum[a_count++] = c; - if (a_count >= 254) flush_char(outs); - - } - - // Clear out the hash table - // table clear for block compress - - var cl_block = function cl_block(outs/*ByteArray*/)/*void*/ - { - - cl_hash(hsize); - free_ent = ClearCode + 2; - clear_flg = true; - output(ClearCode, outs); - - } - - // reset code table - var cl_hash = function cl_hash(hsize/*int*/)/*void*/ - { - - for (var i/*int*/ = 0; i < hsize; ++i) htab[i] = -1; - - } - - var compress = exports.compress = function compress(init_bits/*int*/, outs/*ByteArray*/)/*void*/ - - { - var fcode/*int*/; - var i/*int*/ /* = 0 */; - var c/*int*/; - var ent/*int*/; - var disp/*int*/; - var hsize_reg/*int*/; - var hshift/*int*/; - - // Set up the globals: g_init_bits - initial number of bits - g_init_bits = init_bits; - - // Set up the necessary values - clear_flg = false; - n_bits = g_init_bits; - maxcode = MAXCODE(n_bits); - - ClearCode = 1 << (init_bits - 1); - EOFCode = ClearCode + 1; - free_ent = ClearCode + 2; - - a_count = 0; // clear packet - - ent = nextPixel(); - - hshift = 0; - for (fcode = hsize; fcode < 65536; fcode *= 2) - ++hshift; - hshift = 8 - hshift; // set hash code range bound - - hsize_reg = hsize; - cl_hash(hsize_reg); // clear hash table - - output(ClearCode, outs); - - outer_loop: while ((c = nextPixel()) != EOF) - - { - - fcode = (c << maxbits) + ent; - i = (c << hshift) ^ ent; // xor hashing - - if (htab[i] == fcode) - { - ent = codetab[i]; - continue; - } else if (htab[i] >= 0) // non-empty slot - { - disp = hsize_reg - i; // secondary hash (after G. Knott) - if (i == 0) - disp = 1; - do - { - - if ((i -= disp) < 0) i += hsize_reg; - - if (htab[i] == fcode) - { - ent = codetab[i]; - continue outer_loop; - } - } while (htab[i] >= 0); - } - - output(ent, outs); - ent = c; - if (free_ent < maxmaxcode) - { - codetab[i] = free_ent++; // code -> hashtable - htab[i] = fcode; - } else cl_block(outs); - } - - // Put out the final code. - output(ent, outs); - output(EOFCode, outs); - - } - - // ---------------------------------------------------------------------------- - var encode = exports.encode = function encode(os/*ByteArray*/)/*void*/ - { - os.writeByte(initCodeSize); // write "initial code size" byte - remaining = imgW * imgH; // reset navigation variables - curPixel = 0; - compress(initCodeSize + 1, os); // compress and write the pixel data - os.writeByte(0); // write block terminator - - } - - // Flush the packet to disk, and reset the accumulator - var flush_char = function flush_char(outs/*ByteArray*/)/*void*/ - { - - if (a_count > 0) - { - outs.writeByte(a_count); - outs.writeBytes(accum, 0, a_count); - a_count = 0; - } - - } - - var MAXCODE = function MAXCODE(n_bits/*int*/)/*int*/ - { - - return (1 << n_bits) - 1; - - } - - // ---------------------------------------------------------------------------- - // Return the next pixel from the image - // ---------------------------------------------------------------------------- - - var nextPixel = function nextPixel()/*int*/ - { - - if (remaining == 0) return EOF; - - --remaining; - - var pix/*Number*/ = pixAry[curPixel++]; - - return pix & 0xff; - - } - - var output = function output(code/*int*/, outs/*ByteArray*/)/*void*/ - - { - cur_accum &= masks[cur_bits]; - - if (cur_bits > 0) cur_accum |= (code << cur_bits); - else cur_accum = code; - - cur_bits += n_bits; - - while (cur_bits >= 8) - - { - - char_out((cur_accum & 0xff), outs); - cur_accum >>= 8; - cur_bits -= 8; - - } - - // If the next entry is going to be too big for the code size, - // then increase it, if possible. - - if (free_ent > maxcode || clear_flg) - { - - if (clear_flg) - { - - maxcode = MAXCODE(n_bits = g_init_bits); - clear_flg = false; - - } else - { - - ++n_bits; - - if (n_bits == maxbits) maxcode = maxmaxcode; - - else maxcode = MAXCODE(n_bits); - - } - - } - - if (code == EOFCode) - { - - // At EOF, write the rest of the buffer. - while (cur_bits > 0) - { - - char_out((cur_accum & 0xff), outs); - cur_accum >>= 8; - cur_bits -= 8; - } - - - flush_char(outs); - - } - - } - LZWEncoder.apply(this, arguments); - return exports; -} - -- cgit v1.2.3-70-g09d2