@mezereon/tracking
Version:
Tracking for Mezereon Smart Search & Filter
260 lines (249 loc) • 8.81 kB
JavaScript
// Copyright (c) 2013 Pieroxy <pieroxy@pieroxy.net>
// This work is free. You can redistribute it and/or modify it
// under the terms of the WTFPL, Version 2
// For more information see LICENSE.txt or http://www.wtfpl.net/
//
// For more information, the home page:
// http://pieroxy.net/blog/pages/lz-string/testing.html
//
// LZ-based compression algorithm, version 1.4.4
var LZString = {
// private property
f: String.fromCharCode,
keyStrUriSafe:
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-$",
//compress into a string that is already URI encoded
compressToEncodedURIComponent: function(input) {
if (input === null) return "";
return LZString._compress(input, 6, function(a) {
return LZString.keyStrUriSafe.charAt(a);
});
},
compress: function(uncompressed) {
return LZString._compress(uncompressed, 16, function(a) {
return LZString.f(a);
});
},
_compress: function(uncompressed, bitsPerChar, getCharFromInt) {
if (uncompressed === null) return "";
var i,
value,
context_dictionary = {},
context_dictionaryToCreate = {},
context_c = "",
context_wc = "",
context_w = "",
context_enlargeIn = 2, // Compensate for the first entry which should not count
context_dictSize = 3,
context_numBits = 2,
context_data = [],
context_data_val = 0,
context_data_position = 0,
ii;
for (ii = 0; ii < uncompressed.length; ii += 1) {
context_c = uncompressed.charAt(ii);
if (
!Object.prototype.hasOwnProperty.call(context_dictionary, context_c)
) {
context_dictionary[context_c] = context_dictSize++;
context_dictionaryToCreate[context_c] = true;
}
context_wc = context_w + context_c;
if (
Object.prototype.hasOwnProperty.call(context_dictionary, context_wc)
) {
context_w = context_wc;
} else {
if (
Object.prototype.hasOwnProperty.call(
context_dictionaryToCreate,
context_w
)
) {
if (context_w.charCodeAt(0) < 256) {
for (i = 0; i < context_numBits; i++) {
context_data_val = context_data_val << 1;
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
}
value = context_w.charCodeAt(0);
for (i = 0; i < 8; i++) {
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = value >> 1;
}
} else {
value = 1;
for (i = 0; i < context_numBits; i++) {
context_data_val = (context_data_val << 1) | value;
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = 0;
}
value = context_w.charCodeAt(0);
for (i = 0; i < 16; i++) {
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if (context_enlargeIn === 0) {
context_enlargeIn = Math.pow(2, context_numBits);
context_numBits++;
}
delete context_dictionaryToCreate[context_w];
} else {
value = context_dictionary[context_w];
for (i = 0; i < context_numBits; i++) {
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if (context_enlargeIn === 0) {
context_enlargeIn = Math.pow(2, context_numBits);
context_numBits++;
}
// Add wc to the dictionary.
context_dictionary[context_wc] = context_dictSize++;
context_w = String(context_c);
}
}
// Output the code for w.
if (context_w !== "") {
if (
Object.prototype.hasOwnProperty.call(
context_dictionaryToCreate,
context_w
)
) {
if (context_w.charCodeAt(0) < 256) {
for (i = 0; i < context_numBits; i++) {
context_data_val = context_data_val << 1;
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
}
value = context_w.charCodeAt(0);
for (i = 0; i < 8; i++) {
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = value >> 1;
}
} else {
value = 1;
for (i = 0; i < context_numBits; i++) {
context_data_val = (context_data_val << 1) | value;
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = 0;
}
value = context_w.charCodeAt(0);
for (i = 0; i < 16; i++) {
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if (context_enlargeIn === 0) {
context_enlargeIn = Math.pow(2, context_numBits);
context_numBits++;
}
delete context_dictionaryToCreate[context_w];
} else {
value = context_dictionary[context_w];
for (i = 0; i < context_numBits; i++) {
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if (context_enlargeIn === 0) {
context_enlargeIn = Math.pow(2, context_numBits);
context_numBits++;
}
}
// Mark the end of the stream
value = 2;
for (i = 0; i < context_numBits; i++) {
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position === bitsPerChar - 1) {
context_data_position = 0;
context_data.push(getCharFromInt(context_data_val));
context_data_val = 0;
} else {
context_data_position++;
}
value = value >> 1;
}
// Flush the last char
while (true) {
context_data_val = context_data_val << 1;
if (context_data_position === bitsPerChar - 1) {
context_data.push(getCharFromInt(context_data_val));
break;
} else context_data_position++;
}
return context_data.join("");
}
};
export default LZString;