Index: bower_components/gif.js/src/LZWEncoder.js |
diff --git a/bower_components/gif.js/src/LZWEncoder.js b/bower_components/gif.js/src/LZWEncoder.js |
deleted file mode 100644 |
index b12edc9d2e01369226859f9d4896b4fdf926f10d..0000000000000000000000000000000000000000 |
--- a/bower_components/gif.js/src/LZWEncoder.js |
+++ /dev/null |
@@ -1,209 +0,0 @@ |
-/* |
- LZWEncoder.js |
- |
- Authors |
- Kevin Weiner (original Java version - kweiner@fmsware.com) |
- Thibault Imbert (AS3 version - bytearray.org) |
- Johan Nordberg (JS version - code@johan-nordberg.com) |
- |
- Acknowledgements |
- GIFCOMPR.C - GIF Image compression routines |
- Lempel-Ziv compression based on 'compress'. GIF modifications by |
- David Rowley (mgardi@watdcsu.waterloo.edu) |
- 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) |
-*/ |
- |
-var EOF = -1; |
-var BITS = 12; |
-var HSIZE = 5003; // 80% occupancy |
-var masks = [0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F, |
- 0x003F, 0x007F, 0x00FF, 0x01FF, 0x03FF, 0x07FF, |
- 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF]; |
- |
-function LZWEncoder(width, height, pixels, colorDepth) { |
- var initCodeSize = Math.max(2, colorDepth); |
- |
- var accum = new Uint8Array(256); |
- var htab = new Int32Array(HSIZE); |
- var codetab = new Int32Array(HSIZE); |
- |
- var cur_accum, cur_bits = 0; |
- var a_count; |
- var free_ent = 0; // first unused entry |
- var maxcode; |
- |
- // block compression parameters -- after all codes are used up, |
- // and compression rate changes, start over. |
- var clear_flg = 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. |
- var g_init_bits, ClearCode, EOFCode; |
- |
- // Add a character to the end of the current packet, and if it is 254 |
- // characters, flush the packet to disk. |
- function char_out(c, outs) { |
- accum[a_count++] = c; |
- if (a_count >= 254) flush_char(outs); |
- } |
- |
- // Clear out the hash table |
- // table clear for block compress |
- function cl_block(outs) { |
- cl_hash(HSIZE); |
- free_ent = ClearCode + 2; |
- clear_flg = true; |
- output(ClearCode, outs); |
- } |
- |
- // Reset code table |
- function cl_hash(hsize) { |
- for (var i = 0; i < hsize; ++i) htab[i] = -1; |
- } |
- |
- function compress(init_bits, outs) { |
- var fcode, c, i, ent, disp, hsize_reg, hshift; |
- |
- // 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 << BITS) + 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 < 1 << BITS) { |
- codetab[i] = free_ent++; // code -> hashtable |
- htab[i] = fcode; |
- } else { |
- cl_block(outs); |
- } |
- } |
- |
- // Put out the final code. |
- output(ent, outs); |
- output(EOFCode, outs); |
- } |
- |
- function encode(outs) { |
- outs.writeByte(initCodeSize); // write "initial code size" byte |
- remaining = width * height; // reset navigation variables |
- curPixel = 0; |
- compress(initCodeSize + 1, outs); // compress and write the pixel data |
- outs.writeByte(0); // write block terminator |
- } |
- |
- // Flush the packet to disk, and reset the accumulator |
- function flush_char(outs) { |
- if (a_count > 0) { |
- outs.writeByte(a_count); |
- outs.writeBytes(accum, 0, a_count); |
- a_count = 0; |
- } |
- } |
- |
- function MAXCODE(n_bits) { |
- return (1 << n_bits) - 1; |
- } |
- |
- // Return the next pixel from the image |
- function nextPixel() { |
- if (remaining === 0) return EOF; |
- --remaining; |
- var pix = pixels[curPixel++]; |
- return pix & 0xff; |
- } |
- |
- function output(code, outs) { |
- 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 == BITS) maxcode = 1 << BITS; |
- 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); |
- } |
- } |
- |
- this.encode = encode; |
-} |
- |
-module.exports = LZWEncoder; |